Microleakage in Class V Composite Restorations after Desensitizing Surface Treatment with Er:YAG and CO2 Lasers.

PubMed

Mozaffari, Hamid Reza; Ehteshami, Alireza; Zallaghi, Farshad; Chiniforush, Nasim; Moradi, Zohreh

2016-12-30

Aims: Glutaraldehyde, CO 2 and Er:YAG lasers can be used for treatment of dentin hypersensitivity. However, their application may have adverse effects on the clinical service of restorations. This study aimed to assess the microleakage in composite restorations following surface treatment with Glutaraldehyde desensitizer, CO 2 and Er:YAG laser irradiation for treatment of dentin hypersensitivity. Materials and methods: This experimental study was conducted on 60 extracted sound human teeth. Class V cavities were prepared measuring 3×3 mm using a diamond bur. Specimens were randomly divided into 4 groups of 15. Group one:no surface treatment, Group two:applying Glutaraldehyde desensitizer, Groups of three and four were irradiated with CO 2 and Er:YAG lasers, respectively. Surfaces were restored with bonding agent (Single Bond 2, 3M, USA) and Z250 composite (3M, USA). Specimens were thermocycled and immersed in 1% methylene blue solution for 24 hours. Microleakage scores were assessed under a stereomicroscope at ×20 magnification. Data were analyzed using SPSS and the Kruskal Wallis test (P=0.05). Results: There was no significant difference between microleakage of groups in enamel margins (P=0.694). The difference in microleakage at the dentin margin was significant between groups (P=0.018). Conclusions: Application of Glutaraldehyde-desensitizer and CO 2 laser irradiation of surfaces prior to composite restoration do not increase microleakage at the enamel or dentin margins but tooth surface treatment with Er:YAG laser significantly increased the microleakage at the dentin margins.

Water evaporation from substrate tooth surface during dentin treatments.

PubMed

Kusunoki, Mizuho; Itoh, Kazuo; Gokan, Yuka; Nagai, Yoshitaka; Tani, Chihiro; Hisamitsu, Hisashi

2011-01-01

The purpose of this study was to evaluate changes in the quantity of water evaporation from tooth surfaces. The amount of water evaporation was measured using Multi probe adapter MPA5 and Tewameter TM300 (Courage+Khazaka Electric GmbH, Köln, Germany) after acid etching and GM priming of enamel; and after EDTA conditioning and GM priming of dentin. The results indicated that the amount of water evaporation from the enamel surface was significantly less than that from the dentin. Acid etching did not affect the water evaporation from enamel, though GM priming significantly decreased the evaporation (83.48 ± 15.14% of that before priming). The evaporation from dentin was significantly increased by EDTA conditioning (131.38 ± 42.08% of that before conditioning) and significantly reduced by GM priming (80.26 ± 7.43% of that before priming). It was concluded that dentin priming reduced water evaporation from the dentin surface.

Influence of laser etching on enamel and dentin bond strength of Silorane System Adhesive.

PubMed

Ustunkol, Ildem; Yazici, A Ruya; Gorucu, Jale; Dayangac, Berrin

2015-02-01

The aim of this in vitro study was to evaluate the shear bond strength (SBS) of Silorane System Adhesive to enamel and dentin surfaces that had been etched with different procedures. Ninety freshly extracted human third molars were used for the study. After the teeth were embedded with buccal surfaces facing up, they were randomly divided into two groups. In group I, specimens were polished with a 600-grit silicon carbide (SiC) paper to obtain flat exposed enamel. In group II, the overlying enamel layer was removed and exposed dentin surfaces were polished with a 600-grit SiC paper. Then, the teeth in each group were randomly divided into three subgroups according to etching procedures: etched with erbium, chromium:yttrium-scandium-gallium-garnet laser (a), etched with 35% phosphoric acid (b), and non-etched (c, control). Silorane System Adhesive was used to bond silorane restorative to both enamel and dentin. After 24-h storage in distilled water at room temperature, a SBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed using two-way ANOVA and Bonferroni tests (p < 0.05). The highest SBS was found after additional phosphoric acid treatment in dentin groups (p < 0.05). There were no statistically significant differences between the laser-etched and non-etched groups in enamel and dentin (p > 0.05). The SBS of self-etch adhesive to dentin was not statistically different from enamel (p > 0.05). Phosphoric acid treatment seems the most promising surface treatment for increasing the enamel and dentin bond strength of Silorane System Adhesive.

[Influence of carbodiimide-ethanol solution surface treatment on dentin microtensile bond strength].

PubMed

Zhang, Yi; Liu, Yu-hua; Zhou, Yong-sheng; Chung, Kwok-hung

2015-10-18

To evaluate the microtensile bond strength changes and patterns of fractures of the bonding interface after dentine surface treatment with carbodiimide-ethanol solution. 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) dissolved in ethanol was diluted into different concentrations of 2, 1, 0.3, 0.1 and 0.01 mol/L EDC-ethanol solutions. Twenty-eight caries-free extracted human third molars were ground metallurgically to prepare flat occlusal mid-coronal dentin surfaces and etched with 35% (mass fraction) phosphoric acid gel. Then they were treated with EDC-ethanol solution for 60 s before the bonding procedure and randomly divided into five experimental groups corresponding to the tested EDC-ethanol concentrations. The ethanol treated and no pre-treated surfaces were used as controls. Single Bond 2 adhesive was applied and resin composite disk was stacked on the treated dentine surface. The teeth with resin composite disks were stored in water at room temperature for 24 h and then sectioned longitudinally to produce stick specimens for microtensile bond strength test. Fracture patterns were observed with a stereomicroscope. The dentin surfaces pre-treated with 2 mol/L [(22.17±13.31) MPa] and 1 mol/L [(45.31±17.80) MPa] EDC-ethanol solutions resulted in statistically significant lower bond strength value (P<0.05). Increasing numbers of fracture pattern at the resin-dentin interface were also found in this two groups with percentages of 81.2% and 41.3% respectively. No significant difference was observed in the groups with 0.3, 0.1, 0.01 mol/L EDC surface treatment (P>0.05). No significant difference of immediate bond strengths was found in the 0.3, 0.1, 0.01 mol/L groups compared with the control group. EDC-ethanol solution surface treatment with concentrations of 2 mol/L and 1 mol/L resulted in decreasing of the bonding strength.

The effect of 10% carbamide peroxide bleaching material on microhardness of sound and demineralized enamel and dentin in situ.

PubMed

Basting, R T; Rodrigues Júnior, A L; Serra, M C

2001-01-01

This in situ study evaluated the microhardness of sound and demineralized enamel and dentin submitted to treatment with 10% carbamide peroxide for three weeks. A 10% carbamide peroxide bleaching agent--Opalescence/Ultradent (OPA)--was evaluated against a placebo agent (PLA). Two hundred and forty dental fragments--60 sound enamel fragments (SE), 60 demineralized enamel fragments (DE), 60 sound dentin fragments (SD) and 60 demineralized dentin fragments (DD)--were randomly fixed on the vestibular surface of the first superior molars and second superior premolars of 30 volunteers. The volunteers were divided into two groups that received bleaching or the placebo agent at different sequences and periods at a double blind 2 x 2 crossover study with a wash-out period of two weeks. Microhardness tests were performed on the enamel and dentin surface. The SE and DE submitted to treatment with OPA showed lower microhardness values than the SE and DE submitted to treatment with PLA. There were no statistical differences in microhardness values for SD and DD submitted to the treatment with OPA and PLA. The results suggest that treatment with 10% carbamide peroxide bleaching material for three weeks alters the enamel microhardness, although it does not seem to alter the dentin microhardness.

Efficacy of different whitening modalities on bovine enamel and dentin.

PubMed

Wiegand, Annette; Vollmer, Doreen; Foitzik, Magdalena; Attin, Rengin; Attin, Thomas

2005-06-01

Previous studies have shown that bleaching treatment may be efficient in both enamel and dentin, but it is still unknown how much the subsurface dentin contributes to the color change of teeth. This in vitro study evaluated the whitening effect of different external bleaching agents on enamel-dentin slabs and subsurface dentin. Ninety bovine teeth were distributed among six groups (A, Opalescence 10%; B, Opalescence PF 15%; C, Opalescence Quick; D, Opalescence Extra Boost; E, Rapid White; F, Whitestrips). Two enamel-dentin specimens were prepared from the labial surface of each teeth. In one of the specimens enamel was removed, resulting in a dentin (CD) disc of 1 mm high. The labial and the pulpal sides of the second specimen were ground until the remaining enamel and dentin layers of the enamel-dentin sample (ED) were 1 mm each. Whitening treatment of the ED specimens was performed according to manufacturers' instructions. Pre- and posttreatment Lab values of ED samples were analyzed using CIE-Lab. Baseline Lab values of dentin were analyzed by evaluation of the CD specimen. Finally, enamel of the ED specimens was removed and color change of the exposed dentin (D) was recorded. For all treatment agents significant color changes (DeltaE) were observed for enamel-dentin samples and subsurface dentin specimens compared to controls. In groups A-D DeltaE was significantly higher in dentin than enamel-dentin. Furthermore, L and b values of bleached enamel-dentin and subsurface dentin samples differed significantly from baseline. Treatment with the tested external whitening bleaching agents resulted in color change of both enamel-dentin and subsurface dentin samples. The results indicate that color change of treated teeth might be highly influenced by color change of the subsurface dentin.

Effect of different surface treatments on adhesion of In-Ceram Zirconia to enamel and dentin substrates.

PubMed

Saker, Samah; Ibrahim, Fatma; Ozcan, Mutlu

2013-08-01

Resin bonding of In-Ceram Zirconia (ICZ) ceramics is still a challenge, especially for minimally invasive applications. This study evaluated the adhesion of ICZ to enamel and dentin after different surface treatments of the ceramic. ICZ ceramic specimens (diameter: 6 mm; thickness: 2 mm) (N = 100) were fabricated following the manufacturer's instructions and randomly assigned to 5 groups (n = 20), according to the surface treatment methods applied. The groups were as follows: group C: no treatment; group SB: sandblasting; group SCS-S: CoJet+silane; group SCS-P: CoJet+Alloy Primer; group GE-S: glaze+ hydrofluoric acid etching (9.6%) for 60 s+silane. Each group was randomly divided into two subgroups to be bonded to either enamel or dentin (n = 10 per group) using MDP-based resin cement (Panavia F2.0). All the specimens were subjected to thermocycling (5000x, 5°C-55°C). The specimens were mounted in a universal testing machine and tensile force was applied to the ceramic/cement interface until failure occurred (1 mm/min). After evaluating all the debonded specimens under SEM, the failure types were defined as either "adhesive" with no cement left on the ceramic surface (score 0) or "mixed" with less than 1/2 of the cement left adhered to the surface with no cohesive failure of the substrate (score 1). The data were statistically evaluated using 2-way ANOVA and Tukey's tests (α = 0.05). The highest tensile bond strength for the enamel surfaces was obtained in group GE-S (18.1 ± 2 MPa) and the lowest in group SB (7.1 ± 1.4 MPa). Regarding dentin, group CSC-P showed the highest (12 ± 1.3 MPa) and SB the lowest tensile bond strength (5.7 ± 0.4 MPa). Groups SB, CSC-S, CSC-P, and GE-S did not show significant differences between the different surface treatments on either enamel or dentin surfaces (p < 0.05, p < 0.001, respectively). Groups CSC-P and GE-S presented similar bond strength for both the enamel and dentin substrates (p < 0.8 and p < 0.9), respectively. While on enamel substrates, exclusively adhesive failures from ICZ (score 0) were found, on dentin exclusively mixed failures were observed (score 1). Adhesion of ICZ to both enamel and dentin can be improved when ceramics are glazed, etched, and silanized, or sandblasted, primed, and cemented with an MDP-based cement.

The effect of propolis fluoride on caries dentine activity

NASA Astrophysics Data System (ADS)

Darwita, Risqa Rina; Soekanto, Sri Angky; Finisha, Andanali Rhukul; Wahyuni, Hardiati Nur; Andiani, Salsabila Ghina

2018-02-01

This research was conducted to analyze the effect of propolis fluoride on the occurrence of arrested caries dentine surface. The design of the study was a clinical trial experimental. The respondent were primary school students aged 6-8 years, from primary school in Kukusan, Depok, West Java, Indonesia. They were screened of dental examination and the total number of 296 children with an age range of 6-8 year old were included in the study. All students who had dentin caries were get dental treatment with propolis fluoride topical application in dentin caries surface. After one month, two months and four months all students who were got propolis fluoride topical application in dentin caries surface were controlled. All data were analyzed by Wilcoxon test. The total number of dentinal decay of 296 student was 1740 surfaces indicated to Flolis topical application. After one, two and three months of Flolis application, all arrested of dentinal decay was evaluated, the result of evaluation from the second month to the third month evaluation was found that the arrested dentinal caries surfaces were decreased significantly at 29.36% (p<0.01), while the evaluation of arrested dentinal caries surface from the first month to the third month was decreased significantly at 38.62% (p<0.001). Flolis was proven significantly to be able to arrest the activity of dental caries, and their ability to arrest dental caries was significantly different. Flolis was found to be effective in arresting dentinal caries surface until three months application, and should be repeated after 3 months of Flolis application.

Fracture Forces of Dentin after Surface Treatment with High Speed Drill Compared to Er:YAG and Er,Cr:YSGG Laser Irradiation

PubMed Central

Franzen, Rene; Kianimanesh, Nasrin; Marx, Rudolf; Ahmed, Asma; Gutknecht, Norbert

2016-01-01

Dental tooth restorative procedures may weaken the structural integrity of the tooth, with the possibility of leading to fracture. In this study we present findings of coronal dentin strength after different techniques of surface modification. The fracture strength of dentin beams after superficial material removal with a fine diamond bur high speed drill hand piece, Er:YAG (2.94 μm, 8 J/cm2), and Er,Cr:YSGG (2.78 μm, 7.8 J/cm2) laser irradiation slightly above the ablation threshold was measured by a four-point bending apparatus. Untreated dentin beams served as a control. A total of 58 dentin beams were manufactured from sterilized human extracted molars using the coronal part of the available dentin. Mean values of fracture strength were calculated as 82.0 ± 27.3 MPa for the control group (n = 10), 104.5 ± 26.3 MPa for high speed drill treatment (n = 10), 96.1 ± 28.1 MPa for Er,Cr:YSGG laser irradiation (n = 20), and 89.1 ± 36.3 MPa for Er:YAG laser irradiation (n = 18). Independent Student's t-tests showed no significant difference between each two groups (p > 0.05). Within the parameter settings and the limits of the experimental setup used in this study, both lasers systems as well as the high speed drill do not significantly weaken coronal dentin after surface treatment. PMID:26962473

Assessment of radicular dentin permeability after irradiation with CO2 laser and endodontic irrigation treatments with thermal imaging

NASA Astrophysics Data System (ADS)

Cho, Heajin; Lee, Robert C.; Chan, Kenneth H.; Fried, Daniel

2017-02-01

Previous studies have demonstrated that the permeability changes due to the surface modification of dentin can be quantified via thermal imaging during dehydration. The CO2 laser has been shown to remove the smear layer and disinfect root canals. Moreover, thermal modification via CO2 laser irradiation can be used to convert dentin into a highly mineralized enamel-like mineral. The purpose of this study is to evaluate the radicular dentin surface modification after CO2 laser irradiation by measuring the permeability with thermal imaging. Human molar specimens (n=12) were sectioned into 4 axial walls of the pulp chamber and treated with either 10% NaClO for 1 minute, 5% EDTA for 1 minute, CO2 laser or none. The CO2 laser was operated at 9.4 μm with a pulse duration of 26 μs, pulse repetition rate of 300 Hz and a fluence of 13 J/cm2. The samples were dehydrated using an air spray for 60 seconds and imaged using a thermal camera. The resulting surface morphological changes were assessed using 3D digital microscopy. The images from digital microscopy confirmed melting of the mineral phase of dentin. The area enclosed by the time-temperature curve during dehydration, ▵Q, measured with thermal imaging increased significantly with treatments with EDTA and the CO2 laser (P<0.05). These results indicate that the surface modification due to CO2 laser treatment increases permeability of radicular dentin.

Dentin hypersensitivity treatment by CO2 laser: the influence of the density of dentin tubules and laser-beam incidence

NASA Astrophysics Data System (ADS)

Colojoara, Carmen; Gabay, Shimon; van der Meulen, Freerk W.; van Gemert, Martin J. C.; Miron, Mariana I.; Mavrantoni, Androniki

1997-12-01

Dentin hypersensitivity is considered to be a consequence of the presence of open dentin tubules on the exposed dentin surface. Various methods and materials used in the treatment of this disease are directed to achieve a tubule's occlusion. The purpose of this study was to evaluate under scanning electron microscopy and clinical method the sealing effects of CO2 laser on dentin tubules of human teeth without any damages of the surrounding tissues. Samples of freshly extracted noncarious 3rd molars were used. The teeth were randomly divided in to two groups A and B. The samples of group A were exposed to laser beam in cervical area, directed parallel to their dentin tubules. The teeth of group B were sectioned through a hypothetical carious lesion and lased perpendicularly or obliquely of the dentin tubules. The CO2 laser, at 10.6 micrometers wavelength, was operated only in pulse mode and provided 6.25 - 350 mJ in a burst of 25 pulses each of 250 microsecond(s) time duration with a 2 ms time interval between successive pulses (repetition rate up to 500 mH). Melting of dentin surface and partial closure of exposed dentin tubules were found for all specimens at 6.25 to 31.25 mJ energy. Our results indicated that using CO2 laser in a parallel orientation of laser beam with dentin tubules, the dentin sensitivity can be reduced without any damages of pulp vitality.

Effect of surface treatments on the flexural properties and adhesion of glass fiber-reinforced composite post to self-adhesive luting agent and radicular dentin.

PubMed

Elnaghy, Amr M; Elsaka, Shaymaa E

2016-01-01

This study evaluated the effect of different surface treatments on the flexural properties and adhesion of glass fiber post to self-adhesive luting agent and radicular dentin. Seventy-five single-rooted human teeth were prepared to receive a glass fiber post (Reblida). The posts were divided into five groups according to the surface treatment: Gr C (control; no treatment), Gr S (silanization for 60 s), Gr AP (airborne-particle abrasion), Gr HF (etching with 9 % hydrofluoric acid for 1 min), and Gr M10 (etching with CH2Cl2 for 10 min). Dual-cure self-adhesive luting agent (Rely X Unicem) was applied to each group for testing the adhesion using micropush-out test. Failure types were examined with stereomicroscope and surface morphology of the posts was characterized using a scanning electron microscopy (SEM). Flexural properties of posts were assessed using a three-point bending test. Data were analyzed using ANOVA and Tukey's HSD test. Statistical significance was set at the 0.05 probability level. Groups treated with M10 showed significantly higher bond strength than those obtained with other surface treatments (P < 0.05). In general, improvements in bond strength (MPa) were found in the following order: M10 > C > S > AP > HF. Most failure modes were adhesive type of failures between dentin and luting agent (48.2%). SEM analysis revealed that the fiber post surfaces were modified after surface treatments. The surface treatments did not compromise the flexural properties of fiber posts. Application of M10 to the fiber post surfaces enhanced the adhesion to self-adhesive luting agent and radicular dentin.

Effect of a novel bioactive glass-ceramic on dentinal tubule occlusion: an in vitro study.

PubMed

Zhong, Y; Liu, J; Li, X; Yin, W; He, T; Hu, D; Liao, Y; Yao, X; Wang, Y

2015-03-01

This in vitro study aimed to assess the ability and efficacy of HX-BGC, a novel bioactive glass-ceramic (SiO2-P2 O5-CaO-Na2 O-SrO), to reduce dentine tubule permeability. Dentine discs from human third molars were etched and randomly allocated into five groups: Group 1--distilled water; Group 2--Sensodyne Repair toothpaste (containing NovaMin®); Group 3--HX-BGC toothpaste (containing 7.5% HX-BGC); Group 4--control toothpaste (without HX-BGC); and Group 5--HX-BGC powder. Specimens were treated daily by brushing with an electric toothbrush for 20 seconds. Between daily treatments (7 days total), specimens were immersed in artificial saliva for 24 hours. Dentine permeability was measured at baseline, after the first treatment, after the first 24-hour immersion in artificial saliva and at the end of day 7. Dentine morphology and surface deposits were observed by scanning electron microscopy after one day and 7 days of treatment, respectively. Sensodyne Repair and bioactive glass-ceramic toothpaste significantly and immediately lowered dentine permeability. The HX-BGC powder group showed the highest reduction in dentine permeability after 7 days of treatment. The novel bioactive glass-ceramic material HX-BGC is effective in reducing dentine permeability by occluding open dentine tubules, indicating that HX-BGC may be a potential treatment for dentine hypersensitivity. © 2015 Australian Dental Association.

Evaluation of tartar control dentifrices in in vitro models of dentin sensitivity.

PubMed

Mason, S; Levan, A; Crawford, R; Fisher, S; Gaffar, A

1991-01-01

The effects of anticalculus dentifrices were compared with other commercially available dentifrices in in vitro models of dentin sensitivity. Changes in the hydraulic conductance of dentin discs were measured with and without a smear layer before and after treatment and also after a post-treatment acid etch. The capacity of dentifrices to occlude open dentinal tubules in vitro was also assessed by scanning electron microscopy (SEM). There was good correlation (R = 0.98) between our test and values reported in the literature. Tartar control dentifrices gave reductions in fluid flow rates through the dentin discs comparable to those obtained with Promise, Sensodyne, Thermodent and Denquel. Additionally, tartar control dentifrices did not remove microcrystalline debris (smear layers) from the surfaces of dentin in vitro. These results were confirmed by SEM. Thus, according to the hydrodynamic theory of dentin sensitivity, these in vitro results suggest that pyrophosphate-containing dentifrices should reduce dentinal sensitivity.

Effects of dentin surface treatments on shear bond strength of glass-ionomer cements

PubMed Central

Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Lombardini, Marco

2014-01-01

Summary Aim The aim of this in vitro study was to evaluate the effect of different surface treatments on shear bond strength of a conventional glass-ionomer cement (GIC) and a resin-modified glass-ionomer cement (RMGIC) to dentin. Materials and methods 80 bovine permanent incisors were used. 40 cylindrical specimens of a GIC (Fuji IX GP Extra) and 40 cylindrical specimens of a RMGIC (Fuji II LC) were attached to the dentin. The teeth were then randomly assigned to 8 groups of equal size (n=10), 4 for every type of glass-ionomer cement, corresponding to type of dentin surface treatments. Group 1: GC Cavity Conditioner; Group 2: 37% phosphoric acid gel; Group 3: Clearfil SE Bond; Group 4: no dentin conditioning (control). The specimens were placed in a universal testing machine (Model 3343, Instron Corp., Canton, Mass., USA) and subsequently tested for shear bond strength (MPa). Results ANOVA showed the presence of significant differences among the various groups. Post hoc Tukey test showed different values of shear bond strength for Fuji IX GP Extra and for Fuji II LC. The different conditioners variably influence the adhesion of the glass-ionomer cements tested. Conclusions. RMGIC shear bond to dentin was higher than GIC. The use of a Self-etch adhesive system improved the shear bond strength values of RMGIC and lowered the shear bond strength values of GIC significantly. PMID:24753797

Microtensile bond strength of etch-and-rinse and self-etching adhesives to intrapulpal dentin after endodontic irrigation and setting of root canal sealer.

PubMed

Wattanawongpitak, Nipaporn; Nakajima, Masatoshi; Ikeda, Masaomi; Foxton, Richard M; Tagami, Junji

2009-02-01

To evaluate the effect of endodontic irrigation regimens and calcium hydroxide root canal sealer (Sealapex) on the microtensile bond strengths (muTBS) of dual-curing resin composite (Clearfil DC Core Automix) to the intrapulpal dentin. Forty standardized coronal-half root canal dentin specimens obtained from human premolars were divided into 4 groups: group A, no treatment (control); group B, Sealapex; group C, NaOCl/Sealapex; group D, EDTA/NaOCl/Sealapex. After 7 days of storage in 100% relative humidity, Sealapex was removed. Dentin surfaces were bonded with adhesives, either etch-and-rinse (Single Bond) or self-etching (Clearfil SE Bond), and built up with resin composite. The bonded specimens were trimmed into an hourglass shape with a 1-mm2 cross-sectional area for microtensile testing (n = 20). The muTBS to intrapulpal dentin was analyzed using two-way ANOVA and Dunnett's TC test. Two teeth of each group were prepared for micromorphological analysis of dentin surface. The root canal sealer with or without endodontic irrigation significantly affected the bond strengths of resin composite to intrapulpal dentin compared with the control group (p < 0.05). There were no significant differences in muTBS of each experimental group between etch-and-rinse and self-etching adhesives (p > 0.05). The dentin surface was covered with a mud-like material after sealer application for 7 days. The root canal sealer reduced the muTBS of dual-curing resin composite with etch-and-rinse and self-etching adhesive systems to intrapulpal dentin. Treatment with EDTA followed by NaOCI prior to obturation caused an additional reduction in muTBS of both adhesive systems to intrapulpal dentin.

The influence of the energy density and other clinical parameters on bond strength of Er:YAG-conditioned dentin compared to conventional dentin adhesion.

PubMed

Gisler, Gottfried; Gutknecht, Norbert

2014-01-01

The aim of this in vitro study was to optimise clinical parameters and the energy density of Er:YAG laser-conditioned dentin for class V fillings. Shear tests in three test series were conducted with 24 freshly extracted human third molars as samples for each series. For every sample, two orofacial and two approximal dentin surfaces were prepared. The study design included different laser energies, a thin vs a thick bond layer, the influence of adhesives as well as one-time- vs two-time treatment. The best results with Er:YAG-conditioned dentin were obtained with fluences just above the ablation threshold (5.3 J/cm(2)) in combination with a self-etch adhesive, a thin bond layer and when bond and composite were two-time cured. Dentin conditioned this way reached an averaged bond strength of 23.32 MPa (SD 5.3) and 24.37 MPa (SD 6.06) for two independent test surfaces while showing no statistical significance to conventional dentin adhesion and two-time treatment with averaged bond strength of 24.93 MPa (SD 11.51). Significant reduction of bond strength with Er:YAG-conditioned dentin was obtained when using either a thick bond layer, twice the laser energy (fluence 10.6 J/cm(2)) or with no dentin adhesive. The discussion showed clearly that in altered (sclerotic) dentin, e.g. for class V fillings of elderly patients, bond strengths in conventional dentin adhesion are constantly reduced due to the change of the responsibles, bond giving dentin structures, whereas for Er:YAG-conditioned dentin, the only way to get an optimal microretentive bond pattern is a laser fluence just above the ablation threshold of sclerotic dentin.

Preventive effect of a high fluoride toothpaste and arginine-carbonate toothpaste on dentinal tubules exposure followed by acid challenge: a dentine permeability evaluation

PubMed Central

2014-01-01

Background Considering the current high use of high fluoride toothpastes, the aim of the study was to quantify alterations in the root dentine permeability submitted to treatment with a high fluoride toothpaste and 8% arginine, calcium carbonate, sodium monofluorophosphate toothpaste as a preventive treatment for dentinal tubules exposure followed by acid challenge. Methods Thirty-third molars were sectioned below the cementoenamel. The root segments were connected to a hydraulic pressure apparatus to measure dentine permeability after the following sequential steps (n = 10 per group): I) Baseline; II) treatment with phosphoric acid for 30 s (maximum permeability); III) Toothbrushing (1 min) according to the experimental groups (G1- control; G2- 5000 ppm fluoride toothpaste; G3- 8% arginine-calcium carbonate toothpaste); IV) acid challenge for 5 min (orange juice). The data were converted into percentage, considering stage II as 100%. Results The results have shown a statistically significant decreasing on dentine permeability after treatment with toothpaste (Friedman test and Dunn’s post hoc test). Comparison among groups demonstrated a high increasing on dentine permeability when acid challenge was performed after toothbrushing with distilled water (control group) (Kruskal-Wallis and Dunn’s post hoc test). Conclusion The toothpaste treatment may provide sufficient resistance on dentine surface, preventing dentinal tubules exposure after acid challenge. PMID:24958423

Bacterial reduction and dentin microhardness after treatment by a pulsed fiber optic delivered Nd:YAG laser

NASA Astrophysics Data System (ADS)

Goodis, Harold E.; White, Joel M.; Marshall, Sally J.; Marshall, Grayson W.

1994-09-01

The purpose of this study was to determine the microhardness and extent of bacterial reduction of contaminated dentin following pulsed fiber optic delivered Nd:YAG laser exposure. Knoop hardness was determined before and after laser exposures from 0.3 to 3.0 W and repetition rates of 10 to 30 Hz. Half the sections were covered with an organic black pigment before laser exposure to evaluate the use of the pigment as an initiator to increase laser absorbance on the surface. Repeated measures design was employed to determine the microhardness of cut and polished dentin sections. Additional dentin sections were sterilized by gamma irradiation and then inoculated with B. subtilis, E. coli or B. stearothermophilus. The contaminated sections were exposed to contact delivered Nd:YAG laser. Cultures were obtained from the dentin surfaces and the colony forming units counted. Increased microhardness was found for all laser treatments above the physical modification. Bacterial reduction was obtained but complete sterilization was not.

Effect and Stability of Poly(Amido Amine)-Induced Biomineralization on Dentinal Tubule Occlusion

PubMed Central

Gao, Yuan; Liang, Kunneng; Li, Jianshu; Yuan, He; Liu, Hongling; Duan, Xiaolei; Li, Jiyao

2017-01-01

In recent years, scientists have developed various biomaterials to remineralize human teeth to treat dentine hypersensitivity. Poly(amido amine) (PAMAM) dendrimers have become a research focus in this field. It has been demonstrated that PAMAM is able to create precipitates both on the surface of and within the dentinal tubules, however, there is little information about its effect on reducing dentine permeability in vitro. This study aimed to evaluate the in vitro effectiveness and stability of the fourth generation amine-terminated PAMAM on dentinal tubule occlusion, especially on dentine permeability. Sodium fluoride (NaF), which has been widely used as a desensitizing agent, is regarded as positive control. Demineralized sensitive dentine samples were coated with PAMAM or sodium fluoride solutions and soaked in artificial saliva (AS) at 37 °C for different periods. Four weeks later, samples in each group were then equally split into two subgroups for testing using a brushing challenge and an acid challenge. Dentine permeability of each specimen was measured before and after each challenge using a fluid filtration system. Dentine morphology and surface deposits were characterized by scanning electron microscope (SEM) and analyzed with Image-Pro Plus software. Data were evaluated through multifactorial ANOVA with repeated measures and pair-wise comparisons at a level of 5%. The results showed that PAMAM and NaF significantly reduced dentine permeability to 25.1% and 20.7%. Both of them created precipitates on dentine surfaces after AS immersion for 28 days. PAMAM-induced biomineralization not only on dentine surfaces, but also deeper in dentinal tubules, significantly reduced dentine permeability. Moreover, PAMAM-induced biomineralization elicited excellent stable occlusion effects after acid challenge. In conclusion, PAMAM demonstrated a strong ability to resist acid and showed great potential to be used in the treatment of dentine hypersensitivity in future. PMID:28772744

Dentinal permeation modeling

NASA Astrophysics Data System (ADS)

Trunina, Natalia; Derbov, Vladimir; Tuchin, Valery; Altshuler, Gregory

2008-06-01

Dentinal permeation is of interest in a wide context of tooth care and treatment, in particular, tooth color improvement using combination of chemical whitening agents and light activation. A simple model of dentinal permeation accounting for the morphology of human tooth dentine and including dentinal tubules, more dense and homogeneous peritubular dentine, and less dense and less homogeneous intertubular dentin is proposed. Calculation of permeability of dentine layer is carried out for H IIO and H IIO II versus the tubule diameter and tubule density taken from the microphotograph analysis. This opens the possibility to calculate the distribution of permeability over the tooth surface taking into account the variations of tubule diameter and density as well as those of the diffusion coefficients and layer thickness

Effect of EDTA, sodium hypochlorite, and chlorhexidine gluconate with or without surface modifiers on dentin microhardness.

PubMed

Aslantas, Eda E; Buzoglu, Hatice Dogan; Altundasar, Emre; Serper, Ahmet

2014-06-01

This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents. Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05. EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05). The addition of surface modifiers to the irrigants did not affect the microhardness of the samples. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of sub-surface penetration and bonding durability of self-etching primer systems to Er:YAG laser treated cervical dentin.

PubMed

He, Zhengdi; Chen, Lingling; Shimada, Yasushi; Tagami, Junji; Ruan, Shuangchen

2017-03-31

This study aimed to investigate self-etching bonding systems penetrating in sub-surface dentin layer after Er:YAG laser irradiation and micro-shear bonding durability over a period of 1 year. Dentin slices obtained from extracted human third molars were prepared. Two self-etching adhesive systems were evaluated: Clearfil SE Bond and Clearfil Tri-S Bond. Specimens were tested for micro-shear bond strength with one of the following treatments: Er:YAG laser irradiation and 600-grit silicon paper polishing at 24 h, 7 days, 6 months and 1 year. The adhesive interfaces between bonding agents and lased cervical dentin were studied. No hybrid layer could be observed for lased dentin. The slim resin tags could be seen penetrating through the lased subsurface layer. Bond strength to lased dentin after 6 months and 1 year were significantly decreased (p<0.05).

Evaluation of tensile retention of Y-TZP crowns after long-term aging: effect of the core substrate and crown surface conditioning.

PubMed

Amaral, R; Rippe, M; Oliveira, B G; Cesar, P F; Bottino, M A; Valandro, L F

2014-01-01

This study evaluated the effect of the core substrate type (dentin and composite resin) on the retention of crowns made of yttrium oxide stabilized tetragonal zirconia polycrystal (Y-TZP), submitted to three inner surface conditionings. For this purpose, 72 freshly extracted molars were embedded in acrylic resin, perpendicular to the long axis, and prepared for full crowns: 36 specimens had crown preparations in dentin; the remaining 36 teeth had the crowns removed, and crown preparations were reconstructed with composite resin plus fiber posts with dimensions identical to the prepared dentin. The preparations were impressed using addition silicone, and 72 Y-TZP copings for the tensile test were produced. Cementation was performed with a dual-cured cement containing phosphate monomers. For cementation, the crown preparation (dentin or resin) was conditioned with the adhesive system, and the ceramic was subjected to one of three surface treatments: isopropyl alcohol, tribochemical silica coating, or thin low-fusing glassy porcelain layer application plus silanization. After 24 hours, all specimens were submitted to thermocycling (6000 cycles) and placed in a special tensile testing device in a universal testing machine to determine failure loads. The failure modes of all samples were analyzed under a stereomicroscope. Two-way analysis of variance showed that the surface treatment and substrate type (α=0.05) affected the tensile retention results. The dentin substrate presented the highest tensile retention values, regardless of the surface treatment. When the substrate was resin, the tribochemical silica coating and low-fusing glaze application plus silanization groups showed the higher retention values.

Effect of Er,Cr:YSGG laser on the microtensile bond strength of two different adhesives to the sound and caries-affected dentin.

PubMed

Ergücü, Z; Celik, E U; Unlü, N; Türkün, M; Ozer, F

2009-01-01

This study examined the effect of Er,Cr:YSGG laser irradiation on the microtensile bond strength (microTBS) of a three-step etch-and-rinse and a two-step self-etch adhesive to sound and caries-affected dentin. Sixteen freshly extracted human molars with occlusal dentin caries were used. The caries lesion was removed by one of the following methods: conventional treatment with burs or Er,Cr:YSGG laser (Waterlase MD, Biolase). The adhesive systems (AdheSE, Ivoclar Vivadent and Scotchbond Multi Purpose, 3M ESPE) were applied to the entire tooth surface according to the manufacturers' instructions. Resin composites were applied to the adhesive-treated dentin surfaces and light-cured. Each tooth was sectioned into multiple beams with the "non-trimming" version of the microtensile test. The specimens were subjected to microtensile forces (BISCO Microtensile Tester, BISCO). The data was analyzed by three-way ANOVA and independent t-tests (p=0.05). Er,Cr:YSGG laser irradiation exhibited similar microTBS values compared to that of conventional bur treatment, regardless of the adhesive system and type of treated dentin. The self-etch system revealed lower microTBS values, both with conventional and laser treatment techniques, compared to the etch-and-rinse adhesive in sound and caries-affected dentin (p<0.05). Er,Cr:YSGG laser irradiation did not negatively affect the bonding performance of adhesive systems to sound and caries-affected dentin.

Effect of pulsed Nd:YAG on dentin morphological changes

NASA Astrophysics Data System (ADS)

Moriyama, Eduardo H.; Zangaro, Renato A.; Villaverde, Antonio G. J. B.; Watanabe-Sei, Ii; Munin, Egberto; Sasaki, Luis H.; Otsuka, Daniel K.; Lobo, Paulo D. d. C.; Pacheco, Marcos T. T.; Junior, Durval R.

2002-06-01

Infrared lasers have been used for several clinical applications in dentistry, including laser ablation, oral surgeries and dentin hypersensitivity treatment. Despite of dentin low absorption coefficient in the near infrared spectrum, Nd:YAG laser radiation ((lambda) = 1064 nm) is able to melt the human dentin surface resulting in dentin tubules closure that can suppress the symptoms of dentin hypersensitivity pathology. Objectives: This study aims to analyze, through SEM technique, the morphological changes in dentin surface after Nd:YAG laser irradiation using different parameters in energy distribution. Materials and Methods: In this study sixteen human dentin samples were submitted to Nd:YAG laser radiation using a total energy of 900mJ distributed in one, two, three or six laser pulses with energy for each pulse of 900, 450, 300 or 150 mJ respectively. All the samples were irradiated with laser pulse width of 90ms, pulse intervals of 300 ms and spot size area of 0,005 cm2. Results: SEM analysis suggests that differences in energy distribution results in morphological differences even though the same energy is used for all the samples.

Structural modifications induced in dentin by femtosecond laser

NASA Astrophysics Data System (ADS)

Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

2016-12-01

The structural and chemical modifications induced in dentin by ultrafast laser ablation were studied. The laser experiments were performed with a Yb:KYW chirped-pulse-regenerative amplification laser system (560-fs pulse duration, 1030-nm radiation wavelength), fluences in the range 2 to 14 J/cm2, 1-kHz pulse repetition rate, and 5-mm/s scanning speed. The ablation surfaces were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The ablation surfaces produced with 2 J/cm2 presented an irregular morphology with exposed dentinal tubules and no evidence of thermal effects. For 7 and 14 J/cm2, the ablation surfaces were covered by a layer of redeposited ablation debris, consisting mainly of amorphous calcium phosphate. This layer is weakly adherent to the underlying tissue and can be easily removed by ultrasonication, revealing a surface with a morphology similar to the one obtained with 2 J/cm2. The constitution of the dentin ablation surfaces is similar to the constitution of pristine dentin, showing that, within this fluence range, the laser treatment does not significantly modify the structure and constitution of dentin. The results achieved suggest an ablation mechanism where collagen is preferentially decomposed by the laser radiation, reducing the tissue cohesive strength and leading, ultimately, to its ablation.

Initial and long-term bond strengths of one-step self-etch adhesives with silane coupling agent to enamel-dentin-composite in combined situation.

PubMed

Mamanee, Teerapong; Takahashi, Masahiro; Nakajima, Masatoshi; Foxton, Richard M; Tagami, Junji

2015-01-01

This study evaluated the effect of adding silane coupling agent on initial and long-term bond strengths of one-step self-etch adhesives to enamel-dentin-composite in combined situation. Cervical cavities were prepared on extracted molars and filled with Clearfil AP-X. After water-storage for one-week, the filled teeth were sectioned in halves to expose enamel, dentin and composite surfaces and then enamel-dentin-composite surface was totally applied with one of adhesive treatments (Clearfil SE One, Clearfil SE One with Clearfil Porcelain Bond Activator, Beautibond Multi, Beautibond Multi with Beautibond Multi PR Plus and Scotchbond Universal). After designed period, micro-shear bond strengths (µSBSs) to each substrate were determined. For each period of water-storage, additive silane treatments significantly increased µSBS to composite (p<0.001). On the other hand, they significantly decreased µSBS to dentin (p<0.001), although did not have adverse effect on µSBS to enamel (p>0.05). Moreover, the stability of µSBS was depended on materials and substrates used.

Long-Term Bond Strength of Two Benzalkonium Chloride-Modified Adhesive Systems to Eroded Dentin

PubMed Central

Lussi, Adrian; Peutzfeldt, Anne

2017-01-01

This study investigated the effect of benzalkonium chloride (BAC) modification of two adhesive systems on long-term bond strength to normal and artificially eroded dentin. A total of 128 extracted human molars were sectioned and the buccal and oral surfaces of each molar were ground until the dentin. One half was left untreated (normal dentin) while the other half underwent artificial erosion. Resin composite was bonded to the buccal or oral surface following treatment with Adper Scotchbond 1XT or OptiBond FL without or with 1% BAC incorporation. Shear bond strength (SBS) was measured after 24 h (100% humidity, 37°C) or 1 year (tap water, 37°C). SBS results were statistically analyzed (α = 0.05). SBS was significantly lower to artificially eroded dentin than to normal dentin (p < 0.001). Storage for 1 year had no effect on SBS to normal dentin but led to a significant decrease in SBS to artificially eroded dentin (p < 0.001). BAC incorporation decreased the 24 h SBS to normal dentin (p = 0.018), increased the 24 h SBS to eroded dentin (p = 0.001), and had no effect on the 1-year SBS for either substrate. Consequently, BAC incorporation did not improve bond durability. PMID:28875148

Micro energy-dispersive x-ray fluorescence spectrometry study of dentin coating with nanobiomaterials

NASA Astrophysics Data System (ADS)

Soares, Luís. Eduardo Silva; Nahorny, Sídnei; Marciano, Fernanda Roberta; Zanin, Hudson; Lobo, Anderson de Oliveira

2015-06-01

New biomaterials such as multi-walled carbon nanotubes oxide/graphene oxide (MWCNTO/GO), nanohydroxyapatite (nHAp) and combination of them together or not to acidulated phosphate fluoride gel (F) have been tested as protective coating before root dentin erosion. Fourteen bovine teeth were cleaned, polished, divided into two parts (n=28) and assigned to seven groups: (Control) - without previous surface treatment; F treatment; nHAp; MWCNTO/GO; F+nHAp; F+MWCNTO/GO and F+MWCNTO/GO/nHAp composites. Each sample had two sites of pre-treatments: acid etched area and an area without treatment. After the biomaterials application, the samples were submitted to six cycles (demineralization: orange juice, 10 min; remineralization: artificial saliva, 1 h). Micro energy-dispersive X-ray fluorescence spectrometry (μ-EDXRF) mapping area analyses were performed after erosive cycling on both sites (n=84). μ-EDXRF mappings showed that artificial saliva and MWCNTO/GO/nHAp/F composite treatments produced lower dentin demineralization than in the other groups. Exposed dentin tubules allowed better interaction of nanobiomaterials than in smear layer covered dentin. Association of fluoride with other biomaterials had a positive influence on acid etched dentin. MWCNTO/GO/nHAp/F composite treatment resulted in levels of demineralization similar to the control group.

Influence of ultrasound and diamond burs treatments on microtensile bond strength.

PubMed

Conde, Alexandre; Mainieri, Vivian; Mota, Eduardo Goncalves; Oshima, Hugo Mitsuo

2012-01-01

To compare surface treatments with CVDentUS ultrasound tips (UT) and KGSorensen diamond burs (DB) on etched (e) and non-etched (n/e) dentin. The microtensile bond strength (μTBS) was measured and fractography was assessed by scanning electron microscope (SEM). Sixteen molars were divided into four groups of four teeth each according to treatment (DB-n/e; DB-e; UT-n/e; UT-e). The teeth were restored, sectioned into samples for μTBS (n=40) and tested on a EMIC DL-2000 universal machine (0.5 mm/min) and analyzed by SEM for fracture classification. For analysis of the data on μTBS, the two-way ANOVA, using treatment and acid etching as fixed factor, and the Tukey test were used (α=0.05). To failures classification in cohesive in dentin (CD); cohesive in composite resin (CC); cohesive interfacial on base or top of hybrid layer (CBT); cohesive in adhesive (CA); mixed (M); interfacial on smear layer (S) the Fisher's exact test (α=0.05) was performed. The mean values of μTBS (in MPa) in the different groups were as follows: UT-e: 45.31 ± 8.16; DB-e: 34.04 ± 9.29; UT-n/e: 15.17 ± 3.71; and DB-n/e: 9.86 ± 3.80. On analysis of the SEM micrographs, the DB-n/e group showed total obstruction of dentinal tubules; the UT-n/e group showed partial desobstruction of dentinal tubules and irregular surface; the DB-e group showed complete desobstruction of dentinal tubules; and the UT-e group showed complete desobstruction of dentinal tubules and irregular surface. The combination of ultrasound treatment and acid etching provides high values of μTBS. An association exists between CA/CC failures and the UT method, CBT failure and the DB method, CBT/CC failures and etching, S failure and non-etching.

An in-vitro evaluation of the effect of 980 nm diode laser irradiation on intra-canal dentin surface and dentinal tubule openings after biomechanical preparation: Scanning electron microscopic study

PubMed Central

Jhingan, Pulkit; Sandhu, Meera; Jindal, Garima; Goel, Deepti; Sachdev, Vinod

2015-01-01

Context: Very recently, diode laser has been used for disinfecting the root canals in endodontic treatment and increasing its success rate and longevity utilizing the thermal effect of laser on surrounding tissues. Aims: The aim of this study is to evaluate the effect of 980 nm laser irradiation on intra-canal dentin surface – scanning electron microscopic (SEM) - in-vitro study. Methods: A total of 40 single-rooted freshly extracted permanent teeth were collected. Teeth were sectioned at the cemento-enamel junction using diamond disc. Root canals of all samples were prepared using hand ProTaper, which were randomly assigned into two groups (n = 20 each). Group 1: Receiving no treatment after biomechanical preparation; Group 2: 980 nm diode laser-treated root canals. Teeth were prepared for SEM analysis to check the size of intra-canal dentinal tubule openings. Statistical Analysis Used: Data were analyzed using SPSS V.16 software and compared using Levene's and independent t-test. Results: On statistical analysis, width of intracanal dentinal tubule openings in Group 1 (control) was significantly higher than those observed in Group 2 (diode laser-treated) (P < 0.001). Conclusion: This study showed that the application of 980 nm diode laser on intra-radicular dentin resulted in ultrastructural alterations resulting in melting of dentin. PMID:26097338

Evaluation of metal bond strength to dentin and enamel using different adhesives and surface treatments.

PubMed

Dundar, Mine; Gungor, Mehmet Ali; Cal, Ebru; Darcan, Alev; Erdem, Adalet

2007-01-01

Because adherence of base metal alloys is important for the long-term clinical success of adhesive fixed partial dentures, it has been necessary to improve adhesion to metal substrate by using different surface treatments. This study used different surface conditioning methods and two different luting resins to evaluate the shear bond strength of base metal alloys to dentin and enamel. Sixty noncarious freshly extracted human teeth were mounted in a plastic holder filled with autopolymerized acrylic resin. After the roots were removed and 30 flat enamel and 30 flat dentin surfaces were exposed, the specimens were divided randomly into two main luting cement groups. Sixty nickel chromium (NiCr) metal specimens were fabricated and subjected to three different surface conditioning procedures: sandblasting with 50 microm aluminum oxide, tribochemical silica coating, and a combination of the two. Scanning electron mircoscopy (SEM) evaluations revealed mainly cohesive failures. Self-cure adhesive resulted in higher bond strengths to dental substrates. Higher bond strengths were achieved through a combination of sandblasting and tribochemical silica coating; however, further clinical research is required. A surface treatment that combines sandblasting with tribochemical silica coating can achieve a more effective bond for adhesive restorations with metal substrates.

Mathematical simulation of the thermal diffusion in dentine irradiated with Nd:YAG laser using finite difference method

NASA Astrophysics Data System (ADS)

Moriyama, Eduardo H.; Zangaro, Renato A.; Lobo, Paulo D. d. C.; Villaverde, Antonio G. J. B.; Watanabe-Sei, Ii; Pacheco, Marcos T. T.; Otsuka, Daniel K.

2002-06-01

Thermal damage in dental pulp during Nd:YAG laser irradiation have been studied by several researchers; but due to dentin inhomogeneous structure, laser interaction with dentin in the hypersensitivity treatment are not fully understood. In this work, heat distribution profile on human dentine samples irradiated with Nd:YAG laser was simulated at surface and subjacent layers. Calculations were carried out using the Crank-Nicolson's finite difference method. Sixteen dentin samples with 1,5 mm of thickness were evenly distributed into four groups and irradiated with Nd:YAG laser pulses, according to the following scheme: (I) 1 pulse of 900 mJ, (II) 2 pulses of 450 mJ, (III) 3 pulses of 300 mJ, (IV) 6 pulses of 150 mJ; corresponding to a total laser energy of 900 mJ. The pulse interval was 300ms, the pulse duration of 900 ms and irradiated surface area of 0,005 mm2. Laser induced morphological changes in dentin were observed for all the irradiated samples. The heat distribution throughout the dentin layer, from the external dentin surface to the pulpal chamber wall, was calculated for each case, in order to obtain further information about the pulsed Nd:YAG laser-oral hard tissue interaction. The simulation showed significant differences in the final temperature at the pulpal chamber, depending on the exposition time and the energy contained in the laser pulse.

Etidronate from Medicine to Endodontics: effects of different irrigation regimes on root dentin roughness

PubMed Central

TARTARI, Talita; DUARTE JUNIOR, Anivaldo Pereira; SILVA JÚNIOR, José Otávio Carrera; KLAUTAU, Eliza Burlamaqui; SILVA E SOUZA JUNIOR, Mario Honorato; SILVA E SOUZA, Patrícia de Almeida Rodrigues

2013-01-01

An increase in dentin roughness, associated with surface composition, contributes to bacterial adherence in recontaminations. Surface roughness is also important for micromechanical interlocking of dental materials to dentin, and understanding the characteristics of the surface is essential to obtain the adhesion of root canal sealers that have different physico-chemical characteristics. Objectives To evaluate the effects of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated with different irrigation regimens on root dentin roughness. Material and Methods Forty-five root halves of anterior teeth were used. The root parts were sectioned in thirds, embedded in acrylic resin and polished to a standard surface roughness. Initially, the samples of each third were randomly assigned into 3 groups and treated as follows: G1 - saline solution (control); G2 - 5% NaOCl+18% HEBP mixed in equal parts; and G3 - 2.5% NaOCl. After initial measuments, the G3 samples were distributed into subgroups G4, G5 and G6, which were subjected to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measuments, these groups received a final flush with 2.5% NaOCl, producing G7, G8 and G9. The dentin surface roughness (Ra) was determined before and after treatments using a profilometer. The Wilcoxon test (α<0.05) was used to compare the values before and after treatments, and the Friedman test (α<0.05) to detect any differences among root thirds. Results (i) NaOCl did not affect the surface roughness; (ii) there was a significant increase in roughness after the use of chelating agents (P<0.01); and (iii) only the G3 group showed a difference in surface roughness between apical third and other thirds of the teeth (P<0.0043). Conclusion Only the irrigation regimens that used chelating agents altered the roughness of root dentin. PMID:24212986

Etidronate from medicine to endodontics: effects of different irrigation regimes on root dentin roughness.

PubMed

Tartari, Talita; Duarte Junior, Anivaldo Pereira; Silva Júnior, José Otávio Carrera; Klautau, Eliza Burlamaqui; Silva E Souza Junior, Mario Honorato; Silva E Souza Junior, Patrícia de Almeida Rodrigues

2013-01-01

An increase in dentin roughness, associated with surface composition, contributes to bacterial adherence in recontaminations. Surface roughness is also important for micromechanical interlocking of dental materials to dentin, and understanding the characteristics of the surface is essential to obtain the adhesion of root canal sealers that have different physico-chemical characteristics. To evaluate the effects of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated with different irrigation regimens on root dentin roughness. Forty-five root halves of anterior teeth were used. The root parts were sectioned in thirds, embedded in acrylic resin and polished to a standard surface roughness. Initially, the samples of each third were randomly assigned into 3 groups and treated as follows: G1 - saline solution (control); G2 - 5% NaOCl+18% HEBP mixed in equal parts; and G3 - 2.5% NaOCl. After initial measuments, the G3 samples were distributed into subgroups G4, G5 and G6, which were subjected to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measuments, these groups received a final flush with 2.5% NaOCl, producing G7, G8 and G9. The dentin surface roughness (Ra) was determined before and after treatments using a profilometer. The Wilcoxon test (α<0.05) was used to compare the values before and after treatments, and the Friedman test (α<0.05) to detect any differences among root thirds. (i) NaOCl did not affect the surface roughness; (ii) there was a significant increase in roughness after the use of chelating agents (P<0.01); and (iii) only the G3 group showed a difference in surface roughness between apical third and other thirds of the teeth (P<0.0043). Only the irrigation regimens that used chelating agents altered the roughness of root dentin.

Evaluation of effectiveness of Er,Cr:YSGG laser for root canal disinfection: theoretical simulation of temperature elevations in root dentin.

PubMed

Zhu, L; Tolba, M; Arola, D; Salloum, M; Meza, F

2009-07-01

Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers are currently being investigated for disinfecting the root canal system. Prior to using laser therapy, it is important to understand the temperature distribution and to assess thermal damage to the surrounding tissue. In this study, a theoretical simulation using the Pennes bioheat equation is conducted to evaluate how heat spreads from the canal surface using an Er,Cr:YSGG laser. Results of the investigation show that some of the proposed treatment protocols for killing bacteria in the deep dentin are ineffective, even for long heating durations. Based on the simulation, an alternative treatment protocol is identified that has improved effectiveness and is less likely to introduce collateral damage to the surrounding tissue. The alternative protocol uses 350 mW laser power with repeating laser tip movement to achieve bacterial disinfection in the deep dentin (800 microm lateral from the canal surface), while avoiding thermal damage to the surrounding tissue (T<47 degrees C). The alternative treatment protocol has the potential to not only achieve bacterial disinfection of deep dentin but also shorten the treatment time, thereby minimizing potential patient discomfort during laser procedures.

Influence of Er,Cr:YSGG laser treatment on the microtensile bond strength of adhesives to dentin.

PubMed

Cardoso, Marcio Vivan; Coutinho, Edurado; Ermis, R Banu; Poitevin, André; Van Landuyt, Kirsten; De Munck, Jan; Carvalho, Rubens C R; Lambrechts, Paul; Van Meerbeek, Bart

2008-02-01

In light of the concept of minimally invasive dentistry, erbium lasers have been considered as an alternative technique to the use of diamond burs for cavity preparation. The purpose of this study was to assess the bonding effectiveness of adhesives to Er,Cr:YSGG laser-irradiated dentin using irradiation settings specific for cavity preparation. Fifty-four midcoronal dentin surfaces, obtained from sound human molars, were irradiated with an Er,Cr:YSGG laser or prepared with a diamond bur using a high-speed turbine. One etch-and-rinse (Optibond FL/Kerr) and three self-etching adhesives (Adper Prompt L-Pop/3M ESPE, Clearfil SE Bond/Kuraray, and Clearfil S3 Bond/Kuraray) were used to bond the composite to dentin. The microtensile bond strength (microTBS) was determined after 24 h of storage in water at 37 degrees C. The Kruskal-Wallis test was used to determine pairwise statistical differences (p < 0.05). Prepared dentin surfaces, adhesive interfaces, and failure patterns were analyzed using a stereomicroscope and Field-emission gun Scanning Electron Microscopy (Feg-SEM). Significantly lower microTBS was observed to laser-irradiated than to bur-cut dentin (p < 0.05), irrespective of the adhesive employed. Feg-SEM photomicrographs of lased dentin revealed an imbricate patterned substrate and the presence of microcracks at the dentin surface. Morphological alterations produced by Er,Cr:YSGG laser-irradiation adversely influence the bonding effectiveness of adhesives to dentin.

Review of methyl methacrylate (MMA)/tributylborane (TBB)-initiated resin adhesive to dentin.

PubMed

Taira, Yohsuke; Imai, Yohji

2014-01-01

This review, focusing mainly on research related to methyl methacrylate/tributylborane (MMA/TBB) resin, presents the early history of dentin bonding and MMA/TBB adhesive resin, followed by characteristics of resin bonding to dentin. Bond strengths of MMA/TBB adhesive resin to different adherends were discussed and compared with other bonding systems. Factors affecting bond strength (such as conditioners, primers, and medicaments used for dental treatment), bonding mechanism, and polymerization characteristics of MMA/TBB resin were also discussed. This review further reveals the unique adhesion features between MMA/TBB resin and dentin: in addition to monomer diffusion into the demineralized dentin surface, graft polymerization of MMA onto dentin collagen and interfacial initiation of polymerization at the resin-dentin interface provide the key bonding mechanisms.

In Vitro Adhesion of Streptococcus sanguinis to Dentine Root Surface After Treatment with Er:Yag Laser, Ultrasonic System, or Manual Curette

PubMed Central

Martins, Fernanda L.; Giorgetti, Ana Paula O.; de Freitas, Patrícia M.; Duarte, Poliana M.

2009-01-01

Abstract Objective: The purpose of this in vitro study was to evaluate the dentine root surface roughness and the adherence of Streptococcus sanguinis (ATCC 10556) after treatment with an ultrasonic system, Er:YAG laser, or manual curette. Background Data: Bacterial adhesion and formation of dental biofilm after scaling and root planing may be a challenge to the long-term stability of periodontal therapy. Materials and Methods: Forty flattened bovine roots were randomly assigned to one of the following groups: ultrasonic system (n = 10); Er:YAG laser (n = 10); manual curette (n = 10); or control untreated roots (n = 10). The mean surface roughness (Ra, μm) of the specimens before and after exposure to each treatment was determined using a surface profilometer. In addition, S. sanguinis was grown on the treated and untreated specimens and the amounts of retained bacteria on the surfaces were measured by culture method. Results: All treatments increased the Ra; however, the roughest surface was produced by the curettes. In addition, the specimens treated with curettes showed the highest S. sanguinis adhesion. There was a significant positive correlation between roughness values and bacterial cells counts. Conclusion: S. sanguinis adhesion was the highest on the curette-treated dentine root surfaces, which also presented the greatest surface roughness. PMID:19712018

Pulsed Nd-YAG laser in endodontics

NASA Astrophysics Data System (ADS)

Ragot-Roy, Brigitte; Severin, Claude; Maquin, Michel

1994-12-01

The purpose of this study was to establish an operative method in endodontics. The effect of a pulsed Nd:YAG laser on root canal dentin has been examined with a scanning electron microscope. Our first experimentation was to observe the impacts carried out perpendicularly to root canal surface with a 200 micrometers fiber optic in the presence of dye. Secondarily, the optical fiber was used as an endodontic instrument with black dye. The irradiation was performed after root canal preparation (15/100 file or 40/100 file) or directly into the canal. Adverse effects are observed. The results show that laser irradiation on root canal dentin surfaces induces a nonhomogeneous modified dentin layer, melted and resolidified dentin closed partially dentinal tubules. The removal of debris is not efficient enough. The laser treatment seems to be indicated only for endodontic and periapical spaces sterilization after conventional root canal preparation.

Histologic and SEM evaluation of caries removal and restoration in enamel and dentin using a pulsed fiber optic delivered Nd:YAG laser

NASA Astrophysics Data System (ADS)

White, Joel M.; Goodis, Harold E.; Kudler, Joel J.; Eakle, W. S.; Neev, Joseph

1994-09-01

The pulsed Nd:YAG laser has been proposed as an alternative to the dental handpiece for caries removal in enamel and dentin. The purpose of this study was to systematically evaluate, in vitro, the process of caries removal and restoration in enamel and dentin. The effectiveness of this device was investigated utilizing scanning electron microscopy to determine the behavior of dentin after laser treatment of artificially created carious lesions in dentin. Histologic sections of extracted teeth after laser treatment and restoration demonstrated successful caries removal and restoration using the pulsed fiber optic delivered Nd:YAG laser as compared to both high and low speed rotary instrumentation. The adjacent enamel and dentin were unaffected by the laser irradiation although slight carbonization was seen on the dentin surface. Thermocouples placed in the pulp chamber during caries removal confirmed previous studies that showed laser parameters up to 1 W and 10 Hz being the same as conventional caries removal in the amount of heat generated which reaches the pulp. The addition of air/water coolant decreased pulpal temperature.

The effect of silver fluoride and potassium iodide on the bond strength of auto cure glass ionomer cement to dentine.

PubMed

Knight, G M; McIntyre, J M; Mulyani

2006-03-01

Diamine silver fluoride (Ag(NH3)2F), referred to as AgF, has been shown to reduce the incidence of caries in primary dentitions. The clinical application of this material has been limited by staining associated with both teeth and restorative materials. The application of potassium iodide (KI) after AgF eliminates stain formation. There is a lack of information as to how the addition of AgF followed by KI may affect the bond strength to dentine. The purpose of this study was to compare the bond strengths of auto cure glass ionomer cement to dentine surfaces that had been treated with AgF and KI and without treatment. Ten recently extracted human third molars were embedded into methyl methacrylate resin and sliced to form a square block of exposed dentine surfaces. Each of the four surfaces were treated by one of the following procedures: (a) etching with 37 per cent phosphoric acid; (b) applying GC dentine conditioner; (c) etching, followed by application of AgF/KI then washing off the precipitate and air drying; and (d) etching, applying AgF/KI and air drying the reaction products on the surface. Fuji VII auto cure glass ionomer cement was bonded onto each sample and fracture tested. The dentine samples treated with AgF/KI followed by washing away the precipitate and air drying had bond strengths (2.83 MPa) not significantly different from samples that had been conditioned (2.40 MPa). Samples where the AgF/KI precipitate had been air dried onto the dentine surface had significantly lower bond strengths (1.49 MPa) than the washed samples. Samples that were etched had significantly lower bond strengths (1.91MPa) than the conditioned samples. This study found that the application of AgF/KI to etched dentine samples followed by washing off the precipitate, created bond strengths that were not significantly different to conditioned samples. Leaving the AgF/KI precipitate on the dentine surface significantly reduced the bond strength of auto cured glass ionomer cement to dentine. Washing away the reaction products and air drying is recommended as the clinical protocol for using AgF and KI on dentine surfaces prior to application of an auto cure glass ionomer cement.

Chlorhexidine stabilizes the adhesive interface: a 2 year in vitro study

PubMed Central

Breschi, Lorenzo; Mazzoni, Annalisa; Nato, Fernando; Carrilho, Marcela; Visintini, Erika; Tjäderhane, Leo; Ruggeri, Alessandra; Tay, Franklin R; De Stefano Dorigo, Elettra; Pashley, David H

2013-01-01

Objectives This study evaluated the role of endogenous dentin MMPs in auto-degradation of collagen fibrils within adhesive-bonded interfaces. The null hypotheses tested were that adhesive blends or chlorhexidine digluconate (CHX) application does not modify dentin MMPs activity and that CHX used as therapeutic primer does not improve the stability of adhesive interfaces over time. Methods Zymograms of protein extracts from human dentin powder incubated with Adper Scotchbond 1XT (SB1XT) on untreated or 0.2–2% CHX treated dentin were obtained to assay dentin MMPs activity. Microtensile bond strength and interfacial nanoleakage expression of SB1XT bonded interfaces (with or without CHX pre-treatment for 30s on the etched surface) were analyzed immediately and after 2 yr of storage in artificial saliva at 37°C. Results Zymograms showed that application of SB1XT to human dentin powder increases MMP-2 activity, while CHX pre-treatment inhibited all dentin gelatinolytic activity, irrespective from the tested concentration. CHX significantly lowered the loss of bond strength and nanoleakage seen in acid-etched resin-bonded dentin artificially aged for 2 yr. Significance The study demonstrates the active role of SB1XT in dentin MMP-2 activation and the efficacy of CHX inhibition of MMPs even if used at low concentration (0.2%). PMID:20045177

Surface temperature and thermal penetration depth of Nd:YAG laser applied to enamel and dentin

NASA Astrophysics Data System (ADS)

White, Joel M.; Neev, Joseph; Goodis, Harold E.; Berns, Michael W.

1992-06-01

The determination of the thermal effects of Nd:YAG laser energy on enamel and dentin is critical in understanding the clinical applications of caries removal and surface modification. Recently extracted non-carious third molars were sterilized with gamma irradiation. Calculus and cementum were removed using scaling instruments and 600 grit sand paper. The smear layer produced by sanding was removed with a solution of 0.5 M EDTA (pH 7.4) for two minutes. Enamel and dentin surfaces were exposed to a pulsed Nd:YAG laser with 150 microsecond(s) pulse duration. Laser energy was delivered to the teeth with a 320 micrometers diameter fiberoptic delivery system, for exposure times of 1, 10 and 30 seconds. Laser parameters varied from 0.3 to 3.0 W, 10 to 30 Hz and 30 to 150 mJ/pulse. Other conditions included applications of hot coffee, carbide bur in a dental air-cooled turbine drill and soldering iron. Infrared thermography was used to measure the maximum surface temperature on, and thermal penetration distance into enamel and dentin. Thermographic data were analyzed with a video image processor to determine the diameter of maximum surface temperature and thermal penetration distance of each treatment. Between/within statistical analysis of variance (p

Mechanical properties and molecular structure analysis of subsurface dentin after Er:YAG laser irradiation.

PubMed

He, Zhengdi; Chen, Lingling; Hu, Xuejuan; Shimada, Yasushi; Otsuki, Masayuki; Tagami, Junji; Ruan, Shuangchen

2017-10-01

The purpose of this study was to evaluate the chemical and mechanical modifications in subsurface dentin layer after Er: YAG (Erbium-Yttrium Aluminium Garnet) laser irradiation, as the guidance of new dental restorative materials specific for laser irradiated dentin. Dentin disks obtained from extracted human molars were prepared and exposed to a single pulse Er:YAG laser irradiation at 80mJ/pulse. After laser irradiation the mechanical and chemical characteristics of intertubular dentin in subsurface layer were studied using nanoindentation tester and micro-Raman spectromy (μ-RS). The dentin 5-50µm depth beneath the lased surface was determined as testing area. Two-way analysis of variance (ANOVA) were used to compare the mechanical values between lased and untreated subsurface dentin (P = 0.05). A laser affected subsurface dentin layer after Er:YAG laser treatment is present. The laser irradiation is considered to decrease the mechanical properties in the superficial subsurface layer (<15µm deep). There was no significant difference in nanohardness and Young's modulus between lased subsurface dentin and untreated dentin (p > 0.05) under the depth of 15µm. However, the dentin at 5µm and 10µm depth beneath the lased surface exhibited significantly lower (~ 47.8% and ~ 33.6% respectively) hardness (p < 0.05). Er:YAG laser irradiation affected both mineral and organic components in subsurface dentin layer, a higher degree of crystallinity and reduced organic compounds occurred in the lased subsurface dentin. Under the tested laser parameters, Er:YAG laser irradiation causes lower mechanical values and reduction of organic components in subsurface dentin, which has deleterious effects on resin adhesion to this area. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Biomimetic mineralization: long-term observations in patients with dentin sensitivity.

PubMed

Guentsch, Arndt; Seidler, Karin; Nietzsche, Sandor; Hefti, Arthur F; Preshaw, Philip M; Watts, David C; Jandt, Klaus D; Sigusch, Bernd W

2012-04-01

Cervical tooth erosion is increasingly observed among adults and frequently associated with dentin sensitivity (DS). This study evaluated the effectiveness on DS of a biomimetic mineralization system (BIMIN) in comparison to the current standard treatment (Gluma(®) Desensitizer, Gluma). In this single-blind, 2-arm study, 40 patients with confirmed cervical DS were randomized to either the test group or the positive control group. A Visual-Analog-Scale (VAS) was used to assess DS following stimulation of the exposed dentin with a 2-s air blast. Assessments were made at baseline (pre-treatment), 2 days, 4, 8 and 12 weeks, and 12 months after treatment. Two-stage replicas were obtained from the treated teeth and gold sputtered at baseline, and 2 days, 3 and 12 months after treatment. Surface topography of the treated cervical lesions and occlusion of dentinal tubules were investigated using scanning electron microscopy (SEM). Both treatments led to a statistically significant reduction (P<0.0001) in DS that persisted over the entire 12-month observation period. Differences in DS between the treatments were not statistically significant. SEM photomicrographs demonstrated that a mineral layer concealed the dentinal tubules in the test group. In contrast, numerous dentinal tubules remained visible in cervical defects that were treated with Gluma. A biomimetic mineralization kit was successfully used to treat patients exhibiting DS. The effect was similar to using Gluma, and was likely the result of the deposition of an enamel-like layer on the exposed cervical dentin. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Tooth surface treatment strategies for adhesive cementation

PubMed Central

2017-01-01

PURPOSE The aim of this study was to evaluate the effect of tooth surface pre-treatment steps on shear bond strength, which is essential for understanding the adhesive cementation process. MATERIALS AND METHODS Shear bond strengths of different cements with various tooth surface treatments (none, etching, priming, or etching and priming) on enamel and dentin of human teeth were measured using the Swiss shear test design. Three adhesives (Permaflo DC, Panavia F 2.0, and Panavia V5) and one self-adhesive cement (Panavia SA plus) were included in this study. The interface of the cement and the tooth surface with the different pre-treatments was analyzed using SEM. pH values of the cements and primers were measured. RESULTS The highest bond strength values for all cements were achieved with etching and primer on enamel (25.6 ± 5.3 - 32.3 ± 10.4 MPa). On dentin, etching and priming produced the highest bond strength values for all cements (8.6 ± 2.9 - 11.7 ± 3.5 MPa) except for Panavia V5, which achieved significantly higher bond strengths when pre-treated with primer only (15.3 ± 4.1 MPa). Shear bond strength values were correlated with the micro-retentive surface topography of enamel and the tag length on dentin except for Panavia V5, which revealed the highest bond strength with primer application only without etching, resulting in short but sturdy tags. CONCLUSION The highest bond strength can be achieved for Panavia F 2.0, Permaflo DC, and Panavia SA plus when the tooth substrate is previously etched and the respective primer is applied. The new cement Panavia V5 displayed low technique-sensitivity and attained significantly higher adhesion of all tested cements to dentin when only primer was applied. PMID:28435616

Anatomical analysis of the resected roots of mandibular first molars after failed non-surgical retreatment

PubMed Central

2018-01-01

Objectives Understanding the reason for an unsuccessful non-surgical endodontic treatment outcome, as well as the complex anatomy of the root canal system, is very important. This study examined the cross-sectional root canal structure of mandibular first molars confirmed to have failed non-surgical root canal treatment using digital images obtained during intentional replantation surgery, as well as the causative factors of the failed conventional endodontic treatments. Materials and Methods This study evaluated 115 mandibular first molars. Digital photographic images of the resected surface were taken at the apical 3 mm level and examined. The discolored dentin area around the root canal was investigated by measuring the total surface area, the treated areas as determined by the endodontic filling material, and the discolored dentin area. Results Forty 2-rooted teeth showed discolored root dentin in both the mesial and distal roots. Compared to the original filled area, significant expansion of root dentin discoloration was observed. Moreover, the mesial roots were significantly more discolored than the distal roots. Of the 115 molars, 92 had 2 roots. Among the mesial roots of the 2-rooted teeth, 95.7% of the roots had 2 canals and 79.4% had partial/complete isthmuses and/or accessory canals. Conclusions Dentin discoloration that was not visible on periapical radiographs and cone-beam computed tomography was frequently found in mandibular first molars that failed endodontic treatment. The complex anatomy of the mesial roots of the mandibular first molars is another reason for the failure of conventional endodontic treatment. PMID:29765897

Atraumatic Restorative Treatment: Restorative Component.

PubMed

Leal, Soraya; Bonifacio, Clarissa; Raggio, Daniela; Frencken, Jo

2018-01-01

Atraumatic restorative treatment (ART) is a method of managing dental caries based on 2 pillars: sealants for preventing carious lesions in pits and fissures, and restorations for cavitated dentine carious lesions. ART uses only hand instruments for opening/enlarging the cavity and for removing carious tissue. The amount of carious tissue that should be removed depends mainly on the cavity depth. In cavities of shallow and medium depth, carious tissue is removed up to firm dentine. In deep/very deep cavities, in which there is no sign of pulp exposure, pulp inflammation and/or history of spontaneous pain, some soft dentine can be left in the pulpal floor/wall with the aim of avoiding pulp exposure. The ART restorative method is indicated for treating single-surface cavities in primary and permanent teeth, and in multiple-surface cavities in primary teeth. Insufficient information is available to conclude on its use for treating multiple-surface cavities in permanent teeth. © 2018 S. Karger AG, Basel.

Effect of propolis gel on the in vitro reduction of dentin permeability

PubMed Central

SALES-PERES, Silvia Helena de Carvalho; de CARVALHO, Flávia Negreiros; MARSICANO, Juliane Avansini; MATTOS, Maria Cecília; PEREIRA, José Carlos; FORIM, Moacir Rossi; da SILVA, Maria Fatima das Graças Fernandes

2011-01-01

Objective The aim of this study was to evaluate the capacity of potassium oxalate, fluoride gel and two kinds of propolis gel to reduce the hydraulic conductance of dentin, in vitro. Material and Methods The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on a model proposed in literature. Thirty-six 1-mm-thick dentin discs, obtained from extracted human third molars were divided into 4 groups (n=9). The groups corresponded to the following experimental materials: GI-10% propolis gel, pH 4.1; GII-30% propolis gel; GIII-3% potassium oxalate gel, pH 4,1; and GIV-1.23% fluoride gel, pH 4.1, applied to the dentin under the following surface conditions: after 37% phosphoric acid and before 6% citric acid application. The occluding capacity of the dentin tubules was evaluated using scanning electron microscopy (SEM) at ×500, ×1,000 and ×2,000 magnifications. Data were analyzed statistically by two-way ANOVA and Tukey's test at 5% significance level. Results Groups I, II, III, IV did not differ significantly from the others in any conditions by reducing in hydraulic conductance. The active agents reduced dentin permeability; however they produced the smallest reduction in hydraulic conductance when compared to the presence of smear layer (P<0.05). The effectiveness in reducing dentin permeability did not differ significantly from 10% or 30% propolis gels. SEM micrographs revealed that dentin tubules were partially occluded after treatment with propolis. Conclusions Under the conditions of this study, the application of 10% and 30% propolis gels did not seem to reduce the hydraulic conductance of dentin in vitro, but it showed capacity of partially obliterating the dentin tubules. Propolis is used in the treatment of different oral problems without causing significant great collateral effects, and can be a good option in the treatment of patients with dentin sensitivity. PMID:21956588

Comparison of the shear bond strength of self-adhesive resin cements to enamel and dentin with different protocol of application

PubMed Central

Moghaddas, Mohammad Javad; Hossainipour, Zahra; Majidinia, Sara; Ojrati, Najmeh

2017-01-01

Aim The aim of the present study was to determine the shear bond strength of self-adhesive resin cements to enamel and dentin with and without surface treatments, and compare them with conventional resin cement as the control group. Methods In this experimental study, buccal and lingual surface of the thirty sound human premolars were polished in order to obtain a flat surface of enamel (E) in buccal, and dentin (D) in lingual. Sixty feldspathic ceramic blocks (2×3×3 mm) were prepared and randomly divided into six groups (n=10). Each block was cemented to the prepared surface (30 enamel and 30 dentin surface) according to different protocol: E1 and D1; RelyX ARC as control group, E2, D2; RelyX Unicem, E3, D3; acid etching +RelyX Unicem. The specimens were termocycled and subjected to shear forces by a universal testing machine at a cross head speed of 0.5 mm/min. The mode of fracture were evaluated by stereomicroscope. Data were analyzed with descriptive statistical methods using SPSS version 15. One-way ANOVA, and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at α=0.05. Results Statistical analysis showed no significant differences within the enamel subgroups, but there were significant differences within the dentinal subgroups, and statistically significant differences were found between the groups D1and D3 (p=0.02). Comparison between similar enamel and dentinal subgroups showed that there was a significant difference just between the subgroups E3 and D3 (p=0.01). Conclusion Elective etching of enamel did not lead to significant increase in the shear bond strength of RelyX Unicem in comparison to RelyX ARC. On the other hand, elective etching of dentin reduces the bond strength of RelyX Unicem with the dentin. PMID:28979732

Comparison of the shear bond strength of self-adhesive resin cements to enamel and dentin with different protocol of application.

PubMed

Moghaddas, Mohammad Javad; Hossainipour, Zahra; Majidinia, Sara; Ojrati, Najmeh

2017-08-01

The aim of the present study was to determine the shear bond strength of self-adhesive resin cements to enamel and dentin with and without surface treatments, and compare them with conventional resin cement as the control group. In this experimental study, buccal and lingual surface of the thirty sound human premolars were polished in order to obtain a flat surface of enamel (E) in buccal, and dentin (D) in lingual. Sixty feldspathic ceramic blocks (2×3×3 mm) were prepared and randomly divided into six groups (n=10). Each block was cemented to the prepared surface (30 enamel and 30 dentin surface) according to different protocol: E1 and D1; RelyX ARC as control group, E2, D2; RelyX Unicem, E3, D3; acid etching +RelyX Unicem. The specimens were termocycled and subjected to shear forces by a universal testing machine at a cross head speed of 0.5 mm/min. The mode of fracture were evaluated by stereomicroscope. Data were analyzed with descriptive statistical methods using SPSS version 15. One-way ANOVA, and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at α=0.05. Statistical analysis showed no significant differences within the enamel subgroups, but there were significant differences within the dentinal subgroups, and statistically significant differences were found between the groups D1and D3 (p=0.02). Comparison between similar enamel and dentinal subgroups showed that there was a significant difference just between the subgroups E3 and D3 (p=0.01). Elective etching of enamel did not lead to significant increase in the shear bond strength of RelyX Unicem in comparison to RelyX ARC. On the other hand, elective etching of dentin reduces the bond strength of RelyX Unicem with the dentin.

Influence of Blood Contamination on Bond Strength of a Self-Etching System

PubMed Central

de Carvalho Mendonça, Ellen Cristina; Vieira, Samuel Nilo; Kawaguchi, Fernando Aparecido; Powers, John; Matos, Adriana Bona

2010-01-01

Objectives: To detect the influence of blood contamination (BC) on the bond strength (BS) of a self-etching bonding system (SES) to enamel and dentine. Methods: 25 human molars were longitudinally sectioned on the mesio-distal axis in order to obtain 50 specimens, which were embedded in acrylic resin. At first, the specimens were ground to expose a flat surface of enamel, and a bond strength test was performed. Afterwards, the samples were ground again in order to obtain a flat surface of dentine. Ten groups (total: n=100) were assigned according to substrate (enamel and dentine), step in the bonding sequence when contamination occurred (before the acidic primer and after the bonding resin), and contamination treatment (dry or rinse and dry procedure). Fresh human blood was introduced either before or after SES application (Clearfil SE Bond) and treated with air drying, or by rinsing and drying following application. Composite resin (Filtek Z-250,3M ESPE) was applied as inverted, truncated cured cones that were debonded in tension. Results: The mean tensile BS values (MPa) for enamel/dentine were 19.4/23.0 and 17.1/10.0 for rinse-and-dry treatment (contamination before and after SES, respectively); while the measurements for the dry treatment, 16.2/23.3 and 0.0/0.0 contamination before and after SES, respectively. Conclusions: It was determined that blood contamination impaired adhesion to enamel and dentine when it occurred after bond light curing. Among the tested contamination treatments, the rinse-and-dry treatment produced the highest bond strength with BC after SES application, but it was not sufficient to recover the BS in the contamination-free group. PMID:20613916

Comparative Evaluation of Efficacy of Iontophoresis with 0.33% Sodium Fluoride Gel and Diode Laser Alone on Occlusion of Dentinal Tubules

PubMed Central

Varma, Siddhartha; Suragimath, Girish; Abbayya, Keshava; Zope, Sameer Anil; Kale, Vishwajeet

2017-01-01

Introduction Dentinal Hypersensitivity (DH) is one of the most commonly encountered clinical problems. Literature reveals no specific therapy to satisfactorily eliminate dentinal hypersensitivity. Aim The aim of this study was to assess and compare the efficacy of iontophoresis with 0.33% Sodium Fluoride (NaF) gel and diode laser alone in dentinal tubule occlusion. Materials and Methods This in vitro study included 20 teeth with intact root surfaces unaltered by extraction procedure for specimen preparation. Each tooth was cleaned, air dried and cut into three sections. Total 60 sections were prepared (30 longitudinal and 30 transverse sections), which were acid etched. In control group, no treatment was carried. In iontophoresis treatment group, samples were inserted into a foam tray containing 0.33 % NaF Gel and subjected to 1.5 mA output current for three minutes. In laser treatment group, specimens were lased with 980 nm diode laser at 0.5 W/PW (62.2J /cm2) in a noncontact mode for 30 seconds. Specimens were evaluated under Scanning Electron Microscope (SEM) at 10KV to 20KV under x 2000, x5000 magnification for surface characteristics and patency of dentinal tubules. Total number of tubules visible, open, completely and partially occluded were recorded in each microphotograph and compared. Results On comparison, laser group showed the least number of open tubules i.e., 130 (31.1%) followed by iontophoresis group, 155 (51.32%) and control group 417 (100%). Conclusion Diode laser application provided better results as compared to iontophoresis on occlusion of dentinal tubules. Hence, it can be used to treat the patients with DH. PMID:28969290

Comparative Evaluation of Efficacy of Iontophoresis with 0.33% Sodium Fluoride Gel and Diode Laser Alone on Occlusion of Dentinal Tubules.

PubMed

Patil, Anup Raghunath; Varma, Siddhartha; Suragimath, Girish; Abbayya, Keshava; Zope, Sameer Anil; Kale, Vishwajeet

2017-08-01

Dentinal Hypersensitivity (DH) is one of the most commonly encountered clinical problems. Literature reveals no specific therapy to satisfactorily eliminate dentinal hypersensitivity. The aim of this study was to assess and compare the efficacy of iontophoresis with 0.33% Sodium Fluoride (NaF) gel and diode laser alone in dentinal tubule occlusion. This in vitro study included 20 teeth with intact root surfaces unaltered by extraction procedure for specimen preparation. Each tooth was cleaned, air dried and cut into three sections. Total 60 sections were prepared (30 longitudinal and 30 transverse sections), which were acid etched. In control group, no treatment was carried. In iontophoresis treatment group, samples were inserted into a foam tray containing 0.33 % NaF Gel and subjected to 1.5 mA output current for three minutes. In laser treatment group, specimens were lased with 980 nm diode laser at 0.5 W/PW (62.2J /cm 2 ) in a noncontact mode for 30 seconds. Specimens were evaluated under Scanning Electron Microscope (SEM) at 10KV to 20KV under x 2000, x5000 magnification for surface characteristics and patency of dentinal tubules. Total number of tubules visible, open, completely and partially occluded were recorded in each microphotograph and compared. On comparison, laser group showed the least number of open tubules i.e., 130 (31.1%) followed by iontophoresis group, 155 (51.32%) and control group 417 (100%). Diode laser application provided better results as compared to iontophoresis on occlusion of dentinal tubules. Hence, it can be used to treat the patients with DH.

In vivo remineralization of dentin using an agarose hydrogel biomimetic mineralization system

NASA Astrophysics Data System (ADS)

Han, Min; Li, Quan-Li; Cao, Ying; Fang, Hui; Xia, Rong; Zhang, Zhi-Hong

2017-02-01

A novel agarose hydrogel biomimetic mineralization system loaded with calcium and phosphate was used to remineralize dentin and induce the oriented densely parallel packed HA layer on defective dentin surface in vivo in a rabbit model. Firstly, the enamel of the labial surface of rabbits’ incisor was removed and the dentin was exposed to oral environment. Secondly, the hydrogel biomimetic mineralization system was applied to the exposed dentin surface by using a custom tray. Finally, the teeth were extracted and evaluated by scanning electron microscopy, X-ray diffraction, and nanoindentation test after a certain time of mineralization intervals. The regenerated tissue on the dentin surface was composed of highly organised HA crystals. Densely packed along the c axis, these newly precipitated HA crystals were perpendicular to the underlying dental surface with a tight bond. The demineralized dentin was remineralized and dentinal tubules were occluded by the grown HA crystals. The nanohardness and elastic modulus of the regenerated tissue were similar to natural dentin. The results indicated a potential clinical use for repairing dentin-exposed related diseases, such as erosion, wear, and dentin hypersensitivity.

Effect of dimethyl sulfoxide on dentin collagen.

PubMed

Mehtälä, P; Pashley, D H; Tjäderhane, L

2017-08-01

Infiltration of adhesive on dentin matrix depends on interaction of surface and adhesive. Interaction depends on dentin wettability, which can be enhanced either by increasing dentin surface energy or lowering the surface energy of adhesive. The objective was to examine the effect of dimethyl sulfoxide (DMSO) on demineralized dentin wettability and dentin organic matrix expansion. Acid-etched human dentin was used for sessile drop contact angle measurement to test surface wetting on 1-5% DMSO-treated demineralized dentin surface, and linear variable differential transformer (LVDT) to measure expansion/shrinkage of dentinal matrix. DMSO-water binary liquids were examined for surface tension changes through concentrations from 0 to 100% DMSO. Kruskal-Wallis and Mann-Whitney tests were used to test the differences in dentin wettability, expansion and shrinkage, and Spearman test to test the correlation between DMSO concentration and water surface tension. The level of significance was p<0.05. Pretreatment with 1-5% DMSO caused statistically significant concentration-dependent increase in wetting: the immediate contact angles decreased by 11.8% and 46.6% and 60s contact angles by 9.5% and 47.4% with 1% and 5% DMSO, respectively. DMSO-water mixtures concentration-dependently expanded demineralized dentin samples less than pure water, except with high (≥80%) DMSO concentrations which expanded demineralized dentin more than water. Drying times of LVDT samples increased significantly with the use of DMSO. Increased dentin wettability may explain the previously demonstrated increase in adhesive penetration with DMSO-treated dentin, and together with the expansion of collagen matrix after drying may also explain previously observed increase in dentin adhesive bonding. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of Dimethyl Sulfoxide on Bond Strength of a Self-Etch Primer and an Etch and Rinse Adhesive to Surface and Deep Dentin.

PubMed

Sharafeddin, Farahnaz; Salehi, Raha; Feizi, Negar

2016-09-01

Composite bond to dentin is crucial in many clinical conditions particularly in deep cavities without enamel margins due to insufficient penetration of adhesive into demineralized dentin. The aim of this study was to assess the shear bond strength (SBS) of a methacrylate-based and a silorane-based composite resin to surface and deep dentin after pretreatment with dimethyl sulfoxide (DMSO). Eighty extracted human premolars were randomly divided into two groups of flat occlusal dentin with different cuts as A: surface group (sections just below the dentinoenamel junction (DEJ) and B: deep group (2 mm below DEJ). Each group was randomly assigned to 4 subgroups and their samples were restored with Adper Single bond (ASB) and Filtek Z350 or Silorane system Adhesive (SA) and Filtek P90 composite resins, using a 3×3mm cylindrical plastic mold. following these steps , the subgroups were assigned as SubgroupA 1 : surface dentin+ Silorane System Primer (SSP)+ Silorane System Bonding (SSB)+ P90; Subgroup A 2 : surface dentin+ 37% etchant (E37%) + Adper Single Bond (ASB)+ Z350; Subgroup A 3 : surface dentin+ DMSO+ SSP+ SSB+ P90; Subgroup A 4 : surface dentin+ E37%+ DMSO+ ASB+ Z350; Subgroup B 1 : deep dentin+ SSP+ SSB+ P90; Subgroup B 2 : deep dentin+ E37%+ ASB+ Z350; Subgroup B 3 : deep dentin+ DMSO+ SSP+ SSB+ P90; Subgroup B 4 :dentin +E37% +DMSO +ASB +Z350. The specimens were thermocycled at 5± 2/55± 2°C for 1000 cycles and then tested for SBS. Using DMSO as dentin conditioner increased SBS of ASB to deep dentin (p< 0.001) and SBS of SA to surface dentin (p= 0.003) but had no effect on SBS of SA to deep dentin (p= 1.00). The ability of DMSO to increase SBS of ASB to deep dentin provides a basis for improving bonding of this composite resin in deep cavities.

Nanoleakage of dentin adhesive systems bonded to Carisolv-treated dentin.

PubMed

Kubo, Shisei; Li, Heping; Burrow, Michael F; Tyas, Martin J

2002-01-01

The hybrid layer created in caries-affected dentin has not been fully elucidated and may influence bond durability. This study investigated the nanoleakage patterns of caries-affected dentin after excavation with Carisolv or conventional instruments treated with one of three adhesive systems. Flat occlusal dentin surfaces, including carious lesions, were prepared from extracted human molars and finished with wet 600-grit silicon carbide paper. Carious dentin was removed with Carisolv or round steel burs in conjunction with Caries Detector. PermaQuik, Single Bond or One-Up Bond F was bonded to the excavated dentin surfaces and adjacent flat occlusal surfaces and it was covered with Silux Plus resin-based composite. After 24-hour storage in 37 degrees C water, the bonded interfaces were polished to remove flash, and the surrounding tooth surfaces were coated with nail varnish. Specimens were immersed in 50% (w/v) silver nitrate solution for 24 hours, exposed to photo developing solution for eight hours, then sectioned longitudinally through the bonded, excavated dentin or "normal" dentin surfaces. The sectioned surfaces were polished, carbon coated and observed in a Field Emission-SEM using back scattered electrons. Silver deposition occurred along the base of the hybrid layer for all specimens. However, Single Bond showed a greater density of silver deposition in the caries-affected dentin compared with normal dentin. PermaQuik had a thicker hybrid layer in caries-affected dentin than normal dentin. One-Up Bond F exhibited a thin hybrid layer in normal dentin, but the hybrid layer was often difficult to detect in caries-affected dentin.

In Vitro Study of Dentin Hypersensitivity Treated by 980-nm Diode Laser.

PubMed

Liu, Ying; Gao, Jie; Gao, Yan; Xu, Shuaimei; Zhan, Xueling; Wu, Buling

2013-01-01

To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (DH). Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm(2); Group B: 2 W/CW (continuous mode), 166 J/cm(2); Group C: 3W/CW, 250 J/cm(2); and Group D: 4W/CW, 333 J/cm(2). Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm(2); and Group F: 2.0 W/CW, 166 J/cm(2). The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW (166 J/cm(2)) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue.

In Vitro Study of Dentin Hypersensitivity Treated by 980-nm Diode Laser

PubMed Central

Liu, Ying; Gao, Jie; Gao, Yan; XU, Shuaimei; Zhan, Xueling; Wu, Buling

2013-01-01

Introduction: To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (DH). Methods: Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm2; Group B: 2 W/CW (continuous mode), 166 J/cm2; Group C: 3W/CW, 250 J/cm2; and Group D: 4W/CW, 333 J/cm2. Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm2; and Group F: 2.0 W/CW, 166 J/cm2. The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. Results: The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Conclusions: Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW (166 J/cm2) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue. PMID:25606318

Non-thermal Atmospheric Plasma Treatment for Deactivation of Oral Bacteria and Improvement of Dental Composite Restoration

NASA Astrophysics Data System (ADS)

Yu, Qing Song; Li, H.; Ritts, A. C.; Yang, B.; Chen, M.; Hong, L.; Xu, C.; Yao, X.; Wang, Y.

This paper reviews our recent research results of using non-thermal ­atmospheric plasmas for oral bacterial deactivation and for composite restoration improvement. Oral bacteria of Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) with an initial bacterial population density between 1.0 × 108 and 5.0 × 108 cfu/ml were seeded on various media and their survivability with plasma exposure was examined. The plasma exposure time for a 99.9999% cell reduction was less than 15 s for S. mutans and within 5 min for L. acidophilus. To evaluate the dentin/composite interfacial bonding, extracted unerupted human third molars were used by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. After dental composite application and light curing, the teeth were then sectioned into micro-bars as the specimens for microtensile test. Student Newman Keuls (SNK) tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s plasma treatment of the dentin surfaces. These findings indicated that non-thermal atmospheric plasma technology is very promising for dental clinical applications.

Tannic acid for smear layer removal: pilot study with scanning electron microscope.

PubMed

Bitter, N C

1989-04-01

The effects of a 25% tannic acid solution applied to the surface of prepared dentin was compared with untreated prepared dentin surfaces. The following results were demonstrated by electron microscope observation: (1) cavity preparations created an amorphous dentinal smear layer, (2) placement of a 25% tannic acid solution for 15 seconds removed the smear layer, (3) the contents of the dentinal tubules were not removed and no enlargement of dentinal tubules was found, and (3) a clean dentinal surface was observed.

Effect of tetracalcium phosphate/monetite toothpaste on dentin remineralization and tubule occlusion in vitro.

PubMed

Medvecky, L; Stulajterova, R; Giretova, M; Mincik, J; Vojtko, M; Balko, J; Briancin, J

2018-03-01

To investigate the tubule occlusion and remineralization potential of a novel toothpaste with active tetracalcium phosphate/monetite mixtures under de/remineralization cycling. Dentin de/remineralization cycling protocol consisted of demineralization in 1% citric acid at pH 4.6 with following remineralization with toothpastes and soaking in artificial saliva. Effectiveness of toothpastes to promote remineralization was evaluated by measurement of microhardness recovery, analysis of surface roughness, thickness of coating and scanning electron microscopy. The novel tetracalcium phosphate/monetite dentifrice had comparable remineralization potential as commercial calcium silicate/phosphate (SENSODYNE ® ) and magnesium aluminum silicate (Colgate ® ) toothpastes and significantly higher than control saliva (p<0.02). Surface roughness was significantly lower after treatment with prepared and SENSODYNE ® dentifirice (p<0.05). The coatings on dentin surfaces was significantly thicker after applying toothpastes as compared to negative control (p<0.001). The new fluoride toothpaste formulation with bioactive tetracalcium phosphate/monetite calcium phosphate mixture effectively occluded dentin tubules and showed good dentin remineralization potential under de/remineralization cycling. It could replace professional powder preparation based on this mixture. It was demonstrated that prepared dentifrice had comparable properties with commercial fluoride calcium silicate/phosphate or magnesium aluminum silicate dentifrices. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

[Effect of three aging challenges on the bonding stability of resin-dentin interface using an etch-and-rinse adhesive].

PubMed

Xu, Shuai; Zhang, Ling; Li, Fang; Zhou, Wei; Chen, Yujiang; Chen, Jihua

2014-06-01

To systematically investigate the aging effect of thermocycling, water storage and bacteria aggression on the stability of resin-dentin bonds. Forty molars were sectioned perpendicularly to the axis of the teeth to expose the middle-coronal dentin surfaces. The dentin surfaces were then treated with Single Bond 2 and made a core build-up. According to random digits table, the bonding specimens were divided into four groups (n = 10) as follows: immediate control group, aging group with thermocycling for 5 000 times, aging group with artificial saliva storage for 6 months and aging group with bacteria aggression for 14 days. The specimens in each group were then subjected to microtensile bond strengths (µTBS) testing and nanoleakage evaluation respectively. After aging treatments, the three aging groups showed significantly lower µTBS than the immediate control group [(44.24 ± 12.75) MPa, P < 0.05]. The immediate control group also showed the lowest value of nanoleakage. The µTBS of aging group with bacteria aggression [(25.53 ± 7.39) MPa] was significantly lower than those of the other aging groups with artificial saliva storage[(29.72 ± 6.51) MPa] and thermocycling [(31.92 ± 11.87) MPa, P < 0.05]. There were no differences in the nanoleakage values among the three aging groups (P > 0.05). All the aging treatments with artificial saliva storage, thermocycling and bacteria aggression could accelerate the degradation of bonding interfaces between an etch-and-rinse adhesive and dentin. Bacteria aggression showed the most impairing effect on the stability of resin-dentin bonds.

Variations in collagen fibrils network structure and surface dehydration of acid demineralized intertubular dentin: effect of dentin depth and air-exposure time.

PubMed

Fawzy, Amr S

2010-01-01

The aim was to characterize the variations in the structure and surface dehydration of acid demineralized intertubular dentin collagen network with the variations in dentin depth and time of air-exposure (3, 6, 9 and 12 min). In addition, to study the effect of these variations on the tensile bond strength (TBS) to dentin. Phosphoric acid demineralized superficial and deep dentin specimens were prepared. The structure of the dentin collagen network was characterized by AFM. The surface dehydration was characterized by probing the nano-scale adhesion force (F(ad)) between AFM tip and intertubular dentin surface as a new experimental approach. The TBS to dentin was evaluated using an alcohol-based dentin self-priming adhesive. AFM images revealed a demineralized open collagen network structure in both of superficial and deep dentin at 3 and 6 min of air-exposure. However, at 9 min, superficial dentin showed more collapsed network structure compared to deep dentin that partially preserved the open network structure. Total collapsed structure was found at 12 min for both of superficial and deep dentin. The value of the F(ad) is decreased with increasing the time of air-exposure and is increased with dentin depth at the same time of air-exposure. The TBS was higher for superficial dentin at 3 and 6 min, however, no difference was found at 9 and 12 min. The ability of the demineralized dentin collagen network to resist air-dehydration and to preserve the integrity of open network structure with the increase in air-exposure time is increased with dentin depth. Although superficial dentin achieves higher bond strength values, the difference in the bond strength is decreased by increasing the time of air-exposure. The AFM probed F(ad) showed to be sensitive approach to characterize surface dehydration, however, further researches are recommended regarding the validity of such approach.

Treatment of dentinal tubules by Nd:YAG laser

NASA Astrophysics Data System (ADS)

Chmelíčkova, Hana; Zapletalova, Zdeňka; Peřina, Jan, Jr.; Novotný, Radko; Kubínek, Roman; Stranyánek, Martin

2005-08-01

Symptom of cervical dentine hypersensitivity attacks from 10% to 15% of population and causes an uncomfortable pain during contact with any matter. Sealing of open dentinal tubules is one of the methods to reach insensibility. Laser as a source of coherent radiation is used to melt dentine surface layers. Melted dentine turns to hard mass with a smooth, non-porous surface. Simulation of this therapy was made in vitro by means of LASAG Nd:YAG pulsed laser system KLS 246-102. Eighty human extracted teeth were cut horizontally to obtain samples from 2 mm to 3 mm thick. First experiments were done on cross section surfaces to find an optimal range of laser parameters. A wide range of energies from 30 mJ to 210 mJ embedded in 0,3 ms long pulse was tested. Motion in X and Y axes was ensured by a CNC driven table and the pulse frequency 15 Hz was chosen to have a suitable overlap of laser spots. Some color agents were examined with the aim to improve surface absorption. Scanning Electron Microscopy was used to evaluate all samples and provided optimal values of energies around 50 J.cm-2. Next experiments were done with the beam oriented perpendicularly to a root surface, close to the real situation. Optical fibers with the diameter of 0,6 mm and 0,2 mm were used to guide a laser beam to teeth surfaces. Laser processing heads with lens F = 100 mm and F = 50 mm were used. The best samples were investigated by means of the Atomic Force Microscopy.

Real-Time Binding Kinetic Analyses of the Interaction of the Dietary Stain Orange II with Dentin Matrix.

PubMed

Alraies, Amr; Cole, David K; S Rees, Jeremy; Glasse, Carl; Young, Nigel; Waddington, Rachel J; Sloan, Alastair J

2018-06-09

Dietary stains can be adsorbed into the dentin of teeth. Using Orange II as a model dietary stain, this study investigated the strength of its interaction with the mineral and protein components of dentin matrix and how hydrogen peroxide (H 2 O 2 ) treatment influences this interaction. Dentin slices were prepared from human teeth and were either deproteinized (5.6% sodium hypochlorite, 12 days), demineralised (0.5 M EDTA, 3 days) or left as intact control samples. Samples were stained with Orange II for 1-168 h, during which staining intensity was quantified by image analysis. Similarly, uptake of stain by deproteinized / demineralized samples treated with 10 or 30% H 2 O 2 was investigated. Using surface plasmon resonance technology, real-time binding kinetics were determined assessing the interaction of orange II with the dentin matrix protein constituents, collagen type I, biglycan, decorin, dentin sialoprotein and osteopontin. Deproteinization of dentin matrix reduced the uptake of the orange II compared to the intact control. Conversely, demineralization of dentin samples increased the uptake of the dye. Treatment of samples for 48 h with H 2 O 2 reduced subsequent uptake of the orange II. Real-time kinetic analysis indicated moderate strength of binding for Orange II with collagen type I, weak binding with decorin and biglycan and negligible binding with dentine sialoprotein and osteopontin. These results indicate a predominant role for collagen type I, which accounts for 90% of the organic protein matrix of teeth, for attracting dietary stains. Binding analyses indicate that the interaction is highly dissociable, and further binding is reduced following H 2 O 2 treatment. This study provides new information regarding adsorption of dietary stains into tooth dentin, suggesting that they are attracted and moderately bound to the collagen type I matrix. This study also contributes valuable information for discussion for considering the effect of H 2 O 2 on bleaching teeth and its influence on subsequent uptake of dietary stains following whitening treatments. Copyright © 2018. Published by Elsevier Ltd.

Effect of surface treatment of fiberglass posts on bond strength to root dentin.

PubMed

Valdivia, Andréa Dolores Correia Miranda; Novais, Veridiana Resende; Menezes, Murilo de Sousa; Roscoe, Marina Guimarães; Estrela, Carlos; Soares, Carlos José

2014-01-01

This study evaluated the influence of the surface treatments of fiberglass posts on bond strength to root dentin using push-out test. Forty bovine incisor roots were endodontically treated. The surface of the fiberglass posts (Exacto #2, Angelus) were treated using 4 different protocols (n=10): Control - 70% ethanol for 1 min; 37% phosphoric acid for 1 min; 10% hydrofluoric acid for 1 min; and 24% hydrogen peroxide for 1 min. After a silane coupling agent was applied for 1 min and all posts were cemented using self-adhesive resin cement (RelyX Unicem, 3M-ESPE). The roots were sectioned and two 1-mm-thick slices were obtained from each third: cervical, middle and apical. The specimens were subjected to the push-out test with a crosshead speed of 0.5 mm/min. Data were analyzed by repeated measures ANOVA followed by Tukey's HSD tests (=0.05). The surface treatment (p<0.001) and root third region (p=0.007) factors were significant. The retention to root canal was affected by surface treatment type. The post surface treatment with 24% hydrogen peroxide for 1 min yielded significantly higher bond strength when the fiberglass posts were cemented with RelyX Unicem.

Effects of different lasers on organic/inorganic ratio of radicular dentin.

PubMed

Lopes, F C; Roperto, R; Akkus, A; Akkus, O; Souza-Gabriel, A E; Sousa-Neto, M D

2016-04-01

The aim of this study was to evaluate the chemical stability of endodontic-treated root dentin after different laser irradiations through Raman spectroscopy. Fifty maxillary canines were selected and prepared with K3 system. Roots were randomly distributed into five groups (n = 10) according to the surface treatment: GI (water), GII (NaOCl + EDTA), GIII (NaOCl + EDTA + 980 nm Diode laser), GIV (NaOCl + EDTA+ 1064 nm Nd: YAG laser) and GV (NaOCl + EDTA+ 2780 nm Er,Cr: YSGG laser). Lasers were applied for 20 s. Samples were bisected, and the organic and inorganic content of dentin was analyzed by Raman spectroscopy. Data were submitted to ANOVA and Tukey tests (p < 0.05). None of the surface treatments alter the inorganic content (cts) (p = 0.183). Roots irradiated with Er,Cr: YSGG laser had a reduced collagen content (GV-290.7 ± 41.7) compared with the water-treated roots (GI-328.3 ± 63.5) and those treated with NaOCl + EDTA (GII-333.9 ± 55.8). Roots irradiated with Er,Cr: YSGG laser also showed a higher inorganic/organic ratio (GV-9.5 ± 1.1) than roots treated with water (GI-7.7 ± 1.5), NaOCl + EDTA (GII-8.0 ± 1.4) and diode laser (GIII-8.2 ± 1.6). Both organic and inorganic contents increased from cervical to apical thirds in all groups. None of the surface treatments were able to promote changes in the inorganic content of the root dentin; treatment with NaOCl + EDTA combined with Er,Cr: YSGG altered collagen.

Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm - caries model.

PubMed

Botelho, Juliana Nunes; Villegas-Salinas, Mario; Troncoso-Gajardo, Pía; Giacaman, Rodrigo Andrés; Cury, Jaime Aparecido

2016-05-20

Sucrose is the most cariogenic dietary carbohydrate and starch is considered non-cariogenic for enamel and moderately cariogenic for dentine. However, the cariogenicity of the combination of starch and sucrose remains unclear. The aim of this study was to evaluate the effect of this combination on Streptococcus mutans biofilm composition and enamel and dentine demineralization. Biofilms of S. mutans UA159 were grown on saliva-coated enamel and dentine slabs in culture medium containing 10% saliva. They were exposed (8 times/day) to one of the following treatments: 0.9% NaCl (negative control), 1% starch, 10% sucrose, or 1% starch and 10% sucrose (starch + sucrose). To simulate the effect of human salivary amylase on the starch metabolization, the biofilms were pretreated with saliva before each treatment and saliva was also added to the culture medium. Acidogenicity of the biofilm was estimated by evaluating (2 times/day) the culture medium pH. After 4 (dentine) or 5 (enamel) days of growth, biofilms (n = 9) were individually collected, and the biomass, viable microorganism count, and polysaccharide content were quantified. Dentine and enamel demineralization was assessed by determining the percentage of surface hardness loss. Biofilms exposed to starch + sucrose were more acidogenic and caused higher demineralization (p < 0.0001) on either enamel or dentine than those exposed to each carbohydrate alone. The findings suggest that starch increases the cariogenic potential of sucrose.

[Clinical research of EDTA pretreatment on the bonding strength of resin].

PubMed

Li, Ting-ting; Sun, Min-min; Kang, Jun-tang; Sun, Zhe

2015-10-01

This study was to evaluate clinical results of adhesives to sclerotic dentin in non-carious cervical lesions pretreated with ethylene diamine tetraacetic acid (EDTA). Twelve patients who had at least one pair of teeth with typical cervical wedge-shaped defects and class III sclerotic dentin were selected. The teeth were randomly divided into experimental and control groups. In the experimental group, EDTA was used to pretreat dentin surface first and then self-etching resin adhesive; In the control group, only self-etching resin adhesive was used. Modified USPHS rating system was applied in baseline, 6 months and 12 months after treatment. SAS 8.02 software package was used for two-sample rank sum test. At the time point of 6-month and 12-month, the scores in the experimental group were significantly better than the control group (P<0.05). EDTA pretreatment of the sclerotic dentin of cervical wedge-shaped defects could improve the resin bonding strength, marginal discoloration, marginal form and surface quality.

Assessment of post-contamination treatments affecting different bonding stages to dentin

PubMed Central

Elkassas, Dina; Arafa, Abla

2016-01-01

Objectives: To assess the effect of cleansing treatments following saliva and blood contamination at different bonding stages to dentin. Materials and Methods: Labial surfaces of 168 permanent maxillary central incisors were ground flat exposing superficial dentin. Specimens were divided into: uncontaminated control (A), contamination after etching (B), contamination after adhesive application (C), contamination after adhesive polymerization (D). Groups were further subdivided according to cleansing treatments into: rinsing (B1, C1, D1), re-etching (B2, D3), sodium hypochlorite application (B3), ethyl alcohol application (C2), acetone application (C3), rinsing and rebonding (D2), re-etching and rebonding (D4). Composite microcylinders were bonded to treated substrates and shear loaded micro-shear bond strength (μSBS) until failure and treated surfaces were examined with scanning electron microscope. Debonded surfaces were classified as adhesive, cohesive or mixed failure. The data were analyzed using one-way ANOVA and Tukey's post hoc test. Results: The μSBS values were ranked as follow; Group B: A > B3 > B2 > B1 > B, Group C: A > C3 > C2 > C1 > C, Group D: A > D4 > D1 = D2 ≥ D3. Debonded surfaces showed adhesive failure in Group B while cohesive failure in Groups C and D. Conclusions: Cleansing treatments differ according to bonding step; re-etching then rebonding suggested if etched substrate or polymerized adhesive were contaminated while acetone application decontaminated affected unpolymerized adhesive. PMID:27403048

Dentin pretreatment and adhesive temperature as affecting factors on bond strength of a universal adhesive system.

PubMed

Sutil, Bruna Gabrielle da Silva; Susin, Alexandre Henrique

2017-01-01

To evaluate the effects of dentin pretreatment and temperature on the bond strength of a universal adhesive system to dentin. Ninety-six extracted non-carious human third molars were randomly divided into 12 groups (n=8) according to Scotchbond Universal Adhesive (SbU) applied in self-etch (SE) and etch-and-rinse (ER) mode, adhesive temperature (20°C or 37°C) and sodium bicarbonate or aluminum oxide air abrasion. After composite build up, bonded sticks with cross-sectional area of 1 mm2 were obtained to evaluate the microtensile bond strength (μTBS). The specimens were tested at a crosshead speed of 0.5 mm/min on a testing machine until failure. Fractured specimens were analyzed under stereomicroscope to determine the failure patterns in adhesive, cohesive (dentin or resin) and mixed fractures. The microtensile bond strength data was analyzed using two-way ANOVA and Tukey's test (α=5%). Interaction between treatment and temperature was statistically significant for SbU applied in self-etch technique. Both dentin treatments showed higher bond strength for ER mode, regardless of adhesive temperature. When compared to control group, sodium bicarbonate increased bond strength of SbU in SE technique. Adhesive temperature did not significantly affect the μTBS of tested groups. Predominantly, adhesive failure was observed for all groups. Dentin surface treatment with sodium bicarbonate air abrasion improves bond strength of SbU, irrespective of adhesive application mode, which makes this approach an alternative to increase adhesive performance of Scotchbond Universal Adhesive to dentin.

Dentin pretreatment and adhesive temperature as affecting factors on bond strength of a universal adhesive system

PubMed Central

Sutil, Bruna Gabrielle da Silva; Susin, Alexandre Henrique

2017-01-01

Abstract Objectives: To evaluate the effects of dentin pretreatment and temperature on the bond strength of a universal adhesive system to dentin. Material and Methods: Ninety-six extracted non-carious human third molars were randomly divided into 12 groups (n=8) according to Scotchbond Universal Adhesive (SbU) applied in self-etch (SE) and etch-and-rinse (ER) mode, adhesive temperature (20°C or 37°C) and sodium bicarbonate or aluminum oxide air abrasion. After composite build up, bonded sticks with cross-sectional area of 1 mm2 were obtained to evaluate the microtensile bond strength (μTBS). The specimens were tested at a crosshead speed of 0.5 mm/min on a testing machine until failure. Fractured specimens were analyzed under stereomicroscope to determine the failure patterns in adhesive, cohesive (dentin or resin) and mixed fractures. The microtensile bond strength data was analyzed using two-way ANOVA and Tukey's test (α=5%). Results: Interaction between treatment and temperature was statistically significant for SbU applied in self-etch technique. Both dentin treatments showed higher bond strength for ER mode, regardless of adhesive temperature. When compared to control group, sodium bicarbonate increased bond strength of SbU in SE technique. Adhesive temperature did not significantly affect the μTBS of tested groups. Predominantly, adhesive failure was observed for all groups. Conclusions: Dentin surface treatment with sodium bicarbonate air abrasion improves bond strength of SbU, irrespective of adhesive application mode, which makes this approach an alternative to increase adhesive performance of Scotchbond Universal Adhesive to dentin. PMID:29069151

Effect of ethanol-wet bonding with hydrophobic adhesive on caries-affected dentine.

PubMed

Huang, Xueqing; Li, Li; Huang, Cui; Du, Xijin

2011-08-01

Frequently encountered in clinical practice, caries-affected dentine (CAD) is the most challenging bonding substrate. This study evaluated the effect of ethanol-wet bonding with hydrophobic adhesive to sound dentine and to CAD. In the control groups, prepared sound dentine and CAD were bonded with Adper Single Bond 2 using a traditional water-wet bonding technique. In the experimental groups, the specimens were treated as follows: Group 1, rinsed with stepwise ethanol dehydration; Group 2, immersion in 100% ethanol, three times, for 20 s each time; and Group 3, immersion in 100% ethanol for 20 s. Microtensile bond strength (μTBS) testing was used to evaluate the effects of the different protocols on bonding. The microhardness of debonded dentine surfaces was measured to ensure the presence of CAD. Interfacial nanoleakage was evaluated by field-emission scanning electron microscopy. Treatment significantly improved the μTBS in CAD in Groups 1 and 2, but had no effect on Group 3. Conversely, treatment significantly reduced the μTBS in sound dentine in Groups 2 and 3, but had no effect in Group 1. The presence of nanoleakage varied with the ethanol-wet protocol used. In conclusion, ethanol-wet bonding can potentially improve bond efficacy to CAD when an appropriate protocol is used. © 2011 Eur J Oral Sci.

Effectiveness of plant-derived proanthocyanidins on demineralization on enamel and dentin under artificial cariogenic challenge

PubMed Central

da SILVA, Ana Paula Pereira; GONÇALVES, Rafael Simões; BORGES, Ana Flávia Sanches; BEDRAN-RUSSO, Ana Karina; SHINOHARA, Mirela Sanae

2015-01-01

Dental caries is considered a disease of high prevalence and a constant problem in public health. Proanthocyanidins (PAs) are substances that have been the target of recent studies aiming to control or treat caries. Objective The aim of this in vitro study was to evaluate the efficacy of a treatment with grape seed extract, under cariogenic challenge, to minimize or even prevent the onset of caries in the enamel and dentin. Material and Methods Blocks of enamel and dentin (6.0x6.0 mm) were obtained from bovine central incisors, polished, and selected by analysis of surface microhardness (SH). The blocks were randomly divided into 3 groups (n=15), according to the following treatments: GC (control), GSE (grape seed extract), GF (fluoride – 1,000 ppm). The blocks were subjected to 6 daily pH cycles for 8 days. Within the daily cycling, the specimens were stored in buffered solution. The blocks were then analyzed for perpendicular and surface hardness and polarized light microscopy. Results The means were subjected to statistical analysis using the ANOVA and Fisher’s PLSD tests (p<0.05). For enamel SH, GF showed the highest hardness values. In the dentin, GF was also the one that showed higher hardness values, followed by GSE. Regarding the cross-sectional hardness values, all groups behaved similarly in both the enamel and dentin. The samples that were treated with GSE and fluoride (GF) showed statistically higher values than the control. Conclusion Based on the data obtained in this in vitro study, it is suggested that grape seed extract inhibits demineralization of artificial carious lesions in both the enamel and dentin, but in a different scale in each structure and in a smaller scale when compared to fluoride. PMID:26221925

Effect of handpiece maintenance method on bond strength.

PubMed

Roberts, Howard W; Vandewalle, Kraig S; Charlton, David G; Leonard, Daniel L

2005-01-01

This study evaluated the effect of dental handpiece lubricant on the shear bond strength of three bonding agents to dentin. A lubrication-free handpiece (one that does not require the user to lubricate it) and a handpiece requiring routine lubrication were used in the study. In addition, two different handpiece lubrication methods (automated versus manual application) were also investigated. One hundred and eighty extracted human teeth were ground to expose flat dentin surfaces that were then finished with wet silicon carbide paper. The teeth were randomly divided into 18 groups (n=10). The dentin surface of each specimen was exposed for 30 seconds to water spray from either a lubrication-free handpiece or a lubricated handpiece. Prior to exposure, various lubrication regimens were used on the handpieces that required lubrication. The dentin surfaces were then treated with total-etch, two-step; a self-etch, two-step or a self-etch, one-step bonding agent. Resin composite cylinders were bonded to dentin, the specimens were then thermocycled and tested to failure in shear at seven days. Mean bond strength data were analyzed using Dunnett's multiple comparison test at an 0.05 level of significance. Results indicated that within each of the bonding agents, there were no significant differences in bond strength between the control group and the treatment groups regardless of the type of handpiece or use of routine lubrication.

Influence of ethanol on dentin roughness, surface free energy, and interaction between AH Plus and root dentin.

PubMed

Pantoja, Carlos Augusto de Morais Souto; Silva, Diogo Henrique da; Soares, Adriana de Jesus; Ferraz, Caio Cezar Randi; Gomes, Brenda Paula Figueiredo de Almeida; Zaia, Alexandre Augusto; Almeida, José Flávio Affonso de

2018-01-01

This study aimed to evaluate the influence of different ethanol concentrations on dentin roughness, surface free energy, and contact angle between AH Plus and the root canal dentin. One hundred human maxillary anterior teeth were split longitudinally and 200 dentin specimens were polished to make the surface flatter and smoother. An acrylic bar was positioned between two dentin specimens and impression material was added to create a block, simulating an instrumented root canal space. Specimens were removed from the mold and cleaned in an ultrasonic bath for 10 min. Thereafter, dentin specimens were divided into four groups (n = 50) according to the drying methods used: a) wet: vacuum only, b) paper points: vacuum + absorbent paper points, c) 70% alcohol: 70% alcohol (1 min) + vacuum + absorbent paper points, and d) 100% alcohol: 100% alcohol (1 min) + vacuum + absorbent paper points. A rugosimeter and a goniometer were used to verify the roughness (Ra) and to measure the surface free energy and the contact angle between the AH Plus sealer and the root canal dentin. ANOVA and Tukey tests (α = 0.05) were used for statistical analysis. The 70% and 100% ethanol groups showed significantly decreased roughness as well as increased surface free energy in the root canal dentin when compared to the wet and paper point groups. In addition, ethanol significantly reduced the contact angle between the AH Plus sealer and the root canal dentin. Ethanol solutions (70% and 100%) provide better wettability of AH Plus sealer on dentin surfaces.

The threshold effects of Nd and Ho: YAG laser-induced surface modification on demineralization of dentin surfaces.

PubMed

Kinney, J H; Haupt, D L; Balooch, M; White, J M; Bell, W L; Marshall, S J; Marshall, G W

1996-06-01

Laser irradiation alters the structure of dentin and produces surface layers that give the appearance of being more enamel-like. The laser-modified surface may be more resistant to demineralization; hence, many investigators are proposing continued development of the laser as a possible preventive treatment for caries. The purpose of this study was to explore the morphological changes that occur in dentin when treated at threshold illuminance with two clinically interesting laser wavelengths, and to evaluate the effectiveness of the laser-treated surface at resisting demineralization in an acid-gel solution. The Nd: YAG laser (wavelength 1060 nm) produced significant recrystallization and grain growth of the apatite, without the formation of second phases such as beta-tricalcium phosphate. This recrystallized surface layer showed resistance to demineralization; however, the layer did not provide protection of the underlying dentin from demineralization because of cracks and macroscopic voids that allowed for penetration of the demineralizing gel. The Ho: YAG laser-treated surface (wavelength 2100 nm) did not show significant evidence of recrystallization and grain growth, and only a trace amount of an acid-resistant layer was observed with demineralization. It is speculated that the Ho:YAG laser is coupling with absorbed water, and that the heat transfer from the water to the mineral phase is inefficient. For the purposes of creating a demineralization-resistant layer, threshold illuminance with both Nd: YAG and Ho: YAG was ineffective.

The durability of phosphoric acid promoted bioglass-dentin interaction layer.

PubMed

Bakry, A S; Takahashi, H; Otsuki, M; Tagami, J

2013-04-01

Phosphoric acid-Bioglass 45S5 paste can create an interaction layer formed of calcium-phosphate crystals on the dentin surface. In this study, the efficiency of decreasing the dentin permeability exerted by the interaction layer formed between bioglass and dentin was compared to a resin-containing oxalate desensitizing agent (MS Coat One) and a resin-free oxalate desensitizing agent (Super Seal). Dentin permeability was measured before/after a brushing abrasion challenge, followed by examining the top and the fractured dentin surfaces with a field emission scanning electron microscope. Moreover, the chemical nature of the compounds formed on top of the dentin surface was examined using the field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive X-ray spectroscope (EDS), and the crystalline structures of the dentinal surfaces were examined by X-ray diffraction (XRD). The results showed that application of 45S5 bioglass paste to dentin was able to occlude patent dentinal tubule orifices with a layer of calcium-phosphate crystals, while the oxalate containing agents were able to form small crystals which were found in dentinal tubule orifices and scattered along the superficial parts of the dentinal tubule lumen. The brushing-abrasion challenge significantly increased the permeability of dentin treated by Super Seal and MS Coat One, while these challenges had no significant effect on the dentin permeability of specimens treated with 45S5 bioglass paste. The new technique provided better durability than two products available on the market. Moreover, our previous research showed the biocompatibility of using this technique on dental pulp cells, suggesting that this technique can aid in treating dentin hypersensitivity cases. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The effect of EDTA, EGTA, EDTAC, and tetracycline-HCl with and without subsequent NaOCl treatment on the microhardness of root canal dentin.

PubMed

Sayin, Taner Cem; Serper, Ahmet; Cehreli, Zafer C; Otlu, Harika G

2007-09-01

The purpose of this study was to evaluate the effect of single and combined use of ethylenediamine tetra acetic acid (EDTA), ethylene glycol bis [b-aminoethylether] N,N,N',N'-tetraacetic acid (EGTA), EDTA plus Cetavlon (EDTAC), tetracycline-HCl, and NaOCl on the microhardness of root canal dentin. The crowns of 30 single-rooted human teeth were discarded at the cementoenamel junction and the roots were bisected longitudinally to obtain root halves (N = 60). The specimens were embedded in autopolymerizing acrylic resin, leaving the root canal dentin exposed. Dentin surfaces were prepared for microhardness test by grinding and polishing. The reference microhardness values of untreated specimens were recorded using a Vicker's microhardness tester at the apical, midroot, and cervical levels of the root canal. Thereafter, the specimens treated with single (test solution only) or combined (test solution, followed by 2.5% NaOCl) versions of the irrigants for 5 minutes. Posttreatment microhardness values were obtained as with initial ones. Statistical comparisons between the test groups and among single and combined treatments were carried out using 2-way ANOVA with repeated measures (P =.05). Comparisons within each group with respect to application regions were made with Friedman's nonparametric 2-way analysis of variance at the same level of significance. All treatment regimens except distilled water significantly decreased the microhardness of the root canal dentin (P < . 05). The single and combined use of EDTA decreased the microhardness of the root canal dentin significantly more than all other treatment regimens (P < .05). Compared with their single-treatment versions, all combined treatment regimens decreased the mean microhardness values significantly (P < .05). A comparison of single and combined treatment regimens revealed significant decreases only for EDTA and EDTA + NaOCl in the coronal region and for EDTAC and EDTAC + NaOCl in the apical and middle regions of the root canal (P < .05). The use of EDTA alone or prior to NaOCl resulted in the maximum decrease in dentin microhardness. The softening effect of subsequent NaOCl treatment was both material and region dependent. However, for combined treatment regimens, subsequent use of NaOCl levels the statistical differences between the regional microhardness values obtained after treatment with EGTA, EDTAC, and tetracycline-HCl.

Morphological Analysis of Dentin Surface after Conditioning with Two Different methods: Chemical and Mechanical.

PubMed

Rafael, Caroline Freitas; Quinelato, Valquíria; Morsch, Carolina Schaffer; DeDeus, Gustavo; Reis, Claudia Mendonca

2016-01-01

Alternative pretreatment strategies of dentin and adhesionare constantly being developed and studied with the goal of improving the adhesion of resin restorative materials with this tissue. The objectives of the present study were to evaluate the ability of airborne-particle abrasion (APA) with aluminum oxide on dentin to remove the smear layer and the effects produced on the dentin microstructure. The phosphoric acid (PA) was used for a comparison. For that, 20 human third molars were randomly allocated into two experimental groups, according to the dentin pretreatment method used: G1 (N = 10) - PA, G2 (N = 10) -APA. For dentin surface analyses, an environmental scanning electron microscope (ESEM) was employed to observe dentin surfaces before and after the procedures. Before pretreatment, the specimens of both groups were smear covered. After pretreatment, the G1 images revealed dentin tubule orifices opened, enlarged and some erosive effects. (G2) exposed tubule orifices without enlargement, but crack-like alterations were observed on the surfaces. In this way, APA with aluminum oxide was able to remove the smear layer. The influences of the dentin roughness on adhesion and the consequences on dentin integrity and hardness need further investigations. A good conditioning of the dentin before cementation is necessary in order to obtain a satisfactory rehabilitation in adhesive dentistry. So, it is necessary to know all methods to do it.

Zinc-Containing Restorations Create Amorphous Biogenic Apatite at the Carious Dentin Interface: A X-Ray Diffraction (XRD) Crystal Lattice Analysis.

PubMed

Toledano, Manuel; Aguilera, Fátima S; López-López, Modesto T; Osorio, Estrella; Toledano-Osorio, Manuel; Osorio, Raquel

2016-10-01

The aim of this research was to assess the ability of amalgam restorations to induce amorphous mineral precipitation at the caries-affected dentin substrate. Sound and caries-affected dentin surfaces were subjected to both Zn-free and Zn-containing dental amalgam restorations. Specimens were submitted to thermocycling (100,000 cycles/5°C-55°C, 3 months). Dentin surfaces were studied by atomic force microscopy (nanoroughness), X-ray diffraction, field emission scanning electron microscopy, and energy-dispersive analysis, for physical and morphological surface characterization. Zn-containing amalgam placement reduced crystallinity, crystallite size, and grain size of calcium phosphate crystallites at the dentin surface. Both microstrain and nanoroughness were augmented in caries-affected dentin restored with Zn-containing amalgams. Caries-affected dentin showed the shortest mineral crystallites (11.04 nm), when Zn-containing amalgams were used for restorations, probably leading to a decrease of mechanical properties which might favor crack propagation and deformation. Sound dentin restored with Zn-free amalgams exhibited a substantial increase in length of grain particles (12.44 nm) embedded into dentin crystallites. Zn-containing amalgam placement creates dentin mineralization and the resultant mineral was amorphous in nature. Amorphous calcium phosphate provides a local ion-rich environment, which is considered favorable for in situ generation of prenucleation clusters, promotong further dentin remineralization.

Microtensile bond strength analysis of adhesive systems to Er:YAG and Er,Cr:YSGG laser-treated dentin.

PubMed

Ramos, Thaysa Monteiro; Ramos-Oliveira, Thayanne Monteiro; Moretto, Simone Gonçalves; de Freitas, Patricia Moreira; Esteves-Oliveira, Marcella; de Paula Eduardo, Carlos

2014-03-01

The aim of this in vitro study was to evaluate the effect of different surface treatments (control, diamond bur, erbium-doped yttrium aluminum garnet (Er:YAG) laser, and erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser) on sound dentin surface morphology and on microtensile bond strength (μTBS). Sixteen dentin fragments were randomly divided into four groups (n = 4), and different surface treatments were analyzed by scanning electron microscopy. Ninety-six third molars were randomly divided into eight groups (n = 12) according to type of surface treatment and adhesive system: G1 = Control + Clearfil SE Bond (SE); G2 = Control + Single Bond (SB); G3 = diamond bur (DB) + SE; G4 = DB + SB, G5 = Er:YAG laser (2.94 μm, 60 mJ, 2 Hz, 0.12 W, 19.3 J/cm(2)) + SE; G6 = Er:YAG + SB, G7 = Er,Cr:YSGG laser (2.78 μm, 50 mJ, 30 Hz, 1.5 W, 4.5 J/cm(2)) + SE; and G8 = Er,Cr:YSGG + SB. Composite blocks were bonded to the samples, and after 24-h storage in distilled/deionized water (37 °C), stick-shaped samples were obtained and submitted to μTBS test. Bond strength values (in megapascal) were analyzed by two-way ANOVA and Tukey tests (α = 0.05). G1 (54.69 ± 7.8 MPa) showed the highest mean, which was statistically significantly higher than all the other groups (p < 0.05). For all treatments, SE showed higher bond strength than SB, except only for Er,Cr:YSGG treatment, in which the systems did not differ statistically from each other. Based on the irradiation parameters considered in this study, it can be concluded that Er:YAG and Er,Cr:YSGG irradiation presented lower values than the control group; however, their association with self-etching adhesive does not have a significantly negative effect on sound dentin (μTBS values of >20 MPa).

Effect of Different Protocols in Preconditioning With EDTA in Sclerotic Dentin and Enamel Before Universal Adhesives Applied in Self-etch Mode.

PubMed

Martini, E C; Parreiras, S O; Gutierrez, M F; Loguercio, A D; Reis, A

The aim of this study was to investigate the effect of different protocols of 17% ethylene diamine tetra-acetic acid (EDTA) conditioning on the etching pattern and immediate bond strength of universal adhesives to enamel and sclerotic dentin. Forty bovine teeth with sclerotic dentin and 20 human third molars were randomly divided into eight groups resulting from the combination of the main factors surface treatment (none, two-minute EDTA conditioning manual application, 30-second EDTA manual application, 30-second EDTA sonic application) and adhesives systems (Scotchbond Universal Adhesive [SBU] and Prime & Bond Elect [PBE]). Resin-dentin and enamel-dentin bond specimens were prepared and tested under the microtensile bond strength (μTBS) and microshear bond strength (μSBS) tests, respectively. The etching pattern produced on the unground enamel and the sclerotic dentin surfaces under the different protocols and adhesive systems was evaluated under scanning electron microscopy. For enamel, only the main factor adhesive was significant (p<0.0001), with SBU showing the highest μSBS. In sclerotic dentin, the lowest mean was observed for the group without EDTA application and the highest mean in the group with EDTA application with the sonic device for 30 seconds. Regardless of the EDTA protocol, the highest means of μTBS were observed for SBU (p<0.05). EDTA conditioning improves the bonding performance of universal adhesives in the self-etch mode on sclerotic dentin, mainly when applied for 30 seconds with the aid of a sonic device. EDTA pretreatment also improves the retentive etching pattern of enamel, but it does not result in higher enamel bond strength.

Ozone Gas Effect on Mineral Content of Dentin exposed to Streptococcus mutans Biofilm: An Energy-dispersive X-ray Evaluation.

PubMed

Chaves, Rafaella M; Estrela, Carlos; Cardoso, Paula C; de Je Barata, Terezinha; de Souza, João B; de Torres, Érica M; Estrela, Cyntia Ra; Magalhães, Ana Pr; Lopes, Lawrence G

2017-04-01

This study aims to assess the effect of ozone gas on dentin exposed to Streptococcus mutans biofilm by evaluation of mineral content [log calcium-to-phosphorus (Ca/P)] using energy-dispersive X-ray (EDX) spectroscopy. Five human third molars were sectioned into four slices of dentin and distributed in four groups: I - control (no treatment); II - ozone therapy; III - biofilm development; IV - ozone therapy followed by biofilm development. Mineral content (log Ca/P) was evaluated by EDX. Data were analyzed by analysis of variance and Tukey's test (p < 0.05). Results showed that the mineral content of control group (I) was similar to ozone group (II), and was statistically higher than biofilm (III) and ozone + biofilm (IV). The lowest log Ca/P was determined in biofilm group (III). It can be concluded that ozone gas did not grant preventive effects of demineralization by S. mutans biofilm on dentin surface. Ozone gas therapy may be an alternative noninvasive treatment aiming to reduce the levels of caries-associated microorganisms. This therapy may, thereby, be an alternative and/or complementary treatment strategy in preventive dentistry.

[Effect of nano-silica coating on bonding strength of zirconia ceramics to dentin].

PubMed

Zhang, Xian-Fang; Zheng, Hu; Han, Dong-Wei

2009-04-01

To investigate the effect of silica coating by sol-gel process on bonding strength of zirconia ceramics to dentin. Blocks of sintered zirconia ceramics were cut and randomly divided into 4 groups,16 slices in each group. Each group was subject to one of the 4 kinds of surface treatment (control group, sandblasting, sandblasting +silicone, sandblasting + silica coating + silicone) and then bonded to dentin with resin cement. After preservation in 37 degrees centigrade distilled water for 24 hours, the shear bonding strength of these specimens was tested and the data was analyzed with SAS6.12 software package for analysis of variance. The surface modality of the ceramics was observed under scanning electron microscopy (SEM). The group of sandblasting+ silica coating + silicone attained the highest shear bonding strength, which was significantly different from the other groups(P=0.000);There was no significant difference between the sandblasting and sandblasting + silicone group (P=0.827), which was significantly different from the control group(P=0.001). Silica coating by sol-gel process, coupled with silicone, can significantly increase the bonding strength of zirconia ceramics to dentin.

Investigation of biomineralization by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Fatscher, Robert William

Biomineralization is a process in which living organism grow composite materials consisting of inorganic and organic materials. This produces a composite material consisting of both inorganic and organic components, with superior mechanical properties. In the human body bone and dentin are both examples of biominerals. In this research Raman spectroscopy was used to characterize dentin from mice and human teeth, to determine composition. In the mouse tooth samples areas of irregular dentin were found, along the inside of the tooth, to be in the process of mineralization. By analyzing the samples along these areas we were able to determine the composition of dentin and track how it changed in these area. By analysis of the mineral to matrix ratio the areas of irregular dentin were determined to have less mineral present. Observations of other organic components and collagen in increased concentrations in this area suggested these area were in the process of biomineralization. The understanding of the structure of dentin and its biomineralization process is of crucial importance when trying reproduce dentin. Scientists and engineers are able to produce dentin minerals in vitro by culturing various dental stem cells. The ability to create dentin mineral from cells could lead to methods of repairing dentin in patients, or even lead to the creation of a completely engineered tooth. While dentin-like materials can be produced in a laboratory environment, analysis and comparison of the composition of these materials must be performed to ensure the mineral produced is consistent with dentin. Mineralized nodules from six different dental stem cell lines were cultured to produce a mineralized deposit. Utilizing Raman spectroscopy, we were able to determine cell source dependent differences in a variety of dental stem cells, and compare the mineral produced to native dentin. Orthopedic implants are implants used to replace damaged bone, examples include knee, hip and dental implants. These implants are designed to osteointegrate with the native healthy tissues in order to create a functionally stable and structural interface. Biomaterials such as hydroxyapatite and titania are known to increase the rate of bone regeneration in vivo.1 By accelerating the early response of bone forming cells to these implants, better fixation is achieved between the implant and the bone, shortening recovery times and increasing the viability of these implants. In the last part of this research an investigation of osteoblasts cultured at 14 days on five different heat-treated titania substrates was investigated by Raman spectroscopy, in order to observe the initial cellular response to the titania substrates. The heat-treatment of titania changes the amount of oxygen on it's surface which in turn effects the surface energy. A change in the surface energy of a material will affect the cellular response, by culturing cells on various heat-treated titania substrates a relationship between the surface energy and cellular response can be investigated. A faster cellular response would lead to an increased rate of bone regeneration shortening healing times and allowing for better fixation of the implant.

Nondestructive assessment of dentin demineralization using polarization sensitive optical coherence tomography after exposure to fluoride and laser irradiation

PubMed Central

Manesh, Saman K.; Darling, Cynthia L.; Fried, Daniel

2009-01-01

Previous studies have demonstrated that polarization sensitive optical coherence tomography (PS-OCT) can be used to image natural and artificial caries in dentin. The purpose of this study was to measure non-destructively the severity of artificial caries lesions in dentin and determine the efficacy of intervention with anti-caries agents including fluoride and lasers. Although several studies have assessed the utility of PS-OCT to image caries lesions in enamel and to quantify the lesion severity, only a few studies have focused on lesions in dentin. In this study images of artificial dentin lesions on extracted human teeth were acquired with PS-OCT. Before exposure to an artificial demineralizing solution, three incisions were made on the sample surfaces using either Er:YAG, Nd:YAG (λ=355-nm), or TEA CO2 lasers and selected areas were treated with topical fluoride to create six unique treatment areas for each of the three laser conditions investigated. The integrated reflectivity and depth of demineralization were calculated for each of the six areas on each sample using the PS-OCT images. Polarized light microscopy (PLM) and transverse microradiography (TMR) were used to measure lesion severity on histological thin sections for comparison. PS-OCT successfully measured the inhibition of demineralization by topical fluoride. Laser irradiation was not particularly effective in increasing or decreasing the rate of dentin demineralization. PLM and TMR corroborated those results. This study demonstrates that PS-OCT can be used to measure demineralization on dentin surfaces and determine the degree of inhibition of demineralization by anti-caries agents. PMID:19283826

Enamel and dentin bond strength following gaseous ozone application.

PubMed

Cadenaro, Milena; Delise, Chiara; Antoniollo, Francesca; Navarra, Ottavia Chiara; Di Lenarda, Roberto; Breschi, Lorenzo

2009-08-01

To evaluate the effects of gaseous ozone application on enamel and dentin bond strength produced by two self-etching adhesive systems. The shear bond strength test was conducted to assess adhesion on enamel (protocol 1), while the microtensile bond strength test was performed on dentin (protocol 2). Protocol 1: 96 bovine incisors were randomly divided into 4 groups, and enamel surfaces were bonded in accordance with the following treatments: (1E) ozone + Clearfil Protect Bond; (2E) Clearfil Protect Bond (control); (3E) ozone + Xeno III; (4E) Xeno III (control). Ozone gas was applied for 80 s. Shear bond strength was measured with a universal testing machine. Protocol 2: 40 noncarious human molars were selected. Middle/deep dentin was exposed and bonded in accordance with the following treatments: (1D) ozone+Clearfil Protect Bond; (2D) Clearfil Protect Bond (control); (3D) ozone+Xeno III (4D) Xeno III (control). Four-mm-thick buildups were built on the adhesives, then specimens were sectioned in accordance with the nontrimming technique. Specimens were stressed until failure occurred, and failure modes were analyzed. Shear bond and microtensile bond strength data were analyzed using two-way ANOVA and Tukey's post-hoc test. No statistical differences were found between ozone treated specimens and controls, neither on enamel nor on dentin irrespective of the tested adhesive. Clearfil Protect Bond showed higher bond strength to enamel than Xeno III, irrespective of the ozone treatment (p < 0.05). The use of ozone gas to disinfect the cavity before placing a restoration had no influence on immediate enamel and dentin bond strength.

Multiscale characterization of partially demineralized superficial and deep dentin surfaces.

PubMed

Pelin, Irina M; Trunfio-Sfarghiu, Ana-Maria; Farge, Pierre; Piednoir, Agnes; Pirat, Christophe; Ramos, Stella M M

2013-08-01

The objective of this study was to address the following question: 'Which properties are modified in partially demineralized surfaces, compared with non-demineralized dentin surfaces, following orthophosphoric acid-etching as performed in clinical procedures?'. For this purpose, the complementary techniques atomic force microscopy/spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements were used to provide a multiscale characterization of the dentin substrate undergoing the acidic preconditioning designed to enhance wetting. Special attention was given to the influence of the etching pretreatment on the nanomechanical properties at different levels of dentin surfaces, in both dry and hydrated conditions. The four-sided pyramid model (extended Hertz contact model) proved to be accurate for calculating the apparent Young's modulus, offering new information on the elasticity of dentin. The modulus value notably decreased following etching and surface hydration. This study underlines that after the acid etching pretreatment the contribution of the nanomechanical, morphological, and physicochemical modifications has a strong influence on the dentin adhesion properties and thus plays a significant role in the coupling of the adhesive-resin composite build-up material at the dentin surface. © 2013 Eur J Oral Sci.

Qualitative comparison of sonic or laser energisation of 4% sodium hypochlorite on an Enterococcus faecalis biofilm grown in vitro.

PubMed

Seet, Aaron N; Zilm, Peter S; Gully, Neville J; Cathro, Peter R

2012-12-01

The effectiveness of sonic activation, laser activation and syringe irrigation of 4% sodium hypochlorite in removing an Enterococcus faecalis biofilm was compared. Biofilms were grown in extracted human single rooted teeth using a flow cell apparatus. After 4 weeks' growth, teeth were subjected to each treatment using 4% sodium hypochlorite and radicular dentinal surfaces of the root canals were analysed by scanning electron microscopy. Results showed that sonic activation and syringe irrigation with sodium hypochlorite showed reduced numbers of bacterial cells on the radicular dentine but were not effective in eliminating E. faecalis in the dentinal tubules. Laser activation of sodium hypochlorite resulted in clean dentine walls and undetectable levels of bacteria within dentinal tubules. Qualitatively, sonic or laser activation of 4% NaOCl resulted in greater bacterial reduction compared with syringe irrigation, with laser activation producing the greatest overall reduction. © 2012 The Authors. Australian Endodontic Journal © 2012 Australian Society of Endodontology.

Influence of temporary cement contamination on the surface free energy and dentine bond strength of self-adhesive cements.

PubMed

Takimoto, Masayuki; Ishii, Ryo; Iino, Masayoshi; Shimizu, Yusuke; Tsujimoto, Akimasa; Takamizawa, Toshiki; Ando, Susumu; Miyazaki, Masashi

2012-02-01

The surface free energy and dentine bond strength of self-adhesive cements were examined after the removal of temporary cements. The labial dentine surfaces of bovine mandibular incisors were wet ground with #600-grit SiC paper. Acrylic resin blocks were luted to the prepared dentine surfaces using HY Bond Temporary Cement Hard (HY), IP Temp Cement (IP), Fuji TEMP (FT) or Freegenol Temporary Cement (TC), and stored for 1 week. After removal of the temporary cements with an ultrasonic tip, the contact angle values of five specimens per test group were determined for the three test liquids, and the surface-energy parameters of the dentine surfaces were calculated. The dentine bond strengths of the self-adhesive cements were measured after removal of the temporary cements in a shear mode at a crosshead speed of 1.0mm/min. The data were subjected to one-way analysis of variance (ANOVA) followed by Tukey's HSD test. For all surfaces, the value of the estimated surface tension component γ(S)(d) (dispersion) was relatively constant at 41.7-43.3 mJm(-2). After removal of the temporary cements, the value of the γ(S)(h) (hydrogen-bonding) component decreased, particularly with FT and TC. The dentine bond strength of the self-adhesive cements was significantly higher for those without temporary cement contamination (8.2-10.6 MPa) than for those with temporary cement contamination (4.3-7.1 MPa). The γ(S) values decreased due to the decrease of γ(S)(h) values for the temporary cement-contaminated dentine. Contamination with temporary cements led to lower dentine bond strength. The presence of temporary cement interferes with the bonding performance of self-adhesive cements to dentine. Care should be taken in the methods of removal of temporary cement when using self-adhesive cements. Copyright © 2011 Elsevier Ltd. All rights reserved.

The shear bond strength of self-adhesive resin cements to dentin and enamel: an in vitro study.

PubMed

Rodrigues, Raphaela F; Ramos, Carla M; Francisconi, Paulo A S; Borges, Ana Flávia S

2015-03-01

Clinicians continue to search for ways to simplify bonding procedures without compromising clinical efficacy. The purpose of this study was to evaluate the shear strength of self-adhesive cements RelyX U100 and RelyX U200, and conventional resin cement RelyX ARC to enamel and dentin after different surface treatments. The crowns of 120 bovine incisor teeth were separated from the roots and embedded in epoxy resin in polyvinyl chloride tubes. In each tooth, the area to be cemented was delimited with central holed adhesive tape. The teeth were distributed into 12 groups (n=10) according to the substrate; etched or not with 37% phosphoric acid; and cement type of enamel-U100, enamel-phosphoric acid-U100, enamel-U200, enamel-phosphoric acid-U200, enamel-ARC, enamel-phosphoric acid-ARC, dentin-U100, dentin-phosphoric acid-U100, dentin-U200, dentin-phosphoric acid-U200, dentin-ARC, and dentin-phosphoric acid-ARC. After 7 days of storage in artificial saliva, shear strength tests were performed by using a universal testing machine (0.5 mm/min). The data were analyzed with 3-way ANOVA and the Tukey test (α=.05). Fracture analysis was performed with a light microscope. Two specimens from each group were analyzed with a scanning electron microscope. In enamel, ARC (9.96 MPa) had higher shear strength (P=.038) than U100 (5.14 MPa); however, after surface etching, U100 (17.81 MPa) and U200 (17.52 MPa) had higher shear strength (P<.001). With dentin, no significant differences were observed (P=.999), except for dentin-ARC (0.34 MPa) (P=.001). Most fractures were of the adhesive type. U200 self-adhesive cement had similar bond strength to the ARC in enamel, but the combination with phosphoric acid had the best bond strength. For dentin, self-adhesive resin cements are equally effective alternatives to conventional resin cement. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effect of Dentin Wetness on the Bond Strength of Universal Adhesives.

PubMed

Choi, An-Na; Lee, Ji-Hye; Son, Sung-Ae; Jung, Kyoung-Hwa; Kwon, Yong Hoon; Park, Jeong-Kil

2017-10-25

The effects of dentin wetness on the bond strength and adhesive interface morphology of universal adhesives have been investigated using micro-tensile bond strength (μTBS) testing and confocal laser scanning microscopy (CLSM). Seventy-two human third molars were wet ground to expose flat dentin surfaces. They were divided into three groups according to the air-drying time of the dentin surfaces: 0 (without air drying), 5, and 10 s. The dentin surfaces were then treated with three universal adhesives: G-Premio Bond, Single Bond Universal, and All-Bond Universal in self-etch or etch-and-rinse mode. After composite build up, a μTBS test was performed. One additional tooth was prepared for each group by staining the adhesives with 0.01 wt % of Rhodamine B fluorescent dye for CLSM analysis. The data were analyzed statistically using ANOVA and Tukey's post hoc tests (α = 0.05). Two-way ANOVA showed significant differences among the adhesive systems and dentin moisture conditions. An interaction effect was also observed ( p < 0.05). One-way ANOVA showed that All-Bond Universal was the only material influenced by the wetness of the dentin surfaces. Wetness of the dentin surface is a factor influencing the micro-tensile bond strength of universal adhesives.

Effect of Dentin Wetness on the Bond Strength of Universal Adhesives

PubMed Central

Lee, Ji-Hye; Son, Sung-Ae; Jung, Kyoung-Hwa; Kwon, Yong Hoon

2017-01-01

The effects of dentin wetness on the bond strength and adhesive interface morphology of universal adhesives have been investigated using micro-tensile bond strength (μTBS) testing and confocal laser scanning microscopy (CLSM). Seventy-two human third molars were wet ground to expose flat dentin surfaces. They were divided into three groups according to the air-drying time of the dentin surfaces: 0 (without air drying), 5, and 10 s. The dentin surfaces were then treated with three universal adhesives: G-Premio Bond, Single Bond Universal, and All-Bond Universal in self-etch or etch-and-rinse mode. After composite build up, a μTBS test was performed. One additional tooth was prepared for each group by staining the adhesives with 0.01 wt % of Rhodamine B fluorescent dye for CLSM analysis. The data were analyzed statistically using ANOVA and Tukey’s post hoc tests (α = 0.05). Two-way ANOVA showed significant differences among the adhesive systems and dentin moisture conditions. An interaction effect was also observed (p < 0.05). One-way ANOVA showed that All-Bond Universal was the only material influenced by the wetness of the dentin surfaces. Wetness of the dentin surface is a factor influencing the micro-tensile bond strength of universal adhesives. PMID:29068404

Comparative Evaluation of the Etching Pattern of Er,Cr:YSGG & Acid Etching on Extracted Human Teeth-An ESEM Analysis

PubMed Central

Mazumdar, Dibyendu; Ranjan, Shashi; Krishna, Naveen Kumar; Kole, Ravindra; Singh, Priyankar; Lakiang, Deirimika; Jayam, Chiranjeevi

2016-01-01

Introduction Etching of enamel and dentin surfaces increases the surface area of the substrate for better bonding of the tooth colored restorative materials. Acid etching is the most commonly used method. Recently, hard tissue lasers have been used for this purpose. Aim The aim of the present study was to evaluate and compare the etching pattern of Er,Cr:YSGG and conventional etching on extracted human enamel and dentin specimens. Materials and Methods Total 40 extracted non-diseased teeth were selected, 20 anterior and 20 posterior teeth each for enamel and dentin specimens respectively. The sectioned samples were polished by 400 grit Silicon Carbide (SiC) paper to a thickness of 1.0 ± 0.5 mm. The enamel and dentin specimens were grouped as: GrE1 & GrD1 as control specimens, GrE2 & GrD2 were acid etched and GrE3 & GrD3 were lased. Acid etching was done using Conditioner 36 (37 % phosphoric acid) according to manufacturer instructions. Laser etching was done using Er,Cr:YSGG (Erbium, Chromium : Ytrium Scandium Gallium Garnet) at power settings of 3W, air 70% and water 20%. After surface treatment with assigned agents the specimens were analyzed under ESEM (Environmental Scanning Electron Microscope) at X1000 and X5000 magnification. Results Chi Square and Student “t” statistical analysis was used to compare smear layer removal and etching patterns between GrE2-GrE3. GrD2 and GrD3 were compared for smear layer removal and diameter of dentinal tubule opening using the same statistical analysis. Chi-square test for removal of smear layer in any of the treated surfaces i.e., GrE2-E3 and GrD2-D3 did not differ significantly (p>0.05). While GrE2 showed predominantly type I etching pattern (Chi-square=2.78, 0.05

0.10) and GrE3 showed type III etching (Chi-square=4.50, p<0.05). The tubule diameters were measured using GSA (Gesellschaft fur Softwareentwicklung und Analytik, Germany) image analyzer and the ‘t’ value of student ‘t’ test was 18.10 which was a highly significant result (p<.001). GrD2 had a mean dentinal tubule diameter of 2.78μm and GrD3 of 1.09μm. Conclusion The present study revealed type I etching pattern after acid etching, while type III etching pattern in enamel after laser etching. The lased dentin showed preferential removal of intertubular dentin while acid etching had more effect on the peritubular dentin. No significant differences was observed in removal of smear layer between the acid etched and lased groups. Although diameter of the exposed dentinal tubules was lesser after lased treatment in comparison to acid etching, further long term in vivo studies are needed with different parameters to establish the usage of Er,Cr:YSGG as a sole etching agent. PMID:27437337

Primum non nocere - The effects of sodium hypochlorite on dentin as used in endodontics.

PubMed

Gu, Li-Sha; Huang, Xue-Qing; Griffin, Brandon; Bergeron, Brian R; Pashley, David H; Niu, Li-Na; Tay, Franklin R

2017-10-01

The medical literature is replete with the maxim 'primum non nocere', cautioning health care providers to avoid doing any harm to human subjects in their delivery of medical care. Sodium hypochlorite (NaOCl) is a well-established irrigant for root canal treatment because of its antimicrobial and organic tissue remnant dissolution capability. However, little is known about the deleterious effect of this strong oxidizing agent on the integrity of human mineralized dentin. Iatrogenically-induced loss of dentin integrity may precipitate post-treatment root fracture and has potential medico-legal complications. In the present work, transmission electron microscopy provided evidence for collagen destruction in the surface/subsurface of dentin treated with high NaOCl concentrations and long contact times. Size exclusion chromatography showed that the hypochlorite anion, because of its small size, penetrated the water compartments of apatite-encapsulated collagen fibrils, degraded the collagen molecules and produced a 25-35µm thick, non-uniform "ghost mineral layer" with enlarged, coalesced dentinal tubules and their lateral branches. Fourier transform-infrared spectroscopy identified increases in apatite/collagen ratio in NaOCl-treated dentin. The apatite-rich, collagen-sparse dentin matrix that remained after NaOCl treatment is more brittle, as shown by the reductions in flexural strength. Understanding the deleterious effects of NaOCl on mineralized dentin enables one to balance the risks and benefits in using high NaOCl concentrations for lengthy periods in root canal debridement. Delineating the mechanism responsible for such a phenomenon enables high molecular weight, polymeric antimicrobial and tissue dissolution irrigants to be designed that abides by the maxim of 'primum non nocere' in contemporary medical practices. The antimicrobial and tissue-dissolution capacities of NaOCl render it a well-accepted agent for root canal debridement. These highly desirable properties, however, appear to be intertwined with the untoward effect of collagen matrix degradation within mineralized dentin. Because of its small size, the hypochlorite anion is capable of infiltrating mineralized collagen and destroying the collagen fibrils, producing a mineral-rich, collagen sparse ghost mineral matrix with reduced flexural strength. Findings from the present work challenge the biosafety of NaOCl when it is used in high concentrations and for lengthy time periods during root canal treatment, and laid the background work for future biomaterials design in debridement of the canal space. Published by Elsevier Ltd.

Influence of handpiece maintenance sprays on resin bonding to dentin.

PubMed

Sugawara, Toyotarou; Kameyama, Atsushi; Haruyama, Akiko; Oishi, Takumi; Kukidome, Nobuyuki; Takase, Yasuaki; Tsunoda, Masatake

2010-01-01

To investigate the influence of maintenance spray on resin bonding to dentin. The crown of extracted, caries-free human molars was transversally sectioned with a model trimmer to prepare the dentin surfaces from mid-coronal sound dentin, and then uniformly abraded with #600 silicon carbide paper. The dentin surfaces were randomly divided into three groups: oil-free spray group where maintenance cleaner for air bearing handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; oil-containing spray group where maintenance cleaner for micro motor handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; and control group where the surface was rinsed with water spray for 30 s and then air-dried. These surfaces were then bonded with Clearfil SE Bond (Kuraray Medical), and resin composite (Clearfil AP-X, Kuraray Medical) build-up crowns were incrementally constructed on the bonded surfaces. After storage for 24 h in 37°C water, the bonded teeth were sectioned into hour-glass shaped slices (0.7-mm thick) perpendicular to the bonded surfaces. The specimens were then subjected to microtensile bond strength (μTBS) testing at a crosshead speed of 1.0 mm/min. Data were analyzed with one-way ANOVA and the Tukey-Kramer test. Maintenance spray-contaminated specimens (oil-free and oil-containing spray groups) showed significantly lower μTBS than control specimens (P < 0.05). However, there was no significant difference between the spray-contaminated groups (P > 0.05). Maintenance spray significantly reduces the bond strength of Clearfil SE Bond to dentin.

The Effects of CO2 Laser with or without Nanohydroxyapatite Paste in the Occlusion of Dentinal Tubules

PubMed Central

Al-maliky, Mohammed Abbood; Mahmood, Ali Shukur; Al-karadaghi, Tamara Sardar; Kurzmann, Christoph; Laky, Markus; Franz, Alexander; Moritz, Andreas

2014-01-01

The aim of this study was to evaluate a new treatment modality for the occlusion of dentinal tubules (DTs) via the combination of 10.6 µm carbon dioxide (CO2) laser and nanoparticle hydroxyapatite paste (n-HAp). Forty-six sound human molars were used in the current experiment. Ten of the molars were used to assess the temperature elevation during lasing. Thirty were evaluated for dentinal permeability test, subdivided into 3 groups: the control group (C), laser only (L−), and laser plus n-HAp (L+). Six samples, two per group, were used for surface and cross section morphology, evaluated through scanning electron microscope (SEM). The temperature measurement results showed that the maximum temperature increase was 3.2°C. Morphologically groups (L−) and (L+) presented narrower DTs, and almost a complete occlusion of the dentinal tubules for group (L+) was found. The Kruskal-Wallis nonparametric test for permeability test data showed statistical differences between the groups (P < 0.05). For intergroup comparison all groups were statistically different from each other, with group (L+) showing significant less dye penetration than the control group. We concluded that CO2 laser in moderate power density combined with n-HAp seems to be a good treatment modality for reducing the permeability of dentin. PMID:25386616

Effect of Collagen Matrix Saturation on the Surface Free Energy of Dentin using Different Agents.

PubMed

de Almeida, Leopoldina de Fátima Dantas; Souza, Samilly Evangelista; Sampaio, Aline Araújo; Cavalcanti, Yuri Wanderley; da Silva, Wander José; Del Bel Cur, Altair A; Hebling, Josimeri

2015-07-01

The surface free energy of conditioned-dentin is one of the factors that interfere with monomeric infiltration of the interfibrillar spaces. Saturation of the tooth matrix with different substances may modulate this energy and, consequently, the wettability of the dentin. To evaluate the influence of different substances used to saturate conditioned-dentin on surface free energy (SFE) of this substrate. Dentin blocks (4 × 7 × 1 mm, n = 6/ group), obtained from the roots of bovine incisors, were etched using phosphoric acid for 15 seconds, rinsed and gently dried. The surfaces were treated for 60 seconds with: ultra-purified water (H20-control); ethanol (EtOH), acetone (ACT), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA); or sodium hypochlorite (NaOCl). The tooth surfaces were once again dried with absorbent paper and prepared for SFE evaluation using three standards: water, formamide and bromonaphthalene. Analysis of variance (ANOVA) and Dunnet's tests (a = 0.05) were applied to the data. Ethylenediaminetetraacetic acid was the only substance that caused a change to the contact angle for the standards water and formamide, while only EtOH influenced the angles formed between formamide and the dentin surface. None of the substances exerted a significant effect for bromonaphtha-lene. In comparison to the control, only EDTA and NaOCl altered both polar components of the SFE. Total SFE was increased by saturation of the collagen matrix by EDTA and reduced when NaOCl was used. Saturation of the collagen matrix by EDTA and EtOH changed the surface free energy of the dentin. In addition, the use of NaOCl negatively interfered with the properties evaluated. The increase of surface free energy and wettability of the dentin surface would allow higher penetration of the the adhesive system, which would be of importance to the clinical success of resin-dentin union.

Potential role of surface wettability on the long-term stability of dentin bonds after surface biomodification

PubMed Central

Leme, Ariene A.; Vidal, Cristina M. P.; Hassan, Lina Saleh; Bedran-Russo, Ana K.

2015-01-01

Degradation of the adhesive interface contributes to the failure of resin composite restorations. The hydrophilicity of the dentin matrix during and after bonding procedures may result in an adhesive interface that is more prone to degradation over time. This study assessed the effect of chemical modification of dentin matrix on the wettability and the long-term reduced modulus of elasticity (Er) of the adhesive interfaces. Human molars were divided into groups according to the priming solutions: distilled water (control), 6.5% Proanthocyanidin-rich grape seed extract (PACs), 5.75% 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/1.4% n-hydroxysuccinimide (EDC/NHS) and 5% Glutaraldehyde (GA). The water-surface contact angle was verified before and after chemical modification of the dentin matrix. The demineralized dentin surface was treated with the priming solutions and restored with One Step Plus (OS) and Single Bond Plus (SB) and resin composite. The Er of the adhesive, hybrid layer and underlying dentin was evaluated after 24 h and 30 months in artificial saliva. The dentin hydrophilicity significantly decreased after application of the priming solutions. Aging significantly decreased the Er in the hybrid layer and underlying dentin of control groups. The Er of GA groups remained stable over time at the hybrid layer and underlying dentin. Significant higher Er was observed for PACs and EDC/NHS groups at the hybrid layer after 24 h. The decreased hydrophilicity of the modified dentin matrix likely influence the immediate mechanical properties of the hybrid layer. Dentin biomodification prevented substantial aging at the hybrid layer and underlying dentin after 30 months storage. PMID:25869721

Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

PubMed Central

Dalby, Robert; Ellakwa, Ayman; Millar, Brian; Martin, F. Elizabeth

2012-01-01

Objectives. To examine the effect of immediate dentin sealing (IDS), with dentin bonding agents (DBAs) applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU) cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E) of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go!) that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic) luted to the sealed dentin surface using RXU. Group E (control) had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent) using RXU following the manufacturer's instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (P < 0.05) applied for multiple paired comparisons. Results. The shear bond strength results for group A to E ranged from 6.94 ± 1.53 to 10.03 ± 3.50 MPa. One-way ANOVA demonstrated a difference (P < 0.05) between the groups tested and the Tukey HSD demonstrated a significant (P < 0.05) difference between the shear bond strength (SBS) of Optibond FL (Group A) and Go! (Group D). There was no statistical difference (P > 0.05) in the SBS between the test groups (A–D) or the control (group E). Conclusion. IDS using the dentin bonding agents tested does not statistically (P > 0.05) affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control. PMID:22287963

Influence of previous acid etching on bond strength of universal adhesives to enamel and dentin.

PubMed

Torres, Carlos Rocha Gomes; Zanatta, Rayssa Ferreira; Silva, Tatiane Josefa; Huhtala, Maria Filomena Rocha Lima; Borges, Alessandra Bühler

2017-01-01

The objective of this study was to evaluate the effect of acid pretreatment on the bond strength of composite resin bonded to enamel and dentin with 2 different universal self-etching adhesives. The null hypothesis was that the acid treatment performed prior to adhesive application would not significantly change the bond strength to enamel or dentin for either universal adhesive tested. A sample of 112 bovine incisors were selected and embedded in acrylic resin. Half were ground until a flat enamel surface was obtained, and the other half were polished until a 6 × 6-mm area of dentin was exposed, resulting into 2 groups (n = 56). The enamel and dentin groups were divided into 2 subgroups according to the adhesive system applied: Futurabond U or Scotchbond Universal. Each of these subgroups was divided into 2 additional subgroups (n = 14); 1 subgroup received phosphoric acid pretreatment, and 1 subgroup did not. The bond strength was assessed with a microtensile test. Data from enamel and dentin specimens were analyzed separately using 1-way analysis of variance. The acid pretreatment did not significantly change the bond strength of the adhesives tested, either to enamel (P = 0.4161) or to dentin (P = 0.4857). The acid etching pretreatment did not affect the bond strength to dentin and enamel when the tested universal multipurpose adhesive systems were used.

Sodium Trimetaphosphate as a Novel Strategy for Matrix Metalloproteinase Inhibition and Dentin Remineralization.

PubMed

Gonçalves, Rafael Simões; Scaffa, Polliana Mendes Candia; Giacomini, Marina Ciccone; Vidal, Cristina de Mattos Pimenta; Honório, Heitor Marques; Wang, Linda

2018-01-01

The effect of sodium trimetaphosphate (STMP) as an antiproteolytic and remineralizing agent on demineralized dentin was evaluated in vitro. The inhibitory potential of STMP at 0.5, 1.5, 3.5, and 5% against recombinant matrix metalloproteinases (MMPs) MMPs-2 and -9 was assessed by zymography. To investigate its remineralization potential, 40 bovine root specimens were obtained and subjected to a demineralization protocol to produce caries-like dentin lesions. After that, dentin surfaces were divided into 3 areas: (1) mineralized (no treatment); (2) demineralized; and (3) demineralized/treated with STMP and submitted to a pH-cycling associated or not with STMP (1.5, 3.5, or 5% STMP, 10 min of treatment). After that, superficial hardness (SH) and cross-sectional hardness (CSH) were determined. Polarized light microscopy (PLM) was used to qualitatively evaluate mineralization within the caries-like lesions. The zymographic analysis showed that STMP solution is a potent inhibitor of the gelatinolytic activity of MMPs-2 and -9 depending on the dose, since the lowest concentration (0.5%) partially inhibited the enzyme activity, while the higher concentrations completely inhibited enzyme activity. Regarding remineralization effect, only 1.5% STMP solution enhanced both the SH and CSH. PLM showed that the area treated with 1.5% STMP presented similar birefringence as mineralized sound dentin. In conclusion, 1.5% STMP solution is effective as an antiproteolytic agent against MMPs and promotes dentin remineralization. © 2018 S. Karger AG, Basel.

Variation on Molecular Structure, Crystallinity, and Optical Properties of Dentin Due to Nd:YAG Laser and Fluoride Aimed at Tooth Erosion Prevention

PubMed Central

Freitas, Anderson Z.; Bachmann, Luciano; Benetti, Carolina; Ana, Patricia A.

2018-01-01

This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process. PMID:29389868

Effect of Er:YAG laser pulse duration on the shear bond strength of bleached dentin

NASA Astrophysics Data System (ADS)

Yu, Ping; Yu, Dandan; Zhao, Peng; Xu, Zhou; Gao, Shanshan

2017-11-01

The influence of different Er:YAG laser pulse durations on the shear bond strength (SBS) of bleached dentin was investigated in this study. In total, 176 crowns of extracted human premolars were cut horizontally, embedded and ground to expose the sound dentin. Of these, 132 specimens were bleached with 12% hydrogen peroxide (HP) and divided into three groups, irradiated by an Er:YAG laser with different pulse lengths of 50 µs super short pulse (SSP), 100 µs moderate short pulse (MSP) and 300 µs short pulse (SP), respectively. The energy density of the three groups was the same at about 15.73 J cm-2 for each. Then, each group was further divided into two subgroups according to whether it had been etched with 37% phosphoric acid or not. The control group (N  =  22) was bleached and etched with acid while the blank group (N  =  22) was just etched with acid. The surface morphology of the dentin was observed using scanning electron microscopy (SEM). The SBS of the composite resin to the conditioned dentin was tested with a universal testing machine. It was found that the SBS of the dentin significantly decreased after bleaching treatment, while it was possible to restore it using Er:YAG laser irradiation. Lasers with various pulse durations led to different surface morphologies but had no effect on the SBS. The SSP laser was more suitable on account of it resulting in less thermal damage, and additional acid etching was not necessary for the irradiated bleached dentin in the clinic because it could not further improve the SBS value.

Restorative Treatment Thresholds for Occlusal Primary Caries by Dentists in “The Dental Practice-Based Research Network”

PubMed Central

Gordan, Valeria V; Bader, James D; Garvan, Cynthia W; Richman, Joshua S; Qvist, Vibeke; Fellows, Jeffrey L; Rindal, D. Brad; Gilbert, Gregg H

2010-01-01

Objectives (1) Quantify at which carious lesion depths dentists intervene surgically for cases of varying caries penetration and caries risk; (2) Identify characteristics that are associated with surgical intervention. Methods Dentists in a practice-based research network who reported doing at least some restorative dentistry were surveyed. Dentists were asked to indicate whether they would surgically intervene in a series of cases depicting occlusal caries. Each case included a photograph of an occlusal surface displaying typical characteristics of caries penetration, and a written description of a patient at a specific level of caries risk. Using logistic regression, we analyzed associations of surgical treatment with dentist and practice characteristics, and patient caries risk levels. Results 519 DPBRN practitioner-investigators responded, of whom 63% indicated that they would surgically restore lesions located on inner enamel surfaces, and 90% of lesions located in outer dentin surfaces in a low caries risk individual. Regarding individuals at high caries risk, 77% reported that they would surgically restore inner enamel lesions and 94% reported restoring lesions located on the outer dentin surface. Dentists who did not assess caries risk were more likely to intervene on dentin lesions (p=.004). Practitioner-investigators who were in private practice were significantly more likely to intervene surgically on enamel lesions, compared to dentists from large group practices (p<.001). Conclusion Most dentists chose to provide some treatment to lesions that were within the enamel surface. Decisions to intervene surgically in the caries process differ by caries lesion depth, patient caries risk, assessment of caries risk, type of practice model, and percent of patients who self-pay. PMID:20123876

Structural changes in the irradiated dentin with Nd:YAG and Er:YAG lasers for cervical hypersensitivity treatment and their influence on the microtensile resistance in resin-dentin interface

NASA Astrophysics Data System (ADS)

Mota, Cláudia C. B. O.; Sena, Tatiane V. N. S.; Castro, Roseane F.; Araújo, Ana C. S.; Gomes, Anderson S. L.

2016-02-01

This study aimed to evaluate, in vitro, the structural changes in dentin surfaces irradiated with Er:YAG (2940 nm, 90 mJ, 2 Hz, 300 μs, spot diameter 0.9 mm, 60 s/cm2, using the handpiece at 6 cm of distance to surface) and Nd:YAG (1064 nm, 1 W, 10 Hz, 300 μs, optical fiber diameter 300 μm, 60 s/cm2, using the handpiece at 2 mm of distance to surface) lasers to the treatment of cervical hypersensitivity and the respective bond strength compromising of resin composite restorations over these surfaces. 45 bovine teeth were selected, and removed the enamel portion of the buccal surface for laser irradiation and restorative procedure. Samples were divided into three groups: G1: control, only fluoride therapy; G2: irradiated with Er:YAG laser; G3: irradiated with Nd:YAG laser. Samples were submitted to optical coherence tomography analysis and subsequently they were restored with resin composite and sectioned into sticks for microtensile tests of achievement. ANOVA analysis of variance for the maximum force (N) and strength (MPa), with a significance level of 5% was performed. It was observed that G3 presented lower performance of maximum force (38,8 +/- 11,3 N) and resistance (26,0 +/- 9,3 MPa), and the G2 presented better results (51,0 +/- 13,5 N and 36,5 +/- 10,1 MPa), but still lower than those one obtained for G1 (56,0 +/- 12,3 N and 43,5 +/- 8,6 MPa). Although both lasers are effective in the cervical hypersensitivity treatment, when the aesthetic factor is the priority, the use of Er:YAG is preferable.

Effect of a single application of TiF(4) and NaF varnishes and solutions on dentin erosion in vitro.

PubMed

Magalhães, Ana Carolina; Levy, Flávia Mauad; Rios, Daniela; Buzalaf, Marília Afonso Rabelo

2010-02-01

This in vitro study aimed to analyse the effect of a single application of TiF(4) and NaF varnishes and solutions to protect against dentin erosion. Bovine root dentin samples were pre-treated with NaF-Duraphat varnish (2.26%F, pH 4.5), NaF/CaF(2)-Duofluorid varnish (5.63%F, pH 8.0), NaF-experimental varnish (2.45%F, pH 4.5), TiF(4)-experimental varnish (2.45%F, pH 1.2), NaF solution (2.26%F, pH 4.5), TiF(4) solution (2.45%F, pH 1.2) and placebo varnish (pH 5.0, no-F varnish control). Controls remained untreated. Ten samples in each group were then subjected to an erosive demineralisation (Sprite Zero, 4x 90s/day) and remineralisation (artificial saliva, between the erosive cycles) cycling for 5 days. Dentin loss was measured profilometrically after pre-treatment and after 1, 3 and 5 days of de-remineralisation cycling. The data were statistically analysed by two-way ANOVA and Bonferroni's post hoc test (p<0.05). After pre-treatment, TiF(4) solution significantly induced surface loss (1.08+/-0.53 microm). Only Duraphat reduced the dentin loss overtime, but it did not significantly differ from placebo varnish (at 3rd and 5th days) and TiF(4) varnish (at 3rd day). Duraphat varnish seems to be the best option to partially reduce dentin erosion. However, the maintenance of the effects of this treatment after successive erosive challenges is limited. Copyright 2009 Elsevier Ltd. All rights reserved.

Starch Combined with Sucrose Provokes Greater Root Dentine Demineralization than Sucrose Alone.

PubMed

Souza, Samilly Evangelista; Sampaio, Aline Araújo; Del Bel Cury, Altair Antoninha; Cavalcanti, Yuri Wanderley; Ricomini Filho, Antônio Pedro; Cury, Jaime Aparecido

2018-02-14

Since there is no consensus about whether starch increases the cariogenic potential of sucrose, we used a validated 3-species biofilm model to evaluate if starch combined with sucrose provokes higher root dentine demineralization than sucrose alone. Biofilms (n = 18) composed by Streptococcus mutans (the most cariogenic bacteria), Actinomces naeslundii (which has amylolytic activity), and Streptococcus gordonii (which binds salivary amylase) were formed on root dentine slabs under exposure 8 ×/day to one of the following treatments: 0.9% NaCl, 1% starch, 10% sucrose, or a combination of 1% starch and 10% sucrose. Before each treatment, biofilms were pretreated with human whole saliva for 1 min. The pH of the culture medium was measured daily as an indicator of biofilm acidogenicity. After 96 h of growth, the biofilms were collected, and the biomass, bacteria viability, and polysaccharides were analyzed. Dentine demineralization was assessed by surface hardness loss (% SHL). Biofilm bioarchitecture was analyzed using confocal laser scanning microscopy. Treatment with a starch and sucrose combination provoked higher (p = 0.01) dentine demineralization than sucrose alone (% SHL = 53.2 ± 7.0 vs. 43.2 ± 8.7). This was supported by lower pH values (p = 0.007) of the culture medium after daily exposure to the starch and sucrose combination compared with sucrose (4.89 ± 0.29 vs. 5.19 ± 0.32). Microbiological and biochemical findings did not differ between biofilms treated with the combination of starch and sucrose and sucrose alone (p > 0.05). Our findings give support to the hypothesis that a starch and sucrose combination is more cariogenic for root dentine than sucrose alone. © 2018 S. Karger AG, Basel.

Effect of 5,000 ppm Fluoride Dentifrice or 1,100 ppm Fluoride Dentifrice Combined with Acidulated Phosphate Fluoride on Caries Lesion Inhibition and Repair.

PubMed

Fernández, Constanza E; Tenuta, Livia Maria Andaló; Del Bel Cury, Altair Antoninha; Nóbrega, Diego Figueiredo; Cury, Jaime Aparecido

2017-01-01

High fluoride dentifrice (FD; 5,000 ppm F) has been recommended to arrest root dentine lesions and to control enamel caries in high-risk patients. Also, standard FD (1,100 ppm F) in combination with professional fluoride application has been recommended to control dentine caries, but the effect of this combination on enamel has been considered modest. Considering the lack of evaluation comparing the use of 5,000 ppm FD (5,000-FD) versus acidulated phosphate fluoride (APF) application combined with 1,100 ppm FD (1,100-FD) on the inhibition and repair of caries lesions in both enamel and dentine, we conducted this in situ, double-blind, crossover study of 3 phases of 14 days. In each phase, 18 volunteers wore palatal appliances containing enamel and root dentine specimens, either sound or carious, to evaluate the effect of the treatments on the inhibition or repair of caries lesions, respectively. The treatments were non-FD (negative control), 5,000-FD, or 1 APF gel application on dental specimens combined with 1,100-FD used twice per day (APF + 1,100-FD). The reduction of demineralization and enhancement of remineralization were assessed by surface and cross-sectional hardness. Fluoride concentration was determined on dental specimens and on the formed biofilm. For enamel, APF + 1,100-FD and 5,000-FD did not differ regarding the inhibition of demineralization and repair of caries lesions. However, for dentine the difference between these treatments was inconclusive because while APF + 1,100-FD was more effective than 5,000-FD in caries lesion reduction and repair, 5,000-FD was more effective than APF + 1,100-FD in the reduction of surface demineralization. Therefore, the findings show that the combination of APF + 1,100-FD is as effective as 5,000-FD in enamel inhibition of demineralization and enhancement of remineralization. © 2017 S. Karger AG, Basel.

Qualitative analysis of precipitate formation on the surface and in the tubules of dentin irrigated with sodium hypochlorite and a final rinse of chlorhexidine or QMiX.

PubMed

Kolosowski, Kamil P; Sodhi, Rana N S; Kishen, Anil; Basrani, Bettina R

2014-12-01

Interaction of sodium hypochlorite (NaOCl) mixed with chlorhexidine (CHX) produces a brown precipitate containing para-chloroaniline (PCA). When QMiX is mixed with NaOCl, no precipitate forms, but color change occurs. The aim of this study was to qualitatively assess the formation of precipitate and PCA on the surface and in the tubules of dentin irrigated with NaOCl, followed either by EDTA, NaOCl, and CHX or by saline and QMiX by using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Dentin blocks were obtained from human maxillary molars, embedded in resin, and cross-sectioned to expose dentin. Specimens in group 1 were immersed in 2.5% NaOCl, followed by 17% EDTA, 2.5% NaOCl, and 2% CHX. Specimens in group 2 were immersed in 2.5% NaOCl, followed by saline and QMiX. The dentin surfaces were subjected to TOF-SIMS spectra analysis. Longitudinal sections of dentin blocks were then exposed and subjected to TOF-SIMS analysis. All samples and analysis were performed in triplicate for confirmation. TOF-SIMS analysis of group 1 revealed an irregular precipitate, containing PCA and CHX breakdown products, on the dentin surfaces, occluding and extending into the tubules. In TOF-SIMS analysis of group 2, no precipitates, including PCA, were detected on the dentin surface or in the tubules. Within the limitations of this study, precipitate containing PCA was formed in the tubules of dentin irrigated with NaOCl followed by CHX. No precipitates or PCA were detected in the tubules of dentin irrigated with NaOCl followed by saline and QMiX. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Efficacy of Nd:YAG and GaAlAs lasers in comparison to 2% fluoride gel for the treatment of dentinal hypersensitivity.

PubMed

Soares, Marília De Lima; Porciúncula, Geane Bandeira; Lucena, Mara Ilka Holanda Medeiros De; Gueiros, Luiz Alcino Monteiro; Leão, Jair Carneiro; Carvalho, Alessandra De Albuquerque Tavares

2016-01-01

Lasers demonstrate excellent therapeutic action and are often employed in dentistry for the treatment of diverse clinical conditions. The aim of this study was to compare the efficacy of neodymium-doped yttrium-aluminum-garnet (Nd:YAG) laser, gallium-aluminum-arsenide (GaAlAs) laser, and 2% neutral fluoride gel in the treatment of dentinal hypersensitivity. Twenty-three patients were evaluated, involving a total of 48 quadrants with at least 1 tooth with dentinal hypersensitivity (89 teeth total). Pain intensity was recorded on a visual analog scale at the time of clinical examination (baseline), immediately after treatment, and 1 week posttreatment. Teeth were treated with 60 seconds of 2% neutral fluoride gel application or 60 seconds of laser treatment-Nd:YAG laser at a distance of 0.5 cm (unfocused; 1 W and 10 Hz for 60 seconds, perpendicular to the cervical surfaces) or GaAlAs laser in contact (40 mW; 4 J/cm²; spot: 0.028 cm²; 15 seconds per point on 4 points [mesial, medial, distal, and apical])-as well as sham treatments so that patients remained blind to their treatment group. All treatments provided adequate pain reduction immediately posttreatment, but laser treatments resulted in significantly greater reductions in pain intensity.

Ultramorphology of the root surface subsequent to hand-ultrasonic simultaneous instrumentation during non-surgical periodontal treatments. An in vitro study

PubMed Central

D. ASPRIELLO, Simone; PIEMONTESE, Matteo; LEVRINI, Luca; SAURO, Salvatore

2011-01-01

Objective The purpose of this study was to investigate the ultramorphology of the root surfaces induced by mechanical instrumentation performed using conventional curettes or piezoelectric scalers when used single-handedly or with a combined technique. Material and Methods Thirty single-rooted teeth were selected and divided into 3 groups: Group A, instrumentation with curettes; Group B instrumentation with titanium nitride coated periodontal tip mounted in a piezoelectric handpiece; Group C, combined technique with curette/ultrasonic piezoelectric instrumentation. The specimens were processed and analyzed using confocal and scanning electron microscopy. Differences between the different groups of instrumentation were determined using Pearson’s χ 2 with significance predetermined at α=0.001. Results Periodontal scaling and root planing performed with curettes, ultrasonic or combined instrumentation induced several morphological changes on the root surface. The curettes produced a compact and thick multilayered smear layer, while the morphology of the root surfaces after ultrasonic scaler treatment appeared irregular with few grooves and a thin smear layer. The combination of curette/ultrasonic instrumentation showed exposed root dentin tubules with a surface morphology characterized by the presence of very few grooves and slender remnants of smear layer which only partially covered the root dentin. In some cases, it was also possible to observe areas with exposed collagen fibrils. Conclusion The curette-ultrasonic simultaneous instrumentation may combine the beneficial effects of each instrument in a single technique creating a root surface relatively free from the physical barrier of smear layer and dentin tubules orifices partial occlusion. PMID:21437474

Atraumatic restorative treatment and minimal intervention dentistry.

PubMed

Frencken, J E

2017-08-11

Too many people worldwide suffer from the consequences of untreated dentine carious lesions. This finding reflects the inability of the currently used traditional mode of treatments to manage such lesions. A change is needed. Dental training institutions should depart from the traditional 'drill and fill' treatments and embrace the holistic oral healthcare approach that is minimal intervention dentistry (MID) and includes within it minimally invasive operative skills. Dental caries is, after all, a preventable disease. The atraumatic restorative treatment (ART) concept is an example of MID. ART consists of a preventive (ART sealant) and a restorative (ART restoration) component. ART sealants using high-viscosity glass-ionomer (HVGIC) have a very high dentine carious lesion preventive effect. The survival rate of these sealants is not significantly different from that of sealants produced with resin. The survival rate of ART/HVGIC restorations matches those of amalgam and resin composite in single- and multiple-surface cavities in primary teeth and in single-surface cavities in permanent teeth. The principles of carious tissue removal within a cavity recommended by the International Caries Consensus Collaboration are in line with those of treating a cavity using ART. Owing to its good performance and the low levels of discomfort/pain and dental anxiety associated with it, ART and/or other evidence-based atraumatic care procedures should be the first treatment for a primary dentine carious lesion. Only if the use of ART is not indicated should other more invasive and less-atraumatic care procedures be used in both primary and permanent dentitions.

The influence of salivary contamination on shear bond strength of dentin adhesive systems.

PubMed

Park, Jeong-won; Lee, Kyung Chae

2004-01-01

This study evaluated the influence of salivary contamination during dentin bonding procedures on shear bond strength and investigated the effect of contaminant-removing treatments on the recovery of bond strength for two dentin bonding agents. One hundred and ten human molars were embedded in cylindrical molds with self-curing acrylic resin. The occlusal dentin surface was exposed by wet grinding with #800 silicon carbide abrasive paper. The teeth were divided into five groups for One-step (OS) (BISCO, Inc) and six groups for Clearfil SE Bond (SE) (Kuraray Co, Ltd, Osaka, Japan). For One-step, the grinding surface was treated with 32% phosphoric acid; BAC (BISCO Inc) and divided into five groups: OS control group (uncontaminated), OS I (salivary contamination, blot dried), OS II (salivary contamination, completely dried), OS III (salivary contamination, wash and blot dried) and OS IV (salivary contamination, re-etching for 10 seconds, wash and blot dried). For SE bond, the following surface treatments were done: SE control group (primer applied to the fresh dentin surface), SE I (after salivary contamination, primer applied), SE II (primer, salivary contamination, dried), SE III (primer, salivary contamination, wash and dried), SE IV (after procedure of SE II, re-application of primer) and SE V (after procedure of SE III, re-application of primer). Each bonding agent was applied and light cured for 10 seconds. Clearfil AP-X (Kuraray Co, Ltd) composite was packed into the Ultradent mount jig mold and light cured for 40 seconds. The bonded specimens were stored for 24 hours in a 37 degrees C waterbath. The shear bond strengths were measured using an Instron testing machine (Model 4202, Instron Corp). The data for each group were subjected to one-way ANOVA followed by the Newman-Keuls test to make comparisons among the groups. The results were as follows: In the One-step groups, the OS II group showed statistically significant lower shear bond strength than the OS control, I, III and IV (p<0.05). In the Clearfil SE Bond groups, the SE II and SE III groups had decreased shear bond strength compared with the control and SE I, SE IV and SE V groups (p<0.05). In conclusion, when using One-step total etch adhesive and when the etched surface is contaminated by saliva, blotting the surface and applying the primer can recover the bond strength. Complete drying of the salivary contaminated surface should be avoided. In the Clearfil SE Bond groups, the re-priming treatment (SE IV and SE V) resulted in the recovery of shear bond strength in the specimens contaminated after priming.

Long-term bonding effectiveness of simplified etch-and-rinse adhesives to dentin after different surface pre-treatments

PubMed Central

Verma, Radhika; Singh, Udai Pratap; Tyagi, Shashi Prabha; Nagpal, Rajni; Manuja, Naveen

2013-01-01

Objective: To evaluate the effect of 2% chlorhexidine (CHX) and 30% proanthocyanidin (PA) application on the immediate and long-term bond strength of simplified etch-and-rinse adhesives to dentin. Materials and Methods: One hundred twenty extracted human molar teeth were ground to expose the flat dentin surface. The teeth were equally divided into six groups according to the adhesives used, either Tetric N Bond or Solobond M and pretreatments given either none, CHX, or PA. Composite cylinder was bonded to each specimen using the respective adhesive technique. Half the samples from each group (n = 10) were then tested immediately. The remaining samples were tested after 6 month storage in distilled water. Results: The mean bond strength of samples was not significantly different upon immediate testing being in the range of 8.4(±0.7) MPa. The bond strength fell dramatically in the control specimens after 6 month storage to around 4.7(±0.33) MPa, while the bond strength was maintained in the samples treated with both CHX and PA. Conclusion: Thirty percent PA was comparable to 2% CHX with respect to preservation of the resin dentin bond over 6 months. PMID:23956543

The effect of dentine surface preparation and reduced application time of adhesive on bonding strength.

PubMed

Saikaew, Pipop; Chowdhury, A F M Almas; Fukuyama, Mai; Kakuda, Shinichi; Carvalho, Ricardo M; Sano, Hidehiko

2016-04-01

This study evaluated the effects of surface preparation and the application time of adhesives on the resin-dentine bond strengths with universal adhesives. Sixty molars were cut to exposed mid-coronal dentine and divided into 12 groups (n=5) based on three factors; (1) adhesive: G-Premio Bond (GP, GC Corp., Tokyo, Japan), Clearfil Universal Bond (CU, Kuraray Noritake Dental Inc., Okayama, Japan) and Scotchbond Universal Adhesive (SB, 3M ESPE, St. Paul, MN, USA); (2) smear layer preparation: SiC paper ground dentine or bur-cut dentine; (3) application time: shortened time or as manufacturer's instruction. Fifteen resin-dentine sticks per group were processed for microtensile bond strength test (μTBS) according to non-trimming technique (1mm(2)) after storage in distilled water (37 °C) for 24h. Data were analyzed by three-way ANOVA and Dunnett T3 tests (α=0.05). Fractured surfaces were observed under scanning electron microscope (SEM). Another 12 teeth were prepared and cut into slices for SEM examination of bonded interfaces. μTBS were higher when bonded to SiC-ground dentine according to manufacturer's instruction. Bonding to bur-cut dentine resulted in significantly lower μTBS (p<0.000). Shortening the application time resulted in significantly lower bond strength for CU on SiC and GP on bur-cut dentine. SEM of fractured surfaces revealed areas with a large amount of porosities at the adhesive resin interface. This was more pronounced when adhesives were bonded with a reduced application time and on bur cut dentine. The performance of universal adhesives can be compromised on bur cut dentine and when applied with a reduced application time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mini-interfacial Fracture Toughness of a Multimode Adhesive Bonded to Plasma-treated Dentin.

PubMed

Ayres, Ana Paula Almeida; Pongprueksa, Pong; De Munck, Jan; Gré, Cristina Parise; Nascimento, Fábio Dupart; Giannini, Marcelo; Van Meerbeek, Bart

2017-01-01

To investigate the bonding efficacy of a multimode adhesive to plasma-treated and -untreated (control) dentin using a mini-interfacial fracture toughness (mini-iFT) test. Twenty human molars were used in a split-tooth design (n = 10). The adhesive Scotchbond Universal (SBU; 3M ESPE) was applied in etch-and-rinse (E&R) and self-etch (SE) modes. Mid-coronal dentin was exposed and covered with a standardized smear layer ground to 320 grit. One half of each dentin surface received 15 s of non-thermal atmospheric plasma (NTAP), while the other half was covered with a metallic barrier and kept untreated. Following the E&R mode, dentin was plasma treated immediately after phosphoric acid etching. SBU and a resin-based composite were applied to dentin following the manufacturer's instructions. Six mini-iFT specimens were prepared per tooth (1.5 x 2.0 x 16 to 18 mm), and a single notch was prepared at the adhesive-dentin interface using a 150-μm diamond blade under water cooling. Half of the mini-iFT specimens were immediately loaded until failure in a 4-point bending test, while the other half were first stored in distilled water for 6 months. After testing, the exact dimensions of the notch were measured with a measuring optical microscope, from which ΚIc was determined. Three-way ANOVA revealed higher mini-iFT for SBU applied in E&R than SE mode for both storage times, irrespective of NTAP treatment. Overall, mini-iFT did not decrease for any of the experimental groups upon 6-month aging, while plasma treatment did not show a direct beneficial effect on mini-iFT of SBU applied in either E&R or SE mode.

Comparative clinical evaluation of the immediate and late analgesic effect of GaAlAs diode lasers of 830 and 660 nm in the treatment of dentine pain: preliminary results

NASA Astrophysics Data System (ADS)

Ladalardo, Thereza C.; Mangabeira Albernaz, Pedro L.; Brugnera, Aldo, Jr.; Zanin, Fatima A. A.; Siqueira, Jose T.; Pinheiro, Antonio L. B.

2002-06-01

In this comparative clinical study, we aimed at evaluating the immediate and late analgesic effect of GaAlAs diode lasers of 660 nm and 830 nm in treatment of dentine pain. We used GaAlAs diode lasers of 660 nm and 830 nm with 35 mW, continuous wave emission, spot size 1 mm2 and a dosage of 4 joules/cm2 applied to the cervical dentine surface. In total 4 treatment sessions were performed at intervals of 7 days in a period of 4 consecutive weeks. A total of 40 teeth treated were divided into two groups comprising 20 teeth each: one group irradiated with a 660 nm wavelength laser, and the other one with a 830 nm wavelength laser. By means of a quantitative visual analogue scale (V.A.S.), we measured the sensitive responses to cold stimulus pre- treatment, and at a follow-up period of 15 and 30 minutes post-treatment in both groups in order to evaluate the immediate analgesic effect. The late effect was evaluated at a follow-up period of 15 and 30 days. Using the GaAlAs diode laser of 660 nm wavelength resulted in better levels of dentine desensitization, at both immediate and late analgesic effect analysis compared with the use of the GaAlAs diode laser of 830 nm wavelength.

Effect of surface treatment on retention of glass-fiber endodontic posts.

PubMed

Balbosh, Ali; Kern, Matthias

2006-03-01

The effects of surface treatment on the retention of prefabricated fiber-reinforced epoxy resin posts are not well understood because most studies measure retention shortly after cementation, without artificial aging. The purpose of this study was to evaluate the effect of surface treatment on the retention of glass-fiber endodontic posts luted with resin cement and subjected to artificial aging. Thirty-two single-rooted teeth were selected, the coronal aspect of each tooth was removed, and the remaining root received endodontic therapy. Specimens were then divided into 4 groups (n = 8). Post spaces were prepared to a depth of 10 mm by using ISO 90 rotary instruments. The tapered posts received 1 of 4 surface treatments: cleaning with alcohol (Alc), cleaning with alcohol and conditioning with ED-Primer material (Alc-ED), airborne-particle abrasion (Air), or airborne-particle abrasion and conditioning with ED-Primer material (Air-ED). All posts were luted with a composite resin luting agent (Panavia F) after conditioning the canal dentin with autopolymerizing dentin primer (ED-Primer) and without acid etching of the canal dentin. After cementation, the specimens were stored in water at 37 degrees C for 30 days and subjected to simulated aging conditions consisting of 7500 thermal cycles (5 degrees C/55 degrees C) and 300,000 mechanical loading cycles with 30 N. Retention (N) of the posts was measured with a universal testing machine with a crosshead speed of 2 mm/min. The data were analyzed using 1-way ANOVA and the Tukey HSD test (alpha = .05). The dislodged posts were also examined microscopically at x8 and x20 magnification to evaluate the mode of failure. The mean retentive values (N) and SDs of the test groups were as follows: Alc, 375.9 +/- 85.0; Alc-ED, 421.2 +/- 46.8; Air, 534.8 +/- 65.8; and Air-ED, 555.8 +/- 86.9. Airborne-particle-abraded posts had significantly higher retention compared with nonabraded posts (P < .001). Treating the post's surface with ED-Primer material prior to cementation had no significant effect on retention. The failure mode was purely adhesive at the resin cement-post interface for all nonabraded posts. A mixed failure mode, adhesive at the resin cement-dentin interface, at the resin cement-post interface, and cohesive in the resin cement, was observed for airborne-particle-abraded posts. Treating the surface of the posts with ED-Primer material before cementation with Panavia F cement produced no significant improvement in the retention of the posts. Airborne-particle abrasion of the surface of the post significantly improved the retention.

Dentin hypersensitivity: from diagnosis to a breakthrough therapy for everyday sensitivity relief.

PubMed

Cummins, Diane

2009-01-01

This paper provides an overview of the current knowledge of diagnosis, epidemiology, etiology, and clinical management of dentin hypersensitivity. It summarizes technical approaches to relieve sensitivity in professional and home-use products, with emphasis on the clinical evidence for the efficacy of desensitizing toothpaste, and introduces a new innovative dentifrice technology containing 8% arginine, calcium carbonate, and 1450 ppm fluoride. Dentin hypersensitivity is characterized by short, sharp pain arising from exposed dentin in response to external stimuli which cannot be ascribed to any other form of dental defect or disease. The hydrodynamic theory proposes that pain-producing stimuli cause a change in dentin fluid flow that activates intra-dental nerve fibers, via a mechanoreceptor response, to cause pain. To be hypersensitive, dentin must be exposed and dentin tubules must be open to external stimuli and patent at the pulp. Gingival recession is the primary cause of dentin exposure, and a major predisposing factor for dentin hypersensitivity. Dentin hypersensitivity is a prevalent condition. It has been reported to afflict 15-20% of the adult population, typically 20 to 50-year-olds, with peak incidence between 30 and 39 years. Some studies have reported higher prevalence levels of up to 57%. The incidence of dentin hypersensitivity is expected to rise with changing diets, and as caries and periodontal disease prevention result in improved oral health status, and retention and functionality of the dentition. Treatments to relieve dentin hypersensitivity are based on interruption of the neural response to pain stimuli or occlusion of open tubules to block the hydrodynamic mechanism. Effective and robust dentin occlusion offers the greatest prospect for instant and lasting relief of dentin hypersensitivity. In particular, materials which can coat exposed dentin surfaces, in addition to plugging and sealing open dentin tubules, offer the intriguing prospect of strengthening dentin and rendering it less susceptible to predisposing factors, while concurrently reducing dentin hypersensitivity. Clinical studies have shown that a new toothpaste containing 8% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate offers significantly increased efficacy in reducing sensitivity, compared to a market-leading toothpaste containing 2% potassium ion. Mechanism of action studies have shown that this technology physically seals dentin tubules with a plug that contains arginine, calcium carbonate, and phosphate. This plug, which is resistant to normal pulpal pressures and to acid challenge, effectively reduces dentin fluid flow and, thereby, reduces sensitivity.

Curing mode affects bond strength of adhesively luted composite CAD/CAM restorations to dentin.

PubMed

Lührs, Anne-Katrin; Pongprueksa, Pong; De Munck, Jan; Geurtsen, Werner; Van Meerbeek, Bart

2014-03-01

To determine the effect of curing mode and restoration-surface pre-treatment on the micro-tensile bond strength (μTBS) to dentin. Sandblasted CAD/CAM composite blocks (LAVA Ultimate, 3M ESPE) were cemented to bur-cut dentin using either the etch & rinse composite cement Nexus 3 ('NX3', Kerr) with Optibond XTR ('XTR', Kerr), or the self-etch composite cement RelyX Ultimate ('RXU', 3M ESPE) with Scotchbond Universal ('SBU', 3M ESPE). All experimental groups included different 'curing modes' (light-curing of adhesive and cement ('LL'), light-curing of adhesive and auto-cure of cement ('LA'), co-cure of adhesive through light-curing of cement ('AL'), or complete auto-cure ('AA')) and different 'restoration-surface pre-treatments' of the composite block (NX3: either a silane primer (Kerr), or the XTR adhesive; RXU: either silane primer (RelyX Ceramic Primer, 3M ESPE) and SBU, or solely SBU). After water-storage (7 days, 37°C), the μTBS was measured. Additionally, the degree of conversion (DC) of both cements was measured after 10min and after 1 week, either auto-cured (21°C/37°C) or light-cured (directly/through 3-mm CAD/CAM composite). The linear mixed-effects model (α=0.05) revealed a significant influence of the factors 'curing mode' and 'composite cement', and a less significant effect of the factor 'restoration-surface pre-treatment'. Light-curing 'LL' revealed the highest μTBS, which decreased significantly for all other curing modes. For curing modes 'AA' and 'AL', the lowest μTBS and a high percentage of pre-testing failures were reported. Overall, DC increased with light-curing and incubation time. The curing mode is decisive for the bonding effectiveness of adhesively luted composite CAD/CAM restorations to dentin. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of hyaluronic acid on morphological changes to dentin surfaces and subsequent effect on periodontal ligament cell survival, attachment, and spreading.

PubMed

Mueller, Andrea; Fujioka-Kobayashi, Masako; Mueller, Heinz-Dieter; Lussi, Adrian; Sculean, Anton; Schmidlin, Patrick R; Miron, Richard J

2017-05-01

Hyaluronic acid (HA) is a natural constituent of connective tissues and plays an important role in their development, maintenance, and regeneration. Recently, HA has been shown to improve wound healing. However, no basic in vitro study to date has investigated its mode of action. Therefore, the purpose of this study was to examine morphological changes of dentin surfaces following HA coating and thereafter investigate the influence of periodontal ligament (PDL) cell survival, attachment, and spreading to dentin discs. HA was coated onto dentin discs utilizing either non-cross-linked (HA) or cross-linked (HA cl) delivery systems. Morphological changes to dentin discs were then assessed using scanning electron microscopy (SEM). Thereafter, human PDL cells were seeded under three in vitro conditions including (1) dilution of HA (1:100), (2) dilution of HA (1:10), and (3) HA coated directly to dentin discs. Samples were then investigated for PDL cell survival, attachment, and spreading using a live/dead assay, cell adhesion assay, and SEM imaging, respectively. While control dentin discs demonstrated smooth surfaces both at low and high magnification, the coating of HA altered surface texture of dentin discs by increasing surface roughness. HA cl further revealed greater surface texture/roughness likely due to the cross-linking carrier system. Thereafter, PDL cells were seeded on control and HA coated dentin discs and demonstrated a near 100 % survival rate for all samples demonstrating high biocompatibility of HA at dilutions of both 1:100 and 1:10. Interestingly, non-cross-linked HA significantly increased cell numbers at 8 h, whereas cross-linked HA improved cell spreading as qualitatively assessed by SEM. The results from the present study demonstrate that both carrier systems for HA were extremely biocompatible and demonstrated either improved cell numbers or cell spreading onto dentin discs. Future in vitro and animal research is necessary to further characterize the optimal delivery system of HA for improved clinical use. HA is a highly biocompatible material that may improve PDL cell attachment or spreading on dentin.

Morphological alterations of radicular dentine pretreated with different irrigating solutions and irradiated with 980-nm diode laser.

PubMed

Alfredo, Edson; Souza-Gabriel, Aline E; Silva, Silvio Rocha C; Sousa-Neto, Manoel D; Brugnera-Junior, Aldo; Silva-Sousa, Yara T C

2009-01-01

The topographical features of intraradicular dentine pretreated with sodium hypochlorite (NaOCl) or ethylenediamine tetraacetic acid (EDTA) followed by diode laser irradiation have not yet been determined. To evaluate the alterations of dentine irradiated with 980-nm diode laser at different parameters after the surface treatment with NaOCl and EDTA. Roots of 60 canines were biomechanically prepared and irrigated with NaOCl or EDTA. Groups were divided according to the laser parameters: 1.5 W/CW; 1.5 W/100 Hz; 3.0 W/CW; 3.0 W/100 Hz and no irradiation (control). The roots were splited longitudinally and analyzed by scanning electron microscopy (SEM) in a quali-quatitative way. The scores were submitted to two-way Kruskal-Wallis and Dunn's tests. The statistical analysis demonstrated that the specimens treated only with NaOCl or EDTA (control groups) were statistically different (P < 0.05) from the laser-irradiated specimens, regardless of the parameter setting. The specimens treated with NaOCl showed a laser-modified surface with smear layer, fissures, and no visible tubules. Those treated with EDTA and irradiated by laser presented absence of smear layer, tubules partially exposed and melting areas. The tested parameters of 980-nm diode laser promoted similar alterations on dentine morphology, dependent to the type of surface pretreatment. Copyright 2008 Wiley-Liss, Inc.

Effects of air polishing and an amino acid buffered hypochlorite solution to dentin surfaces and periodontal ligament cell survival, attachment, and spreading.

PubMed

Schmidlin, Patrick R; Fujioka-Kobayashi, Masako; Mueller, Heinz-Dieter; Sculean, Anton; Lussi, Adrian; Miron, Richard J

2017-06-01

The aim of this study is to examine morphological changes of dentin surfaces following air polishing or amino acid buffered hypochlorite solution application and to assess their influence on periodontal ligament (PDL) cell survival, attachment, and spreading to dentin discs in vitro. Bovine dentin discs were treated with either (i) Classic, (ii) Plus, or (iii) Perio powder (EMS). Furthermore, Perisolv® a hypochlorite solution buffered with various amino acids was investigated. Untreated dentin discs served as controls. Morphological changes to dentin discs were assessed using scanning electron microscopy (SEM). Human PDL cells were seeded onto the respectively treated discs, and samples were then investigated for PDL cell survival, attachment, and spreading using a live/dead assay, adhesion assay, and SEM imaging, respectively. Both control and Perisolv®-rinsed dentin discs demonstrated smooth surfaces at low and high magnifications. The Classic powders demonstrated the thickest coating followed by the Powder Plus. The Perio powder demonstrated marked alterations of dentin discs by revealing the potential to open dentinal tubules even before rinsing. Seeding of PDL cells demonstrated an almost 100 % survival rate on all samples demonstrating very high biocompatibility for all materials. Significantly higher PDL cell numbers were observed on samples treated with the Perio powder and the Perisolv® solution (approximately 40 % more cells; p < 0.05). SEM imaging revealed the potential for PDL cells to attach and spread on all surfaces. The results from the present study demonstrate that cell survival and spreading of PDL cells on root surfaces is possible following either air polishing or application with Perisolv®. Future in vitro and animal testing is necessary to further characterize the beneficial effects of either system in a clinical setting. The use of air polishing or application with Perisolv amino acid buffered hypochlorite solution was effective in treating root surfaces and allowed for near 100 % PDL cell survival, attachment, and spreading onto all root surfaces.

Morphological effects of MMPs inhibitors on the dentin bonding

PubMed Central

Li, He; Li, Tianbo; Li, Xiuying; Zhang, Zhimin; Li, Penglian; Li, Zhenling

2015-01-01

Matrix metalloproteinases (MMPs) have been studied extensively, and MMP inhibitors have been used as dental pretreatment agents prior to dentin bonding because they reduce collagen fiber degradation and improve bonding strength. However, morphologic characteristics of the collagen network after etching and of the post-adhesive dentin hybrid layers (DHL) after MMP inhibitors pretreatment have not been evaluated. Thus, we investigated demineralized dentin pretreated with chlorhexidine (CHX) and minocycline (MI) in an etch- and -rinse adhesive system with field emission scanning electron microscopy (FESEM) and immuno-gold labeling markers to observe the collagen network and DHL. FESEM revealed after CHX and MI, a demineralized dentin surface and improved collagen network formation, reduced collagen degradation, and distinct gold-labeling signals. Applying adhesive after either MMP inhibitor created a better dentin interface as evidenced by immuno-gold staining, better adhesive penetration, and higher DHL quality. With microtensile bond strength tests (µTBS) we estimated bonding strength using µTBS data. Immediate µTBS was enhanced with MMP inhibitor application to the bonding surface, and the CHX group was significantly different than non-treated etched surfaces, but no significant change was detected in the MI group. Surface micromorphology of the fractured dentin resin restoration showed that the CHX group had a better resin and dentin tube combination. Both MMP inhibitors created uniform resin coverage. Thus, morphologic results and µTBS data suggest that CHX and MI can inhibit MMP activity, improve immediate bonding strength, and enhance dentin bonding stability with an etch- and -rinse adhesive system. PMID:26379873

Effect of air-blowing variables on bond strength of all-in-one adhesives to bovine dentin.

PubMed

Shinkai, Koichi; Suzuki, Shiro; Katoh, Yoshiroh

2006-12-01

This study evaluated the effect of air-blowing variables on the microtensile bond strength (microTBS) of two all-in-one adhesives. A bonding agent was applied to the flat dentin surface of extracted bovine teeth, and the surface left undisturbed for 20 seconds. Gentle or intensive air-blowing was applied for five seconds, and the adhesive photopolymerized for 10 seconds. Resin composite paste was placed and cured after each bonding treatment. Specimens were subjected to microTBS test with a crosshead speed of 1.0 mm/min. Data were statistically analyzed using ANOVA, followed by Bonferroni post hoc test. When Clearfil tri-S Bond was bonded to dentin, the microTBS value of specimens applied with intensive air-blowing was significantly higher than that applied with gentle air-blowing (p<0.01). On the other hand, with Fluoro Bond Shake One, the microTBS value of specimens applied with intensive air-blowing was significantly lower than that applied with gentle air-blowing (p<0.01).

The use of acetone to enhance the infiltration of HA nanoparticles into a demineralized dentin collagen matrix.

PubMed

Besinis, Alexandros; van Noort, Richard; Martin, Nicolas

2016-03-01

This study investigates the role of acetone, as a carrier for nano-hydroxyapatite (nano-HA) in solution, to enhance the infiltration of fully demineralized dentin with HA nanoparticles (NPs). Dentin specimens were fully demineralized and subsequently infiltrated with two types of water-based nano-HA solutions (one containing acetone and one without). Characterization of the dentin surfaces and nano-HA particles was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface wettability and infiltration capacity of the nano-HA solutions were quantified by means of contact angle measurements and energy dispersive X-ray spectroscopy (EDS), respectively. Contact angle measurements were taken at baseline and repeated at regular intervals to assess the effect of acetone. The P and Ca levels of infiltrated dentin specimens were measured and compared to sound dentin and non-infiltrated controls. The presence of acetone resulted in an eight-fold decrease in the contact angles of the nano-HA solutions recorded on the surface of demineralized dentin compared to nano-HA solutions without acetone (one-way ANOVA, p<0.05). Perfect wetting of the demineralized dentin surface was achieved 5min after the application of the nano-HA solution containing acetone. Infiltration of demineralized dentin with the nano-HA solution containing acetone restored the lost mineral content by 50%, whereas the mean mineralization values for P and Ca in dentin treated with the acetone-free nano-HA solution were less than 6%. Acetone was shown to act as a vehicle to enhance the capacity to infiltrate demineralized dentin with HA NPs. The successful infiltration of dentin collagen with HA NPs provides a suitable scaffold, whereby the infiltrated HA NPs have the potential to act as seeds that may initiate heterogenous mineral growth when exposed to an appropriate mineral-rich environment. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Morphological and chemical characterization of the dentin/resin cement interface produced with a self-etching primer.

PubMed

Walker, Mary P; Wang, Yong; Spencer, Paulette

2002-01-01

The purpose of this study was to analyze a resin cement/dentin interface by comparing the diffusion of a resin cement into dentin surfaces pretreated with a self-etching primer with or without pretreatment by conventional acid etching. Dentin surfaces of 8 unerupted human third molars were treated with a self-etch primer (Panavia 21) with or without conventional phosphoric acid pretreatment. Panavia 21 resin cement was applied according to manufacturer's instructions. Dentin/resin cement interface sections from each tooth were examined with scanning electron microscopy and micro-Raman spectroscopy. When the self-etch primer was used following conventional acid pretreatment, the resin cement did not penetrate to the depth of the zone of demineralized dentin, leaving a substantial area of exposed dentin matrix at the dentin/cement interface. In contrast, there was substantial resin cement diffusion throughout the demineralized dentin when the self-etch primer was used without acid etching pretreatment. The in vitro evaluation of resin cement penetration throughout the zone of demineralized dentin is an important step in identifying sites of exposed dentin matrix that may promote postoperative sensitivity and may leave the dentin/resin cement interface vulnerable to premature degradation under clinical conditions. In this study, the self-etch primer used alone produced substantial resin cement penetration and left no exposed dentin matrix at the dentin/resin cement interface.

Effect of in vitro chewing and bruxism events on remineralization, at the resin-dentin interface.

PubMed

Toledano, Manuel; Cabello, Inmaculada; Aguilera, Fátima S; Osorio, Estrella; Osorio, Raquel

2015-01-02

The purpose of this study was to evaluate if different in vitro functional and parafunctional habits promote mineralization at the resin-dentin interface after bonding with three different adhesive approaches. Dentin surfaces were subjected to distinct treatments: demineralization by (1) 37% phosphoric acid (PA) followed by application of an etch-and-rinse dentin adhesive, Single Bond (SB) (PA+SB); (2) 0.5 M ethylenediaminetetraacetic acid (EDTA) followed by SB (EDTA+SB); (3) application of a self-etch dentin adhesive, Clearfil SE Bond (SEB). Different loading waveforms were applied: No cycling (I), cycled in sine (II) or square (III) waves, sustained loading hold for 24 h (IV) or sustained loading hold for 72 h (V). Remineralization at the bonded interfaces was assessed by AFM imaging/nano-indentation, Raman spectroscopy and Masson's trichrome staining. In general, in vitro chewing and parafunctional habits, promoted an increase of nano-mechanical properties at the resin-dentin interface. Raman spectroscopy through cluster analysis demonstrated an augmentation of the mineral-matrix ratio in loaded specimens. Trichrome staining reflected a narrow demineralized dentin matrix after loading in all groups except in PA+SB and EDTA+SB samples after sustained loading hold for 72 h, which exhibited a strong degree of mineralization. In vitro mechanical loading, produced during chewing and bruxism (square or hold 24 and 72 h waveforms), induced remineralization at the resin-dentin bonded interface. Copyright © 2014 Elsevier Ltd. All rights reserved.

Validation of a Cariogenic Biofilm Model to Evaluate the Effect of Fluoride on Enamel and Root Dentine Demineralization.

PubMed

Fernández, Constanza E; Tenuta, Livia M A; Cury, Jaime A

2016-01-01

Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine slabs (n = 12 per group) mounted in the same well of culture plates. The biofilms were exposed 8×/day to 10% sucrose and treated 2×/day with fluoridated solutions containing 0, 150, 450, or 1,350 ppm F; thus, simulating the use of low to high fluoride concentration toothpastes. The pH values of the culture medium was monitored 2×/day as a biofilm acidogenicity indicator. After 96 h, biofilms were collected for fluoride concentration analysis. The percentage of surface hardness loss (%SHL) was calculated for slabs. The fluoride uptake by the enamel and dentine was also determined. The model showed a dose-response because the biofilm and fluoride uptake increased and %SHL decreased at increasing fluoride concentrations (p < 0.05). Fluoride in the biofilm formed on dentine and fluoride uptake by dentine were higher than those for enamel. With the same fluoride concentration treatment, the percentage of reduction of demineralization was lower for dentine than for enamel. In conclusion, the model was validated in terms of a dose-response effect of fluoride on enamel and root dentine. Furthermore, the findings support the clinical data, suggesting that higher fluoride concentrations are necessary to control caries of root dentine than of enamel.

Resin-dentin interface of Scotchbond Multi-Purpose dentin adhesive.

PubMed

Griffiths, B M; Watson, T F

1995-08-01

To evaluate the interface between dentin, Scotchbond Multi-Purpose (SMP), and resin composite (Z100) using confocal fluorescence microscopy. Novel techniques were employed to view and record at video rate the application of the SMP primer and adhesive onto the dentin surface. The subsurface morphology of the dentin/restorative interface was also studied. To facilitate this study, the components of the adhesive system were labeled with fluorescent dyes. In an ideal situation, the primer and adhesive penetrated the dentin tubules, a distinct hybrid zone was formed and a thin layer of adhesive was observed at the interfacial region. However, the primed dentin surface was sensitive to disruption by the adhesive application brush during its placement, so that parts of the primer layer could be incorporated into the adhesive. This disruption could only be seen using confocal microscopy and a fluorescence labeling technique. Delamination of the primer layer was not observed when the adhesive film was thinned by air blowing. The application of an air stream to the cavity surface increased the penetration of the primer and adhesive along the dentin tubules, but also increased the thickness of the adhesive within irregularities on the cavity surface and at the cavity line angle. The cause of the problems in the handling properties of SMP may be the difference in viscosity between the two components (primer and adhesive) at the adhesive interface.

Dentinal tubule occluding capability of nano-hydroxyapatite; The in-vitro evaluation.

PubMed

Baglar, Serdar; Erdem, Umit; Dogan, Mustafa; Turkoz, Mustafa

2018-04-29

In this in-vitro study, the effectiveness of experimental pure nano-hydroxyapatite (nHAP) and 1%, 2%, and 3% F¯ doped nano-HAp on dentine tubule occlusion was investigated. And also, the cytotoxicity of materials used in the experiment was evaluated. Nano-HAp types were synthesized by the precipitation method. Forty dentin specimens were randomly divided into five groups of; 1-no treatment (control), 2-specimens treated with 10% pure nano-HAp and 3, 4, 5 specimens treated with 1%, 2%, and 3% F - doped 10% nano-HAp, respectively. To evaluate the effectiveness of the materials used; pH, FTIR, and scanning electron microscopy evaluations were performed before and after degredation in simulated body fluid. To determine cytotoxicity of the materials, MTT assay was performed. Statistical evaluations were performed with F and t tests. All of the nano-HAp materials used in this study built up an effective covering layer on the dentin surfaces even with plugs in tubules. It was found that this layer had also a resistance to degradation. None of the evaluated nano-HAp types were have toxicity. Fluoride doping showed a positive effect on physical and chemical stability until a critical value of 1% F - . The all evaluated nano-HAp types may be effectively used in dentin hypersensitivity treatment. The formed nano-HAp layers were seem to resistant to hydrolic deletion. The pure and 1% F - doped nano-HAp showed the highest biocompatibility thus it was assessed that pure and 1% F - doped materials may be used as an active ingredient in dentin hypersensitivity agents. © 2018 Wiley Periodicals, Inc.

Surface modification of gutta-percha cones by non-thermal plasma.

PubMed

Prado, Maíra; Menezes, Marilia Santana de Oliveira; Gomes, Brenda Paula Figueiredo de Almeida; Barbosa, Carlos Augusto de Melo; Athias, Leonardo; Simão, Renata Antoun

2016-11-01

This study was designed to evaluate the effects of Oxygen and Argon plasma on gutta-percha surfaces. A total of 185 flat smooth gutta-percha surfaces were used. Samples were divided into groups: control: no plasma treatment; Oxygen: treatment with Oxygen plasma for 1min; Argon: treatment with Argon plasma for 1min. Samples were evaluated topographically by scanning electron microscopy and atomic force microscopy; and chemically by Fourier Transform-infrared Spectroscopy. A goniometer was used to determine the surface free energy and the wettability of the endodontic sealers. Additionally 60 bovine teeth were filled using pellets of gutta-percha (control, oxygen and argon plasma) and the sealers. Teeth were evaluated by push-out and microleakage tests. Data were statistically analyzed using specific tests. Argon plasma did not change the surface topography, while Oxygen plasma led to changes. Both treatments chemically modified the gutta-percha surface. Argon and Oxygen plasma increased the surface free energy and favored the wettability of AH Plus and Pulp Canal Sealer EWT. Regarding bond strength analysis, for AH Plus sealer, both plasma treatments on gutta-percha favored the bond strength to dentin. However, for Pulp Canal Sealer, there is no statistically significant influence. For leakage test, dye penetration occurred between sealer and dentin in all groups. In conclusion, Oxygen plasma led to both topographic and chemical changes in the gutta-percha surface, while Argon plasma caused only chemical changes. Both treatments increased the surface free energy, favoring the wettability of AH Plus and Pulp Canal Sealer EWT sealers and influenced positively in the adhesion and leakage. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of Chlorhexidine-Loaded Calcium-Hydroxide Microparticles as a Potential Dental Pulp-Capping Material.

PubMed

Priyadarshini, Balasankar M; Selvan, Subramanian T; Narayanan, Karthikeyan; Fawzy, Amr S

2017-06-22

This study explores the delivery of novel calcium hydroxide [Ca(OH)₂] microparticles loaded with chlorhexidine (CHX) for potential dental therapeutic and preventive applications. Herein, we introduce a new approach for drug-delivery to deep dentin-surfaces in the form of drug-loaded microparticles. Unloaded Ca(OH)₂ [Ca(OH)₂/Blank] and CHX-loaded/Ca(OH)₂ microparticles were fabricated by aqueous chemical-precipitation technique. The synthesized-microparticles were characterized in vitro for determination of surface-morphology, crystalline-features and thermal-properties examined by energy-dispersive X-ray scanning and transmission electron-microscopy (EDX-SEM/TEM), Fourier-transform infrared-spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning-calorimetry (DSC). Time-related pH changes, initial antibacterial/biofilm-abilities and cytotoxicity of CHX-loaded/Ca(OH)₂ microparticles were evaluated. Microparticles were delivered to dentin-surfaces with subsequent SEM examination of treated dentin-substrates. The in vitro and ex vivo CHX-release profiles were characterized. Ca(OH)₂/Blank were hexagonal-shaped with highest z -average diameter whereas CHX-inclusion evidenced micro-metric spheres with distinguishable surface "rounded deposits" and a negative-shift in diameter. CHX:Ca(OH)₂/50 mg exhibited maximum encapsulation-efficiency with good antibacterial and cytocompatible properties. SEM examination revealed an intact layer of microparticles on exposed dentin-surfaces with retention of spherical shape and smooth texture. Microparticles loaded on dentin-surfaces showed prolonged release of CHX indicating substantial retention on dentin-substrates. This study validated the inherent-applicability of this novel drug-delivery approach to dentin-surfaces using micro-metric CHX-loaded/Ca(OH)₂ microparticles.

Surface properties and bond strength measurements of N-vinylcaprolactam (NVC)-containing glass-ionomer cements.

PubMed

Moshaverinia, Alireza; Chee, Winston W; Brantley, William A; Schricker, Scott R

2011-03-01

N-vinylcaprolactam (NVC)-containing glass ionomers are promising dental restorative materials with improved mechanical properties; however, little information is available on other physical characteristics of these types of modified glass ionomers, especially their surface properties. Understanding the surface characteristics and behavior of glass ionomers is important for understanding their clinical behavior and predictability as dental restorative materials. The purpose of this study was to investigate the effect of NVC-containing terpolymers on the surface properties and bond strength to dentin of GIC (glass-ionomer cement), and to evaluate the effect of NVC-containing terpolymer as a dentin conditioner. The terpolymer of acrylic acid (AA)-itaconic acid (IA)-N-vinylcaprolactam (NVC) with a molar ratio of 8:1:1 (AA:IA:NVC) was synthesized by free radical polymerization and characterized using nuclear magnetic resonance ((1)H-NMR) and Fourier transform infrared spectroscopy (FTIR). The synthesized terpolymer was used in glass-ionomer cement formulations (Fuji IX GP). Ten disc-shaped specimens (12 × 1 mm) were mixed and fabricated at room temperature. Surface properties (wettability) of modified cements were studied by contact angle measurements as a function of time. Work of adhesion values of different surfaces were also determined. The effect of NVC-modified polyacid on the bond strength of glass-ionomer cement to dentin was investigated. The mean data obtained from contact angle and bonding strength measurements were subjected to t test and 2-way ANOVA (α=.05). NVC-modified glass-ionomer cements showed significantly (P<.05) lower contact angles (46 degrees) and higher work of adhesion (W(A)=60.33 erg/cm(2)) in comparison to commercially available Fuji IX GP (57 degrees and W(A)=53.01 erg/cm(2)). The wettability of dentin surfaces conditioned with NVC-containing terpolymer was significantly higher (P<.05) (22 degrees, WA=73.77 erg/cm(2)) than dentin conditioned with GC dentin conditioner (29 degrees, W(A)=70.52 erg/cm(2)). The experimental cement also showed significantly higher values for shear bond strength to dentin (8.7 ±0.15 MPa after 1 month) when compared to the control group (8.4 ±0.13 MPa after 1 month). NVC-containing terpolymers may enhance the surface properties of GICs and increase their bond strength to the dentin. Furthermore, NVC-containing polyelectrolytes are better dentin conditioners than a commercially available dentin conditioner (GC dentin conditioner). Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Effect of gamma irradiation on the wear behavior of human tooth dentin.

PubMed

Qing, Ping; Huang, Shengbin; Gao, ShanShan; Qian, LinMao; Yu, HaiYang

2016-12-01

The objective of this study was to evaluate the effect of gamma irradiation on the wear behavior of human tooth dentin in terms of possible alterations in crystallinity, grain size, and composition. Human premolars (n = 19) were collected to obtain the perpendicular or parallel to the direction of the dentin tubule specimens. Each specimen was subjected to 60 Gy of gamma irradiation, in daily increments of 2 Gy. The nanoscratch tests were conducted. The scratch traces were observed via scanning electron microscope (SEM) and surface profilometer. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to investigate the alteration of crystallography and chemical composition of dentin after irradiation. The change of surface microhardness (SMH) was also evaluated. The nanoscratch results showed that the friction coefficient of dentin after irradiation became higher, and the depths and widths of scratch were greater than that of dentin before irradiation. Additionally, irradiation decreased the crystallinity of dentin and induced the formation of bigger crystals. The carbonate/mineral ratio was increased. Furthermore, a significant reduction in microhardness after irradiation was observed. The main damage mechanisms consisted of the formation of delamination and crack in both the specimens cut perpendicular and parallel to tubule dentin after irradiation. Irradiation affected directly the wear behavior of tooth dentin, accompanied by the alterations in crystallography, chemical composition, and surface microhardness of dentin. This would help extend understanding the influence of irradiation on dentin and provide suggestions for selecting more suitable materials for irradiated tooth.

Evaluation of dentin tubule occlusion after laser irradiation and desensitizing agent application.

PubMed

Kim, Min-Ho; Kim, Ryan Jin-Young; Lee, Woo-Cheol; Lee, In-Bog

2015-10-01

To evaluate the effects of lasers (Nd:YAG and Er:YAG) and of topical desensitizing agents on dentin tubule occlusion by measuring real-time dentin fluid flow (DFF). 32 molars were prepared with V-shape cavity at the cervical area, acid-etched, water rinsed, blotted dry, and treated with (1) Nd:YAG laser; (2) Er:YAG laser; (3) SuperSeal, a desensitizing agent; (4) ClinproXT, a resin-modified glass-ionomer (RMGI) varnish (n = 8 each). A real-time fluid flow measuring instrument (nano-Flow) was used to measure the DFF throughout the procedures. The DFF rates before and after the treatment were compared. Moreover, the surface topography of dentin tubules after each desensitizing method was examined using SEM. DFF varied among the groups. The DFF rate was significantly reduced after laser irradiation/application of the desensitizing agents (P < 0.05). ClinproXT showed the greatest reduction of DFF rate (71.9%), followed by the SuperSeal (34.8%) and laser groups (P< 0.05). However, there was no significant difference between the Nd:YAG (24.1%) and Er:YAG (20.6%) groups (P > 0.05). In SEM images, narrowed dentin tubules were observed in both lased groups and SuperSeal group. In the ClinproXT group, the occluded dentin tubules by the RMGI covering were observed.

Influence of dentinal regions on bond strengths of different adhesive systems.

PubMed

Ozer, F; Unlü, N; Sengun, A

2003-06-01

This in vitro study assessed comparatively the shear bond strengths of three composite resins, 3M Valux Plus (3MVP), Herculite (H), Clearfil AP-X (CAP-X), a polyacid modified composite resin Dyract (D), and a resin modified glass-ionomer materials Vitremer (V), to cervical and buccal dentine regions of extracted human molar teeth. Four different bonding systems, 3M ScotchBond Multipurpose (SB), Clearfil Liner Bond 2 (LB2), Opti Bond (OB), and Prime & Bond 2.1 (PB 2.1) were used with the manufacturer's respective composite and compomer materials. One hundred freshly extracted mandibular molar teeth were selected for this study. Flat buccal dentine surfaces were created on 50 teeth and cylindrical rods of the five materials were bonded to the dentine surfaces. For assessment of cervical bond strengths, the materials were bonded to mesial and distal enamel bordered occlusal dentinal surfaces of the remaining 50 teeth. The five groups of restorative procedures were applied as follows; Group 1: SB + 3MVP, Group 2: LB2 + CAP-X, Group 3: OB + H, Group 4: PB2.1 + D, Group 5: Vitremer primer (VP) VP + V. Each restorative procedure thus had 20 specimens (10 buccal + 10 cervical). After 24 h of water storage (37 degrees C), the specimens were tested on a Universal Testing machine in shear with a cross head speed of 0.5 mm min-1. The bond strength values were calculated in MPa and the results were evaluated statistically using Kruskal-Wallis one-way/anova and Mann-Whitney U-tests. It was found that the bond strengths of SB + 3MVP, LB2 + CAP-X and VP + V to buccal dentine surfaces were significantly stronger (P < 0.05) than those to the occluso-cervical dentine floors. When the bond strengths to the occluso-cervical dentine and buccal dentine surface were compared, there was no significant difference between the materials (P > 0.05). Vitremer was found the least successful adhesive material in terms of shear bond strength on both buccal and occluso-cervical dentine surfaces.

Influence of Nd:YAG laser on the bond strength of self-etching and conventional adhesive systems to dental hard tissues.

PubMed

Marimoto, A K; Cunha, L A; Yui, K C K; Huhtala, M F R L; Barcellos, D C; Prakki, A; Gonçalves, S E P

2013-01-01

The aim of this study was to investigate the influence of Nd:YAG laser on the shear bond strength to enamel and dentin of total and self-etch adhesives when the laser was applied over the adhesives, before they were photopolymerized, in an attempt to create a new bonding layer by dentin-adhesive melting. One-hundred twenty bovine incisors were ground to obtain flat surfaces. Specimens were divided into two substrate groups (n=60): substrate E (enamel) and substrate D (dentin). Each substrate group was subdivided into four groups (n=15), according to the surface treatment accomplished: X (Xeno III self-etching adhesive, control), XL (Xeno III + laser Nd:YAG irradiation at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental), S (acid etching + Single Bond conventional adhesive, Control), and SL (acid etching + Single Bond + laser Nd:YAG at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental). The bonding area was delimited with 3-mm-diameter adhesive tape for the bonding procedures. Cylinders of composite were fabricated on the bonding area using a Teflon matrix. The teeth were stored in water at 37°C/48 h and submitted to shear testing at a crosshead speed of 0.5 mm/min in a universal testing machine. Results were analyzed with three-way analysis of variance (ANOVA; substrate, adhesive, and treatment) and Tukey tests (α=0.05). ANOVA revealed significant differences for the substrate, adhesive system, and type of treatment: lased or unlased (p<0.05). The mean shear bond strength values (MPa) for the enamel groups were X=20.2 ± 5.61, XL=23.6 ± 4.92, S=20.8 ± 4.55, SL=22.1 ± 5.14 and for the dentin groups were X=14.1 ± 7.51, XL=22.2 ± 6.45, S=11.2 ± 5.77, SL=15.9 ± 3.61. For dentin, Xeno III self-etch adhesive showed significantly higher shear bond strength compared with Single Bond total-etch adhesive; Nd:YAG laser irradiation showed significantly higher shear bond strength compared with control (unlased). Nd:YAG laser application prior to photopolymerization of adhesive systems significantly increased the bond strength to dentin.

Effect of surface protection on the permeability of eroded dentin

PubMed Central

Martins, Vivian Leite; da Costa Ramos, Rodrigo Vitoria; Pimenta Lima, Max José; Correia de Araújo, Roberto Paulo; Cavalcanti, Andrea Nóbrega

2018-01-01

Context: Eroded dentin might present the opening of dentinal tubules, increasing permeability, and consequently dentinal hypersensitivity. Aims: This study evaluated the permeability of dentin surfaces exposed to different levels of erosion and methods of surface protection. Materials and Methods: Dentine samples (3 mm × 3 mm × 1 mm) were prepared from bovine incisors (n = 90) and divided into three groups according to the method of controlling erosive challenge: Negative control, topical fluoride application, and glass ionomer sealant. Subsequently, they were randomly divided into three subgroups according to the exposure of simulated gastric acid solution (Demineralization – DES) (5% HCl, pH = 2.2), and remineralization (RE); negative control, 9 and 18 cycles DES-RE. The dentin permeability was measured by assessing the hydraulic conductance (μl/min.cmH2O.cm2). Statistical analysis was performed by two-way ANOVA and Tukey's test. Results and Conclusions: Greater permeability was observed after 18 erosive cycles, followed by exposure to 9 cycles and negative control (P < 0.0001). The application of glass ionomer sealant resulted in a major reduction of the hydraulic conductivity, regardless of the erosive challenge. Control groups and topical fluoride application showed similar results. In conclusion, the severity of erosive challenge contributed to the increase of dentin permeability. Besides, the glass ionomer sealant was the only protection agent that promoted significant effects in dentin permeability. PMID:29628641

Dentine Tubule Occlusion by Novel Bioactive Glass-Based Toothpastes

PubMed Central

Hill, Robert G.; Chen, Xiaojing

2018-01-01

There are numerous over-the-counter (OTC) and professionally applied (in-office) products and techniques currently available for the treatment of dentine hypersensitivity (DH), but more recently, the use of bioactive glasses in toothpaste formulations have been advocated as a possible solution to managing DH. Aim. The aim of the present study, therefore, was to compare several bioactive glass formulations to investigate their effectiveness in an established in vitro model. Materials and Methods. A 45S5 glass was synthesized in the laboratory together with several other glass formulations: (1) a mixed glass (fluoride and chloride), (2) BioMinF, (3) a chloride glass, and (4) an amorphous chloride glass. The glass powders were formulated into five different toothpaste formulations. Dentine discs were sectioned from extracted human teeth and prepared for the investigation by removing the cutting debris (smear layer) following sectioning using a 6% citric acid solution for 2 minutes. Each disc was halved to provide test and control halves for comparison following the brushing of the five toothpaste formulations onto the test halves for each toothpaste group. Following the toothpaste application, the test discs were immersed in either artificial saliva or exposed to an acid challenge. Results. The dentine samples were analyzed using scanning electron microscopy (SEM), and observation of the SEM images indicated that there was good surface coverage following artificial saliva immersion. Furthermore, although the acid challenge removed the hydroxyapatite layer on the dentine surface for most of the samples, except for the amorphous chloride glass, there was evidence of tubular occlusion in the dentine tubules. Conclusions. The conclusions from the study would suggest that the inclusion of bioactive glass into a toothpaste formulation may be an effective approach to treat DH. PMID:29849637

Influence of five home whitening gels and a remineralizing gel on the enamel and dentin ultrastructure and hardness.

PubMed

Pinheiro, Helena Burlamaqui; Cardoso, Paulo Eduardo Capel

2011-06-01

To investigate the influence of calcium phosphate enhanced home whitening agents on human enamel and dentin surface microhardness and ultramorphology. Five intact molars crowns were used for ultrastructural analysis and five for microhardness test. Each resulting coronal structure was cut in slices. After measuring baseline Knoop Hardness Number (KHN) of the enamel and dentin, the slices were divided into six experimental groups and one control (n= 5). G1= 15% carbamide peroxide (CP); G2= 16% CP; G3= Ca and PO4 (remineralizing agent); G4= 16% CP with Ca and PO4; G5= 7.5% hydrogen peroxide (HP) with Ca and PO4; G6=7.5% HP with Ca. After each daily session of treatment, specimens were stored in distilled water (37 degrees C) until the next session. Products were applied for 2 weeks, according to manufacturers' instructions. Additional KHN weredetermined. Conventional whitening agents (G1; G2) and the gel with Ca (G6), caused KHN decrease (P< 0.05).The remineralizing and whitening agents with Ca and PO4 (G3; G4; G5) did not change KHN. A change of morphology was observed on enamel and dentin surfaces in G1; G2; G5.

Potential effects of tooth-brushing on human dentin wear following exposure to acidic soft drinks.

PubMed

Choi, S; Park, K-H; Cheong, Y; Moon, S W; Park, Y-G; Park, H-K

2012-08-01

This study used scanning electron microscopy and atomic force microscopy to examine the short-term potential effects of brushing time and the start-time of tooth-brushing after demineralization on primary dentin wear in vitro. Thirty-six noncarious primary central incisors were assigned to 12 experimental groups. Exposure to cola drinks was used to initiate the demineralization process. Three brushing times (5, 15 and 30 s) and four start-times of brushing (0, 30, 60 and 120 min) after an erosive attack were used for the abrasion process. Tooth-brushing the softened dentin surface led to increases in the open tubular fraction and microstructural changes on the dentin surface. Brushing immediately after exposure to cola resulted in the greatest irreversible dentin loss, whereas brushing 60 or 120 min after pretreatment resulted in the least irreversible dentin loss. However, brushing time had no effect on the irreversible loss of dentin wear. Based on these experimental results, tooth-brushing should be performed at least 60 min after consuming a cola drink to achieve the desired tooth cleaning and avoid the introduction of surface lesions on dentin. © 2012 The Authors Journal of Microscopy © 2012 Wadsworth Center, New York State Department of Health.

Influence of air-powder polishing on bond strength and surface-free energy of universal adhesive systems.

PubMed

Tamura, Yukie; Takamizawa, Toshiki; Shimamura, Yutaka; Akiba, Shunsuke; Yabuki, Chiaki; Imai, Arisa; Tsujimoto, Akimasa; Kurokawa, Hiroyasu; Miyazaki, Masashi

2017-11-29

The influences of air-powder polishing with glycine or sodium bicarbonate powders on shear bond strengths (SBS) and surface-free energies of universal adhesives were examined. Scotchbond Universal Adhesive (SU, 3M ESPE), G-Premio Bond (GP, GC), Adhese Universal (AU, Ivoclar Vivadent), and All-Bond Universal (AB, Bisco) were used in this study. Bovine dentin surfaces were air polished with glycine or sodium bicarbonate powders prior to the bonding procedure, and resin pastes were bonded to the dentin surface using universal adhesives. SBSs were determined after 24-h storage in distilled water at 37°C. Surface-free energy was then determined by measuring contact angles using three test liquids on dentin surfaces. Significantly lower SBSs were observed for dentin that was air-powder polished and surface-free energies were concomitantly lowered. This study indicated that air-powder polishing influences SBSs and surface-free energies. However, glycine powder produced smaller changes in these surface parameters than sodium bicarbonate.

Optothermal transfer simulation in laser-irradiated human dentin.

PubMed

Moriyama, Eduardo H; Zangaro, Renato A; Lobo, Paulo D C; Villaverde, Antonio Balbin; Pacheco, Marcos T; Watanabe, Ii-Sei; Vitkin, Alex

2003-04-01

Laser technology has been studied as a potential replacement to the conventional dental drill. However, to prevent pulpal cell damage, information related to the safety parameters using high-power lasers in oral mineralized tissues is needed. In this study, the heat distribution profiles at the surface and subsurface regions of human dentine samples irradiated with a Nd:YAG laser were simulated using Crank-Nicolson's finite difference method for different laser energies and pulse durations. Heat distribution throughout the dentin layer, from the external dentin surface to the pulp chamber wall, were calculated in each case, to investigate the details of pulsed laser-hard dental tissue interactions. The results showed that the final temperature at the pulp chamber wall and at the dentin surface are strongly dependent on the pulse duration, exposure time, and the energy contained in each pulse.

[Evaluation of pH variation and cervical dentin permeability in teeth submitted to bleaching treatment].

PubMed

Dezotti, Mariela S G; Souza, Mário Honorato Silva e; Nishiyama, Celso Kenji

2002-01-01

External cervical root resorption is one of the disadvantages of the bleaching procedure. There are several mechanisms that may be responsible for causing resorption, such as the chemical and physical action of the utilized materials and the morphology of the cementoenamel junction. The purpose of this study was to investigate the presence of a communication between the pulp chamber and the external root surface. The investigation was carried out by means of pH tests and measurement of dye infiltration into cervical dentin after the bleaching procedure. Thirty-four human permanent incisors were submitted to endodontic treatment. The teeth were assigned to three experimental groups, according to the level at which the filling was cut, and to the sealing of the root canal entrance with glass ionomer cement. Sodium perborate and 30% hydrogen peroxide were utilized for bleaching. pH readings were carried out after 30 minutes, 24 h, 48 h and 72 h from the beginning of the procedure. The teeth were immersed in 0.5% basic fuchsin for 24 h in order to determine possible differences in the permeability of cervical dentin. The results revealed that pH tended to change when the root filling was cut at the entrance of the canal, when 2 mm of the filling were removed, and when the canal entrance was sealed with glass ionomer. Dentinal permeability increased in the three experimental groups, in comparison with the control group. These slight differences may suggest a communication between the pulp chamber and the external root surface.

Can 1% chlorhexidine diacetate and ethanol stabilize resin-dentin bonds?

PubMed Central

Manso, Adriana Pigozzo; Grande, Rosa Helena Miranda; Bedran-Russo, Ana Karina; Reis, Alessandra; Loguercio, Alessandro D.; Pashley, David Henry; Carvalho, Ricardo Marins

2014-01-01

Objectives To examine the effects of the combined use of chlorhexidine and ethanol on the durability of resin-dentin bonds. Methods Forty-eight flat dentin surfaces were etched (32% phosphoric acid), rinsed (15 s) and kept wet until bonding procedures. Dentin surfaces were blot-dried with absorbent paper and re-wetted with water (Water, control), 1% chlorhexidine diacetate in water (CHD/Water), 100% ethanol (Ethanol), or 1% chlorhexidine diacetate in ethanol (CHD/Ethanol) solutions for 30 s. They were then bonded with All Bond 3 (AB3, Bisco) or Excite (EX, Ivoclar-Vivadent) using a smooth, continuous rubbing application (10 s), followed by 15 s gentle air stream to evaporate solvents. The adhesives were light-cured (20 s) and resin composite build-ups constructed for the microtensile method. Bonded beams were obtained and tested after 24-hours, 6-months and 15-months of water storage at 37°C. Storage water was changed every month. Effects of treatment and testing periods were analyzed (ANOVA, Holm-Sidak, p<0.05) for each adhesive. Results There were no interactions between factors for both etch-and-rinse adhesives. AB3 was significantly affected only by storage (p = 0.003). Excite was significantly affected only by treatments (p = 0.048). AB3 treated either with ethanol or CHD/ethanol resulted in reduced bond strengths after 15 months. The use of CHD/ethanol resulted in higher bond strengths values for Excite. Conclusions Combined use of ethanol/1% chlorhexidine diacetate did not stabilize bond strengths after 15 months. PMID:24815823

Influence of various bonding techniques on the fracture strength of thin CAD/CAM-fabricated occlusal glass-ceramic veneers.

PubMed

Yazigi, Christine; Kern, Matthias; Chaar, Mohamed Sad

2017-11-01

To evaluate the efficiency of immediate dentin sealing and the effects of different bonding protocols on the fracture strength of CAD/CAM occlusal veneers bonded to exposed dentin. Ninety-six extracted maxillary premolars were initially divided into three main groups with 32 specimens each: without immediate dentin sealing, immediate dentin sealing/total etching and immediate dentin sealing/selective etching. Teeth were identically prepared in the dentin to receive occlusal veneers of 0.8mm thickness, milled from lithium disilicate ceramic blocks (IPS e.max CAD). Each main group was later subdivided, according to the pre-cementation surface etching protocol (total/selective), into two subgroups with 16 specimens each. All restorations were adhesively bonded using a resin cement (Variolink Esthetic). Half of the specimens of each subgroup were subjected to thermo-dynamic loading in a chewing simulator with 1,200,000 cycles at 10kg load. The other half and the surviving specimens were subjected to quasi-static loading until failure. Statistical analysis was performed using three-way ANOVA and Tukey's post-hoc tests. All specimens except one survived the artificial aging. A significantly higher fracture strength of restorations (p ≤ 0.001) was obtained when immediate dentin sealing was followed regardless of the etching method with values ranging from a minimum of 1122 ± 336N to a maximum of 1853 ± 333N. Neither the pre-cementation treatment nor the artificial aging had a statistical significant effect on the fracture strength. Immediate dentin sealing protocol is recommended whenever dentin is exposed during the preparation for thin glass-ceramic occlusal veneers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surface modification of several dental substrates by non-thermal, atmospheric plasma brush.

PubMed

Chen, Mingsheng; Zhang, Ying; Sky Driver, M; Caruso, Anthony N; Yu, Qingsong; Wang, Yong

2013-08-01

The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of four dental substrates. Specimens of dental substrates including dentin, enamel, and two composites Filtek Z250, Filtek LS Silorane were prepared (∼2mm thick, ∼10mm diameter). The prepared surfaces were treated for 5-45s with a non-thermal atmospheric plasma brush working at temperatures from 36 to 38°C. The plasma-treatment effects on these surfaces were studied with contact-angle measurement, X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM). The non-thermal atmospheric argon plasma brush was very efficient in improving the surface hydrophilicity of four substrates studied. The results indicated that water contact angle values decreased considerably after only 5s plasma treatment of all these substrates. After 30s treatment, the values were further reduced to <5°, which was close to a value for super hydrophilic surfaces. XPS analysis indicated that the percent of elements associated with mineral in dentin/enamel or fillers in the composites increased. In addition, the percent of carbon (%C) decreased while %O increased for all four substrates. As a result, the O/C ratio increased dramatically, suggesting that new oxygen-containing polar moieties were formed on the surfaces after plasma treatment. SEM surface images indicated that no significant morphology change was induced on these dental substrates after exposure to plasmas. Without affecting the bulk properties, a super-hydrophilic surface could be easily achieved by the plasma brush treatment regardless of original hydrophilicity/hydrophobicity of dental substrates tested. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Surface modification of several dental substrates by non-thermal, atmospheric plasma brush

PubMed Central

Chen, Mingsheng; Zhang, Ying; Driver, M. Sky; Caruso, Anthony N.; Yu, Qingsong; Wang, Yong

2013-01-01

Objective The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of four dental substrates. Methods Specimens of dental substrates including dentin, enamel, and two composites Filtek Z250, Filtek LS Silorane were prepared (~2 mm thick, ~10 mm diameter). The prepared surfaces were treated for 5–45 s with a non-thermal atmospheric plasma brush working at temperatures from 36 to 38 °C. The plasma-treatment effects on these surfaces were studied with contact-angle measurement, X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM). Results The non-thermal atmospheric argon plasma brush was very efficient in improving the surface hydrophilicity of four substrates studied. The results indicated that water contact angle values decreased considerably after only 5 s plasma treatment of all these substrates. After 30 s treatment, the values were further reduced to <5°, which was close to a value for super hydrophilic surfaces. XPS analysis indicated that the percent of elements associated with mineral in dentin/enamel or fillers in the composites increased. In addition, the percent of carbon (%C) decreased while %O increased for all four substrates. As a result, the O/C ratio increased dramatically, suggesting that new oxygen-containing polar moieties were formed on the surfaces after plasma treatment. SEM surface images indicated that no significant morphology change was induced on these dental substrates after exposure to plasmas. Significance Without affecting the bulk properties, a super-hydrophilic surface could be easily achieved by the plasma brush treatment regardless of original hydrophilicity/hydrophobicity of dental substrates tested. PMID:23755823

Silicone Disclosing Material used after Ceramic Surface Treatment Reduces Bond Strength.

PubMed

Fraga, Sara; Oliveira, Sara Cioccari; Pereira, Gabriel Kalil Rocha; Beekman, Pieter; Rippe, Marília Pivetta; Kleverlaan, Cornelis J

To evaluate the effect of a silicone disclosing procedure performed at different timepoints on the shear bond strength (SBS) of cements (self-adhesive composite cement, self-etch composite cement, resin-reinforced glass-ionomer cement) to different substrates (zirconia, lithium disilicate, bovine dentin). The substrate/cement combinations were assigned to two groups (n = 15) according to the timepoint, at which the vinyl polyether silicone disclosing agent was applied: after (experimental groups, EXP) or before (control groups, CTRL) specific micromechanical treatments of the substrate surface. To increase standardization, the cements were applied into rubber rings (2.2 mm diameter x 1.0 mm thickness) positioned on the substrate surface. After luting procedures, all specimens were stored in 37°C distilled water for 24 h, then subjected to SBS testing using a wire loop of 0.2 mm diameter at a crosshead speed of 1 mm/min until failure. Failure analysis was performed for all tested specimens. SBS data were submitted to Weibull analysis. The silicone disclosing procedure performed after micromechanical surface treatment reduced the characteristic shear bond strength to zirconia and lithium disilicate when compared to CTRL. However, for dentin specimens, there was no significant difference between CTRL and EXP for any of the cements investigated. Failure analysis showed a predominance of interfacial failures. The silicone disclosing procedure performed after the micromechanical treatment of ceramic surfaces negatively affected the cement bond strength. Therefore, after using it to check the fit of a prosthesis, clinicians should carefully clean the ceramic surface.

Effects of acid etching and adhesive treatments on host-derived cysteine cathepsin activity in dentin.

PubMed

Zhang, Wenhao; Yang, Weixiang; Wu, Shuyi; Zheng, Kaibin; Liao, Weili; Chen, Boli; Yao, Ke; Liang, Guobin; Li, Yan

2014-10-01

To analyze the effects of different processes during bonding on endogenous cysteine cathepsin activity in dentin. Dentin powder, prepared from extracted human third molars, was divided into 10 groups. Two lots of dentin powder were used to detect the effects of the procedure of protein extraction on endogenous cathepsin activity. The others were used to study effects of different acid-etching or adhesive treatments on enzyme activity. Concentrations of 37% phosphoric acid or 10% phosphoric acid, two etch-and-rinse adhesive systems, and two self-etching adhesive systems were used as dentin powder treatments. The untreated mineralized dentin powder was set as the control. After treatment, the proteins of each group were extracted. The total cathepsin activity in the extracts of each group was monitored with a fluorescence reader. In the control group, there were no significant differences in cathepsin activity between the protein extract before EDTA treatment and the protein extract after EDTA treatment (p > 0.05). The cathepsin activities of the three different extracts in the 37% phosphoric acid-treated group were different from each other (p < 0.05). The two acid-etching groups and two etch-and-rinse groups showed significant enzyme activity reduction vs the control group (p < 0.05). There were no significant differences between those four groups (p > 0.05). Treating the dentin powder with any of the two self-etching adhesives resulted in an increase in cathepsin activity (p < 0.05). The activity of cysteine cathepsins can be detected in dentin powder. Treatment with EDTA during protein extraction exerted an influence on cathepsin activity. Acid etching or etch-and-rinse adhesive systems may reduce the activity of endogenous cathepsins in dentin. Self-etching adhesive systems may increase the enzyme activity.

Characterization of Chlorhexidine-Loaded Calcium-Hydroxide Microparticles as a Potential Dental Pulp-Capping Material

PubMed Central

Priyadarshini, Balasankar M.; Selvan, Subramanian T.; Narayanan, Karthikeyan; Fawzy, Amr S.

2017-01-01

This study explores the delivery of novel calcium hydroxide [Ca(OH)2] microparticles loaded with chlorhexidine (CHX) for potential dental therapeutic and preventive applications. Herein, we introduce a new approach for drug-delivery to deep dentin-surfaces in the form of drug-loaded microparticles. Unloaded Ca(OH)2 [Ca(OH)2/Blank] and CHX-loaded/Ca(OH)2 microparticles were fabricated by aqueous chemical-precipitation technique. The synthesized-microparticles were characterized in vitro for determination of surface-morphology, crystalline-features and thermal-properties examined by energy-dispersive X-ray scanning and transmission electron-microscopy (EDX-SEM/TEM), Fourier-transform infrared-spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning-calorimetry (DSC). Time-related pH changes, initial antibacterial/biofilm-abilities and cytotoxicity of CHX-loaded/Ca(OH)2 microparticles were evaluated. Microparticles were delivered to dentin-surfaces with subsequent SEM examination of treated dentin-substrates. The in vitro and ex vivo CHX-release profiles were characterized. Ca(OH)2/Blank were hexagonal-shaped with highest z-average diameter whereas CHX-inclusion evidenced micro-metric spheres with distinguishable surface “rounded deposits” and a negative-shift in diameter. CHX:Ca(OH)2/50 mg exhibited maximum encapsulation-efficiency with good antibacterial and cytocompatible properties. SEM examination revealed an intact layer of microparticles on exposed dentin-surfaces with retention of spherical shape and smooth texture. Microparticles loaded on dentin-surfaces showed prolonged release of CHX indicating substantial retention on dentin-substrates. This study validated the inherent-applicability of this novel drug-delivery approach to dentin-surfaces using micro-metric CHX-loaded/Ca(OH)2 microparticles. PMID:28952538

In vitro photodynamic antimicrobial chemotherapy in dentine contaminated by cariogenic bacteria

NASA Astrophysics Data System (ADS)

Melo, M. A. S.; de-Paula, D. M.; Lima, J. P. M.; Borges, F. M. C.; Steiner-Oliveira, C.; Nobre-Dos-Santos, M.; Zanin, I. C. J.; Barros, E. B.; Rodrigues, L. K. A.

2010-06-01

The development of a method to ensure bacterial-free substrates without extensive cavity preparation would be highly useful to dentistry, since there is no currently available effective method for killing residual bacteria in dentinal tissue. This randomized in vitro study determined parameters for using toluidine blue O (TBO) with a light-emitting diode (LED) for dentine caries disinfection and monitored intrapulpal/periodontal temperatures during irradiation. Occlusal human dentine slabs were immersed in Streptococcus mutans culture for demineralization induction. Slabs were allocated to 10 groups ( n = 15), which were treated with 0.1 mg ml-1 TBO with 5 min of incubation time or 0.9% NaCl solution for 5, 10 or 15 min, and submitted or not to irradiation for 5, 10 or 15 min (47, 94, and 144 J/cm2). Before and after treatments, dentine samples were analyzed with regard to S. mutans counts. In whole teeth, temperature in pulp and periodontium was measured by thermocouples during irradiation. Kruskal-Wallis/Student-Newman-Keuls, and ANOVA/Tukey test were respectively utilized to compare log reductions and temperature rises between groups. Bacterial reduction was observed when dentine was exposed to both TBO and LED at all irradiation times, as well as to LED alone for 10 and 15 min. Temperature increases lower than 2°C were observed for either pulp or periodontium. Concluding, LED combined with TBO is a safe and effective approach for dentine caries disinfection. Nevertheless, additional studies should be conducted to determine the influence of the irradiation in S. mutans viability in dentinal surface/tubules.

Influence of CVD diamond tips and Er:YAG laser irradiation on bonding of different adhesive systems to dentin.

PubMed

da Silva, Melissa Aline; Di Nicolo, Rebeca; Barcellos, Daphne Camara; Batista, Graziela Ribeiro; Pucci, Cesar Rogerio; Rocha Gomes Torres, Carlos; Borges, Alessandra Bühler

2013-01-01

The aim of this study was to compare the microtensile bond strength of three adhesive systems, using different methods of dentin preparation. A hundred and eight bovine teeth were used. The dentin from buccal face was exposed and prepared with three different methods, divided in 3 groups: Group 1 (DT)- diamond tip on a high-speed handpiece; Group 2 (CVD)-CVD tip on a ultrasonic handpiece; Group 3 (LA)-Er: YAG laser. The teeth were divided into 3 subgroups, according adhesive systems used: Subgroup 1-Adper Single Bond Plus/3M ESPE (SB) total-etch adhesive; Subgroup 2-Adper Scotchbond SE/3M ESPE (AS) selfetching adhesive; Subgroup 3-Clearfil SE Bond/Kuraray (CS) selfetching adhesive. Blocks of composite (Filtek Z250-3M ESPE) 4 mm high were built up and specimens were stored in deionized water for 24 hours at 37°C. Serial mesiodistal and buccolingual cuts were made and stick-like specimens were obtained, with transversal section of 1.0 mm(2). The samples were submitted to microtensile test at 1 mm/min and load of 10 kg in a universal testing machine. Data (MPa) were subjected to ANOVA and Tukey's tests (p < 0.05). Surface treatment with Diamond or CVD tips associated with Clearfil SE Bond adhesive produced significantly lower bond strength values compared to other groups. Surface treatment with Er: YAG laser associated with Single Bond Plus or Clearfil SE Bond adhesives and surface treatment with CVD tip associated with Adper Scotchbond SE adhesive produced significantly lower bond strength values compared to surface treatment with diamond or CVD tips associated with Single Bond Plus or Adper Scotchbond SE adhesives. Interactions between laser and the CVD tip technologies and the different adhesive systems can produce a satisfactory bonding strength result, so that these associations may be beneficial and enhance the clinical outcomes.

Grinding efficiency of abutment tooth with both dentin and core composite resin on axial plane.

PubMed

Miho, Otoaki; Sato, Toru; Matsukubo, Takashi

2015-01-01

The purpose of this study was to evaluate grinding efficiency in abutment teeth comprising both dentin and core composite resin in the axial plane. Grinding was performed over 5 runs at two loads (0.5 or 0.25 N) and two feed rates (1 or 2 mm/sec). The grinding surface was observed with a 3-D laser microscope. Tomographic images of the grinding surfaces captured perpendicular to the feed direction were also analyzed. Using a non-ground surface as a reference, areas comprising only dentin, both dentin and core composite resin, or only core composite resin were analyzed to determine the angle of the grinding surface. Composite resins were subjected to the Vickers hardness test and scanning electron microscopy. Data were statistically analyzed using a one-way analysis of variance and multiple comparison tests. Multiple regression analysis was performed for load, feed rate, and Vickers hardness of the build-up material depending on number of runs. When grinding was performed at a constant load and feed rate, a greater grinding angle was observed in areas comprising both dentin and composite resin or only composite resin than in areas consisting of dentin alone. A correlation was found between machinability and load or feed rate in areas comprising both dentin and composite resin or composite resin alone, with a particularly high correlation being observed between machinability and load. These results suggest that great caution should be exercised in a clinical setting when the boundary between the dentin and composite resin is to be ground, as the angle of the grinding surface changes when the rotating diamond point begins grinding the composite resin.

Shear bond strength of a new one-bottle dentin adhesive.

PubMed

Swift, E J; Bayne, S C

1997-08-01

To test the shear bond strength of a new adhesive, 3M Single Bond, to dentin surfaces containing different degrees of moisture. Two commercially available one-bottle adhesives (Prime & Bond, One-Step) and a conventional three-step system (Scotchbond Multi-Purpose Plus) were included for comparison. 120 bovine teeth were embedded in acrylic and the labial surfaces were polished to 600 grit to create standardized dentin surfaces for testing. Resin composite was bonded to dentin using a gelatin capsule technique. Four adhesive systems were evaluated with three different degrees of surface moisture (moist, wet, and overwet). Shear bond strengths of adhesives to dentin were determined using a universal testing machine and analyzed by ANOVA and Tukey's post hoc tests. Single Bond had mean shear bond strengths of 19.2, 23.2 and 20.3 MPa to moist, wet, and overwet dentin, respectively. Bond strengths of the three-component system Scotchbond Multi-Purpose Plus ranged from 23.1 to 25.3 MPa, but were not significantly higher than the values for Single Bond. Prime & Bond had bond strengths similar to those of Single Bond, but One-Step had significantly lower bond strengths (P < 0.05) in the wet and overwet conditions.

Mechanical characterization of proanthocyanidin-dentin matrix interaction

PubMed Central

Castellan, Carina Strano; Pereira, Patricia Nobrega; Grande, Rosa Helena Miranda; Bedran-Russo, Ana Karina

2010-01-01

Objectives To characterize the properties of dentin matrix treated with two proanthocyanidin rich cross-linking agents and their effect on dentin bonded interfaces. Methods Sound human molars were cut into 0.5 mm thick dentin slabs, demineralized and either treated with one of two cross-linking agents (grape seed - GSE and cocoa seed - COE extracts) or left untreated. The modulus of elasticity of demineralized dentin was assessed after 10 or 60 min and the swelling ratio after 60 min treatment. Bacterial collagenase was also used to assess resistance to enzymatic degradation of samples subjected to ultimate tensile strength. The effect of GSE or COE on the resin-dentin bond strength was evaluated after 10 or 60 min of exposure time. Data were statistically analyzed at a 95% confidence interval. Results Both cross-linkers increased the elastic modulus of demineralized dentin as exposure time increased. Swelling ratio was lower for treated samples when compared to control groups. No statistically significant changes to the UTS indicate that collagenase had no effect on dentin matrix treated with either GSE or COE. Dentin-resin bonds significantly increased following treatment with GSE regardless of the application time or adhesive system used. Significance Increased mechanical properties and stability of dentin matrix can be achieved by the use of PA-rich collagen cross-linkers most likely due to the formation of a PA-collagen complex. The short term dentin-resin bonds can be improved after 10 minutes dentin treatment. PMID:20650510

[Effects of different surface modifications on micro-structure and adhesion of zirconia ceramic: an in vitro study].

PubMed

Siwen, Li; Shishi, Li; Yanhong, Wang; Hongmei, Ma

2017-02-01

This study evaluated the effect of different mechanical-chemical surface treatments on the characteristics, microstructure, and composition of zirconia ceramics and on the zirconia-dentin adhesion. The sintered commercial zirconia blocks (IPS e.max ZirCAD) were sectioned into 126 beams (6 mm×6 mm×5 mm) and randomly assigned to seven experimental groups (n=18). The zirconia block specimens were further treated as follows: (A) untreated, as control; (B) sandblasted with 50 μm Al2O3; (C) sandblasted with 50 μm Al2O3+30 μm silica powder; (D) sandblasted with 50 μm Al2O3+30% silica-sol coating; (E) sandblasted with 110 μm Al2O3; (F) sandblasted with 110 μm Al2O3+30 μm silica powder; and (G) sandblasted with 110 μm Al2O3+30% silica-sol coating. The surface roughness (Ra) of zirconia ceramics using X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) after seven surface treatments was analyzed. Seventy specimens of dentin surfaces were prepared. A dual-cure resin cement was applied into zirconia surfaces with its corresponding adhesive components to dentin. Shear bond strength (SBS) of each sample was measured using a universal testing machine. The data were analyzed by ANOVA using SPSS 17.0 software. Ra of zirconia were significantly different compared with the control group (P<0.05). The crystalline transformation from tetragonal phase to monoclinic phase was observed after surface modification. Monoclinic volume content of the heat-treated group was highest than that in other groups. The content of element Si in the heat-treated group was higher than that in other treatment groups accompanied by a decrease in elements Zr, Y, and Hf after being treated by two silica-coating methods. Air abrasion significantly increased the micro-cracks in the ceramic surface and caused the grain boundaries to disappear. A serious shrinkage of the thin silica film can be observed after sintering procedure. This process induced cracks and the film to strip away slightly from the surfaces of Y-TZP substrate. The SBS values from large to small were F and G groups, C and D groups, B and E groups (P<0.05), and control group (P<0.05). Alumina sandblasting, silica powder abrasion, and silica-sol coating affect the surface morphology, structure, and composition of the tooth. This effect can also achieve the improved micro-mechanical interlocking or chemical bonding and finally increase the bond strength between zirconia and tooth. Alumina sandblasting followed by silica coating is an effective technique to increase the bonding strength between the zirconia ceramic and dentin.
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EFFECT OF AN ADDITIONAL HYDROPHILIC VERSUS HYDROPHOBIC COAT ON THE QUALITY OF DENTINAL SEALING PROVIDED BY TWO-STEP ETCH-AND-RINSE ADHESIVES

PubMed Central

Silva, Safira Marques de Andrade; Carrilho, Marcela Rocha de Oliveira; Marquezini, Luiz; Garcia, Fernanda Cristina Pimentel; Manso, Adriana Pigozzo; Alves, Marcelo Corrêa; de Carvalho, Ricardo Marins

2009-01-01

Objective: To test the hypothesis that the quality of the dentinal sealing provided by two-step etch-and-rinse adhesives cannot be altered by the addition of an extra layer of the respective adhesive or the application of a more hydrophobic, non-solvated resin. Material and Methods: full-crown preparations were acid-etched with phosphoric acid for 15 s and bonded with Adper Single Bond (3M ESPE), Excite DSC (Ivoclar/Vivadent) or Prime & Bond NT (Dentsply). The adhesives were used according to the manufacturers' instructions (control groups) or after application to dentin they were a) covered with an extra coat of each respective system or b) coated with a non-solvated bonding agent (Adper Scotchbond Multi-Purpose Adhesive, 3M ESPE). Fluid flow rate was measured before and after dentin surfaces were acid-etched and bonded with adhesives. Results: None of the adhesives or experimental treatments was capable to block completely the fluid transudation across the treated dentin. Application of an extra coat of the adhesive did not reduce the fluid flow rate of adhesive-bonded dentin (p>0.05). Conversely, the application of a more hydrophobic non-solvated resin resulted in significant reductions in the fluid flow rate (p<0.05) for all tested adhesives. Conclusions: The quality of the dentinal sealing provided by etch-and-rinse adhesives can be significantly improved by the application of a more hydrophobic, non-solvated bonding agent. PMID:19466248

Characterization of transparent dentin in attrited teeth using optical coherence tomography.

PubMed

Mandurah, Mona M; Sadr, Alireza; Bakhsh, Turki A; Shimada, Yasushi; Sumi, Yasunori; Tagami, Junji

2015-05-01

Attrition and wear of tooth surface occur with aging and result in loss of enamel, with exposure and histological changes in dentin. Dealing with attrited teeth and restoration of the lost tissue are clinically challenging. The main objective of this study is to characterize the exposed transparent dentin in the occlusal surface of attrited teeth by optical coherence tomography (OCT). Naturally attrited, extracted human teeth with occlusal-transparent dentin were investigated in comparison to sound and carious teeth. The teeth were subjected to OCT imaging and then cross-sectioned and polished. OCT B-scans were compared to light microscopy images of the same cross section. In OCT images, some changes were evident at the transparent dentin in attrited teeth. An OCT attenuation coefficient parameter (μ t) was derived based on the Beer-Lambert law as a function of backscatter signal slope. The mean values of μ t were 1.05 ± 0.3, 2.23 ± 0.4, and 0.61 ± 0.27 mm(-1) for sound, carious, and transparent dentins, respectively. One-way ANOVA with Tukey's post-hoc showed a significant difference between groups (p < 0.05). Physiological changes in transparent dentin that involve deposition of mineral casts in the dentinal tubules lead to lower attenuation of OCT signal. OCT has a potential role to detect transparent dentin on the surface of attrited teeth and can be used in the future as a clinical adjunct tool.

Repair of dentin defects from DSPP knockout mice by PILP mineralization

PubMed Central

Nurrohman, H.; Saeki, K.; Carneiro, K.; Chien, Y.C.; Djomehri, S.; Ho, S.P.; Qin, C.; Marshall, S.J.; Gower, L.B.; Marshall, G.W.; Habelitz, S.

2016-01-01

Dentinogenesis imperfecta type II (DGI-II) lacks intrafibrillar mineral with severe compromise of dentin mechanical properties. A Dspp knockout (Dspp−/−) mouse, with a phenotype similar to that of human DGI-II, was used to determine if poly-L-aspartic acid [poly(ASP)] in the “polymer-induced liquid-precursor” (PILP) system can restore its mechanical properties. Dentin from six-week old Dspp−/− and wild-type mice was treated with CaP solution containing poly(ASP) for up to 14 days. Elastic modulus and hardness before and after treatment were correlated with mineralization from Micro x-ray computed tomography (Micro-XCT). Transmission electron microscopy (TEM)/Selected area electron diffraction (SAED) were used to compare matrix mineralization and crystallography. Mechanical properties of the Dspp−/− dentin were significantly less than wild-type dentin and recovered significantly (P < 0.05) after PILP-treatment, reaching values comparable to wild-type dentin. Micro-XCT showed mineral recovery similar to wild-type dentin after PILP-treatment. TEM/SAED showed repair of patchy mineralization and complete mineralization of defective dentin. This approach may lead to new strategies for hard tissue repair. PMID:27239097

An in vitro assessment of the effect of load and pH on wear between opposing enamel and dentine surfaces.

PubMed

Ranjitkar, Sarbin; Kaidonis, John A; Townsend, Grant C; Vu, Anh M; Richards, Lindsay C

2008-11-01

Previous in vitro studies have described the wear characteristics of specimens in which enamel has been opposed to enamel and dentine opposed to dentine. The aim of this study was to assess the characteristics of wear between specimens in which enamel was opposed to dentine at loads simulating attrition and at pH values simulating different erosive environments. It was hypothesized that enamel would wear more slowly than dentine under all conditions. Opposing enamel and dentine specimens from 57 human third molar teeth were worn in electromechanical machines with various loads (32, 62 and 100 N) and lubricants (pH 1.2, 3.0 and 6.1). Tooth wear was quantified by measuring reduction in dentine volume over time using a 3D profilometer. Qualitative assessment was also carried out using scanning electron microscopy. Dentine wear increased with increasing load, and dentine wear was faster at pH 1.2 than at pH 3.0 or 6.1 for all loads tested. Interestingly, enamel wore more rapidly than dentine at pH 1.2 under all loads. At pH values of 3.0 and 6.1, enamel wear rates were not measurably different from zero and they were less than wear rates for opposing dentine specimens at all loads. Micrographic assessment showed extensive surface destruction of dentine wear facets due to erosion at pH 1.2. Dentine wear facets were smoother at pH 3.0 that at pH 6.1. When enamel wears against dentine in an acidic environment enamel will wear more rapidly at very low pH, while under less acid conditions dentine will wear faster than enamel.

Caries preventive efficacy of silver diammine fluoride (SDF) and ART sealants in a school-based daily fluoride toothbrushing program in the Philippines.

PubMed

Monse, Bella; Heinrich-Weltzien, Roswitha; Mulder, Jan; Holmgren, Christopher; van Palenstein Helderman, Wim H

2012-11-21

Occlusal surfaces of erupting and newly erupted permanent molars are particularly susceptible to caries.The objective of the study was to assess and compare the effect of a single application of 38% SDF with ART sealants and no treatment in preventing dentinal (D3) caries lesions on occlusal surfaces of permanent first molars of school children who participated in a daily school-based toothbrushing program with fluoride toothpaste. The prospective community clinical trial in the Philippines was conducted over a period of 18 months and included 704 six- to eight-year-old school children in eight public elementary schools with a daily school-based fluoride toothpaste brushing program. Children were randomly assigned for SDF application or ART sealant treatment. Children from two of the eight schools did not receive SDF or ART sealant treatment and served as controls. SDF or ART sealant treatment was applied on sound occlusal surfaces of permanent first molars. Surfaces that were originally defined as sound at baseline but which changed to dentinal (D3) caries lesions were defined as surfaces with new caries (caries increment). Non-compliance to the daily toothbrushing program in three schools offered the opportunity to analyze the caries preventive effect of SDF and sealants separately in fluoride toothpaste brushing and in non-toothbrushing children. In the brushing group, caries increment in the SDF treatment group was comparable with the non-treatment group but caries increment in the sealant group was lower than in the non-treatment group with a statistically significant lower hazard ratio of 0.12 (0.02-0.61). In the non-brushing group, caries increment in the SDF treatment group and the sealant group was lower than the non-treatment group but the hazard ratio was only statistically significant for the sealant group (HR 0.33; 0.20-0.54). Caries increment was lower in toothbrushing children than in non-toothbrushing children. Hazard ratios reached statistical significance for the non-treated children (HR 0.43; 0.21-0.87) and the sealant-treated children (HR 0.15; 0.03-0.072). A one-time application of 38% SDF on the occlusal surfaces of permanent first molars of six- to eight-year-old children is not an effective method to prevent dentinal (D3) caries lesions. ART sealants significantly reduced the onset of caries over a period of 18 months. German Clinical Trial Register DRKS00003427.

Caries preventive efficacy of silver diammine fluoride (SDF) and ART sealants in a school-based daily fluoride toothbrushing program in the Philippines

PubMed Central

2012-01-01

Background Occlusal surfaces of erupting and newly erupted permanent molars are particularly susceptible to caries. The objective of the study was to assess and compare the effect of a single application of 38% SDF with ART sealants and no treatment in preventing dentinal (D3) caries lesions on occlusal surfaces of permanent first molars of school children who participated in a daily school-based toothbrushing program with fluoride toothpaste. Methods The prospective community clinical trial in the Philippines was conducted over a period of 18 months and included 704 six- to eight-year-old school children in eight public elementary schools with a daily school-based fluoride toothpaste brushing program. Children were randomly assigned for SDF application or ART sealant treatment. Children from two of the eight schools did not receive SDF or ART sealant treatment and served as controls. SDF or ART sealant treatment was applied on sound occlusal surfaces of permanent first molars. Surfaces that were originally defined as sound at baseline but which changed to dentinal (D3) caries lesions were defined as surfaces with new caries (caries increment). Non-compliance to the daily toothbrushing program in three schools offered the opportunity to analyze the caries preventive effect of SDF and sealants separately in fluoride toothpaste brushing and in non-toothbrushing children. Results In the brushing group, caries increment in the SDF treatment group was comparable with the non-treatment group but caries increment in the sealant group was lower than in the non-treatment group with a statistically significant lower hazard ratio of 0.12 (0.02-0.61). In the non-brushing group, caries increment in the SDF treatment group and the sealant group was lower than the non-treatment group but the hazard ratio was only statistically significant for the sealant group (HR 0.33; 0.20-0.54). Caries increment was lower in toothbrushing children than in non-toothbrushing children. Hazard ratios reached statistical significance for the non-treated children (HR 0.43; 0.21-0.87) and the sealant-treated children (HR 0.15; 0.03-0.072). Conclusions A one-time application of 38% SDF on the occlusal surfaces of permanent first molars of six- to eight-year-old children is not an effective method to prevent dentinal (D3) caries lesions. ART sealants significantly reduced the onset of caries over a period of 18 months. Trial registration number German Clinical Trial Register DRKS00003427 PMID:23171244

Fractography and fracture toughness of human dentin.

PubMed

Yan, J; Taskonak, B; Mecholsky, J J

2009-10-01

Dentin, the mineralized tissue forming the bulk of the tooth, serves as an energy-absorbing cushion for the hard, wear-resistant enamel and protects the inner soft tissues. Several studies used fracture mechanics methods to study the fracture toughness of dentin. However, all of them utilized precracks and cannot be used to estimate the intrinsic critical flaw size of dentin. We applied quantitative fractography to study the fracture pattern and fracture toughness of human dentin. Sixteen specimens were prepared from the coronal dentin and fractured in three-point flexure. Fracture surfaces were examined using a scanning electron microscope and the fracture toughness was calculated using a fracture mechanics equation. It was found that human dentin has a fracture surface similar to those of brittle materials. Twist hackle markings were observed and were used to identify the fracture origins. Average fracture toughness of all specimens was found to be 2.3 MPa m(1/2) and the average critical flaw size was estimated to 120 mum. It is suggested that fractography is a promising technique in analyzing the fracture of dentin under catastrophic failure.

In vivo effect of a self-etching primer on dentin.

PubMed

Milia, E; Lallai, M R; García-Godoy, F

1999-08-01

To determine the ultrastructural aspects of the dentin collagen area in the cavity preparation floor produced in vivo after phosphoric acid acid-etching or after using Clearfil Liner Bond 2 self-etching primer (LB2 Primer). Twenty-four non-carious third molars scheduled for extraction from young adult patients (16-30 years old) were used. Conventional Class I cavities (+/- 2 mm deep) were prepared on the occlusal surfaces of all teeth using a cylindrical diamond bur on a high-speed handpiece with copious water spray. To avoid dehydration of the dentin, the smear layer-covered dentin was briefly air-dried for 2 seconds. Cavities were assigned at random to the following groups: Group A: Dentin etched for 15 seconds with 34% phosphoric acid, rinsed for 20 seconds and then briefly air-dried for 2 seconds with oil-free compressed air leaving the surfaces slightly moist. Group B: LB2 Primer was applied to the cavity surfaces for 30 seconds and then briefly air-dried to remove the solvent. Group C: The untreated dentin smear layer was used as a control. In all three groups, the cavities were filled incrementally with a resin-based composite (APX), light curing every increment for 40 seconds. After 30 minutes, the teeth were extracted atraumatically and the samples immediately prepared for evaluation with the transmission electron microscope. The use of a self-etching primer did not produce significant morphological changes in the moist dentin substrate. Adverse morphological conditions where observed when there was an excess water on the dentin surface. Phosphoric acid altered the collagen more severely than the self-etching primer.

Influence of light intensity on surface free energy and dentin bond strength of core build-up resins.

PubMed

Shimizu, Y; Tsujimoto, A; Furuichi, T; Suzuki, T; Tsubota, K; Miyazaki, M; Platt, J A

2015-01-01

We examined the influence of light intensity on surface free energy characteristics and dentin bond strength of dual-cure direct core build-up resin systems. Two commercially available dual-cure direct core build-up resin systems, Clearfil DC Core Automix with Clearfil Bond SE One and UniFil Core EM with Self-Etching Bond, were studied. Bovine mandibular incisors were mounted in acrylic resin and the facial dentin surfaces were wet ground on 600-grit silicon carbide paper. Adhesives were applied to dentin surfaces and cured with light intensities of 0 (no irradiation), 200, 400, and 600 mW/cm(2). The surface free energy of the adhesives (five samples per group) was determined by measuring the contact angles of three test liquids placed on the cured adhesives. To determine the strength of the dentin bond, the core build-up resin pastes were condensed into the mold on the adhesive-treated dentin surfaces according to the methods described for the surface free energy measurement. The resin pastes were cured with the same light intensities as those used for the adhesives. Ten specimens per group were stored in water maintained at 37°C for 24 hours, after which they were shear tested at a crosshead speed of 1.0 mm/minute in a universal testing machine. Two-way analysis of variance (ANOVA) and a Tukey-Kramer test were performed, with the significance level set at 0.05. The surface free energies of the adhesive-treated dentin surfaces decreased with an increase in the light intensity of the curing unit. Two-way ANOVA revealed that the type of core build-up system and the light intensity significantly influence the bond strength, although there was no significant interaction between the two factors. The highest bond strengths were achieved when the resin pastes were cured with the strongest light intensity for all the core build-up systems. When polymerized with a light intensity of 200 mW/cm(2) or less, significantly lower bond strengths were observed. CONClUSIONS: The data suggest that the dentin bond strength of core build-up systems are still affected by the light intensity of the curing unit, which is based on the surface free energy of the adhesives. On the basis of the results and limitations of the test conditions used in this study, it appears that a light intensity of >400 mW/cm(2) may be required for achieving the optimal dentin bond strength.

Laser ablation of hard tissue: correlation between the laser beam parameters and the post-ablative tissue characteristics

NASA Astrophysics Data System (ADS)

Serafetinides, Alexandros A.; Makropoulou, Mersini I.; Khabbaz, Maruan

2003-11-01

Hard dental tissue laser applications, such as preventive treatment, laser diagnosis of caries, laser etching of enamel, laser decay removal and cavity preparation, and more recently use of the laser light to enlarge the root canal during the endodontic therapy, have been investigated for in vitro and in vivo applications. Post-ablative surface characteristics, e.g. degree of charring, cracks and other surface deformation, can be evaluated using scanning electron microscopy. The experimental data are discussed in relevance with the laser beam characteristics, e.g. pulse duration, beam profile, and the beam delivery systems employed. Techniques based on the laser illumination of the dental tissues and the subsequent evaluation of the scattered fluorescent light will be a valuable tool in early diagnosis of tooth diseases, as carious dentin or enamel. The laser induced autofluorescence signal of healthy dentin is much stronger than that of the carious dentin. However, a better understanding of the transmission patterns of laser light in teeth, for both diagnosis and therapy is needed, before the laser procedures can be used in a clinical environment.

Effects of N-vinylpyrrolidone (NVP) containing polyelectrolytes on surface properties of conventional glass-ionomer cements (GIC).

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Ansari, Sahar; Moshaverinia, Maryam; Schricker, Scott; Darr, Jawwad A; Rehman, Ihtesham U

2009-10-01

It has been found that polyacids containing an N-vinylpyrrolidinone (NVP) comonomer produces a glass inomer cement with improved mechanical and handling properties. The objective of this study was to investigate the effect of NVP modified polyelectrolytes on the surface properties and shear bond strength to dentin of glass ionomer cements. Poly(acrylic acid (AA)-co-itaconic acid (IA)-co-N-vinylpyrrolidone) was synthesized by free radical polymerization. The terpolymer was characterized using (1)H NMR, FTIR spectroscopy and viscometry for solution properties. The synthesized polymers were used in glass ionomer cement formulations (Fuji II commercial GIC). Surface properties (wettability) of modified cements were studied by water contact angle measurements as a function of time. Work of adhesion values of different surfaces was also determined. The effect of NVP modified polyacid, on bond strength of glass-ionomer cement to dentin was also investigated. The mean data obtained from contact angle and bonding strength measurements were subjected to one- and two-way analysis of variance (ANOVA) at alpha=0.05. Results showed that NVP modified glass ionomer cements showed significantly lower contact angles (theta=47 degrees) and higher work of adhesion (WA=59.4 erg/cm(2)) in comparison to commercially available Fuji II GIC (theta=60 degrees and WA=50.3 erg/cm(2), respectively). The wettability of dentin surfaces conditioned with NVP containing terpolymer was higher (theta=21 degrees, WA=74.2 erg/cm(2)) than dentin conditioned with Fuji conditioner (theta=30 degrees, WA=69 erg/cm(2)). The experimental cement also showed higher but not statistically significant values for shear bond strength to dentin (7.8 MPa), when compared to control group (7.3 MPa). It was concluded that NVP containing polyelectrolytes are better dentin conditioners than the commercially available dentin conditioner (Fuji Cavity Conditioner, GC). NVP containing terpolymers can enhance the surface properties of GICs and also increase their bond strength to the dentin.

Effect of nano-hydroxyapatite on bone morphogenetic protein-2-induced hard tissue formation and dentin resorption on a dentin surface

NASA Astrophysics Data System (ADS)

Tamagawa, Hiroki; Tenkumo, Taichi; Sugaya, Tsutomu; Kawanami, Masamitsu

2012-12-01

AimThe purpose of this study was to evaluate the effects of the addition of nano-hydroxyapatite to a collagen membrane-carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) on hard tissue formation and dentin resorption on dentin surfaces in vivo. Materials and methodsNano-hydroxyapatite collagen composite (nHAC) membranes or collagen (C) membranes were each immersed in either 100 or 400 μg/ml rhBMP-2 and placed on dentin chips that were implanted into rat thigh muscle. The implants were analyzed at 2 or 4 weeks after surgery by histological observation and histomorphometric analysis. ResultsThe percentage of the hard tissue formed by each nHAC group was significantly higher than that formed by any of the C groups, except for that formed by the group loaded with 400 μg/ml rhBMP-2 at 4 weeks after implantation. No significant differences were observed in the percentage of dentin resorption between the nHAC groups and C groups at any stage or at any rhBMP-2 concentration. ConclusionThese findings showed that addition of nano-hydroxyapatite to a collagen membrane accelerated the formation of hard tissue induced by a low dose of rhBMP-2 on dentin surfaces at an early stage after implantation into rat thigh muscle, without increasing dentin resorption.

Inhibition of endogenous human dentin MMPs by Gluma

PubMed Central

Sabatini, Camila; Scheffel, Débora L.S.; Scheffel, Régis H.; Agee, Kelli A.; Rouch, Katelyn; Takahashi, Masahiro; Breschi, Lorenzo; Mazzoni, Annalisa; Tjäderhane, Leo; Tay, Franklin R.; Pashley, David H.

2014-01-01

Objective The objective of this study was to determine if Gluma dentin desensitizer (5.0% glutaraldehyde and 35% HEMA in water) can inhibit the endogenous MMPs of dentin matrices in 60 sec. and to evaluate its effect on dentin matrix stiffness and dry mass weight. Methods Dentin beams of 2×1×6 mm were obtained from extracted human third molars coronal dentin. To measure the influence of Gluma treatment time on total MMP activity of dentin, beams were dipped in 37% phosphoric acid (PA) for 15 sec. and rinsed in water. The acid-etched beams were then dipped in Gluma for 5, 15, 30 or 60 sec., rinsed in water and incubated into SensoLyte generic MMP substrate (AnaSpec, Inc.) for 60 min. Controls were dipped in water for 60 sec. Additional beams of 1×1×6 mm were completely demineralized in 37% PA for 18 h, rinsed and used to evaluate changes on the dry weight and modulus of elasticity (E) after 60 sec. of Gluma treatment followed by incubation in simulated body fluid buffer for zero, one or four weeks. E was measured by 3-pt flexure. Results Gluma treatment inhibited total MMP activity of acid-etched dentin by 44, 50, 84, 86 % after 5, 15, 30 or 60 sec. of exposure, respectively. All completely demineralized dentin beams lost stiffness after one and four weeks, with no significant differences between the control and Gluma-treated dentin. Gluma treatment for 60 sec. yielded significantly less dry mass loss than the control after four weeks. Significance The use of Gluma may contribute to the preservation of adhesive interfaces by its cross-linking and inhibitory properties of endogenous dentin MMPs. PMID:24846803

Assessment of dentin remineralization with PS-OCT

NASA Astrophysics Data System (ADS)

Manesh, Saman K.; Darling, Cynthia L.; Fried, Daniel

2009-02-01

Previous studies have demonstrated that polarization sensitive optical coherence tomography (PS-OCT) can be used to image natural root caries lesions, measure non-destructively the severity of dentin demineralization and determine the efficacy of intervention with anti-caries agents including fluoride and lasers. The objective of this study was to determine if PS-OCT could be used to nondestructively measure the formation of a layer of remineralized dentin on the surface of dentin lesions after exposure to a remineralization solution. In this study images of artificial dentin lesions on extracted human teeth were acquired using PS-OCT after exposure to an artificial demineralizing solution at pH 4.9 for six days and after subsequent exposure to a remineralizing solution at pH 7.0 for 20 days. Polarized light microscopy and microradiography were used to examine histological thin sections from the samples for comparison. PS-OCT successfully measured the formation of a layer of increased mineral content near the lesion surface. PLM and TMR corroborated those results. This study demonstrates the potential use of PS-OCT for the nondestructive measurement of the remineralization of dentin surfaces.

Toothbrushing abrasion susceptibility of enamel and dentin bleached with calcium-supplemented hydrogen peroxide gel.

PubMed

Borges, A B; Santos, L F T F; Augusto, M G; Bonfiette, D; Hara, A T; Torres, C R G

2016-06-01

The objective of this study was to evaluate enamel and dentin susceptibility to toothbrushing abrasion, after bleaching with 7.5% hydrogen peroxide (HP) gel supplemented or not with 0.5% calcium gluconate (Ca). Toothbrushing was performed immediately and 1h after bleaching, with two suspensions (high and low abrasivity). Bovine enamel and dentin specimens were divided into 12 groups (n=10) according to the bleaching gel (with and without Ca), slurry abrasivity (high or low) and elapsed time after bleaching (immediately and after 1h). As control, a group was not bleached, but abraded. The treatment cycle (7 d) consisted of bleaching (1h) and toothbrushing (135 strokes/day) immediatelly or after 1h of artificial saliva exposure. Surface roughness and surface loss (μm) were measured by profilometry and analysed by three-way ANOVA (5%). Surface roughness means were significantly influenced by slurry abrasivity (p<0.0001). For enamel loss, significant triple interaction was observed (p<0.0001). HP-bleached groups and immediately brushed with high-abrasive slurry exhibited increased loss (1.41±0.14) compared to other groups (μm). Control and HP+Ca-bleached groups brushed after 1h with low abrasive slurry presented the lowest loss (0.21±0.03/0.27±0.02). For dentin loss, significant interaction was observed for bleaching and interval factors (p<0.001). 7.5%HP-bleached groups and immediately brushed showed significantly higher loss (8.71±2.45) than the other groups. It was concluded that surface roughness increased when high abrasive was used, independently of bleaching. 7.5%HP increased enamel and dentin loss, mainly with high abrasive slurries. Calcium supplementation of bleaching gel reduced surface loss. Additionally, in order to minimize tooth wear susceptibility, it is recommended to delay brushing after bleaching. After bleaching gel application, postponing toothbrushing is recommended, as well as brushing with low abrasive dentifrices. Additionally, supplementation of hydrogen peroxide gel with calcium-based remineralizing agent potentially reduces tooth loss after abrasion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-induced vomiting and dental erosion--a clinical study.

PubMed

Uhlen, Marte-Mari; Tveit, Anne Bjørg; Stenhagen, Kjersti Refsholt; Mulic, Aida

2014-07-29

In individuals suffering from eating disorders (ED) characterized by vomiting (e.g. bulimia nervosa), the gastric juice regularly reaches the oral cavity, causing a possible risk of dental erosion. This study aimed to assess the occurrence, distribution and severity of dental erosions in a group of Norwegian patients experiencing self-induced vomiting (SIV). The individuals included in the study were all undergoing treatment at clinics for eating disorders and were referred to a university dental clinic for examinations. One calibrated clinician registered erosions using the Visual Erosion Dental Examination (VEDE) system. Of 72 referred patients, 66 (63 females and three males, mean age 27.7 years) were or had been experiencing SIV (mean duration 10.6 years; range: 3 - 32 years), and were therefore included in the study. Dental erosions were found in 46 individuals (69.7%), 19 had enamel lesions only, while 27 had both enamel and dentine lesions. Ten or more teeth were affected in 26.1% of those with erosions, and 9% had ≥10 teeth with dentine lesions. Of the erosions, 41.6% were found on palatal/lingual surfaces, 36.6% on occlusal surfaces and 21.8% on buccal surfaces. Dentine lesions were most often found on lower first molars, while upper central incisors showed enamel lesions most frequently. The majority of the erosive lesions (48.6%) were found in those with the longest illness period, and 71.7% of the lesions extending into dentine were also found in this group. However, despite suffering from SIV for up to 32 years, 30.3% of the individuals showed no lesions. Dental erosion commonly affects individuals with ED experiencing SIV, and is more often found on the palatal/lingual surfaces than on the buccal in these individuals, confirming a common clinical assumption.

Mechanical properties of components of the bonding interface in different regions of radicular dentin surfaces.

PubMed

Suzuki, Thaís Yumi Umeda; Gomes-Filho, João Eduardo; Gallego, Juno; Pavan, Sabrina; Dos Santos, Paulo Henrique; Fraga Briso, André Luiz

2015-01-01

The mechanical properties of the adhesive materials used in intraradicular treatments could vary according to the interaction between the restorative material and dentin substrate. An evaluation of these properties is essential to determine the success of the luting procedures performed on glass-fiber posts. The purpose of this study was to evaluate the mechanical properties of dentin adhesives, resin cements, and the dentin that underlies the bonding interface in different thirds of intraradicular dentin. Forty extracted, single-rooted human teeth were used in this study. After the endodontic treatment of the post spaces, the teeth were divided into 5 groups (n=8): Adper Single Bond 2 + RelyX ARC, Excite DSC + RelyX ARC, Adper SE Plus + RelyX ARC, RelyX Unicem, and Set. The hardness and elastic modulus values were measured at the adhesive interface in different thirds of the radicular dentin by using an ultramicrohardness tester. The data were subjected to 2-way ANOVA and the Fisher protected least significant difference test (α=.05). In the underlying dentin, the highest Martens hardness values were found in the apical region for all groups; the exceptions were the groups with the self-etching adhesive. In the adhesive layer, the highest Martens hardness values were obtained for the Adper SE Plus + RelyX ARC group; further, no statistical differences were found among the different regions for this group. RelyX ARC had the lowest Martens hardness and elastic modulus values in the apical regions when used with Adper Single Bond 2 and Adper SE Plus. No differences were found in the Martens hardness and elastic modulus values for the self-adhesive resin cement in the regions investigated. The mechanical properties of adhesive materials and the underlying dentin are influenced by the interaction between the two as well as by the depth of the analyzed intraradicular area. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Influence of Er:YAG and Ti:sapphire laser irradiation on the microtensile bond strength of several adhesives to dentin.

PubMed

Portillo, M; Lorenzo, M C; Moreno, P; García, A; Montero, J; Ceballos, L; Fuentes, M V; Albaladejo, A

2015-02-01

The aim of the present study was to evaluate the influence of erbium:yttrium-aluminum-garnet (Er:YAG) and Ti:sapphire laser irradiation on the microtensile bond strength (MTBS) of three different adhesive systems to dentin. Flat dentin surfaces from 27 molars were divided into three groups according to laser irradiation: control, Er:YAG (2,940 nm, 100 μs, 2.7 W, 9 Hz) and Ti:sapphire laser (795 nm, 120 fs, 1 W, 1 kHz). Each group was divided into three subgroups according to the adhesive system used: two-step total-etching adhesive (Adper Scotchbond 1 XT, from now on XT), two-step self-etching adhesive (Clearfil SE Bond, from now on CSE), and all-in-one self-etching adhesive (Optibond All-in-One, from now on OAO). After 24 h of water storage, beams of section at 1 mm(2) were longitudinally cut from the samples. Each beam underwent traction test in an Instron machine. Fifteen polished dentin specimens were used for the surface morphology analysis by scanning electron microscopy (SEM). Failure modes of representative debonded microbars were SEM-assessed. Data were analyzed by ANOVA, chi-square test, and multiple linear regression (p < 0.05). In the control group, XT obtained higher MTBS than that of laser groups that performed equally. CSE showed higher MTBS without laser than that with laser groups, where Er:YAG attained higher MTBS than ultrashort laser. When OAO was used, MTBS values were equal in the three treatments. CSE obtained the highest MTBS regardless of the surface treatment applied. The Er:YAG and ultrashort laser irradiation reduce the bonding effectiveness when a two-step total-etching adhesive or a two-step self-etching adhesive are used and do not affect their effectiveness when an all-in-one self-etching adhesive is applied.

Assessment of resin-dentin interfacial morphology of two ethanol-based universal adhesives: A scanning electron microscopy study

PubMed Central

Awad, Mohamed Moustafa

2017-01-01

Objective: The objective of this study was to assess the resin-dentin interfacial morphology created by two universal adhesives using scanning electron microscopy (SEM). Materials and Methods: The occlusal surfaces of ten (n = 5) molars were reduced to expose a flat surface of dentin. Two universal adhesives, Scotchbond Universal Adhesive and Tetric N-Bond Universal, were independently applied to air-dried dentin. Light-cured resin-based composite restorative materials were used to incrementally build a composite “buildup.” The specimen was sectioned mesiodistally to expose the resin-dentin interface. The inner surfaces of the specimens were polished. Samples were immersed in hydrochloric acid and then rinsed using distilled water. This was followed by immersion of the samples in 1% sodium hypochlorite solution. Then, samples were thoroughly rinsing with distilled water. Dehydration of samples was performed using ascending concentration of ethyl alcohol. Prepared samples were observed SEM at magnifications ×1500 and x4000. Results: Both universal adhesives could penetrate dentin-forming well-defined resin tags, lateral branches as well as a uniform hybrid layer. Conclusions: Two tested universal adhesives applied in self-etch mode can infiltrate into dentin-producing high-quality interfacial morphology. Similar interfacial morphology may be due to the similarity in composition and application mode. PMID:28729794

Polydopamine-induced tooth remineralization.

PubMed

Zhou, Yun-Zhi; Cao, Ying; Liu, Wei; Chu, Chun Hung; Li, Quan-Li

2012-12-01

Inspired by mussel bioadhesion in nature, dopamine is extensively used for biomaterial surface modification. In this study, we coated dopamine on demineralized enamel and dentin surfaces to evaluate the effect of polydopamine coating on dental remineralization. Dental slices containing enamel and dentin were first etched with 37% phosphoric acid for 2 min, followed by immersion in a 2 mg/mL freshly prepared solution of dopamine (10 mM Tris buffer, pH 8.5) for approximately 24 h at room temperature in the dark to obtain polydopamine coating. Then, the dental slices with and without polydopamine coating were immersed in the supersaturated solution of calcium and phosphate at 37 °C for 2 and 7 days. The supersaturated solution of calcium and phosphate was refreshed each day. The precipitates were characterized by SEM, XRD, FTIR, microhardness, and nanoscratch analyses. No significant difference was observed in the remineralization of enamel whether it was coated with polydopamine or not. However, a significant difference was found in dentin remineralization between dentin with and without polydopamine coating. Polydopamine coating remarkably promoted demineralized dentin remineralization, and all dentin tubules were occluded by densely packed hydroxyapatite crystals. Thus, coating polydopamine on dental tissue surface may be a simple universal technique to induce enamel and dentin remineralization simultaneously.

In Vitro Evaluation of Dentin Tubule Occlusion for Novel Calcium Lactate Phosphate (CLP) Paste

PubMed Central

Yang, Jen-Chang; Hu, Hsin-Tai; Lee, Sheng-Yang; Hsieh, Sung-Chih; Huang, Pei-Chi; Ma, Chen-Feng; Ji, Dian-Yu; Chang, Liang-Yu; Teng, Nai-Chia

2017-01-01

Introduction: The objective of this in vitro study is to evaluate the effective and long-term occlusion of dentinal tubules using a novel calcium lactate phosphate (CLP) based desensitizing agent. Methods: Dentin disks (n = 9) were pre-etched using 1 M lactic acid for 30 s and individually treated with Colgate® Pro-Relief™ paste, CLP paste, and double distilled water (ddH2O) by a rubber-cupped handpiece. Dentin disks were analyzed under optical micrographs for pre-treatment, directly after treatment, and 14 days post-treatment. One-way ANOVA and post-hoc Tukey’s test were used to determine whether there were any statistically significant differences in dentinal tubule diameter. Results: A significant decrease occurred in the mean tubule diameter for dentin disks treated with CLP paste. A decrease was observed from 3.52 ± 0.83 µm to 2.62 ± 0.42 µm right after treatment, further decreasing to 1.71 ± 0.45 µm after immersion in artificial saliva for 14 days (p < 0.05). Conclusions: The results suggest that the CLP based desensitizing paste has remineralization properties and provides instant and lasting effectiveness in dentinal tubule occlusion. PMID:28772594

Effect of smear layer deproteinization on bonding of self-etch adhesives to dentin: a systematic review and meta-analysis

PubMed Central

Alshaikh, Khaldoan H.; Mahmoud, Salah H.

2018-01-01

Objectives The aim of this systematic review was to critically analyze previously published studies of the effects of dentin surface pretreatment with deproteinizing agents on the bonding of self-etch (SE) adhesives to dentin. Additionally, a meta-analysis was conducted to quantify the effects of the above-mentioned surface pretreatment methods on the bonding of SE adhesives to dentin. Materials and Methods An electronic search was performed using the following databases: Scopus, PubMed and ScienceDirect. The online search was performed using the following keywords: ‘dentin’ or ‘hypochlorous acid’ or ‘sodium hypochlorite’ and ‘self-etch adhesive.’ The following categories were excluded during the assessment process: non-English articles, randomized clinical trials, case reports, animal studies, and review articles. The reviewed studies were subjected to meta-analysis to quantify the effect of the application time and concentration of sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl) deproteinizing agents on bonding to dentin. Results Only 9 laboratory studies fit the inclusion criteria of this systematic review. The results of the meta-analysis revealed that the pooled average microtensile bond strength values to dentin pre-treated with deproteinizing agents (15.71 MPa) was significantly lower than those of the non-treated control group (20.94 MPa). Conclusions In light of the currently available scientific evidence, dentin surface pretreatment with deproteinizing agents does not enhance the bonding of SE adhesives to dentin. The HOCl deproteinizing agent exhibited minimal adverse effects on bonding to dentin in comparison with NaOCl solutions. PMID:29765895

Effect of Casein Phosphopeptide-amorphous Calcium Phosphate Treatment on Microtensile Bond Strength to Carious Affected Dentin Using Two Adhesive Strategies

PubMed Central

Bahari, Mahmoud; Savadi Oskoee, Siavash; Kimyai, Soodabeh; Pouralibaba, Firoz; Farhadi, Farrokh; Norouzi, Marouf

2014-01-01

Background and aims. The aim was to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on microtensile bond strength (μTBS) to carious affected dentin (CAD) using etch-and-rinse and self-etch adhesive systems. Materials and methods. The occlusal surface of 32 human molars with moderate occlusal caries was removed. Infected dentin was removed until reaching CAD and the teeth were randomly divided into two groups based on the Single Bond (SB) and Clearfil SE Bond (CSE) adhesive systems. Before composite resin bonding, each group was subdivided into three subgroups of ND, CAD and CPP-ACP-treated CAD (CAD-CPP) based on the dentin substrate. After dissecting samples to l-mm-thick cross-sections (each subgroup: n = 13), μTBS was measured at a strain rate of 0.5 mm/min. Data was analyzed using two-way ANOVA, independent samples t-test and post-hoc Tukey tests (α=0.05). Results. Bond strength of both adhesive systems to ND was significantly higher than that to CAD (P <0.001) and CAD/CPP (P < 0.001). There were no significant differences between the μTBS of SB to CAD and CAD-CPP (P > 0.05).μTBS of CSE to CAD-CPP was higher than that to CAD; however, the difference was not significant (P > 0.05). Significant differences were found between SB and CSE systems only with CAD substrate (P < 0.001). Conclusion. Regardless of the adhesive system used, surface treatment of CAD with CPP-ACP did not have a significant effect on bond strength. However, bond strength to CAD was higher with SB rather than with CSE. PMID:25346832

Erosion protection by calcium lactate/sodium fluoride rinses under different salivary flows in vitro.

PubMed

Borges, Alessandra B; Scaramucci, Taís; Lippert, Frank; Zero, Domenick T; Hara, Anderson T

2014-01-01

This study investigated the effect of a calcium lactate prerinse on sodium fluoride protection in an in vitro erosion-remineralization model simulating two different salivary flow rates. Enamel and dentin specimens were randomly assigned to 6 groups (n = 8), according to the combination between rinse treatments - deionized water (DIW), 12 mM NaF (NaF) or 150 mM calcium lactate followed by NaF (CaL + NaF) - and unstimulated salivary flow rates - 0.5 or 0.05 ml/min - simulating normal and low salivary flow rates, respectively. The specimens were placed into custom-made devices, creating a sealed chamber on the specimen surface connected to a peristaltic pump. Citric acid was injected into the chamber for 2 min, followed by artificial saliva (0.5 or 0.05 ml/min) for 60 min. This cycle was repeated 4×/day for 3 days. Rinse treatments were performed daily 30 min after the 1st and 4th erosive challenges, for 1 min each time. Surface loss was determined by optical profilometry. KOH-soluble fluoride and structurally bound fluoride were determined in specimens at the end of the experiment. Data were analyzed by 2-way ANOVA and Tukey tests (α = 0.05). NaF and CaL + NaF exhibited significantly lower enamel and dentin loss than DIW, with no difference between them for normal flow conditions. The low salivary flow rate increased enamel and dentin loss, except for CaL + NaF, which presented overall higher KOH-soluble and structurally bound fluoride levels. The results suggest that the NaF rinse was able to reduce erosion progression. Although the CaL prerinse considerably increased F availability, it enhanced NaF protection against dentin erosion only under hyposalivatory conditions.

Fluoride-dependent formation of mineralized layers in bovine dentin during demineralization in vitro.

PubMed

Damen, J J; Buijs, M J; ten Cate, J M

1998-01-01

Demineralization of dentin in the presence of fluoride produces lesions with a mineralized surface layer which becomes thicker and more mineralized with higher fluoride concentrations whereas the lesion depth is hardly affected. The aim of this study was to investigate the effects of the time of fluoride treatment and the amount of fluoride taken up on the properties of the mineralized layer. Discs of bovine dentin embedded in methylmethacrylate with one surface exposed were demineralized in 50 mM acetic acid, 2.2 mM CaCl2, 2.2 mM KH2PO4, pH 5.0. At the start and/or later during the demineralization period, the specimens were incubated individually for 1 or 2 days in 10 ml of the same demineralization solution supplemented with 0.5, 2.0 or 5.0 ppm fluoride, which was then assessed for changes in calcium and fluoride concentrations. After 2, 5 and 8 days, specimens were sectioned for microradiographic analysis so as to follow development of the lesions and the mineralized layers. The results were the following: While demineralization with fluoride present at the first day led to the formation of a surface layer, fluoride present only at a later day produced a subsurface layer, not at the lesion front but closer to the surface. This layer resulted from (re)precipitation and not from preservation of the original mineral. The 'integrated mineral content' of the surface layer increased linearly with the uptake of fluoride, which resulted in an apparent fluorapatite content of about 20 vol%. The profiles of the surface layers remained unchanged during continued demineralization in the absence of fluoride. It was concluded that in the presence of fluoride mineral loss is reduced as a result of the reprecipitation of dissolved mineral ions as a layer of fluoride-enriched apatite. This layer does not offer protection of underlying dentin against continued demineralization.

Bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure in vitro.

PubMed

Nakajima, Masatoshi; Hosaka, Keiichi; Yamauti, Monica; Foxton, Richard M; Tagami, Junji

2006-06-01

To evaluate the bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure. 18 extracted human molars with occlusal caries were used. Their occlusal dentin surfaces were ground flat to expose normal and caries-affected dentin using #600 SiC paper under running water. Clearfil SE Bond was placed on the dentin surface including the caries-affected dentin according to the manufacturer's instructions and then the crowns were built up with resin composite (Clearfil AP-X) under either a pulpal pressure of 15 cm H2O or none (control). The bonded specimens were stored in 100% humidity for 1 day (control) or for 1 week and 1 month with hydrostatic pulpal pressure. After storage, the specimens were serially sectioned into 0.7 mm-thick slabs and trimmed to an hour-glass shape with a 1 mm2 cross-section, isolated by normal or caries-affected dentin, and then subjected to the micro-tensile bond test. Data were analyzed by two-way ANOVA and Tukey's test (P< 0.05). Hydrostatic pulpal pressure significantly reduced the bond strength to normal dentin after 1-month storage (P< 0.05), but did not affect the bond strength to caries-affected dentin.

In Vitro Ability of a Novel Nanohydroxyapatite Oral Rinse to Occlude Dentine Tubules

PubMed Central

Hill, Robert G.; Chen, Xiaohui; Gillam, David G.

2015-01-01

Objectives. The aim of the study was to investigate the ability of a novel nanohydroxyapatite (nHA) desensitizing oral rinse to occlude dentine tubules compared to selected commercially available desensitizing oral rinses. Methods. 25 caries-free extracted molars were sectioned into 1 mm thick dentine discs. The dentine discs (n = 25) were etched with 6% citric acid for 2 minutes and rinsed with distilled water, prior to a 30-second application of test and control oral rinses. Evaluation was by (1) Scanning Electron Microscopy (SEM) of the dentine surface and (2) fluid flow measurements through a dentine disc. Results. Most of the oral rinses failed to adequately cover the dentine surface apart from the nHa oral rinse. However the hydroxyapatite, 1.4% potassium oxalate, and arginine/PVM/MA copolymer oral rinses, appeared to be relatively more effective than the nHA test and negative control rinses (potassium nitrate) in relation to a reduction in fluid flow measurements. Conclusions. Although the novel nHA oral rinse demonstrated the ability to occlude the dentine tubules and reduce the fluid flow measurements, some of the other oral rinses appeared to demonstrate a statistically significant reduction in fluid flow through the dentine disc, in particular the arginine/PVM/MA copolymer oral rinse. PMID:26161093

Cone-beam Computed Tomography Evaluation of Root Canal Preparation using Various Rotary Instruments: An in vitro Study.

PubMed

Ramanathan, Suhashini; Solete, Pradeep

2015-11-01

To evaluate the remaining dentin thickness of teeth after cleaning and shaping the root canal using three rotary instrumentation technique using cone-beam computed tomography (CBCT). This in vitro study is being done with 30 premolar samples with 20' curvature. The study is divided into three groups a CBCT was taken to measure the shortest distance from the root canal outline to the closest adjacent root surface was measured at each level from the cementoenamel junction (CEJ) (1,3, 5 and 7 mm) before and after root canal instrumentation. The purpose of this study was to compare the effects of different instruments used to prepare curved root canals on the remaining cervical dentin thickness and total amount of dentin removed from root canals during instrumentation by using multi-slice CBCT. The remaining dentin thickness is very much necessary for the success rate of root canal treatment. However, this study helps to prove that a conservative preparation with a sound remaining dentin thickness is much more advisable. It was observed that there was a significant difference at 1 and 3 mm (p < 0.05) and at 5 and 7 mm there was no significant difference ( p > 0.05). Mtwo has removed less amount dentin when compared to ProTaper Universal and ProTaper Next system at 1 and 3 mm. Under the conditions of the study, we concluded that ProTaper Universal and ProTaper Next should be used judiciously, as it causes higher thinning of root dentin of the root when compared with Mtwo.

The Effect of Energy Densities on the Shear Bond Strength of Self-Adhering Flowable Composite to Er:YAG Pretreated Dentin.

PubMed

Nahas, Paul; Zeinoun, Toni; Majzoub, Zeina; Corbani, Karim; Nammour, Samir

2016-01-01

Objective . To investigate the shear bond strength of self-adhering flowable resin composite, to dentin, after exposing it to Er:YAG laser radiation, at different energy densities. Materials and Methods . Sixty freshly extracted human third molars were randomly divided into five groups ( n = 12). In the control group, dentin was left unirradiated, whereas, in the other four groups, dentin was irradiated with Er:YAG laser in noncontact mode (MSP mode = 100  µ s; 10 Hz; beam diameter: 1.3 mm; speed of 1 mm/second; air 6 mL/min; and water 4 mL/min), and respectively, with the following level of energy (50 mJ, 60 mJ, 80 mJ, and 100 mJ). Then, self-adhering flowable resin composite was bonded to all prepared dentin surfaces. Shear bond strength (SBS) was applied and fractured surfaces were examined using scanning electron microscopy. Results . SBS values showed significant differences in 60 mJ ( P < 0.05) compared to other groups. Morphological evaluation revealed tags or plugs in dentinal tubules, especially when 60 mJ and 80 mJ were used. All four groups tended to leave more residues on the dentin surface, than the control group. Conclusion . Er:YAG dentin irradiation may enhance SBS of the self-adhering flowable resin composite when it is used at the appropriate low level of energy density.

The Effect of Energy Densities on the Shear Bond Strength of Self-Adhering Flowable Composite to Er:YAG Pretreated Dentin

PubMed Central

Corbani, Karim

2016-01-01

Objective. To investigate the shear bond strength of self-adhering flowable resin composite, to dentin, after exposing it to Er:YAG laser radiation, at different energy densities. Materials and Methods. Sixty freshly extracted human third molars were randomly divided into five groups (n = 12). In the control group, dentin was left unirradiated, whereas, in the other four groups, dentin was irradiated with Er:YAG laser in noncontact mode (MSP mode = 100 µs; 10 Hz; beam diameter: 1.3 mm; speed of 1 mm/second; air 6 mL/min; and water 4 mL/min), and respectively, with the following level of energy (50 mJ, 60 mJ, 80 mJ, and 100 mJ). Then, self-adhering flowable resin composite was bonded to all prepared dentin surfaces. Shear bond strength (SBS) was applied and fractured surfaces were examined using scanning electron microscopy. Results. SBS values showed significant differences in 60 mJ (P < 0.05) compared to other groups. Morphological evaluation revealed tags or plugs in dentinal tubules, especially when 60 mJ and 80 mJ were used. All four groups tended to leave more residues on the dentin surface, than the control group. Conclusion. Er:YAG dentin irradiation may enhance SBS of the self-adhering flowable resin composite when it is used at the appropriate low level of energy density. PMID:27830151

Temperature changes accompanying near infrared diode laser endodontic treatment of wet canals.

PubMed

Hmud, Raghad; Kahler, William A; Walsh, Laurence J

2010-05-01

Diode laser endodontic treatments such as disinfection or the generation of cavitations should not cause deleterious thermal changes in radicular dentin. This study assessed thermal changes in the root canal and on the root surface when using 940 and 980 nm lasers at settings of 4 W/10 Hz and 2.5 W/25 Hz, respectively, delivered into 2000-mum fibers to generate cavitations in water. The root surface temperature in the apical third was recorded, as was the water temperature in coronal, middle, and apical third regions, by using thermocouples placed inside the canal. Lasing was undertaken with either rest periods or rinsing between 5-second laser exposures. Both diode lasers induced only modest temperature changes on the external root surface at the settings used. Even though the temperature of the water within the canal increased during lasing by as much as 30 degrees C, the external root surface temperature increased by only a maximum of 4 degrees C. Irrigation between laser exposures was highly effective in minimizing thermal changes within the root canal and on the root surface. Diode laser parameters that induce cavitation do not result in adverse thermal changes in radicular dentin. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparison of two different forms of varnishes in the treatment of dentine hypersensitivity: a subject-blind randomised clinical study.

PubMed

Sethna, Gulnar Dara; Prabhuji, M L V; Karthikeyan, B V

2011-01-01

Dentine hypersensitivity is one of the most frequently recorded complaints of dental discomfort. Current evidence implicates patent dentinal tubules in hypersensitive dentine, and it follows that one effective way to reduce dentine sensitivity is to occlude the dentinal tubules. The purpose of this study was to compare the efficacy of two different desensitising agents, Cervitec varnish and Gluma varnish. Two hundred fifty patients self-reporting dentine hypersensitivity completed the paired split mouth randomised, subject-blind study. Each participant had a minimum of two sensitive teeth in at least two different quadrants and displaying a response of ≥3 cm to an evaporative stimulus. The hypersensitivity levels were measured with a tactile stimulus (scratchometer), thermal stimulus (cold water test), and an evaporative stimulus (air blast test) using a visual analogue scale. The teeth were evaluated immediately after treatment, and at 4 and 12 weeks after application of the chlorhexidine-containing varnish Cervitec and the glutaraldehyde-containing varnish, Gluma Desensitizer. Statistical analysis indicated that both the desensitising varnishes were effective in alleviating dentine hypersensitivity at all time intervals compared to baseline. There was a highly statistically significantly greater reduction in dentine hypersensitivity to evaporative stimulus, cold stimulus, and tactile stimulus after application of Cervitec than after Gluma Desensitizer (P < 0.001). Both the varnishes have a therapeutic potential to alleviate dentine hypersensitivity at all time intervals compared to baseline. However, Cervitec varnish is more efficacious in reducing dentine hypersensitivity than Gluma varnish at both 4 weeks and 12 weeks post-treatment.

Monitoring Demineralization and Subsequent Remineralization of Human Teeth at the Dentin-Enamel Junction with Atomic Force Microscopy.

PubMed

Lechner, Bob-Dan; Röper, Stephanie; Messerschmidt, Jens; Blume, Alfred; Magerle, Robert

2015-09-02

Using atomic force microscopy, we monitored the nanoscale surface morphology of human teeth at the dentin-enamel junction after performing successive demineralization steps with an acidic soft drink. Subsequently, we studied the remineralization process with a paste containing calcium and phosphate ions. Repeated atomic force microscopy imaging of the same sample areas on the sample allowed us to draw detailed conclusions regarding the specific mechanism of the demineralization process and the subsequent remineralization process. The about 1-μm-deep grooves that are caused by the demineralization process were preferentially filled with deposited nanoparticles, leading to smoother enamel and dentine surfaces after 90 min exposure to the remineralizing agent. The deposited material is found to homogeneously cover the enamel and dentine surfaces in the same manner. The temporal evolution of the surface roughness indicates that the remineralization caused by the repair paste proceeds in two distinct successive phases.

Effects of potassium oxalate on knoop hardness of etch-and-rinse adhesives.

PubMed

Silva, S M A; Malacarne-Zanon, J; Carvalho, R M; Alves, M C; De Goes, M F; Anido-Anido, A; Carrilho, M R

2012-01-01

The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; p<0.05). Regardless of the adhesive, the treatment with potassium oxalate reduced the adhesives' KHN (p<0.05), with the OS system exhibiting the lowest KHN compared with the MP and SB systems.

Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel-dentine complex bonded with different adhesive luting systems.

PubMed

Öztürk, Elif; Bolay, Şükran; Hickel, Reinhard; Ilie, Nicoleta

2013-02-01

The aim of this study was to evaluate the shear bond strength of porcelain laminate veneers to 3 different surfaces by means of enamel, dentine, and enamel-dentine complex. One hundred thirty-five extracted human maxillary central teeth were used, and the teeth were randomly divided into 9 groups (n=15). The teeth were prepared with 3 different levels for bonding surfaces of enamel (E), dentine (D), and enamel-dentine complex (E-D). Porcelain discs (IPS e.max Press, Ivoclar Vivadent) of 2mm in thickness and 4mm in diameter were luted to the tooth surfaces by using 2 light-curing (RelyX Veneer [RV], 3M ESPE; Variolink Veneer [VV], Ivoclar Vivadent) and a dual-curing (Variolink II [V2], Ivoclar Vivadent) adhesive systems according to the manufacturers' instructions. Shear bond strength test was performed in a universal testing machine at 0.5mm/min until bonding failure. Failure modes were determined under a stereomicroscope, and fracture surfaces were evaluated with a scanning electron microscope. The data were statistically analysed (SPSS 17.0) (p=0.05). Group RV-D exhibited the lowest bond strength value (5.42±6.6MPa). There was statistically no difference among RV-D, V2-D (13.78±8.8MPa) and VV-D (13.84±6.2MPa) groups (p>0.05). Group VV-E exhibited the highest bond strength value (24.76±8.8MPa). The type of tooth structure affected the shear bond strength of the porcelain laminate veneers to the 3 different types of tooth structures (enamel, dentine, and enamel-dentine complex). When dentine exposure is necessary during preparation, enough sound enamel must be protected as much as possible to maintain a good bonding; to obtain maximum bond strength, preparation margins should be on sound enamel. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nanomechanical properties of biochemically modified dentin bonded interfaces

PubMed Central

dos Santos, Paulo H; Karol, Sachin; Bedran-Russo, Ana Karina B

2014-01-01

Summary The effect of biomodification of dentin matrices using collagen cross-linkers, glutaraldehyde (GD) and grape seed extract (GSE), on the reduced modulus of elasticity (Er) and nanohardness (H) of the hybrid layer and underlying dentin was investigated at the dentin-resin bonded interface. The coronal dentin of nine molars were exposed and divided into groups: 5% GD, 6.5% GSE and control. Control samples were etched, bonded with Adper Single Bond Plus and Premise composite. GD and GSE were applied for 1 hour prior to bonding procedures. After 24 hours, samples were sectioned, and resin-dentin beams were either kept in distilled water or exposed to collagenase treatment for 24 hours. Nano-indentations were performed at the hybrid layer and underlying dentin. GD and GSE treatment increased the Er and H of resin-dentin interface structures when compared to the control group (p < 0.05), particularly the hybrid layer, and may be a promising novel approach to strengthen the dentin-resin bonded interface structures when using these adhesive system and resin-based composite. PMID:21058972

[Effect of a nano hydroxyapatite desensitizing paste application on dentin bond strength of three self-etch adhesive systems].

PubMed

Pei, D D; Liu, S Y; Yang, H Y; Gan, J; Huang, C

2017-05-09

Objective: To evaluate a nano-hydroxyapatite (nano-HA) desensitizing paste application on the bond strength of three self-etch adhesives. Methods: Three dentin specimens of about 1 mm thick were cut from two teeth. Scanning electron microscope (SEM) was used to evaluate the dentin surfaces without treatment, after citric acid treatment and after nano-HA treatment. Thirty-six intact third molars extracted for surgical reasons were cut to remove the occlusal enamel with isomet, and then were etched with 1% citric acid for 20 s to simulate the sensitive dentin and divided into two groups randomly using a table of random numbers ( n= 18): the control group (no treatment) and the HA treated group (with nano-HA paste treatment). Each group was divided into three subgroups randomly using a table of random numbers ( n= 6). Subgroup A, B and C was bonded with G-Bond, Clearfil S(3) Bond and FL-Bond Ⅱ according to the manufacture's instruction separately. At 24 h after bonding procedure, and after water storage for 6 months, microtensile bond strength of the specimens was tested and the failure mode was analyzed. Results: SEM obeservation showed that citric acid could open the dentin tubules to set up the sensitive dentin model, and the nano-HA could occlude the dentin tubules effectively. For subgroup A, bonding strength of specimens treated with nano-HA ([41.14±8.91] MPa) was significantly high than that of the control group ([34.27±6.16] MPa) at 24 h after bonding procedure ( P< 0.05). However, after 6 month water ageing, the bonding strength of the control group and the HA treated group showed no significant difference ( P> 0.05). For subgroup B, specimens with nano-HA application showed lower bonding strength ([30.87±6.41] MPa) than that of the control group ([36.73±5.82] MPa) at 24 h after bonding procedure ( P< 0.05), and after 6 month water ageing, the bond strength of nano-HA application ([25.73±6.99] MPa) was also lower than that of the control group ([32.33±5.08] MPa) ( P< 0.05). For subgroup C, the bond strength of the control group and the HA treated group have no significant difference either before or after 6 month water ageing ( P> 0.05). Failure mode analysis showed that more than half of the samples in all groups were adhesive failure. Conclusions: Nano-HA treatment decreased the bond strength of subgroup B, while had no adverse effect on subgroup A and subgroup C.

Comparison of the Effect of Dentin Bonding, Dentin Sealing Agents on the Microleakage of Provisional Crowns Fabricated with Direct and Indirect Technique-An Invitro Study

PubMed Central

Muthukumar, B; Kumar, M Vasantha

2015-01-01

Background Postoperative sensitivity after temporization is a common complaint in Fixed Partial Denture patients. It is caused by weak and ill fitting temporary restorations which results in microleakage. This can be controlled by providing good temporary restorations and by coating the exposed dentinal tubules of the prepared tooth with dentin bonding agent or dental varnish. Aim The purpose of the study was to determine the effect of dentin-bonding, dentin sealing agents on the microleakage of temporary crowns made by tooth colored auto polymerizing resin fabricated with direct and indirect technique. Materials and Methods Thirty premolar and molar human teeth were collected which were extracted recently was used for the study. The teeth were marked and divided into 3 groups each containing 10 nos. They were individually mounted with self-cure acrylic resin. It was then mounted on a milling machine and crown preparations done. Temporary crowns were fabricated by direct and indirect method with two types of materials. In group A (Control group), the temporary crowns fabricated with both direct and indirect method were cemented directly with temporary luting cement. In group B dentine-bonding agent (solobond M) was applied once to the prepared surface of each tooth specimen before the cementation of temporary crowns where as in case of group C a single layer of dental varnish is applied prior to crown cementation. The entire specimens were immersed in 1% methylene blue and allowed to undergo thermal treatment. It was then sectioned in a hard tissue microtome. Each section was evaluated for dye penetration into the dentin tubules by comparing it with a visual scale. Statistical Analysis SPSS Version 13 software was used for non-parametric data analysis by a qualified statistician. P-values less than 0.05 (p-value<0.05) were considered to be statistically significant. Results Group B (Dentin Bonding Agent) specimens cemented with crowns fabricated in direct technique showed the least amount of microleakage when compared with group A and group C. Group C (Dental Varnish) specimen showed comparatively more amount of microleakage than that of group B. Group A (control group) specimens showed the maximum amount of microleakage. Conclusion The application of a single layer of Dental varnish appears to be of no significant benefit when compared to crowns cemented with the application of Dentin bonding agent on the tooth surface. The application of a single layer of Dentin bonding agent (Solobond M) and temporary crowns fabricated with direct technique may be of some benefit for crown preparations as an interim measure prior to the luting of final crown. PMID:26266219

To What Extent is Primate Second Molar Enamel Occlusal Morphology Shaped by the Enamel-Dentine Junction?

PubMed Central

Gilissen, Emmanuel; Thiery, Ghislain

2015-01-01

The form of two hard tissues of the mammalian tooth, dentine and enamel, is the result of a combination of the phylogenetic inheritance of dental traits and the adaptive selection of these traits during evolution. Recent decades have been significant in unveiling developmental processes controlling tooth morphogenesis, dental variation and the origination of dental novelties. The enamel-dentine junction constitutes a precursor for the morphology of the outer enamel surface through growth of the enamel cap which may go along with the addition of original features. The relative contribution of these two tooth components to morphological variation and their respective response to natural selection is a major issue in paleoanthropology. This study will determine how much enamel morphology relies on the form of the enamel-dentine junction. The outer occlusal enamel surface and the enamel-dentine junction surface of 76 primate second upper molars are represented by polygonal meshes and investigated using tridimensional topometrical analysis. Quantitative criteria (elevation, inclination, orientation, curvature and occlusal patch count) are introduced to show that the enamel-dentine junction significantly constrains the topographical properties of the outer enamel surface. Our results show a significant correlation for elevation, orientation, inclination, curvature and occlusal complexity between the outer enamel surface and the enamel dentine junction for all studied primate taxa with the exception of four modern humans for curvature (p<0.05). Moreover, we show that, for all selected topometrical parameters apart from occlusal patch count, the recorded correlations significantly decrease along with enamel thickening in our sample. While preserving tooth integrity by providing resistance to wear and fractures, the variation of enamel thickness may modify the curvature present at the occlusal enamel surface in relation to enamel-dentine junction, potentially modifying dental functionalities such as blunt versus sharp dental tools. In terms of natural selection, there is a balance between increasing tooth resistance and maintaining efficient dental tools. In this sense the enamel cap acts as a functional buffer for the molar occlusal pattern. In primates, results suggest a primary emergence of dental novelties on the enamel-dentine junction and a secondary transposition of these novelties with no or minor modifications of dental functionalities by the enamel cap. Whereas enamel crenations have been reported by previous studies, our analysis do not support the presence of enamel tubercles without dentine relief nuclei. As is, the enamel cap is, at most, a secondary source of morphological novelty. PMID:26406597

Alteration of Dentin-Enamel Mechanical Properties Due to Dental Whitening Treatments

PubMed Central

Zimmerman, B.; Datko, L.; Cupelli, M.; Alapati, S.; Dean, D.; Kennedy, M.

2010-01-01

The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation analysis with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0GPa versus 113.4GPa), while smaller increases were observed in the dentin (17.9GPa versus 27.9GPa). Likewise, there was an increase in the hardness of enamel (2.0GPa versus 4.3GPa) and dentin (0.5GPa versus 0.7GPa) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips™, Opalescence™ or UltraEtch™ caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips™ showed a reduction in the elastic modulus of enamel (55.3GPa to 32.7GPa) and increase in the elastic modulus of dentin (17.2GPa to 24.3GPa). Opalescence™ treatments did not significantly affect the enamel properties, but did result in a decrease in modulus of dentin (18.5GPa to 15.1GPa). Additionally, as expected, UltraEtch™ treatment decreased the modulus and hardness of enamel (48.7GPa to 38.0GPa and 1.9GPa to 1.5GPa, respectively) and dentin (21.4GPa to 15.0GPa and 1.9GPa to 1.5GPa, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy. PMID:20346902

Comparative Morphologic Evaluation and Occluding Effectiveness of Nd: YAG, CO2 and Diode Lasers on Exposed Human Dentinal Tubules: An Invitro SEM Study

PubMed Central

Grover, Harpreet Singh; Choudhary, Pankaj

2016-01-01

Introduction Dentinal hypersensitivity is one of the most common problem, encountered in dental practice but has least predictable treatment outcome. The advent of lasers in dentistry has provided an additional therapeutic option for treating dentinal hypersensitivity. Although various lasers have been tried over a period of time to treat dentinal hypersensitivity, but still the doubt persist as to which laser leads to maximum dentinal tubular occlusion and is most suitable with minimal hazardous effects. Aim To compare the effects of Nd: YAG, CO2 and 810-nm diode lasers on width of exposed dentinal tubule orifices and to evaluate the morphologic changes on dentinal surface of human tooth after laser irradiation by scanning electron microscope (SEM). Materials and Methods Forty root specimens were obtained from ten freshly extracted human premolars, which were randomly divided into four groups of ten each. Group I: control group treated with only saline, Group II: Nd:YAG laser, Group III: CO2 laser and Group IV: 810-nm diode laser. The specimens were examined using SEM. After calculating mean tubular diameter for each group, the values were compared statistically using parametric one-way ANOVA test and Turkey’s post hoc multiple comparison test. Results All the three lased groups showed a highly statistical significant result with p-value of <0.001 as compared to non-lased group. On intergroup comparison within the lased groups, all the three groups showed statistically significant difference in the reduction of dentinal tubular diameter (p-value < 0.001). Conclusion Nd: YAG laser was found to be most effective, followed by the CO2 laser and 810-nm diode laser was found to be least effective. The morphologic changes like craters, cracks and charring effect of the dentine were seen maximum by the use of CO2 laser. PMID:27630957

Comparative Morphologic Evaluation and Occluding Effectiveness of Nd: YAG, CO2 and Diode Lasers on Exposed Human Dentinal Tubules: An Invitro SEM Study.

PubMed

Saluja, Mini; Grover, Harpreet Singh; Choudhary, Pankaj

2016-07-01

Dentinal hypersensitivity is one of the most common problem, encountered in dental practice but has least predictable treatment outcome. The advent of lasers in dentistry has provided an additional therapeutic option for treating dentinal hypersensitivity. Although various lasers have been tried over a period of time to treat dentinal hypersensitivity, but still the doubt persist as to which laser leads to maximum dentinal tubular occlusion and is most suitable with minimal hazardous effects. To compare the effects of Nd: YAG, CO2 and 810-nm diode lasers on width of exposed dentinal tubule orifices and to evaluate the morphologic changes on dentinal surface of human tooth after laser irradiation by scanning electron microscope (SEM). Forty root specimens were obtained from ten freshly extracted human premolars, which were randomly divided into four groups of ten each. Group I: control group treated with only saline, Group II: Nd:YAG laser, Group III: CO2 laser and Group IV: 810-nm diode laser. The specimens were examined using SEM. After calculating mean tubular diameter for each group, the values were compared statistically using parametric one-way ANOVA test and Turkey's post hoc multiple comparison test. All the three lased groups showed a highly statistical significant result with p-value of <0.001 as compared to non-lased group. On intergroup comparison within the lased groups, all the three groups showed statistically significant difference in the reduction of dentinal tubular diameter (p-value < 0.001). Nd: YAG laser was found to be most effective, followed by the CO2 laser and 810-nm diode laser was found to be least effective. The morphologic changes like craters, cracks and charring effect of the dentine were seen maximum by the use of CO2 laser.

Micro-shear bond strengths of adhesive resins to coronal dentin versus the floor of the pulp chamber.

PubMed

Toba, Shigemitsu; Veerapravati, Weeraporn; Shimada, Yasushi; Nikaido, Toru; Tagami, Junji

2003-09-01

To evaluate the micro-shear bond strengths to superficial coronal dentin and the floor of the pulp chamber using two dentin bonding systems and to compare the ultrastructure of the resin-dentin interface of the two regions. 30 non-carious molars were used to obtain 2 mm thick slabs of coronal dentin and dentin at the pulp chamber. The specimens in each region were divided into three sub-groups to be bonded as follows; Clearfil SE Bond was used according to the manufacturer's instructions, Single Bond was applied to either wet dentin (Blot dry Group) or air-dried dentin (Dry Group) after phosphoric acid etching. A resin composite cylinder 0.5 mm high and 0.75 mm in diameter formed using a vinyl tube was bonded to the dentin. Specimens were stored at 37 degrees C for 24 hours in water and then stressed in shear at a crosshead speed of 1 mm/minute. The data were analyzed with one-way ANOVA and Fisher's PLSD test at the 5% level of significance. In addition, the ultrastructure of cross-sectioned dentin surfaces, the conditioned dentin surface and the resin dentin interfaces were observed by SEM. The bond strengths of Clearfil SE Bond and the Single Bond Blot dry group were approximately 40 MPa in coronal dentin and 30 MPa in the dentin at the floor of the pulp chamber respectively. However, the bond strengths of Single Bond were significantly lower in the Dry condition (MPa) (P < 0.05). SEM observations revealed the thickness of the hybrid layer created by Clearfil SE Bond in coronal dentin and at the floor of the pulp chamber were less than 1.0 microm thick. For Single Bond, a 3-4 microm hybrid layer was created in coronal dentin, while a thinner hybrid layer was observed in the floor of the pulp chamber. Morphological and structural variations in dentin may have influenced the bond strengths of the bonding systems to the floor of the pulp chamber.

Reducing the risk of sensitivity and pulpal complications after the placement of crowns and fixed partial dentures.

PubMed

Brännström, M

1996-10-01

Sensitivity after cementation of a crown with glass-ionomer cement is often attributed to an adverse effect on the pulp by the luting agent. Most permanent restorative materials in common use today do not tend to irritate the pulp; the main cause of pulpal damage is infection, the bacteria originating in the smear layer or deep in the dental tubules, inaccessible to caries-excavating procedures. A poorly fitting provisional crown may expose cut dentin to the oral fluids, and mechanical trauma caused by frictional heat during preparation may also damage the pulp. The following precautions are recommended during precementation procedures to reduce the risk of an inflammatory response in the pulp: (1) The provisional crown should be well fitting, covering cervical dentin but not impinging on the periodontal tissues. The permanent crown should be cemented as soon as possible. (2) The superficial smear layer should be removed and the dentinal surface should be treated with an antibacterial solution before the provisional crown is placed. (3) To decrease dentinal permeability under the provisional crown, the dentinal surface should be covered with a liner that can be easily removed before final cementation. (4) to ensure optimal mircomechanical bonding, the dentinal surface should be thoroughly cleaned, and the dentin should be kept moist until cementation. (5) The occlusion should be carefully checked before cementation of the crown.

Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography

PubMed Central

Ueno, Tomoka; Shimada, Yasushi; Matin, Khairul; Zhou, Yuan; Wada, Ikumi; Sadr, Alireza; Sumi, Yasunori; Tagami, Junji

2016-01-01

Abstract. The aim of this study was to evaluate the signal intensity and signal attenuation of swept source optical coherence tomography (SS-OCT) for dental caries in relation to the variation of mineral density. SS-OCT observation was performed on the enamel and dentin artificial demineralization and on natural caries. The artificial caries model on enamel and dentin surfaces was created using Streptococcus mutans biofilms incubated in an oral biofilm reactor. The lesions were centrally cross sectioned and SS-OCT scans were obtained in two directions to construct a three-dimensional data set, from the lesion surface (sagittal scan) and parallel to the lesion surface (horizontal scan). The integrated signal up to 200  μm in depth (IS200) and the attenuation coefficient (μ) of the enamel and dentin lesions were calculated from the SS-OCT signal in horizontal scans at five locations of lesion depth. The values were compared with the mineral density obtained from transverse microradiography. Both enamel and dentin demineralization showed significantly higher IS200 and μ than the sound tooth substrate from the sagittal scan. Enamel demineralization showed significantly higher IS200 than sound enamel, even with low levels of demineralization. In demineralized dentin, the μ from the horizontal scan consistently trended downward compared to the sound dentin. PMID:27704033

Effect of different adhesion strategies on bond strength of resin composite to composite-dentin complex.

PubMed

Özcan, M; Pekkan, G

2013-01-01

Service life of discolored and abraded resin composite restorations could be prolonged by repair or relayering actions. Composite-composite adhesion can be achieved successfully using some surface conditioning methods, but the most effective adhesion protocol for relayering is not known when the composite restorations are surrounded with dentin. This study evaluated the effect of three adhesion strategies on the bond strength of resin composite to the composite-dentin complex. Intact maxillary central incisors (N=72, n=8 per subgroup) were collected and the coronal parts of the teeth were embedded in autopolymerized poly(methyl tfr54methacrylate) surrounded by a polyvinyl chloride cylinder. Cylindrical cavities (diameter: 2.6 mm; depth: 2 mm) were opened in the middle of the labial surfaces of the teeth using a standard diamond bur, and the specimens were randomly divided into three groups. Two types of resin composite, namely microhybrid (Quadrant Anterior Shine; AS) and nanohybrid (Grandio; G), were photo-polymerized incrementally in the cavities according to each manufacturer's recommendations. The composite-enamel surfaces were ground finished to 1200-grit silicone carbide paper until the dentin was exposed. The surfaces of the substrate composites and the surrounding dentin were conditioned according to one of the following adhesion protocols: protocol 1: acid-etching (dentin) + silica coating (composite) + silanization (composite) + primer (dentin) + bonding agent (dentin + composite); protocol 2: silica coating (composite) + acid-etching (dentin) + silanization (composite) + primer (dentin) + bonding agent (dentin + composite); and protocol 3: acid-etching (dentin) + primer (dentin) + silanization (composite) + bonding agent (dentin + composite). Applied primer and bonding agents were the corresponding materials of the composite manufacturer. Silica coating (CoJet sand, 30 μm) was achieved using a chairside air-abrasion device (distance: 10 mm; duration: four seconds in circular motion). After conditioning protocols, the repair resin was adhered to the substrate surfaces using transparent polyethylene molds (diameter: 3.6 mm) incrementally and photo-polymerized. The substrate-adherend combinations were as follows: AS-AS, G-G, AS-G. Shear force was applied to the adhesive interface in a Universal Testing Machine (crosshead speed: 1 mm/min). The types of failures were further evaluated and categorized as follows: 1) cohesive in the composite substrate and 2) adhesive at the interface. Bond strength values (MPa) were statistically analyzed using two-way analysis of variance and least significant difference post hoc tests (α=0.05). Significant effects of the adhesion strategy (p=0.006) and the composite type (p=0.000) were found. Interaction terms were not significant (p=0.292). Regardless of the substrate-adherend combination, protocol 1 (17-22 MPa) showed significantly higher results than did protocols 2 (15-17 MPa) and 3 (11-17 MPa) (p=0.028, p=0.002, respectively). The highest results were obtained from the G-G combination after all three protocols (17-22 MPa). The incidence of cohesive failures was more common when the substrate and the adherend were the same composite type (AS-AS: 87.5%, 87.5%, 75%; G-G: 100%, 75%, 50% for protocols 1, 2, and 3, respectively). When substrate and adherend were used interchangeably, adhesive failures were more frequent (25%, 50%, and 100% for protocol 1, 2, and 3, respectively). When the substrate and the adherend are of the same type, greater repair strength could be expected. In the repair of composites next to the dentin, depending on the composite type, conditioning the composite with silica coating and silanization after etching the dentin adds to the repair strength compared to the results obtained with silane application only.

Effect of EDTA Conditioning and Carbodiimide Pretreatment on the Bonding Performance of All-in-One Self-Etch Adhesives

PubMed Central

Singh, Shipra; Nagpal, Rajni; Tyagi, Shashi Prabha; Manuja, Naveen

2015-01-01

Objective. This study evaluated the effect of ethylenediaminetetraacetic acid (EDTA) conditioning and carbodiimide (EDC) pretreatment on the shear bond strength of two all-in-one self-etch adhesives to dentin. Methods. Flat coronal dentin surfaces were prepared on one hundred and sixty extracted human molars. Teeth were randomly divided into eight groups according to two different self-etch adhesives used [G-Bond and OptiBond-All-In-One] and four different surface pretreatments: (a) adhesive applied following manufacturer's instructions; (b) dentin conditioning with 24% EDTA gel prior to application of adhesive; (c) EDC pretreatment followed by application of adhesive; (d) application of EDC on EDTA conditioned dentin surface followed by application of adhesive. Composite restorations were placed in all the samples. Ten samples from each group were subjected to immediate and delayed (6-month storage in artificial saliva) shear bond strength evaluation. Data collected was subjected to statistical analysis using three-way ANOVA and post hoc Tukey's test at a significance level of p < 0.05.  Results and Conclusion. EDTA preconditioning as well as EDC pretreatment alone had no significant effect on the immediate and delayed bond strengths of either of the adhesives. However, EDC pretreatment on EDTA conditioned dentin surface resulted in preservation of resin-dentin bond strength of both adhesives with no significant fall over six months. PMID:26557850

Mapping large extensions of flat dentin through digital microscopy: introduction to the method and possible applications.

PubMed

Reis, Claudia; De-Deus, Gustavo; Marins, Juliana; Fidel, Sandra; Fidel, Rivail; Paciornik, Sidnei

2012-08-01

To introduce a mapping method to characterize large dentin surfaces using digital microscopy and to discuss the advantages and possible applications of the method. Twenty unerupted third molars were sectioned transversally exposing coronal dentin surfaces. The microscopic mosaic method was used to generate a large field image with the resolution necessary to measure characteristics of dentin tubules. The AxioVision 4.7 software was used to control a motorized optical microscope and the process of acquiring approximately 400 small images to generate each dentin mosaic. An image analysis routine measured the number of tubules (NT) and the ratio between the total area of tubules and the area of the mosaic - the area fraction (AF) - of each mosaic. An automatic procedure transformed the mosaic image into a color map, providing a direct visual representation of tubule density through colors. The dentin maps were used for a comparative qualitative analysis of tubule density distribution of each sample. The results for NT (92450 to 196029 tubules/sample) and AF (4.12% to 11.10%) demonstrated a wide variation among dentin samples. The maps confirmed the microstructure variety, also revealing strong local variations in tubule density within each sample. The mapping method was able to perform dentin morphology characterization and is a valuable tool for producing a baseline for dentin adhesion studies. The method could be also useful in determining the real contribution of dentin structures to the final adhesion quality.

Shear test of composite bonded to dentin: Er:YAG laser versus dental handpiece preparations

NASA Astrophysics Data System (ADS)

Visuri, Steven R.; Gilbert, Jeremy L.; Walsh, Joseph T., Jr.; Wigdor, Harvey A.

1995-05-01

The erbium:YAG laser coupled with a cooling stream of water appears to be an effective means of removing dental hard tissues. However, before the procedure is deemed clinically viable, there are several important issues of safety and efficacy that need to be explored. In this study we investigated the surface that remains following laser ablation of dentin and compared the results to the use of a dental handpiece. Specifically, we studied the effect the laser radiation had on the bonding of composite to dentin. The crowns of extracted human molars were removed revealing the underlying dentin. An additional thickness of material was removed with either a dental handpiece or an Er:YAG laser by raster scanning the samples under a fixed handpiece or laser. Comparable surface roughnesses were achieved. A cylinder of composite was bonded onto the prepared surfaces following the manufacturer's directions. The dentin-composite bond was then shear stressed to failure on a universal testing apparatus and the maximum load recorded. Preliminary results indicated that laser irradiated samples had improved bond strengths. SEM photographs of the surfaces were also taken to compare the two methods of tooth preparation.

Effect of citric acid, tetracycline, and doxycycline on instrumented periodontally involved root surfaces: A SEM study

PubMed Central

Chahal, Gurparkash Singh; Chhina, Kamalpreet; Chhabra, Vipin; Bhatnagar, Rakhi; Chahal, Amna

2014-01-01

Background: A surface smear layer consisting of organic and inorganic material is formed on the root surface following mechanical instrumentation and may inhibit the formation of new connective tissue attachment to the root surface. Modification of the tooth surface by root conditioning has resulted in improved connective tissue attachment and has advanced the goal of reconstructive periodontal treatment. Aim: The aim of this study was to compare the effects of citric acid, tetracycline, and doxycycline on the instrumented periodontally involved root surfaces in vitro using a scanning electron microscope. Settings and Design: A total of 45 dentin samples obtained from 15 extracted, scaled, and root planed teeth were divided into three groups. Materials and Methods: The root conditioning agents were applied with cotton pellets using the Passive burnishing technique for 5 minutes. The samples were then examined by the scanning electron microscope. Statistical Analysis Used: The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 15.0 for Windows). For all quantitative variables means and standard deviations were calculated and compared. For more than two groups ANOVA was applied. For multiple comparisons post hoc tests with Bonferroni correction was used. Results: Upon statistical analysis the root conditioning agents used in this study were found to be effective in removing the smear layer, uncovering and widening the dentin tubules and unmasking the dentin collagen matrix. Conclusion: Tetracycline HCl was found to be the best root conditioner among the three agents used. PMID:24744541

Bond strengths of Scotchbond Multi-Purpose to moist dentin and enamel.

PubMed

Swift, E J; Triolo, P T

1992-12-01

This in vitro study tested the shear bond strengths of the Scotchbond Multi-Purpose adhesive system to moist and dry enamel and dentin. After the tooth was etched, the surface was either dried with compressed air or blotted with tissue paper, leaving the surface visibly moist. Primer and adhesive were applied according to the manufacturer's directions. Resin composite posts were applied, and the specimens were thermocycled. Shear bond strengths were determined using an Instron universal testing machine. For both enamel and dentin, mean shear bond strengths were higher when the surface was left visibly moist after etching. Bond strengths to moist and dry dentin were 21.8 and 17.8 MPa, respectively. Enamel bond strengths were slightly lower, with values of 17.0 and 14.2 MPa to moist and dry enamel, respectively.

Tooth dentin defects reflect genetic disorders affecting bone mineralization

PubMed Central

Vital, S. Opsahl; Gaucher, C.; Bardet, C.; Rowe, P.S.; George, A.; Linglart, A.; Chaussain, C.

2012-01-01

Several genetic disorders affecting bone mineralization may manifest during dentin mineralization. Dentin and bone are similar in several aspects, especially pertaining to the composition of the extracellular matrix (ECM) which is secreted by well-differentiated odontoblasts and osteoblasts, respectively. However, unlike bone, dentin is not remodelled and is not involved in the regulation of calcium and phosphate metabolism. In contrast to bone, teeth are accessible tissues with the shedding of deciduous teeth and the extractions of premolars and third molars for orthodontic treatment. The feasibility of obtaining dentin makes this a good model to study biomineralization in physiological and pathological conditions. In this review, we focus on two genetic diseases that disrupt both bone and dentin mineralization. Hypophosphatemic rickets is related to abnormal secretory proteins involved in the ECM organization of both bone and dentin, as well as in the calcium and phosphate metabolism. Osteogenesis imperfecta affects proteins involved in the local organization of the ECM. In addition, dentin examination permits evaluation of the effects of the systemic treatment prescribed to hypophosphatemic patients during growth. In conclusion, dentin constitutes a valuable tool for better understanding of the pathological processes affecting biomineralization. PMID:22296718

A Sub-microsecond Pulsed Plasma Jet for Endodontic Biofilm Disinfection

NASA Astrophysics Data System (ADS)

Jiang, Chunqi; Schaudinn, Christoph; Jaramillo, David E.; Gundersen, Martin A.; Costerton, J. William

A pulsed, tapered cylindrical plasma jet, several centimeter long and <2 mm in diameter, has been generated by a concentric tubular device for root canal disinfection. This plasma dental probe is typically powered with ˜100 ns, 1 kHz, multi-kilovolt electric pulses and filled with 5 SLPM (standard liter per minute) He/(1%)O2 flow. We report here an in vitro study of the antimicrobial effect of the room temperature plasma jet against monolayer Enterococcus faecalis biofilms on bovine dentins. Resultant colony-forming unit counts were associated with changes in bacterial cell morphology observed using scanning electron microscopy (SEM) following the treatment and control. Treatment of dentin discs cultivated with E. faecalis monolayer biofilms with the plasma (average power ≈ 1 W) for 5 min resulted in 92.4% kill (P < 0.0001). Severe disruption of the cell membranes was observed for the plasma treatment group, while the morphology of the cells remained intact for the negative control group. In addition, a pilot ex vivo test was conducted to examine the bactericidal effect of the plasma against saliva-derived biofilms cultivated in human root canals. Conspicuous biofilm disruption and cleared dentinal surfaces were observed in the canal after the plasma treatment for 5 min. We ­conclude that this non-thermal pulsed plasma-based technology is a potential ­alternative or supplement to existing protocols for root canal disinfection.

A Chemical Phosphorylation-inspired Design for Type I Collagen Biomimetic Remineralization

PubMed Central

Gu, Li-sha; Kim, Jongryul; Kim, Young Kyung; Liu, Yan; Dickens, Sabine H.; Pashley, David H.; Ling, Jun-qi; Tay, Franklin R.

2010-01-01

Objectives Type I collagen alone cannot initiate tissue mineralization. Sodium trimetaphosphate (STMP) is frequently employed as a chemical phosphorylating reagent in the food industry. This study examined the feasibility of using STMP as a functional analog of matrix phosphoproteins for biomimetic remineralization of resin-bonded dentin. Methods Equilibrium adsorption and desorption studies of STMP were performed using demineralized dentin powder (DDP). Interaction between STMP and DDP was examined using Fourier-transform infrared spectroscopy. Based on those results, a bio-inspired mineralization scheme was developed for chemical phosphorylation of acid-etched dentin with STMP, followed by infiltration of the STMP-treated collagen matrix with two etch-and-rinse adhesives. Resin-dentin interfaces were remineralized in a Portland cement-simulated body fluid system, with or without the use of polyacrylic acid (PAA) as a dual biomimetic analog. Remineralized resin-dentin interfaces were examined unstained using transmission electron microscopy. Results Analysis of saturation binding curves revealed the presence of irreversible phosphate group binding sites on the surface of the DDP. FT-IR provided additional evidence of chemical interaction between STMP and DDP, with increased in the peak intensities of the P=O and P–O–C stretching modes. Those peaks returned to their original intensities after alkaline phosphatase treatment. Evidence of intrafibrillar apatite formation could be seen in incompletely resin-infiltrated, STMP-phosphorylated collagen matrices only when PAA was present in the SBF. Significance These results reinforce the importance of PAA for sequestration of amorphous calcium phosphate nanoprecursors in the biomimetic remineralization scheme. They also highlight the role of STMP as a templating analog of dentin matrix phosphoproteins for inducing intrafibrillar remineralization of apatite nanocrystals within the collagen matrix of incompletely resin-infiltrated dentin. PMID:20688381

Effect of different concentrations of fluoride in dentifrices on dentin erosion subjected or not to abrasion in situ/ex vivo.

PubMed

Magalhães, A C; Rios, D; Moino, A L; Wiegand, A; Attin, T; Buzalaf, M A R

2008-01-01

This in situ/ex vivo study assessed the effect of different concentrations of fluoride in dentifrices on dentin subjected to erosion or to erosion plus abrasion. Ten volunteers took part in this crossover and double-blind study performed in 3 phases (7 days). They wore acrylic palatal appliances containing 4 bovine dentin blocks divided in two rows: erosion and erosion plus abrasion. The blocks were subjected to erosion by immersion ex vivo in a cola drink (60 s, pH 2.6) 4 times daily. During this step, the volunteers brushed their teeth with one of three dentifrices D (5,000 ppm F, NaF, silica); C (1,100 ppm F, NaF, silica) and placebo (22 ppm F, silica). Then, the respective dentifrice slurry (1:3) was dripped on dentin surfaces. While no further treatment was performed in one row, the other row was brushed using an electric toothbrush for 30 s ex vivo. The appliances were replaced in the mouth and the volunteers rinsed with water. Dentin loss was determined by profilometry and analyzed by 2-way ANOVA/Bonferroni test (a = 0.05). Dentin loss after erosive-abrasive wear was significantly greater than after erosion alone. Wear was significantly higher for the placebo than for the D and C dentifrices, which were not significantly different from each other. It can be concluded that the presence of fluoride concentrations around 1,100 ppm in dentifrices is important to reduce dentin wear by erosion and erosion + abrasion, but the protective effect does not increase with fluoride concentration. (c) 2008 S. Karger AG, Basel

Evaluation of the effects of the solution used for electrochemical dissolution of nickel-titanium endodontic files on dentine structure, microhardness and cell viability.

PubMed

Amaral, C C F; Ormiga, F; Boldrini, L C; Miranda, P G; Mendonça, T A; Granjeiro, J M; Gomes, J A C P

2018-05-15

To evaluate the effects of the [NaF 12 g/L + NaCl 1 g/L] solution used in the electrochemical dissolution process of fractured endodontic files, as well as its NiTi-containing product, on dentine hardness, topography and human fibroblast viability. Sixty single-rooted human teeth were evaluated for dentine microhardness using the Vickers hardness test and the area and number of dentinal tubules by scanning electron microscopy. The samples were divided according to the dentine surface treatment: distilled water; 17% EDTA; [NaF 12 g/L + NaCl 1 g/L]; and 17% EDTA + [NaF 12 g/L + NaCl 1 g/L]. Thirty-six single-rooted human teeth were divided according to the irrigation protocol: Dulbecco's Modified Eagle's Medium + 10% fetal bovine serum; 5.25% NaOCl; [NaF 12 g/L + NaCl 1 g/L]; and [NaF 12 g/L + NaCl 1 g/L+NiTi]. The extracts in contact with the apical foramen were used in the MTT assay to evaluate human fibroblast viability, with dilutions of 100, 50, 25 and 12.5%. Statistical tests used were paired t-tests, one-way ANOVA, Tukey's test, Kruskal-Wallis test and Dunn's post-test. The [NaF 12 g/L + NaCl 1 g/L] solution did not modify the dentine microhardness or the average dentinal tubule area. However, the EDTA induced changes in the dentine structure and microhardness (p<0.05). The [NaF 12 g/L + NaCl 1 g/L] solution and its NiTi-containing product had lower cytotoxicity than NaOCl at dilutions of 25% and 50% (p<0.01). The [NaF 12 g/L + NaCl 1 g/L] solution did not alter dentine microhardness or damage the dentine structure. It also demonstrated lower cytotoxicity than NaOCl. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Light-attenuating effect of dentin on the polymerization of light-activated restorative resins.

PubMed

Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Ban, Seiji; Takahashi, Hideo

2004-12-01

The light-attenuating effect of dentin on the mechanical properties of light-activated composite resins was evaluated using a simple experimental filter. The filter was designed to simulate the light transmittance and light diffusion characteristics of 1.0-mm thick dentin. The depth of cure, surface hardness, and flexural strength for 13 shades of three light-activated restorative resins were examined. These resins were cured either using direct irradiation with a light source, or indirect irradiation through the filter. The attenuation of light intensity by 1.0-mm thick dentin reached 85-90% in the 400-550 nm wavelength region. For all materials, the values of depth of cure, surface hardness on the top and bottom surfaces, and flexural strength of specimens irradiated indirectly through the simulated 1.0-mm thick dentin filter decreased by 37-60%, 16-55%, 50-83%, and 44-82% in comparison with those by direct irradiation, respectively. Recovery from mechanical properties' reduction was achieved when materials were irradiated 1.5-4 times longer than the standard irradiation time.

Inhibition of demineralization around the enamel-dentin/restoration interface after dentin pretreatment with TiF4 and self-etching adhesive systems.

PubMed

Bridi, Enrico Coser; do Amaral, Flávia Lucisano Botelho; França, Fabiana Mantovani Gomes; Turssi, Cecilia Pedroso; Basting, Roberta Tarkany

2016-05-01

The objective of this study was to evaluate the inhibition of demineralization around enamel-dentin/restoration interface after dentin pretreatment with 2.5% titanium tetrafluoride (TiF4). Forty dental class V cavities at the cementoenamel junction were distributed into four groups (n = 10), according to the presence or absence of TiF4 and to the adhesive system (Clearfil SE Bond/CL and Adper EasyOne/AD), and restored with a resin composite. A dynamic pH cycling model was used to induce the development of artificial caries lesions. After sectioning the dental blocks, Knoop microhardness tests were performed at different depths (20, 40, and 60 μm from the occlusal margin of the restoration) and at different distances (100, 200, and 300 μm from the adhesive interface). Repeated measures three-way analysis of variance (ANOVA) and Tukey's test were used (α = 0.05). For enamel, there were no differences in the microhardness values for CL, AD, and TiF4-AD at depths, regardless of the distances. Considering each depth, there were no significant differences among treatments. For dentin, ANOVA showed no significant interaction among the independent variables treatment*distance*depth (p = 0.994), no significant interaction between treatment*depth (p = 0.722), no significant interaction between treatment*distance (p = 0.265), no significant interaction between depth*distance (p = 0.365), and no significant effect on treatment (p = 0.151), depth (p = 0.067), or distance (p = 0.251). Dentin pretreatment of the cavity walls with TiF4 before self-etching adhesive systems was not effective in inhibiting demineralization around the enamel-dentin/restoration interfaces. The mechanism of incorporating fluoride in enamel and dentin of the cavity walls to inhibit demineralization around restorations seems ineffective when using TiF4 as a dentin pretreatment.

Interferon-gamma improves impaired dentinogenic and immunosuppressive functions of irreversible pulpitis-derived human dental pulp stem cells

PubMed Central

Sonoda, Soichiro; Yamaza, Haruyoshi; Ma, Lan; Tanaka, Yosuke; Tomoda, Erika; Aijima, Reona; Nonaka, Kazuaki; Kukita, Toshio; Shi, Songtao; Nishimura, Fusanori; Yamaza, Takayoshi

2016-01-01

Clinically, irreversible pulpitis is treated by the complete removal of pulp tissue followed by replacement with artificial materials. There is considered to be a high potential for autologous transplantation of human dental pulp stem cells (DPSCs) in endodontic treatment. The usefulness of DPSCs isolated from healthy teeth is limited. However, DPSCs isolated from diseased teeth with irreversible pulpitis (IP-DPSCs) are considered to be suitable for dentin/pulp regeneration. In this study, we examined the stem cell potency of IP-DPSCs. In comparison with healthy DPSCs, IP-DPSCs expressed lower colony-forming capacity, population-doubling rate, cell proliferation, multipotency, in vivo dentin regeneration, and immunosuppressive activity, suggesting that intact IP-DPSCs may be inadequate for dentin/pulp regeneration. Therefore, we attempted to improve the impaired in vivo dentin regeneration and in vitro immunosuppressive functions of IP-DPSCs to enable dentin/pulp regeneration. Interferon gamma (IFN-γ) treatment enhanced in vivo dentin regeneration and in vitro T cell suppression of IP-DPSCs, whereas treatment with tumor necrosis factor alpha did not. Therefore, these findings suggest that IFN-γ may be a feasible modulator to improve the functions of impaired IP-DPSCs, suggesting that autologous transplantation of IFN-γ-accelerated IP-DPSCs might be a promising new therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment. PMID:26775677

Smear layer-deproteinizing improves bonding of one-step self-etch adhesives to dentin.

PubMed

Thanatvarakorn, Ornnicha; Prasansuttiporn, Taweesak; Thittaweerat, Suppason; Foxton, Richard M; Ichinose, Shizuko; Tagami, Junji; Hosaka, Keiichi; Nakajima, Masatoshi

2018-03-01

Smear layer deproteinizing was proved to reduce the organic phase of smear layer covered on dentin surface. It was shown to eliminate hybridized smear layer and nanoleakage expression in resin-dentin bonding interface of two-step self-etch adhesive. This study aimed to investigate those effects on various one-step self-etch adhesives. Four different one-step self-etch adhesives were used in this study; SE One (SE), Scotchbond™ Universal (SU), BeautiBond Multi (BB), and Bond Force (BF). Flat human dentin surfaces with standardized smear layer were prepared. Smear layer deproteinizing was carried out by the application of 50ppm hypochlorous acid (HOCl) on dentin surface for 15s followed by Accel ® (p-toluenesulfinic acid salt) for 5s prior to adhesive application. No surface pretreatment was used as control. Microtensile bond strength (μTBS) and nanoleakage under TEM observation were investigated. The data were analyzed by two-way ANOVA and Tukey's post-hoc test and t-test at the significant level of 0.05. Smear layer deproteinizing significantly improved μTBS of SE, SU, and BB (p<0.001). Hybridized smear layer observed in control groups of SE, BB, and BF, and reticular nanoleakage presented throughout the hybridized complex in control groups of BB and BF were eliminated upon the smear layer deproteinizing. Smear layer deproteinizing by HOCl and Accel ® application could enhance the quality of dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized smear layer and preventing reticular nanoleakage formation in resin-dentin bonding interface. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Toothbrushing before or after an acidic challenge to minimize tooth wear? An in situ/ex vivo study.

PubMed

Wiegand, Annette; Egert, Sebastian; Attin, Thomas

2008-02-01

To evaluate whether patients should be advised to perform toothbrushing before or after an acidic challenge to minimize enamel and dentin wear by brushing abrasion. The study was a two-period crossover design (A and B, each 14 days) in which three enamel and dentin specimens were fixed in intraoral appliances of 10 volunteers. The following regimens were performed three times a day with at least 4 hours in between: A: 20-second brushing treatment in an automatic brushing machine, 5 minutes intraoral exposure of the specimens, extraoral erosion of enamel and dentin specimens for 40 seconds or B: Extraoral erosion for 40 seconds, 5 minutes intraoral exposure of the specimens, 20-second brushing treatment in an automatic brushing machine. Enamel and dentin loss at the end of each 14-day regimen was assessed by profilometry and statistically analyzed by t-test. For all volunteers, mean enamel and dentin wear was significantly lower when brushing treatment was performed before erosion (A: enamel: 2.3 +/- 1.0 microm, dentin: 4.1 +/- 1.6 microm) than when brushing was applied after erosion (B: enamel: 6.4 +/- 3.0 microm, dentin: 15.3 +/- 6.8 microm). It was concluded that patients awaiting an erosive attack should perform toothbrushing prior to rather than after an acidic challenge to minimize enamel and dentin wear.

Effect of different diode laser wavelengths on root dentin decontamination infected with Enterococcus faecalis.

PubMed

Borges, Caroline Cristina; Estrela, Carlos; Lopes, Fabiane Carneiro; Palma-Dibb, Regina Guenka; Pecora, Jesus Djalma; De Araújo Estrela, Cyntia Rodrigues; Sousa-Neto, Manoel Damião de

2017-11-01

The objective of this study was to evaluate the antibacterial effect and the ultrastructural alterations of diode laser with different wavelengths (808nm and 970nm) and its association with irrigating solutions (2.5% sodium hypochlorite and 2% chlorhexidine) in root dentin contaminated by a five days biofilm. Thirteen uniradicular teeth were sectioned into 100 dentin intraradicular blocks. Initially, the blocks were immersed for 5min in 17% EDTA and washed with distilled water for 5min, then samples were sterilized for 30min at 120°C. The dentin samples were inoculated with 0.1mL of E. faecalis suspension in 5mL BHI (Brain Heart Infusion) and incubated at 37°C for 5days. After contamination, the specimens were distributed into ten groups (n=10) according to surface treatment: GI - 5mL NaOCl 2.5%, GII - 5mL NaOCl 2.5%+808nm diode (0.1W for 20s), GIII - 5mL NaOCl 2.5%+970nm diode (0.5W for 4s), GIV - 808nm diode (0.1W for 20s), GV - 970nm diode (0.5W for 4s), GVI - CHX 2%, GVII - CHX 2%+808nm diode (0.1W for 20s), GVIII - CHX 2%+970nm diode (0.5W for 4s), GIX - positive control and GX - negative control. Bacterial growth was analyzed by turbidity and optical density of the growth medium by spectrophotometry (nm). Then, the specimens were processed for analysis ultrastructural changes of the dentin surface by SEM. The data was subject to the One-way ANOVA test. GI (77.5±12.1), GII (72.5±12.2), GIII (68.7±8.7), GV (68.3±8.7), GVI (62.0±5.5) and GVII (67.5±3.3) were statistically similar and statistically different from GIV (58.8±25.0), GVIII (59.2±4.0) and control groups (p<0.05). SEM analysis showed a modified amorphous organic matrix layer with melted intertubular dentin when dentin samples were irradiated with 970nm diode laser; erosion of the intertubular dentin in blocks submitted to 808nm diode laser irradiation; and an increased erosion of the intertubular dentin when 2.5% NaOCl was associated to the different wavelengths lasers. All the therapeutic protocols were able to reduce the bacterial contingent in dentin blocks, and the association of diode laser and solutions did not significantly improve the reduction of the bacterial contingent. Copyright © 2017 Elsevier B.V. All rights reserved.

Alteration of dentin-enamel mechanical properties due to dental whitening treatments.

PubMed

Zimmerman, B; Datko, L; Cupelli, M; Alapati, S; Dean, D; Kennedy, M

2010-05-01

The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation analysis with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0 GPa versus 113.4 GPa), while smaller increases were observed in the dentin (17.9 GPa versus 27.9 GPa). Likewise, there was an increase in the hardness of enamel (2.0 GPa versus 4.3 GPa) and dentin (0.5 GPa versus 0.7 GPa) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in the literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips, Opalescence or UltraEtch caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips showed a reduction in the elastic modulus of enamel (55.3 GPa to 32.7 GPa) and increase in the elastic modulus of dentin (17.2 GPa to 24.3 GPa). Opalescence treatments did not significantly affect the enamel properties, but did result in a decrease in the modulus of dentin (18.5 GPa to 15.1 GPa). Additionally, as expected, UltraEtch treatment decreased the modulus and hardness of enamel (48.7 GPa to 38.0 GPa and 1.9 GPa to 1.5 GPa, respectively) and dentin (21.4 GPa to 15.0 GPa and 1.9 GPa to 1.5 GPa, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy. Published by Elsevier Ltd.

The effect of dentinal stimulation on pulp nerve function and pulp morphology in the dog.

PubMed

Hirvonen, T J; Närhi, M V

1986-11-01

The effect of dentinal stimulation on pulpal nerve responses and pulp morphology has been studied in the dog. Canine tooth (n = 25) dentin was stimulated by drilling, probing, and air-blasting for from two to five hours. Acid-etching was used to open dentinal tubules. All test teeth showed disruption of the odontoblast layer and its separation from the predentin; also, dislocation of odontoblast nuclei into dentinal tubules was found in most cases. Single-fiber (n = 14, conduction velocity = 24.3 +/- 7.4 (SD) m/s) recordings of the responses of canine tooth pulpal nerves to dentinal stimulation were made in ten of the stimulated teeth. No changes in the sensitivity of the nerves to dentinal stimulation could be detected. It is concluded that pulpal nerve function and morphological changes of the pulp are not clearly correlated. The condition of the dentin surface seems to be the important factor.

Regeneration of dental pulp/dentine complex with a three-dimensional and scaffold-free stem-cell sheet-derived pellet.

PubMed

Na, Sijia; Zhang, Hao; Huang, Fang; Wang, Weiqi; Ding, Yin; Li, Dechao; Jin, Yan

2016-03-01

Dental pulp/dentine complex regeneration is indispensable to the construction of biotissue-engineered tooth roots and represents a promising approach to therapy for irreversible pulpitis. We used a tissue-engineering method based on odontogenic stem cells to design a three-dimensional (3D) and scaffold-free stem-cell sheet-derived pellet (CSDP) with the necessary physical and biological properties. Stem cells were isolated and identified and stem cells from root apical papilla (SCAPs)-based CSDPs were then fabricated and examined. Compact cell aggregates containing a high proportion of extracellular matrix (ECM) components were observed, and the CSDP culture time was prolonged. The expression of alkaline phosphatase (ALP), dentine sialoprotein (DSPP), bone sialoprotein (BSP) and runt-related gene 2 (RUNX2) mRNA was higher in CSDPs than in cell sheets (CSs), indicating that CSDPs have greater odonto/osteogenic potential. To further investigate this hypothesis, CSDPs and CSs were inserted into human treated dentine matrix fragments (hTDMFs) and transplanted into the subcutaneous space in the backs of immunodeficient mice, where they were cultured in vivo for 6 weeks. The root space with CSDPs was filled entirely with a dental pulp-like tissue with well-established vascularity, and a continuous layer of dentine-like tissue was deposited onto the existing dentine. A layer of odontoblast-like cells was found to express DSPP, ALP and BSP, and human mitochondria lined the surface of the newly formed dentine-like tissue. These results clearly indicate that SCAP-CSDPs with a mount of endogenous ECM have a strong capacity to form a heterotopic dental pulp/dentine complex in empty root canals; this method can be used in the fabrication of bioengineered dental roots and also provides an alternative treatment approach for pulp disease. Copyright © 2013 John Wiley & Sons, Ltd.

In vitro dentin permeability after application of Gluma® desensitizer as aqueous solution or aqueous fumed silica dispersion

PubMed Central

ISHIHATA, Hiroshi; FINGER, Werner J.; KANEHIRA, Masafumi; SHIMAUCHI, Hidetoshi; KOMATSU, Masashi

2011-01-01

Objectives To assess and to compare the effects of Gluma® Desensitizer (GDL) with an experimental glutaraldehyde and HEMA containing fumed silica dispersion (GDG) on dentin permeability using a chemiluminous tracer penetration test. Material and Methods Twenty disc-shaped dentin specimens were dissected from extracted human third molars. The dentin specimens were mounted in a split chamber device for determination of permeability under liquid pressure using a photochemical method. Ten specimens were randomly selected and allocated to the evaluation groups Gluma® Desensitizer as aqueous solution and glutaraldehyde/HEMA as fumed silica dispersion, respectively. Dentin disc permeability was determined at two pressure levels after removal of smear with EDTA, after albumin soaking, and after application of the desensitizing agents. Two desensitizer-treated and rinsed specimens of each group were examined by scanning electron microscopy (SEM) for surface remnants. Results Comparatively large standard deviations of the mean EDTA reference and albumin soaked samples permeability values reflected the differences of the dentin substrates. The mean chemiluminescence values of specimen treated with GDL and GDG, respectively, were significantly reduced after topical application of the desensitizing agents on albumin-soaked dentin. The effects of GDL and GDG on permeability were not significantly different. Treated specimens showed no surface remnants after rinsing. Conclusions The experimental desensitizer gel formulation reduced dentin permeability as effectively as the original Gluma® Desensitizer solution. PMID:21552716

Mechanisms of silver diamine fluoride on arresting caries: a literature review.

PubMed

Zhao, Irene Shuping; Gao, Sherry Shiqian; Hiraishi, Noriko; Burrow, Michael Francis; Duangthip, Duangporn; Mei, May Lei; Lo, Edward Chin-Man; Chu, Chun-Hung

2018-04-01

To review the evidence regarding the mechanisms of silver diamine fluoride (SDF) for arresting caries. A literature search was conducted using the keywords silver diamine fluoride, and its alternative names, in seven databases: PubMed, Embase and Scopus (English); China National Knowledge Infrastructure (Chinese); Bilioteca Virtual em Saude (Portuguese); Biblioteca Virtual en Salud Espana (Spanish); and Ichushi-Web (Japanese). The titles and abstracts were screened. Full texts were retrieved for publications that studied mechanisms of actions of SDF, including its effects on remineralisation of carious lesions and on cariogenic bacteria. A total of 1,123 publications were identified. Twenty-nine articles were included and they investigated the effect of SDF on cariogenic bacteria and dental hard tissues. Eleven studies investigated the antibacterial properties of SDF. They found that SDF was bactericidal to cariogenic bacteria, mainly Streptococcus mutans. It inhibited the growth of cariogenic biofilms on teeth. Twenty studies reported the remineralisation of demineralised enamel or dentine by SDF. They found that mineral loss of demineralised enamel and dentine was reduced after SDF treatment. A highly mineralised surface rich in calcium and phosphate was formed on arrested carious lesions. Four studies examined the effect of SDF on dentine collagen. They found that SDF inhibited collagenases (matrix metalloproteinases and cysteine cathepsins) and protected dentine collagen from destruction. SDF is a bactericidal agent and reduces the growth of cariogenic bacteria. It inhibits demineralisation and promotes the remineralisation of demineralised enamel and dentine. It also hampers degradation of the dentine collagen. © 2017 FDI World Dental Federation.

Effect of 2% Chlorhexidine Digluconate on the Bond Strength to Normal versus Caries-Affected Dentin

PubMed Central

Komori, Paula C. P.; Pashley, David H.; Tjäderhane, Leo; Breschi, Lorenzo; Mazzoni, Annalisa; de Goes, Mario Fernando; Wang, Linda; Carrilho, Marcela R.

2013-01-01

SUMMARY This study evaluated the effect of 2% chlorhexidine digluconate (CHX) used as a therapeutic primer on the long-term bond strengths of two etch-and-rinse adhesives to normal (ND) and caries-affected (CAD) dentin. Forty extracted human molars with coronal carious lesions, surrounded by normal dentin, were selected for this study. Flat surfaces of two types of dentin (i.e. ND and CAD) were prepared with a water-cooled high speed diamond disc, and then acid-etched, rinsed and air-dried. In control groups, dentin was re-hydrated with distilled water, blot-dried and bonded with a three-step (Scotchbond Multi-Purpose-MP) or a two-step (Single Bond 2-SB) etch-and-rinse adhesive. In experimental groups, dentin was re-hydrated with 2% CHX (60 s), blot-dried and bonded with the same adhesives. Resin composite build-ups were made. Specimens were prepared for microtensile bond testing in accordance with the non-trimming technique and then tested either immediately or after 6-month storage in artificial saliva. Data were analyzed by ANOVA/Bonferroni tests (α = 0.05). CHX did not affect the immediate bond strength to ND or CAD (p>0.05). CHX treatment significantly lowered the loss of bond strength after 6 months seen in control bonds for ND (p<0.05), but it did not alter the bond strength of CAD (p>0.05). Application of MP on CHX-treated ND or CAD produced bonds that did not change over 6 months of storage. PMID:19363971

Effect of 2% chlorhexidine digluconate on the bond strength to normal versus caries-affected dentin.

PubMed

Komori, Paula C P; Pashley, David H; Tjäderhane, Leo; Breschi, Lorenzo; Mazzoni, Annalisa; de Goes, Mario Fernando; Wang, Linda; Carrilho, Marcela R

2009-01-01

This study evaluated the effect of 2% chlorhexidine digluconate (CHX) used as a therapeutic primer on the long-term bond strengths of two etch-and-rinse adhesives to normal (ND) and caries-affected (CAD) dentin. Forty extracted human molars with coronal carious lesions, surrounded by normal dentin, were selected for this study. The flat surfaces of two types of dentin (ND and CAD) were prepared with a water-cooled high-speed diamond disc, then acid-etched, rinsed and air-dried. In the control groups, the dentin was re-hydrated with distilled water, blot-dried and bonded with a three-step (Scotchbond Multi-Purpose-MP) or two-step (Single Bond 2-SB) etch-and-rinse adhesive. In the experimental groups, the dentin was rehydrated with 2% CHX (60 seconds), blot-dried and bonded with the same adhesives. Resin composite build-ups were made. The specimens were prepared for microtensile bond testing in accordance with the non-trimming technique, then tested either immediately or after six-months storage in artificial saliva. The data were analyzed by ANOVA/Bonferroni tests (alpha = 0.05). CHX did not affect the immediate bond strength to ND or CAD (p > 0.05). CHX treatment significantly lowered the loss of bond strength after six months as seen in the control bonds for ND (p < 0.05), but it did not alter the bond strength of CAD (p > 0.05). The application of MP on CHX-treated ND or CAD produced bonds that did not change over six months of storage.

Evaluation of desensitizing agents on dentin permeability and dentinal tubule occlusion: an in vitro study.

PubMed

Oberg, Carolina; Pochapski, Marcia Thais; Farago, Paulo Vitor; Granado, Carlos Jose Fernandes; Pilatti, Gibson Luiz; Santos, Fabio Andre

2009-01-01

One hundred twelve specimens from bovine incisors were divided into eight groups: Group 1 (treated with 10% strontium chloride gel), Group 2 (treated with 2% sodium fluoride gel), Group 3 (treated with 2% stannous fluoride gel), Group 4 (treated with 5% potassium nitrate gel), Group 5 (treated with 10% potassium nitrate gel), Group 6 (treated with 3% potassium oxalate gel), Group 7 (treated with hydroxyethylcellulose gel), and Group 8 (which received no treatment). Dentinal tubules were exposed after 0.5 mm of deep abrasion using a carbide bur and EDTA gel application. After each treatment, dentin permeability, tubule occlusion, and chemical elements on dentin were analyzed. There was a significant difference among groups in dentin permeability (p < 0.05 ANOVA). Groups 4, 5, and 6 showed the lowest values, while Groups 1, 7, and 8 exhibited the highest. Groups 1, 2, 3, 7, and 8 showed open dentinal tubules, Groups 4 and 5 had partial tubule occlusion, and most of the tubules in Group 6 were obliterated. Energy-dispersive x-rays revealed similar chemical characteristics among the experimental agents used, with traces of strontium, fluoride, sodium, and potassium. Within the limits of the study, 3% potassium oxalate gel showed the best results in terms of dentin permeability and dentinal tubule occlusion.

Evaluation of a 6% hydrogen peroxide tooth whitening gel on enamel and dentine microhardness in vitro.

PubMed

Joiner, Andrew; Thakker, Gopal; Cooper, Yvonne

2004-01-01

The aims of this study were to evaluate the effects of a novel 6% hydrogen peroxide containing tooth whitener, Xtra White (XW), on enamel and dentine microhardness in vitro. Polished human enamel and dentine specimens were prepared and baseline microhardness determined. In study 1, enamel specimens were exposed to 20 min cycles of either water, XW or Sprite Light for up to 28 cycles. In studies 2 and 3, enamel specimens were treated with 20 min cycles of either XW or water and exposed to whole saliva at all other times. In study 3, an additional exposure to a fluoride containing toothpaste was conducted. In total, 28 treatments were conducted in order to simulate a 2 weeks product use. In study 4, dentine specimens were treated as per study 3. Final microhardness measurements were taken and for studies 3 and 4 colour measurements were additionally taken. XW and water gave no statistically significant (p>0.05) changes in enamel and dentine microhardness after 28 treatments. Sprite Light gave a significant (p<0.00002) reduction in enamel microhardness after one 20 min treatment. XW showed significant bleaching of enamel and dentine specimens as compared to the water control. XW does not have any significant effect on enamel and dentine microhardness.

Self-induced vomiting and dental erosion – a clinical study

PubMed Central

2014-01-01

Background In individuals suffering from eating disorders (ED) characterized by vomiting (e.g. bulimia nervosa), the gastric juice regularly reaches the oral cavity, causing a possible risk of dental erosion. This study aimed to assess the occurrence, distribution and severity of dental erosions in a group of Norwegian patients experiencing self-induced vomiting (SIV). Methods The individuals included in the study were all undergoing treatment at clinics for eating disorders and were referred to a university dental clinic for examinations. One calibrated clinician registered erosions using the Visual Erosion Dental Examination (VEDE) system. Results Of 72 referred patients, 66 (63 females and three males, mean age 27.7 years) were or had been experiencing SIV (mean duration 10.6 years; range: 3 – 32 years), and were therefore included in the study. Dental erosions were found in 46 individuals (69.7%), 19 had enamel lesions only, while 27 had both enamel and dentine lesions. Ten or more teeth were affected in 26.1% of those with erosions, and 9% had ≥10 teeth with dentine lesions. Of the erosions, 41.6% were found on palatal/lingual surfaces, 36.6% on occlusal surfaces and 21.8% on buccal surfaces. Dentine lesions were most often found on lower first molars, while upper central incisors showed enamel lesions most frequently. The majority of the erosive lesions (48.6%) were found in those with the longest illness period, and 71.7% of the lesions extending into dentine were also found in this group. However, despite suffering from SIV for up to 32 years, 30.3% of the individuals showed no lesions. Conclusions Dental erosion commonly affects individuals with ED experiencing SIV, and is more often found on the palatal/lingual surfaces than on the buccal in these individuals, confirming a common clinical assumption. PMID:25069878

High-speed scanning ablation of dental hard tissues with a λ = 9.3 μm CO2 laser: adhesion, mechanical strength, heat accumulation, and peripheral thermal damage

PubMed Central

Nguyen, Daniel; Chang, Kwang; Hedayatollahnajafi, Saba; Staninec, Michal; Chan, Kenneth; Lee, Robert; Fried, Daniel

2011-01-01

CO2 lasers can be operated at high laser pulse repetition rates for the rapid and precise removal of dental decay. Excessive heat accumulation and peripheral thermal damage is a concern when using high pulse repetition rates. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. The interpulpal temperature rise was recorded using microthermocouples situated at the roof of the pulp chamber on teeth that were occlusally ablated using a rapidly-scanned CO2 laser operating at 9.3 μm with a pulse duration of 10 to 15 μs and repetition rate of 300 Hz over a 2 min time course. The adhesion strength of laser treated enamel and dentin surfaces was measured for various laser scanning parameters with and without post-ablation acid etching using the single-plane shear test. The mechanical strength of laser-ablated dentin surfaces were determined via the four-point bend test and compared to control samples prepared with 320 grit wet sand paper to simulate conventional preparations. Thermocouple measurements indicated that the temperature remained below ambient temperature if water-cooling was used. There was no discoloration of either dentin or enamel laser treated surfaces, the surfaces were uniformly ablated, and there were no cracks visible. Four-point bend tests yielded mean mechanical strengths of 18.2 N (s.d. = 4.6) for ablated dentin and 18.1 N (s.d. = 2.7) for control (p > 0.05). Shear tests yielded mean bond strengths approaching 30 MPa for both enamel and dentin under certain irradiation conditions. These values were slightly lower than nonirradiated acid-etched control samples. Additional studies are needed to determine if the slightly lower bond strength than the acid-etched control samples is clinically significant. These measurements demonstrate that enamel and dentin surfaces can be rapidly ablated by CO2 lasers with minimal peripheral thermal and mechanical damage and without excessive heat accumulation. PMID:21806256

Adhesive permeability affects coupling of resin cements that utilise self-etching primers to dentine.

PubMed

Carvalho, R M; Pegoraro, T A; Tay, F R; Pegoraro, L F; Silva, N R F A; Pashley, D H

2004-01-01

To examine the effects of an experimental bonding technique that reduces the permeability of the adhesive layer on the coupling of resin cements to dentine. Extracted human third molars had their mid to deep dentin surface exposed flat by transversally sectioning the crowns. Resin composite overlays were constructed and cemented to the surfaces using either Panavia F (Kuraray) or Bistite II DC (Tokuyama) resin cements mediated by their respective one-step or two-step self-etch adhesives. Experimental groups were prepared in the same way, except that the additional layer of a low-viscosity bonding resin (LVBR, Scotchbond Multi-Purpose Plus, 3M ESPE) was placed on the bonded dentine surface before luting the overlays with the respective resin cements. The bonded assemblies were stored for 24 h in water at 37 degrees C and subsequently prepared for microtensile bond strength testing. Beams of approximately 0.8 mm(2) were tested in tension at 0.5 mm/min in a universal tester. Fractured surfaces were examined under scanning electron microscopy (SEM). Additional specimens were prepared and examined with TEM using a silver nitrate-staining technique. Two-way ANOVA showed significant interactions between materials and bonding protocols (p<0.05). When bonded according to manufacturer's directions, Panavia F produced bond strengths that were significantly lower than Bistite II DC (p<0.05). The placement of an additional layer of a LVBR improved significantly the bond strengths of Panavia F (p<0.05), but not of Bistite II DC (p>0.05). SEM observation of the fractured surfaces in Panavia F showed rosette-like features that were exclusive for specimens bonded according to manufacturer's directions. Such features corresponded well with the ultrastructure of the interfaces that showed more nanoleakage associated with the more permeable adhesive interface. The application of the additional layer of the LVBR reduced the amount of silver impregnation for both adhesives suggesting that reduced permeability of the adhesives resulted in improved coupling of the resin cements to dentin. Placement of an intermediate layer of a LVBR between the bonded dentine surface and the resin cements resulted in improved coupling of Panavia F to dentine.

High-speed scanning ablation of dental hard tissues with a λ = 9.3 μm CO2 laser: adhesion, mechanical strength, heat accumulation, and peripheral thermal damage

NASA Astrophysics Data System (ADS)

Nguyen, Daniel; Chang, Kwang; Hedayatollahnajafi, Saba; Staninec, Michal; Chan, Kenneth; Lee, Robert; Fried, Daniel

2011-07-01

CO2 lasers can be operated at high laser pulse repetition rates for the rapid and precise removal of dental decay. Excessive heat accumulation and peripheral thermal damage is a concern when using high pulse repetition rates. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. The interpulpal temperature rise was recorded using microthermocouples situated at the roof of the pulp chamber on teeth that were occlusally ablated using a rapidly-scanned CO2 laser operating at 9.3 μm with a pulse duration of 10 to 15 μs and repetition rate of 300 Hz over a 2 min time course. The adhesion strength of laser treated enamel and dentin surfaces was measured for various laser scanning parameters with and without post-ablation acid etching using the single-plane shear test. The mechanical strength of laser-ablated dentin surfaces were determined via the four-point bend test and compared to control samples prepared with 320 grit wet sand paper to simulate conventional preparations. Thermocouple measurements indicated that the temperature remained below ambient temperature if water-cooling was used. There was no discoloration of either dentin or enamel laser treated surfaces, the surfaces were uniformly ablated, and there were no cracks visible. Four-point bend tests yielded mean mechanical strengths of 18.2 N (s.d. = 4.6) for ablated dentin and 18.1 N (s.d. = 2.7) for control (p > 0.05). Shear tests yielded mean bond strengths approaching 30 MPa for both enamel and dentin under certain irradiation conditions. These values were slightly lower than nonirradiated acid-etched control samples. Additional studies are needed to determine if the slightly lower bond strength than the acid-etched control samples is clinically significant. These measurements demonstrate that enamel and dentin surfaces can be rapidly ablated by CO2 lasers with minimal peripheral thermal and mechanical damage and without excessive heat accumulation.

High-speed scanning ablation of dental hard tissues with a λ = 9.3 μm CO2 laser: adhesion, mechanical strength, heat accumulation, and peripheral thermal damage.

PubMed

Nguyen, Daniel; Chang, Kwang; Hedayatollahnajafi, Saba; Staninec, Michal; Chan, Kenneth; Lee, Robert; Fried, Daniel

2011-07-01

CO(2) lasers can be operated at high laser pulse repetition rates for the rapid and precise removal of dental decay. Excessive heat accumulation and peripheral thermal damage is a concern when using high pulse repetition rates. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. The interpulpal temperature rise was recorded using microthermocouples situated at the roof of the pulp chamber on teeth that were occlusally ablated using a rapidly-scanned CO(2) laser operating at 9.3 μm with a pulse duration of 10 to 15 μs and repetition rate of 300 Hz over a 2 min time course. The adhesion strength of laser treated enamel and dentin surfaces was measured for various laser scanning parameters with and without post-ablation acid etching using the single-plane shear test. The mechanical strength of laser-ablated dentin surfaces were determined via the four-point bend test and compared to control samples prepared with 320 grit wet sand paper to simulate conventional preparations. Thermocouple measurements indicated that the temperature remained below ambient temperature if water-cooling was used. There was no discoloration of either dentin or enamel laser treated surfaces, the surfaces were uniformly ablated, and there were no cracks visible. Four-point bend tests yielded mean mechanical strengths of 18.2 N (s.d. = 4.6) for ablated dentin and 18.1 N (s.d. = 2.7) for control (p > 0.05). Shear tests yielded mean bond strengths approaching 30 MPa for both enamel and dentin under certain irradiation conditions. These values were slightly lower than nonirradiated acid-etched control samples. Additional studies are needed to determine if the slightly lower bond strength than the acid-etched control samples is clinically significant. These measurements demonstrate that enamel and dentin surfaces can be rapidly ablated by CO(2) lasers with minimal peripheral thermal and mechanical damage and without excessive heat accumulation.

Study on the potential inhibition of root dentine wear adjacent to fluoride-containing restorations.

PubMed

Turssi, Cecilia Pedroso; Hara, Anderson Takeo; Domiciano, Silvia Jorge; Serra, Mônica Campos

2008-01-01

The purpose of this in vitro study was to determine whether the vicinity of root dentine that had been restored with fluoride-releasing materials was at reduced risk for erosive/abrasive wear compared to root dentine restored with a non-fluoride-containing material. According to a randomized complete block design, standardized cavities prepared on the surface of 150 bovine root dentine slabs were restored with glass-ionomer cement, resin-modified glass ionomer, polyacid-modified resin composite, fluoride-containing or conventional composite. Specimens were coated with two layers of an acid-resistant nail varnish exposing half of the dentine surface and half of the restoration. Subsequently, specimens were either eroded in an acidic drink or left uneroded, then exposed to artificial saliva and abraded in a toothbrushing machine. Wear depth in the vicinity of restorations was quantified by a stylus profilometer, based on the nonabraded areas surrounding the erosion/abrasion region. Two-way ANOVA did not demonstrate significant interaction between restoratives and eroded-uneroded dentine (p=0.5549) nor significant difference among restorative materials (p=0.8639). Tukey's test ascertained that the wear depth was higher for eroded than for uneroded groups. Fluoride-releasing materials seemed to negligibly inhibit wear in the vicinity of restored root dentine subjected to erosive/abrasive challenges.

Comparative morphology, histology and growth of the dental plates of the Devonian dipnoan Chirodipterus.

PubMed

Smith, M M; Campbell, K S

1987-10-14

The dental plates of the Devonian lungfish Chirodipterus australis Miles (Osteichthyes; Dipnoi) are shown to have achieved their characteristic morphology by a growth process different from that assumed for the plates of genera such as Dipterus. Each plate was thickened by the addition of layers of bone that also extended the plate labially, thus providing the base on which and into which dentine grew. Distinctive features of the dentition are: (a) labial increase of the dentine mass by the addition of blister-like denticles of simple enamel-covered dentine, which is initially ingrown by pleromic dentine and subsequently resorbed and replaced by petrodentine; (b) increase in the midline by a similar process that results in the addition of one (or possibly two) new ridges; (c) resorption of the posterior edge of the pterygoid plates and the posterior and posteromedial edges of the prearticular plates, with subsequent development over the resorbed surfaces of several generations of simple regenerative dentine; (d) resorption and redeposition of pleromic dentine and bone in a triangular region posteromedially on the pterygoid plates; (e) the formation of tuberosities that simulate teeth at a short distance in from the labial edge, by four processes: formation of an undulating plate margin, differential growth of petrodentine (hard compact dentine) within the pulp cavity, differential wear of the petrodentine and the adjacent bone plus pleromic dentine, and slightly greater growth of the petrodentine towards the occlusal surface relative to the adjacent bone and dentine; (f) expansion of the large flat surfaces of the plates by gradual replacement of the bone and dentine at the proximal ends of the furrows and also by the development of linkages of petrodentine across the furrows; (g) development of isolated tuberosities on the flat posterolateral parts of the plates. The petrodentine of the ridges, tuberosities and plateaus of the plates is indistinguishable structurally and in its mode of growth from the petrodentine in extant species of dipnoans. Plates similar to those of C. australis have been observed in Stomiahykus, Archaeonectes, Conchodus, Palaedaphus and Sunwapta, as well as several species usually referred to as Dipterus. Sunwapta may be congeneric with C. australis.(ABSTRACT TRUNCATED AT 400 WORDS)

Polymerization contraction stress in dentin adhesives bonded to dentin and enamel.

PubMed

Hashimoto, Masanori; de Gee, Anton J; Feilzer, Albert J

2008-10-01

In a previous study on of polymerization contraction stress determinations of adhesives bonded to dentin a continuous decline of stress was observed after the adhesives had been light-cured. The decline was ascribed to stress relief caused by diffusion into the adhesive layer of water and/or solvents, left in the impregnated dentin surface after drying and/or evaporation in the application procedure. The purpose of the present study was to test the hypothesis that the contraction stress of adhesives bonded to enamel will not decline after light-curing, based on the assumption that water and/or solvents are more efficiently removed from impregnated enamel surfaces in the drying and/or evaporation step. Contraction stress was determined in a tensilometer for three total-etching adhesives Scotchbond multi-purpose, Single bond and One-step plus and four self-etching adhesives Clearfil SE Bond, Clearfil Protect Bond, AdheSE, and Xeno III. The adhesives were placed in a thin layer between a glass plate and a flat dentin or enamel surface pre-treated with phosphoric acid or self-etching primer and light-cured under constrained conditions. All adhesives bonded to enamel showed a stress decline, but significantly less than for dentin with the exception of two self-etching adhesives. The greatest decline was found for the total-etching adhesive systems bonded to dentin. The presence of hydrophobic monomers in the adhesives had a significant influence on the decline. The experiments indicate that fluids are withdrawn from the resin impregnated tooth structures, which may result in small defects in the tooth-resin interfaces.

Erosion and abrasion on dental structures undergoing at-home bleaching

PubMed Central

Demarco, Flávio Fernando; Meireles, Sônia Saeger; Sarmento, Hugo Ramalho; Dantas, Raquel Venâncio Fernandes; Botero, Tatiana; Tarquinio, Sandra Beatriz Chaves

2011-01-01

This review investigates erosion and abrasion in dental structures undergoing at- home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled. PMID:23674914

The comparison of the effect of endodontic irrigation on cell adherence to root canal dentin.

PubMed

Ring, Karla C; Murray, Peter E; Namerow, Kenneth N; Kuttler, Sergio; Garcia-Godoy, Franklin

2008-12-01

The purpose of this study was to compare the effect of 10 different endodontic irrigation and chelating treatments on dental pulp stem cell (DPSC) attachment to root canal surfaces. Thirty-eight extracted human nondiseased single-canal teeth were cleaned and shaped using ProTaper and ProFile rotary instrumentation (Tulsa Dentsply, Tulsa, OK). The irrigation treatments investigated were 6% sodium hypochlorite, 2% chlorhexidine gluconate, Aquatine Endodontic Cleanser, and Morinda citrifolia juice. The irrigation treatments were used in conjunction with EDTA or MTAD. The instrumented teeth were immediately placed in cell culture with confluent DPSCs for 1 week. The number of attached DPSCs appeared to be correlated with the cytotoxicity of the root canal irrigating solution (analysis of variance, p < 0.0001). The presence or absence of the smear layer had little influence on DPSC activity (chi-square, p > 0.05). The results suggest that biocompatible irrigants are needed to promote DPSC attachment to root canal dentin, which is essential to accomplish some regenerative endodontic therapies.

Cariostatic effect of fluoride-containing restorative materials associated with fluoride gels on root dentin

PubMed Central

BORGES, Fernanda Tavares; CAMPOS, Wagner Reis da Costa; MUNARI, Lais Sant'ana; MOREIRA, Allyson Nogueira; PAIVA, Saul Martins; MAGALHÃES, Claudia Silami

2010-01-01

Secondary caries is still the main cause of restoration replacement, especially on the root surface Objective This in vitro study evaluated the cariostatic effects of fluoride-containing restorative materials associated with fluoride gels, on root dentin. Materials and Methods A randomized complete block design was used to test the effects of the restorative systems, fluoride regimes and the interactions among them at different distances from restoration margins. Standardized cavities were prepared on 240 bovine root specimens and randomly assigned to 15 groups of treatments (n=16). Cavities were filled with the following restorative materials: Ketac-Fil (3M-ESPE); Vitremer (3M-ESPE); Dyract/Prime & Bond NT (Dentsply); Charisma/Gluma One Bond (Heraeus Kulzer) and the control, Z250/Single Bond (3M-ESPE). The specimens were subjected to a pH-cycling model designed to simulate highcaries activity. During the cycles, 1.23% acidulated phosphate fluoride, 2.0% neutral sodium fluoride or deionized/distilled water (control) was applied to the specimens for 4 min. The surface Knoop microhardness test was performed before (KHNi) and after (KHNf) the pH cycles at 100, 200 and 300 mm from the margins. Dentin microhardness loss was represented by the difference in initial and final values (KHNi - KHNf). Data were analyzed by Friedman's and Wilcoxon's tests, ANOVA and Tukey's test (α=5%). Results The interaction of restorative systems and topical treatments was not significant (p=0.102). Dentin microhardness loss was lowest closer to the restoration. Ketac-fil presented the highest cariostatic effect. Vitremer presented a moderate effect, while Dyract and Charisma did not differ from the control, Z250. The effects of neutral and acidulated fluoride gels were similar to each other and higher than the control. Conclusion Conventional and resin-modified glass ionomer cements as well as neutral and acidulated fluoride gels inhibit the progression of artificial caries adjacent to restorations. The associated effect of fluoride-containing restorative materials and gels could not be demonstrated. PMID:21085800

Time of Application of Sodium Ascorbate on Bonding to Bleached Dentin.

PubMed

Jung, Kyoung-Hwa; Seon, Eun-Mi; Choi, An-Na; Kwon, Yong-Hoon; Son, Sung-Ae; Park, Jeong-Kil

2017-01-01

This study examined the effects of different application times of sodium ascorbate (SA) on the bond strength of composite resin to bleached dentin. Specimens with an exposed dentin surface were divided into 3 groups according to the type of bleaching agent used: Group A, mixture of sodium perborate (SP) and distilled water (DW); Group B, mixture of SP and hydrogen peroxide (HP); control group, no bleaching. Each group was classified into 10 subgroups. Subgroups IB and DB underwent immediate bonding and delayed bonding, respectively. 10% SA was applied to 3, 5, 10, and 30 minutes and 1, 24, 48, and 72 hours, respectively. Microtensile bond strength ( μ TBS) was measured after restoration, and the data was analyzed by one-way ANOVA and Scheffé's test. Before restoration, the dentin surfaces were examined by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). SEM showed that most dentin surfaces were filled with crystals when SA was applied to more than 24 hours. EDS revealed peaks of calcium, carbon, oxygen, and sodium. The application of SA for 5 minutes to 48 hours or for 30 minutes to 24 hours is suggested when a mixture of SP and DW or HP is used, respectively.

In Vitro Evaluation of Dentin Hydraulic Conductance After 980 nm Diode Laser Irradiation.

PubMed

Rizzante, Fabio A P; Maenosono, Rafael M; Duarte, Marco A H; Furuse, Adilson Y; Palma-Dibb, Regina G; Ishikiriama, Sérgio K

2016-03-01

Dentin hypersensitivity treatments are based on the physical obliteration of the dentinal tubules to reduce hydraulic conductance. The aim of the present study is to evaluate the hydraulic conductance of bovine root dentin after irradiation with a 980-nm diode laser, with or without associated fluoride varnish. Sixty bovine root dentin specimens were divided into six groups (n = 10 in each group): G1, G3, and G5 (0.5 W, 0.7 W, and 1 W diode laser, respectively); G2, G4, and G6 (fluoride varnish application + 0.5 W, 0.7 W, and 1 W diode laser, respectively). The dentin hydraulic conductance was evaluated at four time periods with a fluxmeter: 1) with smear layer, 2) after 37% phosphoric acid etching, 3) after the treatments, and 4) after 6% citric acid challenge. After the dentinal fluid flow measurements, specimens were also evaluated for mineral composition using energy dispersive X-ray spectroscopy (EDS). Analysis demonstrated a better result with increased irradiation power (P < 0.001), especially if the diode laser irradiation was associated with the application of fluoride varnish (P < 0.001), ensuring a greater reduction in permeability. Considering the groups treated only with laser irradiation, the 1 W group was superior when compared with the 0.5 W and 0.7 W irradiated groups immediately after treatment (P < 0.001). After citric acid testing, all groups showed similar results, except when comparing the 1 W groups with the 0.5 W groups (P = 0.04). EDS results of the irradiated groups showed an increase in the proportion of calcium and phosphorus ions, which demonstrates a superficial composition modification after laser treatments. Laser irradiation of exposed dentin promoted significant reduction in the dentin hydraulic conductance, mainly with higher energy densities and association with fluoride varnish.

EDTA conditioning of dentine promotes adhesion, migration and differentiation of dental pulp stem cells.

PubMed

Galler, K M; Widbiller, M; Buchalla, W; Eidt, A; Hiller, K-A; Hoffer, P C; Schmalz, G

2016-06-01

To evaluate the effect of dentine conditioning on migration, adhesion and differentiation of dental pulp stem cells. Dentine discs prepared from extracted human molars were pre-treated with EDTA (10%), NaOCl (5.25%) or H2 O. Migration of dental pulp stem cells towards pre-treated dentine after 24 and 48 h was assessed in a modified Boyden chamber assay. Cell adhesion was evaluated indirectly by measuring cell viability. Expression of mineralization-associated genes (COL1A1, ALP, BSP, DSPP, RUNX2) in cells cultured on pre-treated dentine for 7 days was determined by RT-qPCR. Nonparametric statistical analysis was performed for cell migration and cell viability data to compare different groups and time-points (Mann-Whitney U-test, α = 0.05). Treatment of dentine with H2 O or EDTA allowed for cell attachment, which was prohibited by NaOCl with statistical significance (P = 0.000). Furthermore, EDTA conditioning induced cell migration towards dentine. The expression of mineralization-associated genes was increased in dental pulp cells cultured on dentine after EDTA conditioning compared to H2 O-pre-treated dentine discs. EDTA conditioning of dentine promoted the adhesion, migration and differentiation of dental pulp stem cells towards or onto dentine. A pre-treatment with EDTA as the final step of an irrigation protocol for regenerative endodontic procedures has the potential to act favourably on new tissue formation within the root canal. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

A safety study in vitro for the effects of an in-office bleaching system on the integrity of enamel and dentine.

PubMed

Sulieman, M; Addy, M; Macdonald, E; Rees, J S

2004-09-01

The aim of this study was to investigate safety concerns with bleaching procedures by studying the effects of a high concentration hydrogen peroxide (HP) in-surgery bleaching product on enamel and dentine. Flat enamel and dentine samples embedded in epoxy resin were prepared from human third molar teeth. Erosion of enamel: groups of enamel samples were treated with 35% HP then citric acid (CA) or brushing with toothpaste or CA alone and water alone. Enamel Loss was measured using a profilometer. Abrasion/erosion of dentine: groups of dentine specimens were treated as follows: Group 1--brushed with water for 30 min. Group 2--brushed with 35% HP for 30 min. Group 3--power bleached for 30 min and then Group 4--brushed with toothpaste for 1 minute. Group 5--water soaked for 30 min followed by brushing with toothpaste for 1 min. Group 6--orange juice soaked for 30 min followed by brushing with toothpaste for 1 min. Treatment effects were measured using a profilometer. Hardness tests: enamel and dentine specimens were hardness tested using a Wallace indenter prior to and post bleaching. Scanning Electron Microscopy: enamel and dentine specimens were taped and the exposed tissue treated with 35% HP and then studied under scanning electronmicroscopy (SEM). Enamel erosion: bleaching enamel samples had no measurable effect on enamel. Pre-bleaching had no significant effect on subsequent CA erosion or brushing. Abrasion/erosion of dentine: no significant differences were found between treatments 1-5 with little change from baseline detected. Orange juice (Group 6) produced considerable and significantly more erosion than other treatments. Hardness tests: there were no significant changes in hardness values for enamel and dentine. SEM: there was no evidence of any topographical changes to either enamel or dentine. Using one of the highest concentrations of HP for tooth bleaching procedures and maximum likely peroxide exposure, there was no evidence of deleterious effects on enamel or dentine. It must be assumed that studies which reported adverse effects on enamel and or dentine of bleaches reflect not the bleach itself but the pH of the formulation used.

Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration.

PubMed

Lee, Sang-Bae; González-Cabezas, Carlos; Kim, Kwang-Mahn; Kim, Kyoung-Nam; Kuroda, Kenichi

2015-08-10

This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe(3+) additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe-catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives.

Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration

PubMed Central

2015-01-01

This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe3+ additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe–catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives. PMID:26176305

Sodium Hypochlorite Irrigation and Its Effect on Bond Strength to Dentin

PubMed Central

Abuhaimed, Tariq S.

2017-01-01

Effective shaping and cleaning of root canals are essential for the success of endodontic treatment. Due to the complex anatomy of root canal spaces, the use of various instrumentation techniques alone is not effective in producing bacteria-free root canal spaces. Irrigation, disinfectants, rinses, and intervisit medications are used in conjunction with the mechanical instrumentation to ensure the success of endodontic treatment. Sodium hypochlorite (NaOCl), a halogenated compound, is routinely used to irrigate the root canal during endodontic treatments. NaOCl has been known for its antibacterial action, proteolytic and dissolution capacity, and debridement properties. NaOCl, however, can alter the composition of dentin and hence its interaction with the adhesive resins used to bond the restorative materials to treated dentin. This review therefore covers in depth the action of NaOCl on dentin-adhesive resin bond strength including both enhancement and reduction, then mechanisms proposed for such action, and finally how the adverse action of NaOCl on dentin can be reversed. PMID:28904947

Sodium Hypochlorite Irrigation and Its Effect on Bond Strength to Dentin.

PubMed

Abuhaimed, Tariq S; Abou Neel, Ensanya A

2017-01-01

Effective shaping and cleaning of root canals are essential for the success of endodontic treatment. Due to the complex anatomy of root canal spaces, the use of various instrumentation techniques alone is not effective in producing bacteria-free root canal spaces. Irrigation, disinfectants, rinses, and intervisit medications are used in conjunction with the mechanical instrumentation to ensure the success of endodontic treatment. Sodium hypochlorite (NaOCl), a halogenated compound, is routinely used to irrigate the root canal during endodontic treatments. NaOCl has been known for its antibacterial action, proteolytic and dissolution capacity, and debridement properties. NaOCl, however, can alter the composition of dentin and hence its interaction with the adhesive resins used to bond the restorative materials to treated dentin. This review therefore covers in depth the action of NaOCl on dentin-adhesive resin bond strength including both enhancement and reduction, then mechanisms proposed for such action, and finally how the adverse action of NaOCl on dentin can be reversed.

The acid-base resistant zone in three dentin bonding systems.

PubMed

Inoue, Go; Nikaido, Toru; Foxton, Richard M; Tagami, Junji

2009-11-01

An acid-base resistant zone has been found to exist after acid-base challenge adjacent to the hybrid layer using SEM. The aim of this study was to examine the acid-base resistant zone using three different bonding systems. Dentin disks were applied with three different bonding systems, and then a resin composite was light-cured to make dentin disk sandwiches. After acid-base challenge, the polished surfaces were observed using SEM. For both one- and two-step self-etching primer systems, an acid-base resistant zone was clearly observed adjacent to the hybrid layer - but with differing appearances. For the wet bonding system, the presence of an acid-base resistant zone was unclear. This was because the self-etching primer systems etched the dentin surface mildly, such that the remaining mineral phase of dentin and the bonding agent yielded clear acid-base resistant zones. In conclusion, the acid-base resistant zone was clearly observed when self-etching primer systems were used, but not so for the wet bonding system.

Influence of laboratory degradation methods and bonding application parameters on microTBS of self-etch adhesives to dentin.

PubMed

Erhardt, Maria Carolina G; Pisani-Proença, Jatyr; Osorio, Estrella; Aguilera, Fátima S; Toledano, Manuel; Osorio, Raquel

2011-04-01

To evaluate the laboratory resistance to degradation and the use of different bonding treatments on resin-dentin bonds formed with three self-etching adhesive systems. Flat, mid-coronal dentin surfaces from extracted human molars were bonded according to manufacturer's directions and submitted to two challenging regimens: (A) chemical degradation with 10% NaOC1 immersion for 5 hours; and (B) fatigue loading at 90 N using 50,000 cycles at 3.0 Hz. Additional dentin surfaces were bonded following four different bonding application protocols: (1) according to manufacturer's directions; (2) acid-etched with 36% phosphoric acid (H3PO4) for 15 seconds; (3) 10% sodium hypochlorite (NaOClaq) treated for 2 minutes, after H3PO4-etching; and (4) doubling the application time of the adhesives. Two one-step self-etch adhesives (an acetone-based: Futurabond/FUT and an ethanol-based: Futurabond NR/FNR) and a two-step self-etch primer system (Clearfil SE Bond/CSE) were examined. Specimens were sectioned into beams and tested for microtensile bond strength (microTBS). Selected debonded specimens were observed under scanning electron microscopy (SEM). Data (MPa) were analyzed by ANOVA and multiple comparisons tests (alpha= 0.05). microTBS significantly decreased after chemical and mechanical challenges (P< 0.05). CSE showed higher microTBS than the other adhesive systems, regardless the bonding protocol. FUT attained the highest microTBS after doubling the application time. H3PO4 and H3PO4 + NaOCl pretreatments significantly decreased bonding efficacy of the adhesives.

Effect of silica coating on fracture strength of glass-infiltrated alumina ceramic cemented to dentin.

PubMed

Xie, Haifeng; Zhu, Ye; Chen, Chen; Gu, Ning; Zhang, Feimin

2011-10-01

To examine the availability of sol-gel processed silica coating for alumina-based ceramic bonding, and determine which silica sol concentration was appropriate for silica coating. Sixty disks of In-Ceram alumina ceramic were fabricated and randomly divided into 5 main groups. The disks received 5 different surface conditioning treatments: Group Al, sandblasted; Group AlC, sandblasted + silane coupling agent applied; Groups Al20C, Al30C, and Al40C, sandblasted, silica coating via sol-gel process prepared using 20 wt%, 30 wt%, and 40 wt% silica sols, and then silane coupling agent applied. Before bonding, one-step adhesives were applied on pre-prepared ceramic surfaces of all groups. Then, 60 dentin specimens were prepared and conditioned with phosphoric acid and one-step adhesive. Ceramic disks of all groups were cemented to dentin specimens with dual-curing resin cements. Fracture strength was determined at 24 h and after 20 days of storage in water. Groups Al20C, Al30C, and Al40C revealed significantly higher fracture strength than groups Al and AlC. No statistically significant difference in fracture strength was found between groups Al and AlC, or among groups Al20C, Al30C, and Al40C. Fracture strength values of all the groups did not change after 20 days of water storage. Sol-gel processed silica coating can enhance fracture strength of In-Ceram alumina ceramic after bonding to dentin, and different silica sol concentrations produced the same effects. Twenty days of water storage did not decrease the fracture strength.

Shear bond strength of resin composite bonded with two adhesives: Influence of Er: YAG laser irradiation distance

PubMed Central

Shirani, Farzaneh; Birang, Reza; Malekipour, Mohammad Reza; Hourmehr, Zahra; Kazemi, Shantia

2014-01-01

Background: Dental surfaces prepared with different Er:YAG laser distance may have different characteristics compared with those prepared with conventional instruments. The aim of this study was to investigate the effect of Er:YAG laser irradiation distance from enamel and dentin surfaces on the shear bond strength of composite with self-etch and etch and rinse bonding systems compared with conventional preparation method. Materials and Methods: Two hundred caries-free human third molars were randomly divided into twenty groups (n = 10). Ten groups were designated for enamel surface (E1-E10) and ten for dentin surface (D1-D10). Er: YAG laser (2940 nm) was used on the E1-E8 (240 mJ, 25 Hz) and D1-D8 (140 mJ, 30 Hz) groups at four different distances of 0.5 (standard), 2, 4 and 11 mm. Control groups (E9, E10, D9 and D10) were ground with medium grit diamond bur. The enamel and dentin specimens were divided into two subgroups that were bonded with either Single Bond or Clearfil SE Bond. Resin composite (Z100) was dispensed on prepared dentin and enamel. The shear bond strengths were tested using a universal testing machine. Data were analyzed by SPSS12 statistical software using three way analysis of variance, Tukey and independent t-test. P < 0.05 was considered as significant. Results: There was a significant difference between enamel and dentin substrates (P < 0.001) and between lased and un-lased groups; the un-lased group had significantly higher bond strength (P < 0.001). Shear bond strength increased significantly with an increase in the laser irradiation distance (P < 0.05) on enamel surfaces (in both bonding agent subgroups) and on dentin surfaces (in the Single Bond subgroup). Conclusion: Laser irradiation decreases shear bond strength. Irradiation distance affects shear bond strength and increasing the distance would decrease the negative effects of laser irradiation. PMID:25540665

Application of Diode Laser in the Treatment of Dentine Hypersensitivity.

PubMed

Gojkov-Vukelic, Mirjana; Hadzic, Sanja; Zukanovic, Amila; Pasic, Enes; Pavlic, Veriva

2016-12-01

Dentine hypersensitivity is characterized by acute, sharp pain arising from the exposed dentine, most commonly in response to thermal, tactile, or chemical stimuli, and which cannot be linked to any other pathological changes in the tooth or the environment. Therapy uses various impregnating agents in the form of solutions or gels and, in more recent times, laser. The aim of this research was to examine the effects of treatment of hypersensitive dental cervix with diode laser. The study included 18 patients with 82 sensitive teeth. The degree of dentine hypersensitivity was evaluated by visual analogue scale (VAS), and the treatment was carried out by application of low-power diode laser over the span of three visits, which depended on the initial sensitivity. There is a significant difference in VAS values measured at the onset of treatment (baseline) and immediately after the first laser treatment (t=9.275; p=0.000), after 7 days, after the second laser treatment (14 days) (t=7.085, p=0.000), as well as after 14 days and the third laser treatment (t=5.517, p=0.000), which confirms the effectiveness of this therapeutic procedure. The results showed a reduction of hypersensitivity in response to tactile stimulus with a probe after the third treatment, even with teeth whose value on the VAS was very high at the beginning of treatment (baseline). Within the scope of the conducted study, laser therapy has provided extremely safe and effective results in the treatment of cervical dentine hypersensitivity.

Effects of Dentifrice Containing Hydroxyapatite on Dentinal Tubule Occlusion and Aqueous Hexavalent Chromium Cations Sorption: A Preliminary Study

PubMed Central

Liu, Jing; Hou, Yarong; Zhu, Manqun; Huang, Jiansheng; Xu, Pingping

2012-01-01

In order to endow environmental protection features to dentifrice, hydroxyapatite (HA) was added to ordinary dentifrice. The effects on dentinal tubule occlusion and surface mineralization were compared after brushing dentine discs with dentifrice with or without HA. The two types of dentifrice were then added to 100 µg/ml of hexavalent chromium cation (Cr6+) solution in order to evaluate their capacities of adsorbing Cr6+ from water. Our results showed that the dentifrice containing HA was significantly better than the ordinary dentifrice in occluding the dentinal tubules with a plugging rate greater than 90%. Moreover, the effect of the HA dentifrice was persistent and energy-dispersive spectrometer (EDS) revealed that the atomic percentages of calcium and phosphorus on the surface of dentine discs increased significantly. Adding HA to ordinary dentifrice significantly enhanced the ability of dentifrice to adsorb Cr6+ from water with the removal rate up to 52.36%. In addition, the sorption was stable. Our study suggests that HA can be added to ordinary dentifrice to obtain dentifrice that has both relieving dentin hypersensitivity benefits and also helps to control environmental pollution. PMID:23300511

Enamel and Dentin Surface Finishing Influence on the Roughness and Microshear Bond Strength of a Lithium Silicate Glass-Ceramic for Laminate Veneers

PubMed Central

Gonzaga, Carla Castiglia; Bravo, Ruth Peggy; Pavelski, Thiago Vinícius; Garcia, Paula Pontes; Correr, Gisele Maria; Leonardi, Denise Piotto; da Cunha, Leonardo Fernandes; Furuse, Adilson Yoshio

2015-01-01

Objectives. This study evaluated the influence of cavity surface finishing with diamond burs of different grit mounted on high-speed turbine and ultrasound on the roughness and microshear bond strength (MBS) of a lithium silicate glass-ceramic to enamel and dentin. Methods. Enamel and dentin specimens were divided into seven groups, according to the type of surface finishing: 1200-grit sandpaper (control), two different brands of medium-grit and fine-grit diamond burs in a high-speed turbine; medium-grit and fine-grit CVD (chemical vapor deposition) tips in an ultrasonic device. Roughness parameters (n = 5) and MSBS to a glass-ceramic (n = 10) were determined. Data were analyzed using ANOVA and Tukey's test (α = 5%). Results. Control group showed lower mean roughness readings and groups that used medium-grit diamond burs showed the highest mean roughness values. Regarding MSBS, there was no statistical difference when comparing the groups gritted with the same brand of medium- and fine-grit burs and tips. Conclusions. Cavity surface finishing influenced the roughness parameters and MSBS of a glass-ceramic to enamel and dentin. Medium-grit diamond burs in high-speed turbine showed the highest mean roughness values. Fine-grit CVD tips in ultrasound presented the highest MSBS values for both enamel and dentin. PMID:27347507

Enamel and Dentin Surface Finishing Influence on the Roughness and Microshear Bond Strength of a Lithium Silicate Glass-Ceramic for Laminate Veneers.

PubMed

Gonzaga, Carla Castiglia; Bravo, Ruth Peggy; Pavelski, Thiago Vinícius; Garcia, Paula Pontes; Correr, Gisele Maria; Leonardi, Denise Piotto; da Cunha, Leonardo Fernandes; Furuse, Adilson Yoshio

2015-01-01

Objectives. This study evaluated the influence of cavity surface finishing with diamond burs of different grit mounted on high-speed turbine and ultrasound on the roughness and microshear bond strength (MBS) of a lithium silicate glass-ceramic to enamel and dentin. Methods. Enamel and dentin specimens were divided into seven groups, according to the type of surface finishing: 1200-grit sandpaper (control), two different brands of medium-grit and fine-grit diamond burs in a high-speed turbine; medium-grit and fine-grit CVD (chemical vapor deposition) tips in an ultrasonic device. Roughness parameters (n = 5) and MSBS to a glass-ceramic (n = 10) were determined. Data were analyzed using ANOVA and Tukey's test (α = 5%). Results. Control group showed lower mean roughness readings and groups that used medium-grit diamond burs showed the highest mean roughness values. Regarding MSBS, there was no statistical difference when comparing the groups gritted with the same brand of medium- and fine-grit burs and tips. Conclusions. Cavity surface finishing influenced the roughness parameters and MSBS of a glass-ceramic to enamel and dentin. Medium-grit diamond burs in high-speed turbine showed the highest mean roughness values. Fine-grit CVD tips in ultrasound presented the highest MSBS values for both enamel and dentin.

In Vivo Effect of Calcium Hydroxide and Resin-modified Glass Ionomer Cement on Carious Dentin in Young Permanent Molars: An Ultrastructural and Macroscopic Study.

PubMed

Opal, Shireen; Garg, Shalini; Sharma, Deepak; Dhindsa, Abhishek; Jatana, Isha

2017-01-15

The purpose of this study was to evaluate macroscopically and ultrastructurally the effect of calcium hydroxide cement (CH) and resin-modified glass ionomer cement (RMGIC) compared with gutta percha (control) as a lining material on carious dentin after partial caries removal and sealing. Twenty-seven permanent molars with deep carious lesions underwent partial caries removal with the application of CH, RMGIC, or gutta percha (control) and were then sealed for three months. After a partial caries removal and sealing period, the dentin was macroscopically assessed (for color, consistency, and humidity) and further analyzed by scanning electron microscope to assess the ultrastructural changes in dentin (lumen size, mineralization of tubules, occlusion of tubules by cements, and bacterial ingress). The effect of treatment in each group was statistically analyzed. Dentin darkening and hardening were observed after the sealing period in all groups. However, there was no difference in the color after treatment among the three groups. It was observed that RMGIC showed a significant reduction in the size of the lumen compared to CH and the control. Partial caries removal and sealing resulted in dentin hardening, darkening, and dentin remineralization, irrespective of the dentin protection used.

Carbodiimide Inactivation of MMPs and Effect on Dentin Bonding

PubMed Central

Mazzoni, A.; Apolonio, F.M.; Saboia, V.P.A.; Santi, S.; Angeloni, V.; Checchi, V.; Curci, R.; Di Lenarda, R.; Tay, F.R.; Pashley, D.H.; Breschi, L.

2014-01-01

The use of protein cross-linking agents during bonding procedures has been recently proposed to improve bond durability. This study aimed to use zymography and in situ zymography techniques to evaluate the ability of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linker to inhibit matrix metalloproteinase (MMP) activity. The hypotheses tested were that: (1) bonding procedures increase dentin gelatinolytic activity and (2) EDC pre-treatment prevents this enzymatic activity. The zymographic assay was performed on protein extracts obtained from dentin powder treated with Optibond FL or Scotchbond 1XT with or without 0.3M EDC pre-treatment. For in situ zymography, adhesive/dentin interfaces were created with the same adhesives applied to acid-etched dentin slabs pre-treated or not with EDC conditioner. Zymograms revealed increased expression of dentin endogenous MMP-2 and -9 after adhesive application, while the use of EDC as a primer inactivated dentin gelatinases. Results of in situ zymograpy showed that hybrid layers of tested adhesives exhibited intense collagenolytic activity, while almost no fluorescence signal was detected when specimens were pre-treated with EDC. The correlative analysis used in this study demonstrated that EDC could contribute to inactivate endogenous dentin MMPs within the hybrid layer created by etch-and-rinse adhesives. PMID:24334409

[Updates on rickets and osteomalacia. dental diseases in rickets].

PubMed

Kubota, Takuo

2013-10-01

Rickets is characterized by mineralization defect in bone and cartilage. X-linked hypophosphatemic rickets (XLH) is the most common form of inherited rickets. Mineralization defect is observed in dentin as well as in bone and cartilage in XLH. The dominant feature is the occurrence of infectious periradicular abscesses on deciduous and permanent teeth, not associated with trauma or decay. Dental care including the maintenance of good oral hygiene and periodical examinations should be performed. A preventive sealing of occlusal surfaces can be considered. Endodontic treatment or extraction are carried out in the presence of periradicular abscesses. Further studies are necessary for elucidating mechanisms of dentin mineralization defect and the occurrence of periradicular abscesses and for developing preventive and curative measures in XLH.

Evaluation of the bond strength of resin cements used to lute ceramics on laser-etched dentin.

PubMed

Giray, Figen Eren; Duzdar, Lale; Oksuz, Mustafa; Tanboga, Ilknur

2014-07-01

The purpose of this study was to investigate the shear bond strength (SBS) of two different adhesive resin cements used to lute ceramics on laser-etched dentin. Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation has been claimed to improve the adhesive properties of dentin, but results to date have been controversial, and its compatibility with existing adhesive resin cements has not been conclusively determined. Two adhesive cements, one "etch-and-rinse" [Variolink II (V)] and one "self-etch" [Clearfil Esthetic Cement (C)] luting cement, were used to lute ceramic blocks (Vita Celay Blanks, Vita) onto dentin surfaces. In total, 80 dentin specimens were distributed randomly into eight experimental groups according to the dentin surface-etching technique used Er,Cr:YSGG laser and Er:YAG laser: (1) 37% orthophosphoric acid+V (control group), (2) Er,Cr:YSGG laser+V, (3) Er,Cr:YSGG laser+acid+V, (4) Er:YAG laser+V, (5) Er:YAG laser+acid+V, (6) C, (7) Er,Cr:YSGG laser+C, and (8) Er:YAG laser+C. Following these applications, the ceramic discs were bonded to prepared surfaces and were shear loaded in a universal testing machine until fracture. SBS was recorded for each group in MPa. Shear test values were evaluated statistically using the Mann-Whitney U test. No statistically significant differences were evident between the control group and the other groups (p>0.05). The Er,Cr:YSGG laser+A+V group demonstrated significantly higher SBS than did the Er,Cr:YSGG laser+V group (p=0.034). The Er,Cr:YSGG laser+C and Er:YAG laser+C groups demonstrated significantly lower SBS than did the C group (p<0.05). Dentin surfaces prepared with lasers may provide comparable ceramic bond strengths, depending upon the adhesive cement used.

Evaluation of the effect of photodynamic antimicrobial therapy in dentin caries: a pilot in vivo study

NASA Astrophysics Data System (ADS)

Borges, F. M. C.; de-Melo, M. A. S.; Lima, J. M. P.; Zanin, I. C. J.; Rodrigues, L. K. A.; Nobre-dos-Santos, M.

2010-02-01

In vitro and in situ studies have demonstrated that the photodynamic antimicrobial therapy (PACT) is effective in reducing Streptococcus mutans population in artificially carious dentin. This pilot in vivo study evaluated the antimicrobial effect of PACT using toluidine blue O (TBO) and a light-emitting diode (LED) in carious dentin lesions. Five healthy adult volunteers (19-36 yr), with at least 4 active carious cavities each, participated in this study. Teeth of each volunteer were randomly divided into four groups: (1) without TBO and without light (Control); (2) with TBO alone (TBO); (3) with LED at 94/J cm2 alone (LED); and (4) with TBO plus LED at 94 J/cm2 (PACT). Each cavity was divided into two halves. The baseline carious dentin sample was collected from half of each cavity. Following, the treatments were performed using a random distribution of tooth into treatments. Then, the second collection of carious dentin samples was performed. Before and after treatments, dentin samples were analyzed with regard to the counts of total viable microorganisms, total streptococci, mutans streptococci, and lactobacilli. The data were statistically analyzed by Kruskal-Wallis and Student-Newman-Keuls tests (α=5%). Log reductions ranged from -0.12 to 2.68 and significant reductions were observed for PACT (group 4) when compared to the other groups (1, 2, and 3) for total streptococci and mutans streptococci. Concluding, PACT was effective in killing oral microorganisms present in in vivo carious dentin lesions and may be a promising technique for eliminating bacteria from dentin before restoration.

Molecular and morphological surface analysis: effect of filling pastes and cleaning agents on root dentin

PubMed Central

DAINEZI, Vanessa Benetello; IWAMOTO, Alexsandra Shizue; MARTIN, Airton Abrahão; SOARES, Luís Eduardo Silva; HOSOYA, Yumiko; PASCON, Fernanda Miori; PUPPIN-RONTANI, Regina Maria

2017-01-01

Abstract The quality of the dentin root is the most important factor for restoration resin sealing and drives the outcome of endodontic treatment. Objective This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis. Material and Methods Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05). Results Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA. Conclusion The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules. PMID:28198982

Effect of Nd:YAG Laser Irradiation on the Number of Open Dentinal Tubules and Their Diameter with and without Smear of Graphite: An in Vitro Study

PubMed Central

Maleki-pour, Mohammad Reza; Birang, Reza; Khoshayand, Maryam; Naghsh, Narges

2015-01-01

Introduction: Dentin hypersensitivity (DH) is characterized by tooth pain arising from exposure of dental roots. In this study the efficiency of neodymium yttrium-aluminum-garnet (Nd:YAG) laser in association with graphite on dentinal surface changes as the alternative to the treatment of DH was evaluated. Methods: Sixteen noncarious human third molars were collected and sectioned into 5 parts from cementoenamel junction (CEJ) to the furcation area. The prepared samples were randomly assigned into five groups (Gs) of each 16: Control (G1), treated by Nd:YAG laser at 0.5 W (G2), irradiation of Nd:YAG with a 0.25 W output power(G3), smeared with graphite and then using Nd:YAG laser at output powers of 0.5 W (G4) and 0.25 W (G5). For all groups the parameters were 15 Hz, 60 s, at two stages and with a right angle irradiation. The number and diameter of dentinal tubules (DT) were compared and analyzed by SPSS software, One way ANOVA and Post hoc LSD tests. Results:The number of open dentinal tubules varied significantly between all groups except among G1 with G3 and G2 with G5. Multiple comparison tests also exhibited significant differences regarding the diameter of tubules between the groups two by two except among G2 with G5. Conclusion: Nd:YAG laser used at 0.25 W and 0.5 W with application of graphite smear was able to reduce the number and diameter of dentinal tubules. PMID:25699166

Effect of high energy X-ray irradiation on the nano-mechanical properties of human enamel and dentine.

PubMed

Liang, Xue; Zhang, Jing Yang; Cheng, Iek Ka; Li, Ji Yao

2016-01-01

Radiotherapy for malignancies in the head and neck can cause common complications that can result in tooth damage that are also known as radiation caries. The aim of this study was to examine damage to the surface topography and calculate changes in friction behavior and the nano-mechanical properties (elastic modulus, nanohardness and friction coefficient) of enamel and dentine from extracted human third molars caused by exposure to radiation. Enamel and dentine samples from 50 human third molars were randomly assigned to four test groups or a control group. The test groups were exposed to high energy X-rays at 2 Gy/day, 5 days/week for 5 days (10 Gy group), 15 days (30 Gy group), 25 days (50 Gy group), 35 days (70 Gy group); the control group was not exposed. The nanohardness, elastic modulus, and friction coefficient were analyzed using a Hysitron Triboindenter. The nano-mechanical properties of both enamel and dentine showed significant dose-response relationships. The nanohardness and elastic modulus were most variable between 30-50 Gy, while the friction coefficient was most variable between 0-10 Gy for dentine and 30-50 Gy for enamel. After exposure to X-rays, the fracture resistance of the teeth clearly decreased (rapidly increasing friction coefficient with increasing doses under the same load), and they were more fragile. These nano-mechanical changes in dental hard tissue may increase the susceptibility to caries. Radiotherapy caused nano-mechanical changes in dentine and enamel that were dose related. The key doses were 30-50 Gy and the key time points occurred during the 15th-25th days of treatment, which is when application of measures to prevent radiation caries should be considered.

Interaction between Octenidine-based Solution and Sodium Hypochlorite: A Mass Spectroscopy, Proton Nuclear Magnetic Resonance, and Scanning Electron Microscopy-based Observational Study.

PubMed

Thaha, Khaleel Ahamed; Varma, R Luxmi; Nair, Mali G; Sam Joseph, V G; Krishnan, Unni

2017-01-01

Octenisept (OCT; Schülke & Mayr, Nordersdedt, Germany), an antimicrobial, antibiofilm agent and a promising root canal irrigant, can be potentially combined with sodium hypochlorite (NaOCl) during endodontic treatment. The aim of this study was first to identify the precipitate formed on the interaction between OCT and NaOCl and secondly to compare its effect on dentinal tubules with that of precipitate formed on combining chlorhexidine (CHX) and NaOCl. This observational study was conducted in 3 stages. Initially, the color changes and precipitate formation were assessed when the test solution 0.1% OCT and 5.2% NaOCl were mixed. Color changes were compared with those observed when 2% CHX was mixed with 5.2% NaOCl. The residue obtained on combining OCT and NaOCl was subjected to proton nuclear magnetic resonance ( 1 H NMR) and mass spectrometric (MS) analysis. In the final stage, dentinal surfaces irrigated alternatively with OCT and NaOCl were compared using scanning electron microscopy (SEM) with the dentinal surface irrigated with CHX and NaOCl. The OCT-NaOCl mixture changed in color from initial milky white to transparent over time, whereas the CHX-NaOCl mixture showed an immediate peach-brown discoloration. 1 H NMR and MS analysis established that the whitish precipitate obtained on combining OCT and NaOCl solutions correlated with the structure of phenoxyethanol (PE). SEM revealed dense precipitate occluding the dentinal tubules with the CHX and NaOCl group, whereas the precipitate was sparse and partially occluded in the OCT and NaOCl group. The whitish precipitate formed with the OCT-NaOCl mixture was identified as PE, a compound already present in OCT, and it partly occluded the dentinal tubules. Copyright © 2016 American Association of Endodontists. All rights reserved.

A study of cavity preparation by Er:YAG laser. Effects on the marginal leakage of composite resin restoration.

PubMed

Shigetani, Yoshimi; Tate, Yasuaki; Okamoto, Akira; Iwaku, Masaaki; Abu-Bakr, Neamat

2002-09-01

The purpose of this study was to evaluate marginal leakage of composite resin restoration from cavities prepared by Er:YAG laser. The observation of the dentin surface after the application of laser irradiation was performed by LSM, the cutting surface showed a rough surface similar to scales, and exposed dentinal tubules were observed without striations or a smeared layer formation that were observed when using a rotary cutting device. Leakage tests revealed no significant differences in the marginal seal for both enamel and dentin between cavities prepared by Er:YAG laser irradiation and when using an air-turbine. In this study, the usefulness of cavity preparation by Er:YAG laser irradiation in composite resin restoration was suggested.

Effect of CO2 laser on Class V cavities of human molar teeth under a scanning electron microscope.

PubMed

Watanabe, I; Lopes, R A; Brugnera, A; Katayama, A Y; Gardini, A E

1996-01-01

The purpose of this study was to evaluate the effects of CO2 laser on dentin of class V cavities of extracted human molar teeth using a scanning electron microscope. SEM showed a smooth area with concentric lines formed by melting with subsequent recrystallization of dentin, areas of granulation, vitrified surface, numerous cracks, and irregular areas of descamative dentin. These data indicate that CO2 laser (4 and 6 watts) produces dentin alterations and limit its clinical applications.

Presence of matrix vesicles in the body of odontoblasts and in the inner third of dentinal tissue: a scanning electron microscopic study.

PubMed

Garcés-Ortíz, Maricela; Ledesma-Montes, Constantino; Reyes-Gasga, José

2013-05-01

The aim of this report is to present the results of a scanning electron microscopic study on the presence of matrix vesicles (MVs) found in human dentine. Dentin tissue from 20 human bicuspids was analyzed by means of scanning electron microscopy. MVs were found as outgrowths of the cellular membrane of the odontoblastic body, the more proximal portion of the odontoblastic process before entering the dentinal tubule and in the odontoblastic process within the inner third of the dentin. Size of MVs varied depending on location. In the inner third of dentin, they were seen in diverse positions; as membranal outgrowths, deriving from the odontoblastic process, lying free in the intratubular space and attached to the dentinal wall. Sometimes, they were seen organized forming groups of different sizes and shapes or as multivesicular chains running from the surface of the odontoblastic process to the tubular wall. MVs were present in places never considered: 1) the body of odontoblasts; 2) the most proximal part of the odontoblastic processes before entering the circumpulpal dentine and also: 3) in the inner third of dentinal tissue. According to our results, MVs not only participate during mantle dentin mineralization during early dentinogenesis, they also contribute during the mineralization process of the inner dentin.

Effect of bioactive glass-containing resin composite on dentin remineralization.

PubMed

Lee, Myoung Geun; Jang, Ji-Hyun; Ferracane, Jack L; Davis, Harry; Bae, Han Eul; Choi, Dongseok; Kim, Duck-Su

2018-05-25

The purpose of this study was to evaluate the effect of bioactive glass (BAG)-containing composite on dentin remineralization. Sixty-six dentin disks with 3 mm thickness were prepared from thirty-three bovine incisors. The following six experimental groups were prepared according to type of composite (control and experimental) and storage solutions (simulated body fluid [SBF] and phosphate-buffered saline [PBS]): 1 (undemineralized); 2 (demineralized); 3 (demineralized with control in SBF); 4 (demineralized with control in PBS); 5 (demineralized with experimental composite in SBF); and 6 (demineralized with experimental composite in PBS). BAG65S (65% Si, 31% Ca, and 4% P) was prepared via the sol-gel method. The control composite was made with a 50:50 Bis-GMA:TEGDMA resin matrix, 57 wt% strontium glass, and 15 wt% aerosol silica. The experimental composite had the same resin and filler, but with 15 wt% BAG65S replacing the aerosol silica. For groups 3-6, composite disks (20 × 10 × 2 mm) were prepared and approximated to the dentin disks and stored in PBS or SBF for 2 weeks. Micro-hardness measurements, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and field-emission scanning electron microscopy (FE-SEM) was investigated. The experimental BAG-containing composite significantly increased the micro-hardness of the adjacent demineralized dentin. ATR-FTIR revealed calcium phosphate peaks on the surface of the groups which used experimental composite. FE-SEM revealed surface deposits partially occluding the dentin surface. No significant difference was found between SBF and PBS storage. BAG-containing composites placed in close proximity can partially remineralize adjacent demineralized dentin. Copyright © 2018. Published by Elsevier Ltd.

Degradation of Multimode Adhesive System Bond Strength to Artificial Caries-Affected Dentin Due to Water Storage.

PubMed

Follak, A C; Miotti, L L; Lenzi, T L; Rocha, R O; Soares, F Z

The purpose of this study was to evaluate the influence of water storage on bond strength of multimode adhesive systems to artificially induced caries-affected dentin. One hundred twelve sound bovine incisors were randomly assigned to 16 groups (n=7) according to the dentin condition (sound; SND, artificially induced caries-affected dentin; CAD, cariogenic challenge by pH cycling for 14 days); the adhesive system (SU, Scotchbond Universal Adhesive; AB, All-Bond Universal; PB, Prime & Bond Elect; SB, Adper Single Bond 2; and CS, Clearfil SE Bond), and the etching strategy (etch-and-rinse and self-etch). All adhesive systems were applied under manufacturer's instructions to flat dentin surfaces, and a composite block was built up on each dentin surface. After 24 hours of water storage, the specimens were sectioned into stick-shaped specimens (0.8 mm 2 ) and submitted to a microtensile test immediately (24 hours) or after six months of water storage. Bond strength data (MPa) were analyzed using three-way repeated-measures analysis of variance and post hoc Tukey test (α=5%), considering each substrate separately (SND and CAD). The etching strategy did not influence the bond strength of multimode adhesives, irrespective of the dentin condition. Water storage only reduced significantly the bond strength to CAD. The degradation of bond strength due to water storage was more pronounced in CAD, regardless of the etching strategy.

The Effect of Four Commonly Used Root Conditioner Agents in Different Time Periods Applied on Periodontally Diseased and Healthy Teeth

PubMed Central

P, Torkzaban; S, Seyedzadeh Sabounchi

2016-01-01

Statement of Problem: Root surface contamination or infection can potentially change the consequences of regenerative periodontal therapies and therefore the modification and disinfection of the contaminated root surfaces are necessary. Objectives: This study aimed to compare the surface characteristics of the extracted human teeth after exposure to four root conditioners in different time periods. Materials and Methods: The study samples were prepared from 40 freshly extracted teeth including 20 affected teeth with periodontal diseases and 20 healthy teeth. After performing root planning, 240 dentinal block samples were prepared and each affected and healthy sample was randomly allocated to receive one of the following root conditioners; Ethylenediaminetetraaceti acid (EDTA), citric acid, doxycycline, and tetracycline or rinsed with normal saline as the control agent. The prepared specimens were evaluated using scanning electron microscope and the inter-group differences and changes in study indices; dentin (%), tubular spaces (%), and diameter of dentinal tubules (μm²) were compared using one-way ANOVA test. Results: In the control group receiving normal saline, the changes in the indicators of dentin, tubular spaces, and diameter of dentinal tubules remained insignificant in all time periods. EDTA, citric acid, and tetracycline had chelating effects on the study indices; however, doxycycline led to gradual decrease of the tubular space and diameter as well as increase in dentin percentage. Conclusions: In different time intervals and when considering healthy or affected tooth surfaces, the effect of conditioning agents could be different. Amongst the four agents used, EDTA and tetracycline consistently increased the diameter of tubules and percentage of patent tubules in both healthy and diseased teeth. PMID:28959749

Dentin Hypersensitivity: Etiology, Diagnosis and Treatment; A Literature Review

PubMed Central

Davari, AR; Ataei, E; Assarzadeh, H

2013-01-01

The objective of this review is to inform practitioners about dentin hypersensitivity (DH); to provide a brief overview of the diagnosis, etiology and clinical management of dentin hypersensitivity and to discuss technical approaches to relieve sensitivity. This clinical information is described in the context of the underlying biology. The author used PUBMED to find relevant English-language literature published in the period 1999 to 2010. The author used combinations of the search terms “dentin*”, “tooth”, “teeth”, “hypersensit*”, “desensitiz*”. Abstracts and also full text articles to identify studies describing etiology, prevalence, clinical features, controlled clinical trials of treatments and relevant laboratory research on mechanisms of action were used. PMID:24724135

12-month color stability of enamel, dentine, and enamel-dentine samples after bleaching.

PubMed

Wiegand, Annette; Drebenstedt, Steffi; Roos, Malgorzata; Magalhães, Ana Carolina; Attin, Thomas

2008-12-01

The study aimed to quantify the color regression of enamel (E), dentine (D), and combined enamel-dentine (ED) of differently bleached ED specimens over a period of 12 months in vitro. Two ED samples were obtained from the labial surfaces of bovine teeth and prepared to a standardized thickness with the enamel and dentine layer each 1 mm. The ED samples were distributed on four groups (each n = 80), in which the different bleaching products were applied on enamel (1, Whitestrips; 2, Illuminé 15%; 3, Opalescence Xtra Boost) or dentine surfaces (4, mixture of sodium perborate/distilled water). Eighty ED samples were not bleached (control). Color (L*a*b*) of ED was assessed at baseline, subsequently after bleaching and at 3, 6, and 12 months of storage after bleaching (each 20 samples/group). E and D samples were prepared by removing the dentine or enamel layer of ED samples to allow for separate color analysis. Bleaching resulted in a significant color change (Delta E) of ED specimens. Within the observation period, Delta L but not Delta b declined to baseline. L* values of E and D samples also declined and were not significantly different from control samples after 12 months, while b* values did not decrease to baseline. Generally, no differences between the bleaching agents could be observed. Color change of enamel, dentine, and combined ED of in vitro bleached tooth samples is not stable over time with regard to lightness. However, yellowness did not return to baseline within 1 year.

The effect of retreatment procedure on the pH changes at the surface of root dentin using two different calcium hydroxide pastes

PubMed Central

Kazemipoor, Maryam; Tabrizizadeh, Mehdi; Dastani, Milad; Hakimian, Roqayeh

2012-01-01

Aim: To compare pH changes at the cervical, middle and apical surfaces of root dentin in retreated and non- retreated teeth, after canal obturation with two different calcium hydroxide pastes. Materials and Methods: After instrumentation of 55 extracted teeth, three cavities with 0.75 mm depth and 1.5 mm in diameter were drilled at buccal root surface. The teeth were randomly divided into five groups. Canals in the first two groups were filled with either mixture of calcium hydroxide and saline solution and calcium hydroxide and 2% chlorhexidine (CHX). In the third and fourth groups canals were first obturated with gutta-percha and AH26 sealer, and then materials were removed. After 2 days canals were filled with two different calcium hydroxide pastes similar to the first and the second groups. The pH was measured in the prepared cavities at 1, 3, 7 and 14 days. Results: In the non-retreated groups, pH at the surface of the roots was significantly higher in comparison to the retreated ones (P value < 0.001). pH values were significantly higher in the non-retreated teeth filling with calcium hydroxide and saline solution (P value < 0.001). Conclusion: Regarding to the little pH changes at the surface of dentin in retreated teeth, the hydroxyl ions cannot penetrate into the dentinal tubules. Thus, to achieve higher pH at the root surface in retreated teeth, it is clinically advisable to remove more dentin from the inner walls and to use normal saline as a vehicle for calcium hydroxide rather than acidic pH materials. PMID:23112482

The effect of retreatment procedure on the pH changes at the surface of root dentin using two different calcium hydroxide pastes.

PubMed

Kazemipoor, Maryam; Tabrizizadeh, Mehdi; Dastani, Milad; Hakimian, Roqayeh

2012-10-01

To compare pH changes at the cervical, middle and apical surfaces of root dentin in retreated and non- retreated teeth, after canal obturation with two different calcium hydroxide pastes. After instrumentation of 55 extracted teeth, three cavities with 0.75 mm depth and 1.5 mm in diameter were drilled at buccal root surface. The teeth were randomly divided into five groups. Canals in the first two groups were filled with either mixture of calcium hydroxide and saline solution and calcium hydroxide and 2% chlorhexidine (CHX). In the third and fourth groups canals were first obturated with gutta-percha and AH26 sealer, and then materials were removed. After 2 days canals were filled with two different calcium hydroxide pastes similar to the first and the second groups. The pH was measured in the prepared cavities at 1, 3, 7 and 14 days. In the non-retreated groups, pH at the surface of the roots was significantly higher in comparison to the retreated ones (P value < 0.001). pH values were significantly higher in the non-retreated teeth filling with calcium hydroxide and saline solution (P value < 0.001). Regarding to the little pH changes at the surface of dentin in retreated teeth, the hydroxyl ions cannot penetrate into the dentinal tubules. Thus, to achieve higher pH at the root surface in retreated teeth, it is clinically advisable to remove more dentin from the inner walls and to use normal saline as a vehicle for calcium hydroxide rather than acidic pH materials.

Adhesion of Porphyromonas gingivalis and Tannerella forsythia to dentin and titanium with sandblasted and acid etched surface coated with serum and serum proteins - An in vitro study.

PubMed

Eick, Sigrun; Kindblom, Christian; Mizgalska, Danuta; Magdoń, Anna; Jurczyk, Karolina; Sculean, Anton; Stavropoulos, Andreas

2017-03-01

To evaluate the adhesion of selected bacterial strains incl. expression of important virulence factors at dentin and titanium SLA surfaces coated with layers of serum proteins. Dentin- and moderately rough SLA titanium-discs were coated overnight with human serum, or IgG, or human serum albumin (HSA). Thereafter, Porphyromonas gingivalis, Tannerella forsythia, or a six-species mixture were added for 4h and 24h. The number of adhered bacteria (colony forming units; CFU) was determined. Arg-gingipain activity of P. gingivalis and mRNA expressions of P. gingivalis and T. forsythia proteases and T. forsythia protease inhibitor were measured. Coating specimens never resulted in differences exceeding 1.1 log10 CFU, comparing to controls, irrespective the substrate. Counts of T. forsythia were statistically significantly higher at titanium than dentin, the difference was up to 3.7 log10 CFU after 24h (p=0.002). No statistically significant variation regarding adhesion of the mixed culture was detected between surfaces or among coatings. Arg-gingipain activity of P. gingivalis was associated with log10 CFU but not with the surface or the coating. Titanium negatively influenced mRNA expression of T. forsythia protease inhibitor at 24h (p=0.026 uncoated, p=0.009 with serum). The present findings indicate that: a) single bacterial species (T. forsythia) can adhere more readily to titanium SLA than to dentin, b) low expression of T. forsythia protease inhibitor may influence the virulence of the species on titanium SLA surfaces in comparison with teeth, and c) surface properties (e.g. material and/or protein layers) do not appear to significantly influence multi-species adhesion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioactive glass for dentin remineralization: A systematic review.

PubMed

Fernando, Delihta; Attik, Nina; Pradelle-Plasse, Nelly; Jackson, Phil; Grosgogeat, Brigitte; Colon, Pierre

2017-07-01

Strategies to achieve dentin remineralization is at present an important target of restorative dentistry. Remineralization of dentin by a bioactive material is complete only when the tissue regains its functionality. This is achieved when there is adequate apatite formation which most importantly translates into improved mechanical properties of dentin as a result of intrafibrillar mineralization. Bioactive glass (BAG) is a well-known implant material for bone regeneration and is proven to have excellent ability of apatite formation. Hence, recent studies have proposed BAGs as one of the most desired materials for remineralization of dentin. Therefore the aim of this systematic review was to scope the evidence of bioactive glass to remineralize dentin. The following research question was formulated: "Is there strong evidence for bioactive glass to remineralize dentin?" Three databases (Web of science, PubMed and Science direct) were scanned independently following PRISMA guidelines. Inclusion and exclusion criteria were set to identify relevant articles based on title and abstract screening. Finally, potentially relevant articles were downloaded and the full text was scrutinized to select the articles included in this review. The first phase of search returned 303 articles. A total of 19 papers with full text were scrutinized for inclusion, of which 3 papers were chosen for the final synthesis. All three studies confirm that BAG treatment leads to enhanced apatite formation in dentin. Only 1 of the 3 studies has reported the mechanical properties of dentin after BAG treatment and it revealed that the Young's modulus and flexural bend strength of BAG treated dentin were much lower than natural dentin even though they had similar apatite content. This review highlights the importance of assessing the mechanical properties of dentin alongside to the newly formed apatite content in order to prove BAGs efficiency to remineralize this tissue. Though studies have confirmed that BAGs stimulate excellent apatite formation in dentin, it should be concluded that there isn't sufficient evidence for bioactive glass to effectively remineralize this tissue as the mechanical properties of the BAG treated dentin haven't been well explored. Copyright © 2017 Elsevier B.V. All rights reserved.

Prospective in (Primate) Dental Analysis through Tooth 3D Topographical Quantification

PubMed Central

Guy, Franck; Gouvard, Florent; Boistel, Renaud; Euriat, Adelaïde; Lazzari, Vincent

2013-01-01

The occlusal morphology of the teeth is mostly determined by the enamel-dentine junction morphology; the enamel-dentine junction plays the role of a primer and conditions the formation of the occlusal enamel reliefs. However, the accretion of the enamel cap yields thickness variations that alter the morphology and the topography of the enamel–dentine junction (i.e., the differential deposition of enamel by the ameloblasts create an external surface that does not necessarily perfectly parallel the enamel–dentine junction). This self-reliant influence of the enamel on tooth morphology is poorly understood and still under-investigated. Studies considering the relationship between enamel and dentine morphologies are rare, and none of them tackled this relationship in a quantitative way. Major limitations arose from: (1) the difficulties to characterize the tooth morphology in its comprehensive tridimensional aspect and (2) practical issues in relating enamel and enamel–dentine junction quantitative traits. We present new aspects of form representation based exclusively on 3D analytical tools and procedures. Our method is applied to a set of 21 unworn upper second molars belonging to eight extant anthropoid genera. Using geometrical analysis of polygonal meshes representatives of the tooth form, we propose a 3D dataset that constitutes a detailed characterization of the enamel and of the enamel–dentine junction morphologies. Also, for the first time, to our knowledge, we intend to establish a quantitative method for comparing enamel and enamel–dentine junction surfaces descriptors (elevation, inclination, orientation, etc.). New indices that allow characterizing the occlusal morphology are proposed and discussed. In this note, we present technical aspects of our method with the example of anthropoid molars. First results show notable individual variations and taxonomic heterogeneities for the selected topographic parameters and for the pattern and strength of association between enamel–dentine junction and enamel, the enamel cap altering in different ways the “transcription” of the enamel–dentine junction morphology. PMID:23826088

Multi-walled carbon nanotubes/graphene oxide hybrid and nanohydroxyapatite composite: A novel coating to prevent dentin erosion.

PubMed

Nahorny, Sídnei; Zanin, Hudson; Christino, Vinie Abreu; Marciano, Fernanda Roberta; Lobo, Anderson Oliveira; Soares, Luís Eduardo Silva

2017-10-01

To date is emergent the development of novel coatings to protect erosion, especially to preventive dentistry and restorative dentistry. Here, for the first time we report the effectiveness of multi-walled carbon nanotube/graphene oxide hybrid carbon-base material (MWCNTO-GO) combined with nanohydroxyapatite (nHAp) as a protective coating for dentin erosion. Fourier transform Raman spectroscopy (FT-Raman), scanning electron (SEM), and transmission electron (TEM) microscopy were used to investigated the coatings and the effect of acidulated phosphate fluoride gel (APF) treatment on bovine teeth root dentin before and after erosion. The electrochemical corrosion performance of the coating was evaluated. Raman spectra identified that: (i) the phosphate (ν 1 PO 4 3- ) content of dentin was not significantly affected by the treatments and (ii) the carbonate (ν 1 CO 3 2- ) content in dentin increased when nHAp was used. However, the nHAp/MWCNTO-GO composite exposited lower levels of organic matrix (CH bonds) after erosion compared to other treatments. Interesting, SEM micrographs identified that the nHAp/MWCNTO-GO formed layers after erosive cycling when associate with APF treatment, indicating a possible chemical bond among them. Treatments of root dentin with nHAp, MWCNTO-GO, APF_MWCNTO-GO, and APF_nHAp/MWCNTO-GO increased the carbonate content, carbonate/phosphate ratio, and organic matrix band area after erosion. The potentiodynamic polarization curves and Nyquist plot showed that nHAp, MWCNT-GO and nHAp/MWCNT-GO composites acted as protective agents against corrosion process. Clearly, the nHAp/MWCNTO-GO composite was stable after erosive cycling and a thin and acid-resistant film was formed when associated to APF treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of the etch-and-rinse technique: New perspectives to improve resin-dentin bonding and hybrid layer integrity by reducing residual water using dimethyl sulfoxide pretreatments.

PubMed

Stape, Thiago Henrique Scarabello; Tjäderhane, Leo; Abuna, Gabriel; Sinhoreti, Mário Alexandre Coelho; Martins, Luís Roberto Marcondes; Tezvergil-Mutluay, Arzu

2018-04-13

To determine whether bonding effectiveness and hybrid layer integrity on acid-etched dehydrated dentin would be comparable to the conventional wet-bonding technique through new dentin biomodification approaches using dimethyl sulfoxide (DMSO). Etched dentin surfaces from extracted sound molars were randomly bonded in wet or dry conditions (30s air drying) with DMSO/ethanol or DMSO/H 2 O as pretreatments using a simplified (Scotchbond Universal Adhesive, 3M ESPE: SU) and a multi-step (Adper Scotchbond Multi-Purpose, 3M ESPE: SBMP) etch-and-rinse adhesives. Untreated dentin surfaces served as control. Bonded teeth (n=8) were stored in distilled water for 24h and sectioned into resin-dentin beams (0.8mm 2 ) for microtensile bond strength test and quantitative interfacial nanoleakage analysis (n=8) under SEM. Additional teeth (n=2) were prepared for micropermeability assessment by CFLSM under simulated pulpar pressure (20cm H 2 O) using 5mM fluorescein as a tracer. Microtensile data was analyzed by 3-way ANOVA followed by Tukey Test and nanoleakage by Kruskal-Wallis and Dunn-Bonferroni multiple comparison test (α=0.05). While dry-bonding of SBMP produced significantly lower bond strengths than wet-bonding (p<0.05), DMSO/H 2 O and DMSO/ethanol produced significantly higher bond strengths for SBMP irrespective of dentin condition (p<0.05). SU presented significantly higher nanoleakage levels (p<0.05) and micropermeability than SBMP. Improvement in hybrid layer integrity occurred for SBMP and SU for both pretreatments, albeit most pronouncedly for DMSO/ethanol regardless of dentin moisture. DMSO pretreatments may be used as a new suitable strategy to improve bonding of water-based adhesives to demineralized air-dried dentin beyond conventional wet-bonding. Less porous resin-dentin interfaces with higher bond strengths on air-dried etched dentin were achieved; nonetheless, overall efficiency varied according to DMSO's co-solvent and adhesive type. DMSO pretreatments permit etched dentin to be air-dried before hybridization facilitating residual water removal and thus improving bonding effectiveness. This challenges the current paradigm of wet-bonding requirement for the etch-and-rinse approach creating new possibilities to enhance the clinical longevity of resin-dentin interfaces. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Desensitizing Agent Reduces Dentin Hypersensitivity During Ultrasonic Scaling: A Pilot Study

PubMed Central

Suda, Tomonari; Akiyama, Toshiharu; Takano, Takuya; Gokyu, Misa; Sudo, Takeaki; Khemwong, Thatawee; Izumi, Yuichi

2015-01-01

Background Dentin hypersensitivity can interfere with optimal periodontal care by dentists and patients. The pain associated with dentin hypersensitivity during ultrasonic scaling is intolerable for patient and interferes with the procedure, particularly during supportive periodontal therapy (SPT) for patients with gingival recession. Aim This study proposed to evaluate the desensitizing effect of the oxalic acid agent on pain caused by dentin hypersensitivity during ultrasonic scaling. Materials and Methods This study involved 12 patients who were incorporated in SPT program and complained of dentin hypersensitivity during ultrasonic scaling. We examined the availability of the oxalic acid agent to compare the degree of pain during ultrasonic scaling with or without the application of the dentin hypersensitivity agent. Evaluation of effects on dentin hypersensitivity was determined by a questionnaire and visual analog scale (VAS) pain scores after ultrasonic scaling. The statistical analysis was performed using the paired Student t-test and Spearman rank correlation coefficient. Results The desensitizing agent reduced the mean VAS pain score from 69.33 ± 16.02 at baseline to 26.08 ± 27.99 after application. The questionnaire revealed that >80% patients were satisfied and requested the application of the desensitizing agent for future ultrasonic scaling sessions. Conclusion This study shows that the application of the oxalic acid agent considerably reduces pain associated with dentin hypersensitivity experienced during ultrasonic scaling. This pain control treatment may improve patient participation and treatment efficiency. PMID:26501012

Desensitizing Agent Reduces Dentin Hypersensitivity During Ultrasonic Scaling: A Pilot Study.

PubMed

Suda, Tomonari; Kobayashi, Hiroaki; Akiyama, Toshiharu; Takano, Takuya; Gokyu, Misa; Sudo, Takeaki; Khemwong, Thatawee; Izumi, Yuichi

2015-09-01

Dentin hypersensitivity can interfere with optimal periodontal care by dentists and patients. The pain associated with dentin hypersensitivity during ultrasonic scaling is intolerable for patient and interferes with the procedure, particularly during supportive periodontal therapy (SPT) for patients with gingival recession. This study proposed to evaluate the desensitizing effect of the oxalic acid agent on pain caused by dentin hypersensitivity during ultrasonic scaling. This study involved 12 patients who were incorporated in SPT program and complained of dentin hypersensitivity during ultrasonic scaling. We examined the availability of the oxalic acid agent to compare the degree of pain during ultrasonic scaling with or without the application of the dentin hypersensitivity agent. Evaluation of effects on dentin hypersensitivity was determined by a questionnaire and visual analog scale (VAS) pain scores after ultrasonic scaling. The statistical analysis was performed using the paired Student t-test and Spearman rank correlation coefficient. The desensitizing agent reduced the mean VAS pain score from 69.33 ± 16.02 at baseline to 26.08 ± 27.99 after application. The questionnaire revealed that >80% patients were satisfied and requested the application of the desensitizing agent for future ultrasonic scaling sessions. This study shows that the application of the oxalic acid agent considerably reduces pain associated with dentin hypersensitivity experienced during ultrasonic scaling. This pain control treatment may improve patient participation and treatment efficiency.

Relationship between surface area for adhesion and tensile bond strength--evaluation of a micro-tensile bond test.

PubMed

Sano, H; Shono, T; Sonoda, H; Takatsu, T; Ciucchi, B; Carvalho, R; Pashley, D H

1994-07-01

The purpose of this study was to test the null hypothesis that there is no relationship between the bonded surface area of dentin and the tensile strength of adhesive materials. The enamel was removed from the occlusal surface of extracted human third molars, and the entire flat surface was covered with resin composite bonded to the dentin to form a flat resin composite crown. Twenty-four hours later, the bonded specimens were sectioned parallel to the long axis of the tooth into 10-20 thin sections whose upper part was composed of resin composite with the lower half being dentin. These small sections were trimmed using a high speed diamond bur into an hourglass shape with the narrowest portion at the bonded interface. Surface area was varied by altering the specimen thickness and width. Tensile bond strength was measured using custom-made grips in a universal testing machine. Tensile bond strength was inversely related to bonded surface area. At surface areas below 0.4 mm2, the tensile bond strengths were about 55 MPa for Clearfil Liner Bond 2 (Kuraray Co., Ltd.), 38 MPa for Scotchbond MP (3M Dental Products), and 20 MPa for Vitremer (3M Dental Products). At these small surface areas all of the bond failures were adhesive in nature. This new method permits measurement of high bond strengths without cohesive failure of dentin. It also permits multiple measurements to be made within a single tooth.

Residual antibacterial activity of chlorhexidine and MTAD in human root dentin in vitro.

PubMed

Mohammadi, Zahed; Shahriari, Shahriar

2008-03-01

The purpose of this in vitro study was to compare the antimicrobial substantivity of BioPure MTAD, 2% chlorhexidine (CHX) and 2.6% sodium hypochlorite (NaOCl) in human root dentin. One hundred and ten dentin tubes prepared from human maxillary incisors were infected in vitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups as follows: CHX; BioPure MTAD; NaOCl; infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected with round burs into Brain Heart Infusion (BHI) broth. After culturing, the number of colony-forming units (CFU) was counted. In all experimental groups, CFU was minimum after treatment (day 0), and the results obtained were significantly different from each other at any time period (P < 0.05). After treatment, the NaOCI group and BioPure MTAD group showed the lowest and highest number of CFU, respectively. In each group, the number of CFUs increased significantly by time-lapse (P < 0.05). In conclusion, the substantivity of BioPure MTAD was significantly greater than CHX and NaOCl.

Influence of irrigation regimens on the adherence of Enterococcus faecalis to root canal dentin.

PubMed

Kishen, Anil; Sum, Chee-Peng; Mathew, Shibi; Lim, Chwee-Teck

2008-07-01

Enterococcus faecalis is frequently associated with post-treatment endodontic infections. Because adherence of bacteria to a substrate is the earliest stage in biofilm formation, eliciting the factors that links adherence of this bacterium to dentin would help in understanding its association with treatment-failed root canals. This investigation aimed to study the effects of endodontic irrigants on the adherence of E. faecalis to dentin. The bacteria adherence assay was conducted by using fluorescence microscopy, and the adhesion force was measured by using atomic force microscopy. There were significant increases in adherence and adhesion force after irrigation of dentin with ethylenediaminetetraacetic acid (EDTA), whereas sodium hypochlorite (NaOCl) reduced it. With the use of chlorhexidine (CHX), the force of adhesion increased, but the adherence assay showed a reduction in the number of adhering bacteria. The irrigation regimen of EDTA, NaOCl, and CHX resulted in the least number of adhering E. faecalis cells. This study highlighted that chemicals that alter the physicochemical properties of dentin will influence the nature of adherence, adhesion force, and subsequent biofilm formation of E. faecalis to dentin.

The effect of air thinning on dentin adhesive bond strength.

PubMed

Hilton, T J; Schwartz, R S

1995-01-01

The purpose of this study was to determine if air thinning three dentin adhesives would affect bond strength to dentin. Ninety human molars were mounted in acrylic and the occlusal surfaces ground to expose a flat dentin surface. Thirty teeth were randomly assigned to one of the following dentin bonding agent/composite combinations: A) Universal Bond 3/TPH (Caulk), B) All-Bond 2/Bis-Fil-P (Bisco), and C) Scotchbond Multi-Purpose/Z-100 (3m). The primers were applied following the manufacturers' instructions. The adhesives were applied by two methods. A thin layer of adhesive was applied with a brush to 15 specimens in each group and light cured. Adhesive was brushed on to the remaining 15 teeth in the group, air thinned for 3 seconds, and then polymerized. The appropriate composite was applied in 2 mm increments and light cured utilizing a 5 mm-in-diameter split Teflon mold. Following 3 months of water storage, all groups were shear tested to failure on an Instron Universal Testing Machine. Bond strength was significantly higher in all groups when the dentin bonding agent was painted on without being air thinned. Scotchbond Multi-Purpose had significantly higher bond strength than All-Bond 2, which had significantly higher bond strength than Universal Bond 3.

Structural analysis of strontium in human teeth treated with surface pre-reacted glass-ionomer filler eluate by using extended X-ray absorption fine structure analysis.

PubMed

Uo, Motohiro; Wada, Takahiro; Asakura, Kiyotaka

2017-03-31

The bioactive effects of strontium released from surface pre-reacted glass-ionomer (S-PRG) fillers may aid in caries prevention. In this study, the local structure of strontium taken up by teeth was estimated by extended X-ray absorption fine structure analysis. Immersing teeth into S-PRG filler eluate increased the strontium content in enamel and dentin by more than 100 times. The local structure of strontium in enamel and dentin stored in distilled water was the same as that in synthetic strontium-containing hydroxyapatite (SrHAP). Moreover, the local structure of strontium in enamel and dentin after immersion in the S-PRG filler eluate was also similar to that of SrHAP. After immersion in the S-PRG filler eluate, strontium was suggested to be incorporated into the hydroxyapatite (HAP) of enamel and dentin at the calcium site in HAP.

Ultrasonographic Detection of Tooth Flaws

NASA Astrophysics Data System (ADS)

Bertoncini, C. A.; Hinders, M. K.; Ghorayeb, S. R.

2010-02-01

The goal of our work is to adapt pulse-echo ultrasound into a high resolution imaging modality for early detection of oral diseases and for monitoring treatment outcome. In this talk we discuss our preliminary results in the detection of: demineralization of the enamel and dentin, demineralization or caries under and around existing restorations, caries on occlusal and interproximal surfaces, cracks of enamel and dentin, calculus, and periapical lesions. In vitro immersion tank experiments are compared to results from a handpiece which uses a compliant delay line to couple the ultrasound to the tooth surface. Because the waveform echoes are complex, and in order to make clinical interpretation of ultrasonic waveform data in real time, it is necessary to automatically interpret the signals. We apply the dynamic wavelet fingerprint algorithms to identify and delineate echographic features that correspond to the flaws of interest in teeth. The resulting features show a clear distinction between flawed and unflawed waveforms collected with an ultrasonic handpiece on both phantom and human cadaver teeth.

Crack propagation in teeth: a comparison of perimortem and postmortem behavior of dental materials and cracks.

PubMed

Hughes, Cris E; White, Crystal A

2009-03-01

This study presents a new method for understanding postmortem heat-induced crack propagation patterns in teeth. The results demonstrate that patterns of postmortem heat-induced crack propagation differ from perimortem and antemortem trauma-induced crack propagation patterns. Dental material of the postmortem tooth undergoes dehydration leading to a shrinking and more brittle dentin material and a weaker dentin-enamel junction. Dentin intertubule tensile stresses are amplified by the presence of the pulp cavity, and initiates crack propagation from the internal dentin, through the dentin-enamel junction and lastly the enamel. In contrast, in vivo perimortem and antemortem trauma-induced crack propagation initiates cracking from the external surface of the enamel toward the dentin-enamel junction where the majority of the energy of the crack is dissipated, eliminating the crack's progress into the dentin. These unique patterns of crack propagation can be used to differentiate postmortem taphonomy-induced damage from antemortem and perimortem trauma in teeth.

Effect of functional monomers in all-in-one adhesive systems on formation of enamel/dentin acid-base resistant zone.

PubMed

Nikaido, Toru; Ichikawa, Chiaki; Li, Na; Takagaki, Tomohiro; Sadr, Alireza; Yoshida, Yasuhiro; Suzuki, Kazuomi; Tagami, Junji

2011-01-01

This study aimed at evaluating the effect of functional monomers in all-in-one adhesive systems on formation of acid-base resistant zone (ABRZ) in enamel and dentin. Experimental adhesive systems containing one of three functional monomers; MDP, 3D-SR and 4-META were applied to enamel or dentin surface and light-cured. A universal resin composite was then placed. The specimens were subjected to a demineralizing solution (pH 4.5) and 5% NaClO for acid-base challenge and then observed by SEM. The ABRZ was clearly observed in both enamel and dentin interfaces. However, enamel ABRZ was thinner than dentin ABRZ in all adhesives. Morphology of the ABRZ was different between enamel and dentin, and also among the adhesives. Funnel-shaped erosion was observed only in the enamel specimen with the 4-META adhesive. The formation of enamel/dentin ABRZ was confirmed in all adhesives, but the morphology was influenced by the functional monomers.

Histological and ultrastructural effect of an Nd:YAG pulsed laser beam on dental hard tissue and pulp

NASA Astrophysics Data System (ADS)

Vignato, Costantino; Vignato, Giuseppe; Nardelli, Antonella; Baldan, Arianna; Mason, Pier N.

1994-09-01

The purpose of this study was to determine histological and ultrastructural modifications produced by an Nd:YAG pulsed laser beam after an in vivo exposure of human molars. Using a Nd:YAG pulsed laser beam delivered by a 600 micrometers optical fiber and concurrent air and water cooling spray, 14 human third molars with artificial first class cavities were exposed at different power levels (6, 7, and 8 W). All the teeth were extracted at different time periods between 10 and 25 days and prepared for histological examination. The results of the histological examination showed no evidence of degeneration or necrosis of the pulpar tissue. Analysis of the dentinal surfaces after exposure demonstrated that the dentinal tubules are completely closed due to the melted dentin. In conclusion a Nd:YAG pulsed laser beam with an air and water cooling spray is safe for treatments of class I decay and no necrosis or degeneration of the pulp was found for laser powers of 6, 7, and 8 W.

Effect of Saliva on the Tensile Bond Strength of Different Generation Adhesive Systems: An In-Vitro Study.

PubMed

Gupta, Nimisha; Tripathi, Abhay Mani; Saha, Sonali; Dhinsa, Kavita; Garg, Aarti

2015-07-01

Newer development of bonding agents have gained a better understanding of factors affecting adhesion of interface between composite and dentin surface to improve longevity of restorations. The present study evaluated the influence of salivary contamination on the tensile bond strength of different generation adhesive systems (two-step etch-and-rinse, two-step self-etch and one-step self-etch) during different bonding stages to dentin where isolation is not maintained. Superficial dentin surfaces of 90 extracted human molars were randomly divided into three study Groups (Group A: Two-step etch-and-rinse adhesive system; Group B: Two-step self-etch adhesive system and Group C: One-step self-etch adhesive system) according to the different generation of adhesives used. According to treatment conditions in different bonding steps, each Group was further divided into three Subgroups containing ten teeth in each. After adhesive application, resin composite blocks were built on dentin and light cured subsequently. The teeth were then stored in water for 24 hours before sending for testing of tensile bond strength by Universal Testing Machine. The collected data were then statistically analysed using one-way ANOVA and Tukey HSD test. One-step self-etch adhesive system revealed maximum mean tensile bond strength followed in descending order by Two-step self-etch adhesive system and Two-step etch-and-rinse adhesive system both in uncontaminated and saliva contaminated conditions respectively. Unlike One-step self-etch adhesive system, saliva contamination could reduce tensile bond strength of the two-step self-etch and two-step etch-and-rinse adhesive system. Furthermore, the step of bonding procedures and the type of adhesive seems to be effective on the bond strength of adhesives contaminated with saliva.

Influence of sodium hypochlorite and edta on the microtensile bond strength of a self-etching adhesive system.

PubMed

Cecchin, Doglas; Farina, Ana Paula; Galafassi, Daniel; Barbizam, João Vicente Baroni; Corona, Silmara Aparecida Milori; Carlini-Júnior, Bruno

2010-01-01

Chemical substances used during biomechanical preparation of root canals can alter the composition of dentin surface and affect the interaction with restorative materials. The purpose of this study was to evaluate the microtensile bond strength (µTBS) of a self-etching adhesive system to dentin irrigated with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA). Thirty human third molars were sectioned 3 mm below the occlusal surface, polished with 600- to 1200-grit silicon carbide papers, and randomly divided into 3 groups: G1 (control): no irrigating solution; G2: 1% NaOCl; and G3: 1% NaOCl followed by the application of 17% EDTA. The specimens received the self-etching adhesive system (XENO III - Dentsply), restored with microhybrid composite resin (Z250 - 3M ESPE), sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test. Mean µTBS values and standard deviations in MPa were: G1 = 11.89 ± 4.22; G2 = 19.41 ± 5.32; G3 = 11.34 ± 4.73. 1% NaOCl increased the adhesive resistance significantly (p<0.001/F=22.5763). The application of 1% NaOCl/17% EDTA resulted in statistically similar µTBS to the control group. None of the irrigants affected negatively the µTBS of XENO III to dentin. The use of 1% NaOCl alone resulted in higher bond strength than the other treatments. The combination of 1% NaOCl and 17% EDTA produced similar bond strength to that of untreated dentin.

Near infrared transillumination compared with radiography to detect and monitor proximal caries: A clinical retrospective study.

PubMed

Abdelaziz, Marwa; Krejci, Ivo; Perneger, Thomas; Feilzer, Albert; Vazquez, Lydia

2018-03-01

To compare near infrared transillumination device, DIAGNOcam (DC) and bitewing radiography (BW) for the detection of proximal caries. This retrospective analysis of DC and BW images of 18 students in dental medicine who had consented to the anonymous use of their dental record. The data included BW and DC images performed for a check-up in 2013, and corresponding follow-up images performed in 2015. Two observers rated 376 proximal surfaces on a 4-level dentin lesion scale and reached a unanimous rating for each surface. Calculated measures of agreement for each assessment method over time provided the reproducibility of the information obtained by each method. Agreement between 2013 and 2015 within each method was excellent (intraclass correlation coefficient, BW: 0.86, DC: 0.90). Agreement between DC and BW was similar for dentin lesion detection, but was low for enamel caries detection; DC detected more enamel caries than BW. Agreement between DC and BW was modest (0.33 in 2013 and 0.36 in 2015), chiefly because DC identified more enamel caries. This study shows that DC is as reliable as BW to detect proximal dentin lesions. DC detects proximal enamel lesions at an earlier stage than BW. DC enables clinicians to differentiate lesions limited to the enamel from lesions that have reached the enamel dentin junction. Regular monitoring with DC should help provide individualized preventive measures and early non-invasive caries management. The early detection of enamel lesions with near infrared transillumination can help clinicians undertake early non invasive treatments to prevent or slow down the progression of initial proximal lesions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of endodontic irrigating solutions on the microhardness and roughness of root canal dentin: an in vitro study.

PubMed

Patil, Chetan R; Uppin, Veerendra

2011-01-01

To evaluate the effect of widely used endodontic irrigating solutions on root dentin microhardness and surface roughness. One hundred twenty, non-carious extracted human permanent incisor teeth were selected. The crowns of the teeth were sectioned and the roots were separated longitudinally to get 240 specimens. These specimens were then divided into six groups according to the irrigating solutions used. The solutions used were 5% and 2.5% NaOCl solutions, 3% H2 O2 , 17% EDTA solution, 0.2% chlorhexidine gluconate, and distilled water. Then, the specimens were subjected to microhardness and roughness testing. The data were analyzed using ANOVA and Tukey's multiple comparison tests. The results of this study indicated that all irrigation solutions, except 0.2% chlorhexidine gluconate, decreased the microhardness of root dentin, and 3% H2 O2 and 0.2% chlorhexidine gluconate had no effect on surface roughness. Within the limitation of this study, it is concluded that 0.2% chlorhexidine gluconate seems to be an appropriate irrigation solution, because of its harmless effect on the microhardness and surface roughness of root canal dentin.

Characterization of two types of osteoclasts from human peripheral blood monocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuasa, Kimitaka; Mori, Kouki; Ishikawa, Hitoshi

2007-05-04

The two osteoclastogenesis pathways, receptor activator nuclear factor (NF)-{kappa}B ligand (RANKL)-mediated and fusion regulatory protein-1 (FRP-1)-mediated osteoclastogenesis, have recently been reported. There were significant differences in differentiation and activation mechanisms between the two pathways. When monocytes were cultured with FRP-1 without adding M-CSF, essential for the RANKL system, TRAP-positive polykaryocyte formation occurred. FRP-1-mediated osteoclasts formed larger pits on mineralized calcium phosphate plates than RANKL+M-CSF-mediated osteoclasts did. Lacunae on dentin surfaces induced by FRP-1-mediated osteoclasts were inclined to be single and isolated. However, osteoclasts induced by RANKL+M-CSF made many connected pits on dentin surfaces as if they crawled on there. Interestingly,more » FRP-1 osteoclastogenesis was enhanced by M-CSF/IL-1{alpha}, while chemotactic behavior to the dentin slices was not effected. There were differences in pH and concentration of HCO3- at culture endpoint and in adherent feature to dentin surfaces. Our findings indicate there are two types of osteoclasts with distinct properties.« less

Effect of temporary cements on the microtensile bond strength of self-etching and self-adhesive resin cement.

PubMed

Carvalho, Edilausson Moreno; Carvalho, Ceci Nunes; Loguercio, Alessandro Dourado; Lima, Darlon Martins; Bauer, José

2014-11-01

The aim of this study was to evaluate the microtensile bond strength (µTBS) of self-etching and self-adhesive resin cement systems to dentin affected by the presence of remnants of either eugenol-containing or eugenol-free temporary cements. Thirty extracted teeth were obtained and a flat dentin surface was exposed on each tooth. Acrylic blocks were fabricated and cemented either with one of two temporary cements, one zinc oxide eugenol (ZOE) and one eugenol free (ZOE-free), or without cement (control). After cementation, specimens were stored in water at 37°C for 1 week. The restorations and remnants of temporary cements were removed and dentin surfaces were cleaned with pumice. Resin composite blocks were cemented to the bonded dentin surfaces with one of two resin cements, either self-etching (Panavia F 2.0) or self-adhesive (RelyX U-100). After 24 h, the specimens were sectioned to obtain beams for submission to µTBS. The fracture mode was evaluated under a stereoscopic loupe and a scanning electron microscope (SEM). Data from µTBS were submitted to two-way repeated-measure ANOVA and the Tukey test (alpha = 0.05). The cross-product interaction was statistically significant (p < 0.0003). The presence of temporary cements reduced the bond strength to Panavia self-etching resin cements only (p < 0.05). Fracture occurred predominantly at the dentin-adhesive interface. The presence of eugenol-containing temporary cements did not interfere in the bond strength to dentin of self-adhesive resin cements.

Experimental resin cements containing bioactive fillers reduce matrix metalloproteinase-mediated dentin collagen degradation.

PubMed

Osorio, Raquel; Yamauti, Monica; Sauro, Salvatore; Watson, Thimoty F; Toledano, Manuel

2012-09-01

Collagen dentin matrix may represent a suitable scaffold to be remineralized in the presence of bioactive materials. The purpose of this study was to determine if experimental resin cements containing bioactive fillers may modulate matrix metalloproteinase-mediated collagen degradation of etched dentin. Human dentin beams demineralized using 10% phosphoric acid or 0.5 mol/L EDTA were infiltrated with the following experimental resins: (1) unfilled resin, (2) resin with Bioglass 45S5 particles (Sylc; OSspray Ltd, London, UK), and (3) resin with β-tricalcium phosphate-modified calcium silicate cement (HCAT-β) particles. The filler/resin ratio was 40/60 wt%. The specimens were stored in artificial saliva, and the determination of C-terminal telopeptide (ICTP) was performed by radioimmunoassay after 24 hours, 1 week, and 4 weeks. Scanning electron microscopic analysis of dentin surfaces after 4 weeks of storage was also executed. Collagen degradation was prominent both in phosphoric acid and EDTA-treated dentin. Resin infiltration strongly reduced the MMP activity in demineralized dentin. Resin-containing Bioglass 45S5 particles exerted higher and more stable protection of collagen at all tested dentin states and time points. HCAT-β induced collagen protection from MMPs only in EDTA-treated specimens. Dentin remineralization was achieved when dentin was infiltrated with the resin cements containing bioactive fillers. MMP degradation of dentin collagen is strongly reduced in resin-infiltrated dentin. The inclusion of Bioglass 45S5 particles exerted an additional protection of collagen during dentin remineralization. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Tunicate-Inspired Gallic Acid/Metal Ion Complex for Instant and Efficient Treatment of Dentin Hypersensitivity.

PubMed

Prajatelistia, Ekavianty; Ju, Sung-Won; Sanandiya, Naresh D; Jun, Sang Ho; Ahn, Jin-Soo; Hwang, Dong Soo

2016-04-20

Dentin hypersensitivity is sharp and unpleasant pains caused by exposed dentinal tubules when enamel outside of the tooth wears away. The occlusion of dentinal tubules via in situ remineralization of hydroxyapatite is the best method to alleviate the symptoms caused by dentin hypersensitivity. Commercially available dental desensitizers are generally effective only on a specific area and are relatively toxic, and their performance usually depends on the skill of the clinician. Here, a facile and efficient dentin hypersensitivity treatment with remarkable aesthetic improvement inspired by the tunicate-self-healing process is reported. As pyrogallol groups in tunicate proteins conjugate with metal ions to heal the torn body armor of a tunicate, the ingenious mechanism by introducing gallic acid (GA) as a cheap, abundant, and edible alternative to the pyrogallol groups of the tunicate combined with a varied daily intake of metal ion sources is mimicked. In particular, the GA/Fe(3+) complex exhibits the most promising results, to the instant ≈52% blockage in tubules within 4 min and ≈87% after 7 d of immersion in artificial saliva. Overall, the GA/metal ion complex-mediated coating is facile, instant, and effective, and is suggested as an aesthetic solution for treating dentin hypersensitivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Is chlorhexidine-methacrylate as effective as chlorhexidine digluconate in preserving resin dentin interfaces?

PubMed

Abu Nawareg, Manar; Elkassas, Dina; Zidan, Ahmed; Abuelenain, Dalia; Abu Haimed, Tariq; Hassan, Ali H; Chiba, Ayaka; Bock, Thorsten; Agee, Kelli; Pashley, David H

2016-02-01

The aim of the current study was to evaluate the effect of 2% CHX and 2% CHX-methacrylate compared to the resin-dentin bonds created by a two-step etch-and-rinse adhesive system after 24h, 6min and 12min. Microtensile bond strengths and interfacial nanoleakage within resin-dentin interfaces created by Adper Single Bond 2, with or without CHX or CHX-methacrylate pre-treatment for 30s on acid-etched dentin surfaces, were evaluated after 24h, 6min and 12min of storage in distilled water at 37°C. Twelve months of storage resulted in a significant decrease in microtensile bond strength in the control group, and significant increases in silver nanoleakage. In contrast, Single Bond 2+CHX, and to a greater extent CHX-methacrylate, significantly reduced the rate of deterioration of resin-dentin interfaces over the 12min water storage period, in terms of bond strength. Similar to Single Bond 2+CHX, Single Bond+CHX-methacrylates reduced the degradation of resin-bonded interfaces over a 12 month storage period. Thus it can be concluded that Single Bond 2+CHX-methacrylate may be important to improve durability of bonded interfaces and therefore, prolong the life span of adhesive restorations. Although CHX primers have been shown to enhance the durability of etch-and-rinse adhesives, that protection is lost after 2h. The use of CHX-methacrylate should last much longer since it may copolymerize with adhesive monomers, unlike CHX. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prevalence of dentine hypersensitivity: A cross-sectional study in rural Punjabi Indians

PubMed Central

Dhaliwal, Jagjit Singh; Palwankar, Pooja; Khinda, Paramjit K.; Sodhi, Sachinjeet K.

2012-01-01

Aims and Objectives: To study the prevalence of dentine hypersensitivity and related risk factors in rural population of Punjab, India. Materials and Methods: A total of 650 subjects reporting dentine sensitivity were included in the study comprising of 270 males and 380 females. All the subjects completed an interview and the subjects reporting dentine hypersensitivity were examined further using air syringe to put a blast of air to confirm the diagnosis of dentine hypersensitivity. Periodontal attachment loss and gingival recession of all the sensitive teeth were examined and recorded. Results: The prevalence of dentine hypersensitivity was 25% in the oral test. The subjects receiving the treatment of hypersensitivity were only 15.1%. The older group in the 50-59 years had the highest number (98%) of subjects with dentine hypersensitivity. Most commonly affected teeth were mandibular incisors. The other factors related to dentine hypersensitivity were the socioeconomic status, lower education level, and access to dental care. The periodontal factors related to hypersensitivity were gingival recession and poor oral hygiene. Conclusions: The prevalence of dentine hypersensitivity was 25% in the rural population of Punjab. PMID:23162341

Effect of Er,Cr:YSGG Laser at Different Output Powers on the Micromorphology and the Bond Property of Non-Carious Sclerotic Dentin to Resin Composites.

PubMed

Sun, Xiang; Ban, Jinghao; Sha, Xinjia; Wang, Weiguo; Jiao, Yang; Wang, Wanshan; Yang, Yanwei; Wei, Jingjing; Shen, Lijuan; Chen, Jihua

2015-01-01

The objective of this study was to investigate the influence of Er,Cr:YSGG laser irradiated at different powers on the micromorphology and the bonding property of non-carious sclerotic dentin to resin composites. Two hundred bovine incisors characterized by non-carious sclerotic dentin were selected, and the seventy-two teeth of which for surface morphological analysis were divided into nine groups according to various treatments (A: the control group, B: only treated with the adhesive Adper Easy One, C: diamond bur polishing followed by Adper Easy One, D-I: Er,Cr:YSGG laser irradiating at 1W, 2W, 3W, 4W, 5W, 6W output power, respectively, followed by Adper Easy One). The surface roughness values were measured by the non-contact three-dimensional morphology scanner, then the surface micromorphologies of surfaces in all groups were assessed by scanning electron microscopy (SEM); meanwhile, Image Pro-Plus 6.0 software was used to measure the relative percentage of open tubules on SEM images. The rest, one hundred twenty-eight teeth for bond strength test, were divided into eight groups according to the different treatments (A: only treated with the adhesive Adper Easy One, B: diamond bur polishing followed by the above adhesive, C-H: Er,Cr:YSGG laser irradiating at 1 W, 2 W, 3 W, 4 W, 5 W, 6 W output power, respectively, followed by the above adhesive), and each group was subsequently divided into two subgroups according to whether aging is performed (immediately tested and after thermocycling). Micro-shear bond strength test was used to evaluate the bond strength. The 4W laser group showed the highest roughness value (30.84±1.93μm), which was statistically higher than the control group and the diamond bur groups (p<0.05). The mean percentages ((27.8±1.8)%, (28.0±2.2)%, (30.0±1.9)%) of open tubules area in the 4W, 5W, 6W group were higher than other groups (p<0.05). The 4W laser group showed the highest micro-shear bond strength not only in immediately tested (17.60±2.55 PMa) but after thermocycling (14.35±2.08MPa). The Er,Cr:YSGG laser at 4W power can effectively improve the bonding property between non-carious sclerotic dentin and resin composites by increasing the roughness and mean percentage area of open tubules.

Effect of Er,Cr:YSGG Laser at Different Output Powers on the Micromorphology and the Bond Property of Non-Carious Sclerotic Dentin to Resin Composites

PubMed Central

Wang, Weiguo; Jiao, Yang; Wang, Wanshan; Yang, Yanwei; Wei, Jingjing; Shen, Lijuan; Chen, Jihua

2015-01-01

Background The objective of this study was to investigate the influence of Er,Cr:YSGG laser irradiated at different powers on the micromorphology and the bonding property of non-carious sclerotic dentin to resin composites. Methods Two hundred bovine incisors characterized by non-carious sclerotic dentin were selected, and the seventy-two teeth of which for surface morphological analysis were divided into nine groups according to various treatments (A: the control group, B: only treated with the adhesive Adper Easy One, C: diamond bur polishing followed by Adper Easy One, D-I: Er,Cr:YSGG laser irradiating at 1W, 2W, 3W, 4W, 5W, 6W output power, respectively, followed by Adper Easy One). The surface roughness values were measured by the non-contact three-dimensional morphology scanner, then the surface micromorphologies of surfaces in all groups were assessed by scanning electron microscopy (SEM); meanwhile, Image Pro-Plus 6.0 software was used to measure the relative percentage of open tubules on SEM images. The rest, one hundred twenty-eight teeth for bond strength test, were divided into eight groups according to the different treatments (A: only treated with the adhesive Adper Easy One, B: diamond bur polishing followed by the above adhesive, C-H: Er,Cr:YSGG laser irradiating at 1 W, 2 W, 3 W, 4 W, 5 W, 6 W output power, respectively, followed by the above adhesive), and each group was subsequently divided into two subgroups according to whether aging is performed (immediately tested and after thermocycling). Micro-shear bond strength test was used to evaluate the bond strength. Results The 4W laser group showed the highest roughness value (30.84±1.93μm), which was statistically higher than the control group and the diamond bur groups (p<0.05). The mean percentages ((27.8±1.8)%, (28.0±2.2)%, (30.0±1.9)%) of open tubules area in the 4W, 5W, 6W group were higher than other groups (p<0.05). The 4W laser group showed the highest micro-shear bond strength not only in immediately tested (17.60±2.55 PMa) but after thermocycling (14.35±2.08MPa). Conclusion The Er,Cr:YSGG laser at 4W power can effectively improve the bonding property between non-carious sclerotic dentin and resin composites by increasing the roughness and mean percentage area of open tubules. PMID:26544034

Contemporary research findings on dentine remineralization.

PubMed

Zhong, Bo; Peng, Ce; Wang, Guanhong; Tian, Lili; Cai, Qiang; Cui, Fuzhai

2015-09-01

Dentine remineralization is important for the treatment of dentine caries and the bonding durability of dentine and resin materials in clinical practice. Early studies of dentine remineralization were mostly based on the classical pathway of crystallization, which involves large-scale deposition of calcium phosphate crystals on collagen and is achieved in a liquid environment containing mineral ions. Results from these studies were unsatisfactory and not suitable for clinical application because they did not simulate the ordering of hydroxyapatite in the collagen fibres of natural teeth. As studies on collagen type I and non-collagenous proteins have advanced, dentine biomimetic remineralization has become a popular research topic and has shifted to processes involving intrafibrillar remineralization, which is more similar to natural tooth formation. The objective of this review was to summarize current theory and research progress as it relates to dentine remineralization. Copyright © 2013 John Wiley & Sons, Ltd.

External apical root resorption diagnosis by using FII human dentine fraction and salivary IGg.

PubMed

Da-Costa, Tânia Maris Pedrini Soares; Hidalgo, Mirian Marubayashi; Consolaro, Alberto; Lima, Carlos Eduardo de Oliveira; Tanaka, Evelise Ono; Itano, Eiko Nakagawa

2018-06-01

External apical root resorption as a consequence of orthodontic treatment is an inflammatory pathological process that results in permanent loss of tooth structure from the root apex. This study aimed to investigate the diagnostic potential of human dentine fractions and salivary IgG in external apical root resorption. Saliva samples were collected from 10 patients before (T0) and after 3 (T3), 6 (T6) and 12 (T12) months of orthodontic treatment. The total dentinal extract, obtained from human third molars, was fractioned by gel filtration chromatography in three fractions denominated FI, FII and FIII. The root resorption analysis of the upper central incisors was performed by digital image subtraction method. Reactivity of salivary IgG to antigenic fractions of dentine was determined by enzyme-linked immunosorbent assay (Elisa). Regardless of treatment, FI dentin fraction with high MM (<300kDa) was the one that presented highest reactivity with salivary IgG. However, it was found higher salivary IgG reactivity for FII (69 to 45 kilodalton [kDa]) as compared to FIII (<45kDa) at (T6) and (T12), (P<0.05), the same periods in that the root resorptions were detected. Our results suggest that FII human dentine fraction and salivary IgG have potential to be used in diagnosis and monitoring of external apical root resorption. The development of a practical and accessible biochemical test using saliva and FII dentine fraction may help in the prevention of severe root resorption. Copyright © 2018. Published by Elsevier Masson SAS.

Roles of Heparan Sulfate Sulfation in Dentinogenesis*

PubMed Central

Hayano, Satoru; Kurosaka, Hiroshi; Yanagita, Takeshi; Kalus, Ina; Milz, Fabian; Ishihara, Yoshihito; Islam, Md. Nurul; Kawanabe, Noriaki; Saito, Masahiro; Kamioka, Hiroshi; Adachi, Taiji; Dierks, Thomas; Yamashiro, Takashi

2012-01-01

Cell surface heparan sulfate (HS) is an essential regulator of cell signaling and development. HS traps signaling molecules, like Wnt in the glycosaminoglycan side chains of HS proteoglycans (HSPGs), and regulates their functions. Endosulfatases Sulf1 and Sulf2 are secreted at the cell surface to selectively remove 6-O-sulfate groups from HSPGs, thereby modifying the affinity of cell surface HSPGs for its ligands. This study provides molecular evidence for the functional roles of HSPG sulfation and desulfation in dentinogenesis. We show that odontogenic cells are highly sulfated on the cell surface and become desulfated during their differentiation to odontoblasts, which produce tooth dentin. Sulf1/Sulf2 double null mutant mice exhibit a thin dentin matrix and short roots combined with reduced expression of dentin sialophosphoprotein (Dspp) mRNA, encoding a dentin-specific extracellular matrix precursor protein, whereas single Sulf mutants do not show such defective phenotypes. In odontoblast cell lines, Dspp mRNA expression is potentiated by the activation of the Wnt canonical signaling pathway. In addition, pharmacological interference with HS sulfation promotes Dspp mRNA expression through activation of Wnt signaling. On the contrary, the silencing of Sulf suppresses the Wnt signaling pathway and subsequently Dspp mRNA expression. We also show that Wnt10a protein binds to cell surface HSPGs in odontoblasts, and interference with HS sulfation decreases the binding affinity of Wnt10a for HSPGs, which facilitates the binding of Wnt10a to its receptor and potentiates the Wnt signaling pathway, thereby up-regulating Dspp mRNA expression. These results demonstrate that Sulf-mediated desulfation of cellular HSPGs is an important modification that is critical for the activation of the Wnt signaling in odontoblasts and for production of the dentin matrix. PMID:22351753

Micro-Computed Tomography Analysis of the Root Canal Morphology of Palatal Roots of Maxillary First Molars.

PubMed

Marceliano-Alves, Marília; Alves, Flávio Rodrigues Ferreira; Mendes, Daniel de Melo; Provenzano, José Claudio

2016-02-01

A thorough knowledge of root canal anatomy is critical for successful root canal treatments. This study evaluated the internal anatomy of the palatal roots of maxillary first molars with micro-computed tomography (microCT). The palatal roots of extracted maxillary first molars (n = 169) were scanned with microCT to determine several anatomic parameters, including main canal classification, lateral canal occurrence and location, degree of curvature, main foramen position, apical constriction presence, diameters 1 and 2 mm from the apex and 1 mm from the foramen, minor dentin thickness in those regions, canal volume, surface area, and convexity. All canals were classified as Vertucci type I. The cross sections were oval in 61% of the canals. Lateral canals were found in 25% of the samples. The main foramen did not coincide with the root apex in 95% of the cases. Only 8% of the canals were classified as straight. Apical constriction was identified in 38% of the roots. The minor and major canal diameters and minor dentin thickness were decreased near the apex. The minor dentin thickness 1 mm from the foramen was 0.82 mm. The palatal canals exhibited a volume of 6.91 mm(3) and surface area of 55.31 mm(2) and were rod-shaped. The root canals of the palatal roots were classified as type I. However, some factors need to be considered during the treatment of these roots, including the frequent ocurrence of moderate/severe curvatures, oval-shaped cross-sections, and lateral canals, noncoincidence of the apical foramen with the root apex, and absence of apical constriction in most cases. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Evaluating the shear bond strength of enamel and dentin with or without etching: A comparative study between dimethacrylate-based and silorane-based adhesives

PubMed Central

Hajizadeh, Hila; Nasseh, Atefeh; Rahmanpour, Naim

2015-01-01

Background Silorane-based composites and their specific self-etch adhesive were introduced to conquest the polymerization shrinkage of methacrylate-based composites. It has been shown that additional etching of enamel and dentin can improve the bond strength of self-etch methacrylate-based adhesives but this claim is not apparent about silorane-based adhesives. Our objective was to compare the shear bond strength (SBS) of enamel and dentin between silorane-based adhesive resin and a methacrylate-based resin with or without additional etching. Material and Methods 40 sound human premolars were prepared and divided into two groups: 1- Filtek P60 composite and Clearfil SE Bond adhesive; 2- Filtek P90 composite and Silorane adhesive. Each group divided into two subgroups: with or without additional etching. For additional etching, 37% acid phosphoric was applied before bonding procedure. A cylinder of the composite was bonded to the surface. After 24 hours storage and 500 thermo cycling between 5-55°C, shear bond strength was assessed with the cross head speed of 0.5 mm/min. Then, bonded surfaces were observed under stereomicroscope to determine the failure mode. Data were analyzed with two-way ANOVA and Fischer exact test. Results Shear bond strength of Filtek P60 composite was significantly higher than Filtek P90 composite both in enamel and dentin surfaces (P<0.05). However, additional etching had no significant effect on shear bond strength in enamel or dentin for each of the composites (P>0.05). There was no interaction between composite type and additional etching (P>0.05). Failure pattern was mainly adhesive and no significant correlation was found between failure and composite type or additional etching (P>0.05). Conclusions Shear bond strength of methacrylate-based composite was significantly higher than silorane-based composite both in enamel and dentin surfaces and additional etching had no significant effect on shear bond strength in enamel or dentin for each of the composites. The mode of failure had no meaningful relation to the type of composite and etching factor. Key words:Shear bond strength, adhesive, composite resin, silorane, methacrylate. PMID:26644830

The effect of MTA application on the affected dentine remineralization after partial caries excavation (in vivo)

NASA Astrophysics Data System (ADS)

Pratiwi, A. R.; Meidyawati, R.; Djauharie, N.

2017-08-01

On deep carious lesions, only thin dentine remains, causing a high risk of pulp exposure during the removal of all infected dentine. A minimally invasive technique is required, such as a partial caries excavation method in the infected dentine tissue and the use of bioactive material that can promote (Mineral Trioxide Aggregate) MTA remineralization. To compare the remineralization of deep carious lesion-affected dentine with the removal of some and all the infected dentine after the application of MTA. Subjects were divided into two groups: group I had only some parts of the infected dentine removed before MTA application, while group II had all the infected dentine removed before MTA application. Each group was measured on the pixel grey value before the treatment and again four weeks after the MTA application, and then the results were compared. Furthermore, the enhancement of both groups’ grey values were compared. Remineralization occurred in both groups after the MTA application. There was no significant difference in the remineralization level of the affected dentine in both groups I and II four weeks after the MTA application. Remineralization occurred in the affected dentine in both groups, either by removing only some parts or all the infected dentine in the deep carious lesion.

Dentin matrix degradation by host matrix metalloproteinases: inhibition and clinical perspectives toward regeneration

PubMed Central

Chaussain, Catherine; Boukpessi, Tchilalo; Khaddam, Mayssam; Tjaderhane, Leo; George, Anne; Menashi, Suzanne

2013-01-01

Bacterial enzymes have long been considered solely accountable for the degradation of the dentin matrix during the carious process. However, the emerging literature suggests that host-derived enzymes, and in particular the matrix metalloproteinases (MMPs) contained in dentin and saliva can play a major role in this process by their ability to degrade the dentin matrix from within. These findings are important since they open new therapeutic options for caries prevention and treatment. The possibility of using MMP inhibitors to interfere with dentin caries progression is discussed. Furthermore, the potential release of bioactive peptides by the enzymatic cleavage of dentin matrix proteins by MMPs during the carious process is discussed. These peptides, once identified, may constitute promising therapeutical tools for tooth and bone regeneration. PMID:24198787

Demonstration of a focused ion-beam cross-sectioning technique for ultrastructural examination of resin-dentin interfaces.

PubMed

Van Meerbeek, B; Conn, L J; Duke, E S; Schraub, D; Ghafghaichi, F

1995-03-01

focused ion-beam (FIB) etching, commonly used as a cross-sectioning technique for failure analysis of semiconductor devices, has recently been applied to biological tissues to expose their ultrastructure for examination. It was the aim of this investigation to determine the practical utility of FIB to cross-section resin-dentin interfaces in order to morphologically evaluate the completeness of resin penetration into the exposed collagen scaffold at the resin-dentin bond interface. Two representative commercially available dentin adhesive systems were bonded to mid-coronal dentin. After appropriate fixation and dehydration of the resin-bonded dentin samples, a scanned focused ion-beam of a few tens of nano-meters in diameter was used to cross=section the resin-dentin interface. Examination of the interfacial ultrastructure was accomplished using a field-emission SEM. Results indicate possible artifact production at the cross-sectioned interface, hiding its actual ultrastructure, probably due to a heat-effect with possible recrystallization. Further studies of FIB are needed to optimize its usefulness for resin-dentin interface examinations and other biological tissue applications. Complete resin saturation of the demineralized dentin surface-layer has been claimed to be the key factor for a long-lasting resin-dentin bond. A "clean" artifact-free micro-cross-sectioning technique may provide indisputable ultra-structural information about the depth of resin penetration into the demineralized zone. Such a test would be useful in the development of dentin adhesive systems.

Clinical efficacy of a herbal dentifrice on dentinal hypersensitivity: a randomized controlled clinical trial.

PubMed

Kumari, M; Naik, S B; Rao, N S; Martande, S S; Pradeep, A R

2013-12-01

Dentinal hypersensitivity is a common problem and there is a growing interest in herbal based formulations for the treatment of oral diseases. This study was conducted to assess the efficacy of a commercially available novel herbal dentifrice in reduction of dentinal hypersensitivity. A total of 73 subjects (38 males and 35 females; aged 25-60 years) were randomly divided into two groups: Group 1 - a placebo dentifrice (The Himalaya Drug Company Research and Development, Makali, Bangalore) and Group 2 - (test group), a commercially available herbal dentifrice (Hi Ora K, The Himalaya Drug Company Research and Development, Makali, Bangalore). Sensitivity scores for controlled air stimulus and cold water were recorded at baseline, 6 weeks and 12 weeks. The test group was found to be significantly better compared to the placebo group at the end of 6 and 12 weeks in reduction of dentinal hypersensitivity. The novel herbal dentifrice can be recommended for treatment of dentinal hypersensitivity. © 2013 Australian Dental Association.

Effects of pulsed CO2 laser in caries selective ablation

NASA Astrophysics Data System (ADS)

Colojoara, Carmen; David, Ion; Marinovici, Mariana

1995-03-01

We have evaluated the effect of pulsed carbon dioxide laser in the treatment for deep carious decay. The so called `caries profonda' is still a problem for conservative dentistry. A `Valvfivre' Master 20S carbon dioxide laser was pulsed to determine the effects on dentine and for testing the properties of softened dentine in selective ablation. Laser treatment parameters were from 1 to 2 W, 50 to 150 ms, 200 to 320 Hz. Fifteen human teeth samples were exposed to irradiation: extracted third molar were exposed to CO2 pulsed laser to determine in vitro the effects on pulp morphology. The tissue samples were analyzed histologically and by means of scanning electron microscopy for evidence of thermal damage. Next, we have evaluated the morphologic changes in vivo on 10 cases in patients with deep carious decay. Pulsed infrared lasers are capable of inducing physical and chemical changes in dentine structure. The results showed an artificially sclerosing and micro-hardness on the remaining dentine. CO2 laser can vaporized carious dentine.

Effect of time on tensile bond strength of resin cement bonded to dentine and low-viscosity composite.

PubMed

Duarte, Rosângela Marques; de Goes, Mario Fernando; Montes, Marcos Antonio Japiassú Resende

2006-01-01

The purpose of this study was to evaluate the tensile bond strength (TBS) of Panavia F resin cement (PF) applied on dentine pre-treated with ED Primer (ED) and Clearfil Liner Bond 2V (CLB) coated with a layer of low-viscosity composite Protect Liner F (PLF) at 10 min, 24 h and 12 months after curing. The labial surfaces of 60 bovine lower incisors were ground to obtain a flat dentine surface, allowing a demarcation of a 4.0 mm-diameter area with adhesive tape. The teeth were randomly divided in six groups; ED was applied in groups A I, A II and A III and CLB was applied, followed by PLF, in groups B I, B II and B III. A resin composite rod with a wire loop was luted directly to the prepared surface of each group with PF. The specimens of groups A I and B I were submitted to TBS test after 10 min. Groups A II and B II were submitted to TBS test after 24 h storage and groups A III and B III were submitted to TBS test after 12 months storage. Each specimen was inspected by SEM and classified according to the failure mode. Additionally, two representative specimens of each failure mode were sectioned for a composite/dentine interface SEM evaluation. No significant statistical differences were observed among the groups at 10 min and 24 h. Groups A III and B III presented the lowest TBS values (p<0.05) after 12 months storage. PF on resin-coated dentin (PLF) showed the highest TBS values and was statistically different to PF on dentine for all the groups. The fracture pattern was generally cohesive on the adhesive/hybrid layer for groups A I, A II and A III and cohesive on composite resin for B I, B II and B III. The use of a less hydrophilic self-etching system to pre-treat dentine, coating with a low-viscosity composite layer prior luting with resin cement, may provide a protection of the hybridised complex, allowing a dentine seal during the 12 months storage period.

Phosphorus Effects of Mesoporous Bioactive Glass on Occlude Exposed Dentin

PubMed Central

Chen, Wen-Cheng; Chen, Cheng-Hwei; Kung, Jung-Chang; Hsiao, Yu-Cheng; Shih, Chi-Jen; Chien, Chi-Sheng

2013-01-01

In recent studies, sealing of exposed dentinal tubules is generally considered as one of the most effective strategies to treat dentin hypersensitivity. Mesoporous bioactive glass (MBG) is a potential material for treating dentin hypersensitivity due to its highly specific areas for dissolution and re-precipitated reaction for reduction in dentin permeability. The groups of commercial products of PerioGlas®, synthetic MBG and MBG without phosphorus (MBGNP) were compared. The MBG and MBGNP powders were prepared by the sol-gel method and mixed with different calculated ratios of phosphoric acid (PA) and then was brushed onto dentin surfaces. We used X-ray diffractometer (XRD), scanning electronic microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) to investigate the physiochemistry and the occlusion ability of dentinal tubules. The results showed that MBG paste mixed with PA solution has a better ability for occluding dentinal tubules than MBGNP; it has a short reaction time and good operability. The major crystallite phase of MBG agents was monocalcium phosphate monohydrate [Ca(H2PO4)2·H2O] in the early stages of the reactions. MBG pastes that were mixed with 30% and 40% PA had the ability to create excellent penetration depth greater than 80 μm. These agents have the potential to treat dentin hypersensitivity. PMID:28788393

Tensile bond strength of indirect composites luted with three new self-adhesive resin cements to dentin.

PubMed

Türkmen, Cafer; Durkan, Meral; Cimilli, Hale; Öksüz, Mustafa

2011-08-01

The aims of this study were to evaluate the tensile bond strengths between indirect composites and dentin of 3 recently developed self-adhesive resin cements and to determine mode of failure by SEM. Exposed dentin surfaces of 70 mandibular third molars were used. Teeth were randomly divided into 7 groups: Group 1 (control group): direct composite resin restoration (Alert) with etch-and-rinse adhesive system (Bond 1 primer/adhesive), Group 2: indirect composite restoration (Estenia) luted with a resin cement (Cement-It) combined with the same etch-and-rinse adhesive, Group 3: direct composite resin restoration with self-etch adhesive system (Nano-Bond), Group 4: indirect composite restoration luted with the resin cement combined with the same self-etch adhesive, Groups 5-7: indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem, Maxcem, and Embrace WetBond, respectively) onto the non-pretreated dentin surfaces. Tensile bond strengths of groups were tested with a universal testing machine at a constant speed of 1 mm/min using a 50 kgf load cell. Results were statistically analyzed by the Student's t-test. The failure modes of all groups were also evaluated. The indirect composite restorations luted with the self-adhesive resin cements (groups 5-7) showed better results compared to the other groups (p<0.05). Group 4 showed the weakest bond strength (p>0.05). The surfaces of all debonded specimens showed evidence of both adhesive and cohesive failure. The new universal self-adhesive resins may be considered an alternative for luting indirect composite restorations onto non-pretreated dentin surfaces.

Composite cements benefit from light-curing.

PubMed

Lührs, Anne-Katrin; De Munck, Jan; Geurtsen, Werner; Van Meerbeek, Bart

2014-03-01

To investigate the effect of curing of composite cements and a new ceramic silanization pre-treatment on the micro-tensile bond strength (μTBS). Feldspathic ceramic blocks were luted onto dentin using either Optibond XTR/Nexus 3 (XTR/NX3; Kerr), the silane-incorporated 'universal' adhesive Scotchbond Universal/RelyX Ultimate (SBU/RXU; 3M ESPE), or ED Primer II/Panavia F2.0 (ED/PAF; Kuraray Noritake). Besides 'composite cement', experimental variables were 'curing mode' ('AA': complete auto-cure at 21°C; 'AA*': complete auto-cure at 37°C; 'LA': light-curing of adhesive and auto-cure of cement; 'LL': complete light-curing) and 'ceramic surface pre-treatment' ('HF/S/HB': hydrofluoric acid ('HF': IPS Ceramic Etching Gel, Ivoclar-Vivadent), silanization ('S': Monobond Plus, Ivoclar-Vivadent) and application of an adhesive resin ('HB': Heliobond, Ivoclar-Vivadent); 'HF/SBU': 'HF' and application of the 'universal' adhesive Scotchbond Universal ('SBU'; 3M ESPE, only for SBU/RXU)). After water storage (7 days at 37°C), ceramic-dentin sticks were subjected to μTBS testing. Regarding the 'composite cement', the significantly lowest μTBSs were measured for ED/PAF. Regarding 'curing mode', the significantly highest μTBS was recorded when at least the adhesive was light-cured ('LA' and 'LL'). Complete auto-cure ('AA') revealed the significantly lowest μTBS. The higher auto-curing temperature ('AA*') increased the μTBS only for ED/PAF. Regarding 'ceramic surface pre-treatment', only for 'LA' the μTBS was significantly higher for 'HF/S/HB' than for 'HF/SBU'. Complete auto-cure led to inferior μTBS than when either the adhesive (on dentin) or both adhesive and composite cement were light-cured. The use of a silane-incorporated adhesive did not decrease luting effectiveness when also the composite cement was light-cured. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Efficacy of a new filler-containing root coating material for dentin remineralization.

PubMed

Okuyama, Katsushi; Kadowaki, Yoshitaka; Matsuda, Yasuhiro; Hashimoto, Naoki; Oki, Saiko; Yamamoto, Hiroko; Tamaki, Yukimichi; Sano, Hidehiko

2016-08-01

To evaluate a new root coating material containing surface pre-reacted glass-ionomer (S-PRG) filler for remineralization of demineralized dentin. The dentin was exposed on root surfaces of human third molars and demineralized by immersion in demineralization solution for 4 days. The demineralized dentin surface was divided into three areas. The center area was left untreated. The area on one side of the center area was coated with protective wax. The area on the other side was coated with one of four test materials: fluoride-containing S-PRG filler (PRG Barrier Coat: PR), fluoride-containing bonding agent (Bond Force: BF), fluoride-containing glass-ionomer cement as a positive control (Fuji IX EXTRA: EX), or non-fluoride-containing bonding agent as a negative control (Clearfil MegaBond: MB). The samples were stored in remineralization solution for 7 days, and then cut into two slices. The mineral changes, defined as variation in mineral loss between wax-coated area and the central untreated area, were measured in one slice by transversal microradiography. The fluoride concentration was measured in the other slice by µ-particle-induced gamma/X-ray emission. Seven thin specimens (0.25-mm thickness) of each test material were used to determine fluoride ion release from the materials over 21 days. The mineral changes were greatest for EX, followed by PR, with no difference between BF and MB (P> 0.05). Regarding the fluoride concentrations in dentin, there was no difference between EX and PR (P> 0.05). MB had the lowest value (P< 0.01). Fluoride release from EX was largest, followed by PR, with BF showing low fluoride release (P< 0.05). MB had no fluoride release. A new coating material with S-PRG filler can be applied in a thin layer on root dentin, which could be especially useful for hard-to-access lesions. This material remineralized demineralized root dentin and had fluoride diffusion characteristics similar to those of glass-ionomer cement in vitro.

An experiment on the attrition of acid demineralized dentine in vitro.

PubMed

Li, H; Liu, M C; Deng, M; Moazzez, R; Bartlett, D W

2011-03-01

A laboratory investigation was designed to test the hypothesis that acids increase the rate of wear caused by attrition on dentine. Dentine sections from 10 teeth were polished, cleaned in an ultrasonic bath and divided into 8 equally sized areas. The occlusal tip of a tooth, placed vertically in a wear machine and loaded at 150 N, was moved against each dentine section for 5000 return strokes with artificial saliva acting as a lubricant. Each dentine section was divided into 8 sections and half randomly immersed in a 1% citric acid solution (pH 2.3) for 20 minutes. The wear regime produced 8 wear scars in total per dentine sample. The volume of each wear scar was measured using a contacting digitizing profilometer. A total of 80 wear scars were produced with 40 treated with acid and 40 acting as controls. The mean for wear volume of the dentine scars with acid was 4.84 μm(3) (1.38) and for the non-acid surface 2.95 μm(3) (0.86). This difference was statistically significant (p < 0.05). These results support the hypothesis that acids increase the rate of wear caused by attrition on dentine. © 2011 Australian Dental Association.

Grape seed extracts inhibit dentin matrix degradation by MMP-3

PubMed Central

Khaddam, Mayssam; Salmon, Benjamin; Le Denmat, Dominique; Tjaderhane, Leo; Menashi, Suzanne; Chaussain, Catherine; Rochefort, Gaël Y.; Boukpessi, Tchilalo

2014-01-01

Since Matrix metalloproteinases (MMPs) have been suggested to contribute to dentin caries progression, the hypothesis that MMP inhibition would affect the progression of dentin caries is clinically relevant. Grape seed extracts (GSE) have been previously reported to be natural inhibitors of MMPs. Objective: To evaluate the capacity of a GSE mouthrinse to prevent the degradation of demineralized dentin matrix by MMP-3 (stromelysin-1). Materials and Methods: Standardized blocks of dentin obtained from sound permanent teeth extracted for orthodontic reasons were demineralized with Ethylenediaminetetraacetic acid (EDTA) and pretreated either with (A) GSE (0.2% w/v), (B) amine fluoride (AmF) (20% w/v), (C) a mouthrinse which contains both, (D) placebo, (E) sodium fluoride (0.15 mg.ml−1), (F) PBS, (G) Chlorhexidine digluconate (CHX), or (H) zinc chloride (ZnCl2). The dentin blocks were then incubated with activated recombinant MMP-3. The supernatants were analyzed by Western Blot for several dentin matrix proteins known to be MMP-3 substrate. In parallel, scanning electron microscopy (SEM) was performed on resin replica of the dentin blocks. Results: Western blot analysis of the supernatants revealed that MMP-3 released from the dentin matrix small proteoglycans (decorin and biglycan) and dentin sialoprotein (DSP) in the AmF, sodium fluoride, PBS and placebo pretreated groups, but not in the GSE and mouthrinse pretreated groups. SEM examination of resin replica showed that the mouthrinse and its active components not only had an anti-MMP action but also modified the dentin surface accessibility. Conclusion: This study shows that GSE either alone or combined with AmF as in the evaluated mouthrinse limits dentin matrix degradation. This association may be promising to prevent the progression of caries within dentin. However, the procedure should be adapted to clinically relevant durations. PMID:25400590

Clinical Evaluation of Ozone on Dentinal Lesions in Young Permanent Molars using the Stepwise Excavation.

PubMed

Safwat, Osama; Elkateb, Mona; Dowidar, Karin; El Meligy, Omar

To evaluate the clinical changes in dentin of deep carious lesions in young permanent molars, following ozone application with and without the use of a remineralizing solution, using the stepwise excavation. The sample included 162 first permanent immature molars, showing deep occlusal carious cavities that were indicated for indirect pulp capping. Teeth were divided into 2 main groups according to the method of ozone treatment. Each group was further subdivided equally into test and control subgroups. Following caries excavation, color, consistency and DIAGNOdent assessments of dentin were evaluated after 6 and 12 months. Regarding dentin color and consistency, no significant differences were observed following ozone application, with and without a remineralizing solution. There were no significant differences between ozone treatment, and calcium hydroxide during the different evaluation periods, except in group I cases after 6 months, concerning the dentin color. The DIAGNOdent values were significantly reduced following ozone application, with or without a remineralizing solution, as well as between test and control cases in group I after 6 months. Ozone application through the stepwise excavation had no significant effect on dentin color and consistency in young permanent molars. DIAGNOdent was unreliable in monitoring caries activity.

Effects of desensitizing toothpastes on the permeability of dentin after different brushing times: An in vitro study.

PubMed

Yang, Meng; Lin, Hong; Jiang, Ruodan; Zheng, Gang

2016-12-01

To investigate the effects of three commercially available desensitizing toothpastes on dentin permeability, and compare the efficacy of each product for reducing dentin permeability in the short term according to the frequency and duration of usage. 100 dentin discs with no caries were prepared from freshly extracted human third molar teeth. The dentin discs were brushed with three desensitizing toothpastes or with a non-desensitizing toothpaste and distilled water, which served as control. The 100 dentin slices were randomly divided into two groups (n= 50): one group underwent continuous brushing (brushed for 3 minutes continuously), and the other group underwent discontinuous brushing (brushed three times, each time for 1 minute). Then, the two groups were divided into five subgroups (n = 10) for the five brushing applications. Dentin permeability was measured with a hydraulic permeability system before and after brushing. All desensitizing toothpastes reduced dentin permeability significantly after treatment. Sensodyne Repair and Protect (calcium sodium phosphosilicate) and discontinuous brushing reduced dentin permeability significantly compared with continuous brushing. Dentin permeability values showed no significant difference between the three toothpastes after 3 minutes of continuous brushing. When comparing the three toothpastes under discontinuous brushing conditions after 3 minutes, Sensodyne Repair and Protect (calcium sodium phosphosilicate) reduced dentin permeability significantly. Sensodyne Repair and Protect (calcium sodium phosphosilicate) and discontinuous brushing reduced dentin permeability significantly compared with continuous brushing. Moreover, brushing with Sensodyne Repair and Protect (calcium sodium phosphosilicate) resulted in the lowest dentin permeability compared with those of the other two toothpastes. These results indicated that Sensodyne Repair and Protect may relieve dentin hypersensitivity.

Effects of water storage on bond strength and dentin sealing ability promoted by adhesive systems.

PubMed

Cantanhede de Sá, Renata Bacelar; Oliveira Carvalho, Adriana; Puppin-Rontani, Regina Maria; Ambrosano, Glaúcia Maria; Nikaido, Toru; Tagami, Junji; Giannini, Marcelo

2012-12-01

To evaluate the dentin bond strength (BS) and sealing ability (SA) promoted by adhesive systems after 24 h or 6 months of water storage. The tested adhesive systems were: one three-step etch-and-rinse adhesive (Adper Scotchbond Multi-Purpose, SBMP) and three single-step self-etching systems (Adper Easy Bond, Bond Force, and G-Bond Plus). Bovine incisors were used for both evaluations, BS (n = 11) and SA (n = 5). To examine BS, the buccal surface was ground with SiC paper to expose a flat dentin surface. After adhesive application, a block of resin composite was incrementally built up over the bonded surface and sectioned into sticks. These bonded specimens were subjected to microtensile bond strength testing after 24 h and 6 months of water storage using a universal testing machine. For SA analysis, enamel was removed from the buccal surfaces. The teeth were connected to a device to measure the initial SA (10 psi), and the second measurement was taken after treating dentin with EDTA. Afterwards, the adhesive systems were applied to dentin and the SA was re-measured for each adhesive after 24 h and 6 months of water storage. The SA was expressed in terms of percentage of dentinal sealing. BS and SA data were submitted to two-way ANOVA and Tukey's test (α = 0.05). All adhesives showed a reduction of SA after 6 months of water storage. The SA promoted by self-etching adhesives was higher than that of SBMP. No adhesive system showed a reduction of the BS after 6 months. Sealing ability was affected by water storage, while no changes in microtensile bond strength were observed after 6 months of water storage. The single-step self-etching systems showed greater sealing ability than did SBMP, even after 6 months of storage in water.

Shear bond strength of one-step self-etch adhesives to dentin: Evaluation of NaOCl pretreatment.

PubMed

Colombo, Marco; Beltrami, Riccardo; Chiesa, Marco; Poggio, Claudio; Scribante, Andrea

2018-02-01

The aim of this study was to evaluate the influence of dentin pretreatment with NaOCl on shear bond strength of four one-step self-etch adhesives with different pH values. Bovine permanent incisors were used. Four one-step self-etch adhesives were tested: Adper™ Easy Bond, Futurabond NR, G-aenial Bond, Clearfil S3 Bond. One two-step self-etch adhesive (Clearfil SE Bond) was used as control. Group 1- no pretreatment; group 2- pretratment with 5,25 % NaOCl; group 3- pretreatment with 37 % H3PO4 etching and 5,25 % NaOCl. A hybrid composite resin was inserted into the dentin surface. The specimens were tested in a universal testing machine. The examiners evaluated the fractured surfaces in optical microscope to determine failure modes, quantified with adhesive remnant index (ARI). Dentin pretreatment variably influenced bond strength values of the different adhesive systems. When no dentin pretreatment was applied, no significant differences were found ( P >.05) among four adhesives tested. No significant differences were recorded when comparing NaOCl pretreatment with H3PO4 + NaOCl pretreatment for all adhesive tested ( P >.05) except Clearfil S3 Bond that showed higher shear bond strength values when H3PO4 was applied. Frequencies of ARI scores were calculated. The influence of dentin pretreatment with NaOCl depends on the composition of each adhesive system used. There was no difference in bond strength values among self-etch adhesives with different pH values. Key words: Dentin, pretreatment, self-etch adhesives.

Effect of photoactivated riboflavin on the biodegradation-resistance of root-dentin collagen.

PubMed

Priyadarshini, Balasankar Meera; Lu, Thong Beng; Fawzy, Amr S

2017-12-01

This study was conducted to evaluate the effect of UVA-activated 1% riboflavin solution on structural integrity; mechanical properties and stability; and collagenase-mediated collagen solubilisation resistance of demineralized root dentin collagen matrix. Root dentin specimens demineralized with 17% EDTA for 7days were treated with 1% RF for 1min followed by UVA photo-activation at intensity 7mW/cm 2 for 1min. Control specimens were completely devoid of riboflavin and/or UVA treatments. Specimens were challenged with bacterial collagenase type-I solution for different time-periods at 37°C. Collagen solubilisation resistance was evaluated in terms of hydroxyproline (HYP) liberation. Mechanical characterization of dentin specimens before and after 24h of exposure to collagenase solution was done in terms of apparent-elastic modulus (E appr ) and ultimate tensile strength (UTS). Variations in dentin collagen-network structure with exposure time in collagenase were visualized by TEM. Crosslinking dentin with UVA-activated riboflavin significantly decreased HYP release and increased E appr and UTS compared to control specimens with storage time in collagenase. Moreover, crosslinked specimens showed higher structural resistance to collagenase effect reflected from dense, well-formed collagen fibrils-network with characteristic collagen cross-banding. UVA-activated riboflavin treatment increased collagenase-mediated collagen degradation resistance and enhanced mechanical stability against collagenase challenges of root dentin after EDTA demineralization. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of various final irrigants on the shear bond strength of resin-based sealer to dentin.

PubMed

Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu; Arathi, Ganesh; Roohi, Riaz; Anand, Suresh

2011-01-01

This study has been designed to evaluate the effect of strong (MTAD) or soft (1- hydroxyethylidene - 1, 1-bisphosphonate (HEBP) final irrigating solution on the shear bond strength of AH plus sealer to coronal dentin. 17% EDTA was used as the reference. Forty freshly extracted human maxillary first premolars were prepared using different irrigation protocols (n=10). All the test groups had 1.3% NaOCl as initial rinse and followed by specific final rinse for each group: G1 - distilled water(control), G2 - 17% EDTA, G3- 18% HEBP and G4 - MTAD. Sections of polyethylene tubes that are 3mm long were filled with freshly mixed sealer and placed on the dentin surfaces. The bonding between the sealer and dentine surface was evaluated using shear bond testing. The values were statistically evaluated using one-way ANOVA followed by Tukey's test. Significant difference was found among the irrigating regimes. EDTA showed highest bond strength followed by HEBP and MTAD.

A biomimetic approach to ameliorate dental hypersensitivity by amorphous polyphosphate microparticles.

PubMed

Müller, Werner E G; Neufurth, Meik; Tolba, Emad; Wang, Shunfeng; Geurtsen, Werner; Feng, Qingling; Schröder, Heinz C; Wang, Xiaohong

2016-06-01

Dental hypersensitivity has become one of the most common and most costly diseases in the world, even though those maladies are very rarely life threatening. Using amorphous microparticles, fabricated from the natural polymer (polyphosphate), we intend to reseal the dentinal tubules exposed and reduce by that the hypersensitivity. Amorphous microparticles (termed aCa-polyP-MP) were prepared from Na-polyphosphate (polyP) and CaCl2, then incubated with human teeth. The potential of the microparticles to plug the dentinal tubules was determined by microscopic and spectroscopic techniques. We demonstrate that, in contrast to polyP, the aCa-polyP-MP efficiently reseal dentinal tubules exposed at the tooth surface. Scanning electron microscopical (SEM) and energy dispersive X-ray spectroscopic (EDX) studies showed that the tooth cement and dentin surfaces, incubated with aCa-polyP-MP, form a nearly homogenous, approximately 50-μm thick solid polyP layer on the tooth cement and dentin surfaces, while no coating on the tooth surface, incubated with Na-polyP [Ca(2+)], was observed. Determination of the mechanical properties of the polyP coating revealed a Martens hardness of 3.85±0.64GPa and a reduced elastic modulus of 94.72±8.54GPa already after a 3h exposure to the aCa-polyP-MP, which become close to those of the natural enamel (4.33±0.69GPa and 101.61±8.52GPa, respectively) after prolonged incubation periods. In addition, aCa-polyP-MP turned out to display morphogenetic activity. Incubation of precursor odontoblasts cultures in the presence of aCa-polyP-MP resulted in a 7-fold increase of the steady-state-expression level of the gene encoding for the alkaline phosphatase (ALP) during a 7 d incubation period. Ca-polyP microparticles, consisting of the biocompatible natural polymer polyP, provide a potential sealing material for dentinal tubules on the tooth surface. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Evaluation of Temperature Elevation During Root Canal Treatment with Dual Wavelength Laser: 2780 nm Er,Cr:YSGG and 940 nm Diode.

PubMed

Al-Karadaghi, Tamara Sardar; Gutknecht, Norbert; Jawad, Hussein A; Vanweersch, Leon; Franzen, Rene

2015-09-01

The purpose of this study was to evaluate the effects of dual wavelength (2780 nm Er,Cr:YSGG and 940 nm diode) laser with radial firing tip (RFT) on the external root surface and sub-surfaces, in terms of temperature changes during laser-assisted root canal treatment. A significant factor that may limit the use of lasers in endodontics is the possible thermal injury to tooth supporting structures. A total of 50 sound single-rooted extracted teeth were divided randomly into two groups (n = 25). Group A, irradiated with Er,Cr:YSGG laser at 1.06 W, 50 Hz, and 50 μs was a control group, and group B was irradiated with dual wavelength of Er,Cr:YSGG laser with the same settings as group A and a diode laser of 0.51 W at 4 ms and 10 ms pulse duration. K-type thermocouples were used to record temperature changes at the cervical, middle, and apical root thirds, on root surfaces and sub-surfaces, arising from delivery of laser energy through RFT. Temperature elevation in group B was significantly higher in the middle and apical thirds of the prepared samples than in group A (p < 0.0001). Group B presented a mean temperature elevation of 5.07°C on the apical surface region corresponding to a 1.48 mm dentin thickness, whereas a mean temperature increase of 7.72°C was recorded corresponding to dentin thickness of 0.95 mm. Within the studied parameters, the dual wavelength laser did not result in adverse thermal changes on the external root surface in vitro.

Influence of dental restorations and mastication loadings on dentine fatigue behaviour: Image-based modelling approach.

PubMed

Vukicevic, Arso M; Zelic, Ksenija; Jovicic, Gordana; Djuric, Marija; Filipovic, Nenad

2015-05-01

The aim of this study was to use Finite Element Analysis (FEA) to estimate the influence of various mastication loads and different tooth treatments (composite restoration and endodontic treatment) on dentine fatigue. The analysis of fatigue behaviour of human dentine in intact and composite restored teeth with root-canal-treatment using FEA and fatigue theory was performed. Dentine fatigue behaviour was analysed in three virtual models: intact, composite-restored and endodontically-treated tooth. Volumetric change during the polymerization of composite was modelled by thermal expansion in a heat transfer analysis. Low and high shrinkage stresses were obtained by varying the linear shrinkage of composite. Mastication forces were applied occlusally with the load of 100, 150 and 200N. Assuming one million cycles, Fatigue Failure Index (FFI) was determined using Goodman's criterion while residual fatigue lifetime assessment was performed using Paris-power law. The analysis of the Goodman diagram gave both maximal allowed crack size and maximal number of cycles for the given stress ratio. The size of cracks was measured on virtual models. For the given conditions, fatigue-failure is not likely to happen neither in the intact tooth nor in treated teeth with low shrinkage stress. In the cases of high shrinkage stress, crack length was much larger than the maximal allowed crack and failure occurred with 150 and 200N loads. The maximal allowed crack size was slightly lower in the tooth with root canal treatment which induced somewhat higher FFI than in the case of tooth with only composite restoration. Main factors that lead to dentine fatigue are levels of occlusal load and polymerization stress. However, root canal treatment has small influence on dentine fatigue. The methodology proposed in this study provides a new insight into the fatigue behaviour of teeth after dental treatments. Furthermore, it estimates maximal allowed crack size and maximal number of cycles for a specific case. Copyright © 2015 Elsevier Ltd. All rights reserved.

The scientific rationale and development of an optimized dentifrice for the treatment of dentin hypersensitivity.

PubMed

Tavss, Edward A; Fisher, Steven W; Campbell, Shannon; Bonta, Yolanda; Darcy-Siegel, Joann; Blackwell, Bernie L; Volpe, Anthony R; Miller, Steven E

2004-02-01

To describe the development of a new dentin hypersensitivity treatment, Colgate Sensitive Maximum Strength dentifrice, containing 5% potassium nitrate as the anti-hypersensitivity active agent. The objective was to develop a home-use hypersensitivity dentifrice that would be superior to the market leader, improving on what is available, which also contains 5% potassium nitrate as the anti-hypersensitivity active agent. In vivo (clinicals, taste evaluation and rat caries), in vitro (potassium flux) and analytical (rheology, dispensed volume, scanning electron microscopy, electron scanning chemical analysis and radioactive dentin abrasion) methods were performed. The objective was accomplished with the development of a new activated silica technology that resulted in enhanced potassium ion activity. In vitro documentation, supported by clinical studies, demonstrated that the resulting formula is more effective than the market leader for relief of hypersensitivity pain. Fast pain relief in less than 2 weeks and long-lasting protection against pain with regular use have also been clinically documented. Furthermore, FDA-required in vivo and in vitro studies indicate that this formula, which contains 0.45% stannous fluoride (1100 ppm fluoride) as the anti-caries active agent, is effective against caries. Good taste, acceptable rheology, acceptable abrasivity, and cosmetic and chemical stability have all been engineered into this unique dentin hypersensitivity treatment. In summary, a highly efficacious consumer friendly treatment for dentin hypersensitivity has been developed.

Effect of the coating material on root dentin remineralization in vitro.

PubMed

Shiiya, Toru; Tomiyama, Kiyoshi; Iizuka, Junko; Hasegawa, Haruhiko; Kuramochi, Erika; Fujino, Fukue; Ohashi, Katsura; Nihei, Tomotaro; Teranaka, Toshio; Mukai, Yoshiharu

2014-10-01

A fluoride-releasing coating material containing surface pre-reacted glass-ionomer (S-PRG) filler has become commercially available. However, there has been no detailed investigation of its remineralization effects at various tooth surface regions. The remineralization effects of S-PRG filler-containing coating material at different sites of demineralized dentin surfaces in vitro were evaluated. Baseline lesions were prepared on bovine root dentin surfaces by immersion in demineralization buffer and divided into four groups: (B)--baseline lesion; (P)--S-PRG filler-containing material; (V)--S-PRG filler-free coating material as negative control; and (X)--resin-modified glass- ionomer as positive control. Material was applied to half the lesion surface, then P, V and X were remineralized in a gel system. Mineral profiles, integrated mineral loss (IML) and lesion depth (LD) at four regions, i.e. 1--exposed dentin surface adjacent to the material; 2--at a distance from the material; 3--beneath the material near to the edge; and 4--at a distance from the edge, were analyzed by transversal microradiography. Data were analyzed using ANOVA and Games-Howell test with α = 0.05. B showed typical artificial demineralized lesion. The IMLs of V, P and X at regions 1 and 2, and P and X at region 3 were significantly lower than that of B, however, those of V at region 3 and the other three groups at region 4 were not significantly different from that of B. At region 1, P and X showed significantly lower IMLs than V. At region 2, the IML of X showed significantly lower IML than V. There was no significant difference between P and X. The LD values of V, P and X at all regions were not significantly different from that of B. Fluoride, strontium and silicate ions released from the S-PRG filler would provide a favorable environment for remineralization of the demineralized dentin in P.

Effect of restoration volume on stresses in a mandibular molar: a finite element study.

PubMed

Wayne, Jennifer S; Chande, Ruchi; Porter, H Christian; Janus, Charles

2014-10-01

There can be significant disagreement among dentists when planning treatment for a tooth with a failing medium-to-large--sized restoration. The clinician must determine whether the restoration should be replaced or treated with a crown, which covers and protects the remaining weakened tooth structure during function. The purpose of this study was to evaluate the stresses generated in different sized amalgam restorations via a computational modeling approach and reveal whether a predictable pattern emerges. A computer tomography scan was performed of an extracted mandibular first molar, and the resulting images were imported into a medical imaging software package for tissue segmentation. The software was used to separate the enamel, dentin, and pulp cavity through density thresholding and surface rendering. These tissue structures then were imported into 3-dimensional computer-aided design software in which material properties appropriate to the tissues in the model were assigned. A static finite element analysis was conducted to investigate the stresses that result from normal occlusal forces. Five models were analyzed, 1 with no restoration and 4 with increasingly larger restoration volume proportions: a normal-sized tooth, a small-sized restoration, 2 medium-sized restorations, and 1 large restoration as determined from bitewing radiographs and occlusal surface digital photographs. The resulting von Mises stresses for dentin-enamel of the loaded portion of the tooth grew progressively greater as the size of the restoration increased. The average stress in the normal, unrestored tooth was 4.13 MPa, whereas the smallest restoration size increased this stress to 5.52 MPa. The largest restoration had a dentin-enamel stress of 6.47 MPa. A linear correlation existed between restoration size and dentin-enamel stress, with an R(2) of 0.97. A larger restoration volume proportion resulted in higher dentin-enamel stresses under static loading. A comparison of the von Mises stresses to the yield strengths of the materials revealed a relationship between a tooth's restoration volume proportion and the potential for failure, although factors other than restoration volume proportion may also impact the stresses generated in moderate-sized restorations. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The effect of dentine pre-treatment using bioglass and/or polyacrylic acid on the interfacial characteristics of resin-modified glass ionomer cements.

PubMed

Sauro, Salvatore; Watson, Timothy; Moscardó, Agustin Pascual; Luzi, Arlinda; Feitosa, Victor Pinheiro; Banerjee, Avijit

2018-06-01

To evaluate the effect of load-cycle aging and/or 6 months artificial saliva (AS) storage on bond durability and interfacial ultramorphology of resin-modified glass ionomer cement (RMGIC) applied onto dentine air-abraded using Bioglass 45S5 (BAG) with/without polyacrylic acid (PAA) conditioning. RMGIC (Ionolux, VOCO) was applied onto human dentine specimens prepared with silicon-carbide abrasive paper or air-abraded with BAG with or without the use of PAA conditioning. Half of bonded-teeth were submitted to load cycling (150,000 cycles) and half immersed in deionised water for 24 h. They were cut into matchsticks and submitted immediately to microtensile bond strength (μTBS) testing or 6 months in AS immersion and subsequently μTBS tested. Results were analysed statistically by two-way ANOVA and Student-Newman-Keuls test (α = 0.05). Fractographic analysis was performed using FE-SEM, while further RMGIC-bonded specimens were surveyed for interfacial ultramorphology characterisation (dye-assisted nanoleakage) using confocal microscopy. RMGIC applied onto dentine air-abraded with BAG regardless PAA showed no significant μTBS reduction after 6 months of AS storage and/or load cycling (p > 0.05). RMGIC-dentine interface showed no sign of degradation/nanoleakage after both aging regimens. Conversely, interfaces created in PAA-conditioned SiC-abraded specimens showed significant reduction in μTBS (p < 0.05) after 6 months of storage and/or load cycling with evident porosities within bonding interface. Dentine pre-treatment using BAG air-abrasion might be a suitable strategy to enhance the bonding performance and durability of RMGIC applied to dentine. The use of PAA conditioner in smear layer-covered dentine may increase the risk of degradation at the bonding interface. A combined dentine pre-treatment using bioglass followed by PAA may increase the bond strength and maintain it stable over time. Conversely, the use of PAA conditioning alone may offer no significant contribute to the immediate and prolonged bonding performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dentin and pulp sense cold stimulus.

PubMed

Tokuda, Masayuki; Tatsuyama, Shoko; Fujisawa, Mari; Morimoto-Yamashita, Yoko; Kawakami, Yoshiko; Shibukawa, Yoshiyuki; Torii, Mistuso

2015-05-01

Dentin hypersensitivity is a common symptom, and recent convergent evidences have reported transient receptor potential (TRP) channels in odontoblasts act as mechanical and thermal molecular sensor, which detect stimulation applied on the exposed dentin surface, to drive multiple odontoblastic cellular functions, such as sensory transduction and/or dentin formation. In the present study, we confirmed expression of TRP melastatin subfamily member-8 (TRPM8) channels in primary cultured cells derived from human dental pulp cells (HPCs) and mouse odontoblast-lineage cells (OLCs) as well as in dentin matrix protein-1 (DMP-1) and dentin sialoprotein (DSP) positive acutely isolated rat odontoblasts from dental pulp tissue slice culture by immunohistochemical analyses. In addition, we detected TRPM8 channel expression on HPCs and OLCs by RT-PCR and Western blotting analyses. These results indicated that both odontoblasts and dental pulp cells express TRPM8 channels in rat, mouse and human, and therefore we hypothesize they may contribute as cold sensor in tooth. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dental hard tissue ablation using mid-infrared tunable nanosecond pulsed Cr:CdSe laser.

PubMed

Lin, Taichen; Aoki, Akira; Saito, Norihito; Yumoto, Masaki; Nakajima, Sadahiro; Nagasaka, Keigo; Ichinose, Shizuko; Mizutani, Koji; Wada, Satoshi; Izumi, Yuichi

2016-12-01

Mid-infrared erbium: yttrium-aluminum-garnet (Er:YAG) and erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers (2.94- and 2.78-μm, respectively) are utilized for effective dental hard tissue treatment because of their high absorption in water, hydroxide ion, or both. Recently, a mid-infrared tunable, nanosecond pulsed, all-solid-state chromium-doped: cadmium-selenide (Cr:CdSe) laser system was developed, which enables laser oscillation in the broad spectral range around 2.9 μm. The purpose of this study was to evaluate the ablation of dental hard tissue by the nanosecond pulsed Cr:CdSe laser at a wavelength range of 2.76-3.00 μm. Enamel, dentin, and cementum tissue were irradiated at a spot or line at a fluence of 0-11.20 J/cm 2 /pulse (energy output: 0-2.00 mJ/pulse) with a repetition rate of 10 Hz and beam diameter of ∼150 μm on the target (pulse width ∼250 ns). After irradiation, morphological changes, ablation threshold, depth, and efficiency, and thickness of the structurally and thermally affected layer of irradiated surfaces were analyzed using stereomicroscopy, scanning electron microscopy (SEM), and light microscopy of non-decalcified histological sections. The nanosecond pulsed irradiation without water spray effectively ablated dental hard tissue with no visible thermal damage such as carbonization. The SEM analysis revealed characteristic micro-irregularities without major melting and cracks in the lased tissue. The ablation threshold of dentin was the lowest at 2.76 μm and the highest at 3.00 μm. The histological analysis revealed minimal thermal and structural changes ∼20 μm wide on the irradiated dentin surfaces with no significant differences between wavelengths. The efficiency of dentin ablation gradually increased from 3.00 to 2.76 μm, at which point the highest ablation efficiency was observed. The nanosecond pulsed Cr:CdSe laser demonstrated an effective ablation ability of hard dental tissues, which was remarkably wavelength-dependent on dentin at the spectral range of 2.76-3.00 μm. These results demonstrate the potential feasibility of the use of pulsed Cr:CdSe laser as a novel laser system for dental treatment. Lasers Surg. Med. 48:965-977, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Effect of generation 4.0 polyamidoamine dendrimer on the mineralization of demineralized dentinal tubules in vitro.

PubMed

Jia, Ru; Lu, Yi; Yang, Chang-Wei; Luo, Xiao; Han, Ying

2014-10-01

Dentine hypersensitivity is a type of clinical oral disease, which is highly prevalent worldwide. Although there are many materials to treat dentine hypersensitivity, their long-term therapeutic effects are not satisfactory. Therefore, the aim of this research was to observe and identify the biological mineralization of the generation 4.0 polyamidoamine dendrimer on the demineralized dentinal tubules at different time points. 2mm-thick slices were obtained from the cemento-enamel junction of 36 third molar teeth that simulated the condition of sensitivity with acid etching. Slices were treated with generation 4.0 polyamidoamine dendrimer and peptide bond condensing agent, while no treatment was applied on the slices of the control group. Following immersion in artificial saliva for 2, 4, 6, and 8 weeks respectively, the mineralization condition of dentine slices was observed using the scanning electron microscope (SEM). In addition, the differences in the samples of dental slices between the 2 groups were also detected using the microhardness test. SEM results showed that the average diameter and density of the dentinal tubules in the experimental group were significantly lower than those in the control group (P<0.001). The microhardness test exhibited a similar result, which suggested that the microhardness of the experimental group was significantly higher than the control group (P<0.001). Generation 4.0 polyamidoamine dendrimer promotes the biomineralization of demineralized dentinal tubules. Moreover, this result also suggests that the 4.0th generation polyamidoamine dendrimer has the potential value for dentine hypersensitivity treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dentin remineralization in acid challenge environment via PAMAM and calcium phosphate composite.

PubMed

Liang, Kunneng; Weir, Michael D; Xie, Xianju; Wang, Lin; Reynolds, Mark A; Li, Jiyao; Xu, Hockin H K

2016-11-01

The objective of this study was to investigate the effects of poly (amido amine) (PAMAM), composite with nanoparticles of amorphous calcium phosphate (NACP), and the combined PAMAM+NACP nanocomposite treatment, on remineralization of demineralized dentin in a cyclic artificial saliva/lactic acid environment for the first time. Dentin specimens were prepared and demineralized with 37% phosphoric acid for 15s. Four groups were prepared: (1) dentin control, (2) dentin coated with PAMAM, (3) dentin with NACP composite, (4) dentin with PAMAM+NACP. Specimens were treated with a cyclic artificial saliva/lactic acid regimen for 21days. Acid neutralization and calcium (Ca) and phosphate (P) ion concentrations were measured. The remineralized dentin specimens were examined by scanning electron microscopy (SEM) and hardness testing. NACP nanocomposite had mechanical properties similar to commercial control composites (p>0.1). NACP composite had acid-neutralization and Ca and P ion release capability. PAMAM or NACP composite each alone achieved remineralization and increased the hardness of demineralized dentin (p<0.05). PAMAM+NACP nanocomposite achieved the greatest mineral regeneration in demineralized dentin and the greatest hardness increase in demineralized dentin, which approached the hardness of healthy dentin (p>0.1). The superior remineralization efficacy of PAMAM+NACP was demonstrated for the first time. PAMAM+NACP induced remineralization in demineralized dentin in an acid challenge environment, when conventional remineralization methods such as PAMAM did not work well. The novel PAMAM+NACP composite approach is promising for a wide range of dental applications to inhibit caries and protect tooth structures. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of an arginine-containing toothpaste on bond strength of different adhesive systems to eroded dentin.

PubMed

Bergamin, Ana Cláudia Pietrobom; Bridi, Enrico Coser; Amaral, Flávia Lucisano Botelho; Turssi, Cecília Pedroso; Basting, Roberta Tarkany; Aguiar, Flávio Henrique Baggio; França, Fabiana Mantovani Gomes

2016-01-01

The aim of this study was to evaluate the bond strength of different adhesive systems to eroded dentin following toothbrushing with an arginine-containing toothpaste. Sixty standardized 3 × 3 × 2-mm fragments of root dentin (n = 10) were prepared. After all surfaces except the buccal surfaces were impermeabilized, specimens were subjected to an erosive wear protocol and stored for 24 hours at 37°C. The specimens underwent 1000 toothbrushing cycles with an arginine-containing toothpaste, an arginine-free toothpaste (positive control group), or artificial saliva (negative control group). Following application of a self-etching or an etch-and-rinse adhesive to the buccal surfaces of the specimens, 6-mm-high composite resin blocks were built up in 2-mm increments. After 24 hours' storage in 100% relative humidity, microtensile test specimens with an approximate area of 1 mm² were prepared. The test was performed at a speed of 0.5 mm/min until specimen fracture, and the failure patterns were evaluated using a stereoscopic loupe. Two-way analysis of variance revealed no significant difference between the toothpastes, the adhesive systems, or the interactions between toothpaste and adhesive system in terms of the bond strength to eroded dentin (P > 0.05). The predominant failure pattern was adhesive in all groups. It was concluded that a toothpaste containing arginine did not interfere with the bond between either the self-etching or the etch-and-rinse adhesive system and eroded dentin.

Amalgam shear bond strength to dentin using single-bottle primer/adhesive systems.

PubMed

Cobb, D S; Denehy, G E; Vargas, M A

1999-10-01

To evaluate the in vitro shear bond strengths (SBS) of a spherical amalgam alloy (Tytin) to dentin using several single-bottle primer/adhesive systems both alone: Single Bond (SB), OptiBond Solo (Sol), Prime & Bond 2.1 (PB), One-Step (OS) and in combination with the manufacturer's supplemental amalgam bonding agent: Single Bond w/3M RelyX ARC (SBX) and Prime & Bond 2.1 w/Amalgam Bonding Accessory Kit (PBA). Two, three-component adhesive systems, Scotchbond Multi-Purpose (SBMP) and Scotchbond Multi-Purpose Plus w/light curing (S + V) and w/o light curing (S+) were used for comparison. One hundred eight extracted human third molars were mounted lengthwise in phenolic rings with acrylic resin. The proximal surfaces were ground to expose a flat dentin surface, then polished to 600 grit silicon carbide paper. The teeth were randomly assigned to 9 groups (n = 12), and dentin surfaces in each group were treated with an adhesive system according to the manufacturer's instructions, except for S + V specimens, where the adhesive was light cured for 10 s before placing the amalgam. Specimens were then secured in a split Teflon mold, having a 3 mm diameter opening and amalgam was triturated and condensed onto the treated dentin surfaces. Twenty minutes after condensation, the split mold was separated. Specimens were placed in distilled water for 24 hrs, then thermocycled (300 cycles, between 5 degrees C and 55 degrees C, with 12 s dwell time). All specimens were stored in 37 degrees C distilled water for 7 days, prior to shear strength testing using a Zwick Universal Testing Machine at a cross-head speed of 0.5 mm/min. The highest to the lowest mean dentin shear bond strength values (MPa) for the adhesive systems tested were: S + V (10.3 +/- 2.3), SBX (10.2 +/- 3.5), PBA, (6.4 +/- 3.6), SOL (5.8 +/- 2.5), SBMP (5.7 +/- 1.8), S+ (4.8 +/- 2.3), PB (2.7 +/- 2.6), SB (2.7 +/- 1.1) and OS (2.5 +/- 1.8). One-way ANOVA and Duncan's Multiple Range Test indicated significant differences among groups. SBX and S + V produced significantly higher amalgam to dentin shear bond strengths than all other adhesive systems. Bond strengths of amalgam to dentin for the single-bottle adhesives, SOL and PBA were comparable to the three-component systems, SBMP and S+ and were significantly greater than OS, SB and PB (P < 0.05).

Laser-assisted treatment of dentinal hypersensitivity: a literature review

PubMed Central

Biagi, Roberto; Cossellu, Gianguido; Sarcina, Michele; Pizzamiglio, Ilaria Tina; Farronato, Giampietro

2015-01-01

Summary The purpose of this literature review was to evaluate the effectiveness of the laser-assisted treatment of dentinal hypersensitivity. A review with inclusion and exclusion criteria was performed from January 2009 to December 2014 with electronic data-bases: MedLine via PubMed, Science Direct and Cochrane Library. Research of paper magazines by hand was not considered. Forty-three articles were selected between literature reviews, in vitro studies, clinical trials, pilot and preliminary studies. The items were divided into laser-used groups for an accurate description, and then the reading of results into various typologies. Laser-assisted treatment reduces dentinal hypersensitivity-related pain, but also a psychosomatic component must be considered, so further studies and more suitable follow-ups are necessary. PMID:26941892

Effects of different peracetic acid formulations on post space radicular dentin.

PubMed

Belizário, Lauriê Garcia; Kuga, Milton Carlos; Castro-Núñez, Gabriela Mariana; Escalante-Otárola, Wilfredo Gustavo; Só, Marcus Vinicius Reis; Pereira, Jefferson Ricardo

2018-01-05

The optimal irrigating solution with antimicrobial and dentin cleansing properties for post space preparation for fiber posts is unclear. Peracetic acid is one option but is available in various chemical formulations that require evaluation. The purpose of this in vitro study was to evaluate dentin surface cleanliness based on the presence of a smear layer and the number of open dentin tubules. It also investigates the chemical composition of residues after canal irrigation with a 1% peracetic acid solution (PA) at low or high concentration of hydrogen peroxide during the preparation of intracanal fiber posts. After filling the root canals of 40 mandibular incisors, a rotary instrument was used for intracanal preparation to place fiber posts. The teeth were divided into 4 groups (n=10) according to the post space irrigation protocol as follows: CG (control): distilled water; NA (NaOCl): 2.5% sodium hypochlorite; LH: PA with low concentration of hydrogen peroxide; and HH: PA with high concentrations of hydrogen peroxide. After irrigation, the teeth were sectioned, and the intracanal dentin surface was subjected to analysis using energy dispersive spectroscopy to evaluate chemical composition and to scanning electron microscopy (×500) to evaluate the presence of the smear layer. The number of open dentin tubules was measured by scanning electron microscopy analysis (×2000) using photo-editing software. ANOVA and the Tukey test (α=.05) were used to evaluate the data, except for the presence of a smear layer, for which the Kruskal-Wallis and Dunn tests were used (α=.05). The highest concentrations of oxygen in the dentin residues were detected in LH and HH (P<.05); CG and NA showed similar oxygen concentrations (P>.05). NA had a higher concentration of chlorine (P<.05), whereas LH had a lower amount of smear layer and a larger number of open dentin tubules than the other groups (P<.05). These were equivalent to each other (P>.05), except for HH, which also had a larger number of open dentin tubules than CG and NA (P<.05). PA 1% with a low concentration of hydrogen peroxide yielded a lower amount of smear layer and a larger number of open dentin tubules in the dentin of the post space when compared with PA 1% with a high concentration of hydrogen peroxide, despite maintaining a similar oxygen concentration in these dentin residues. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Remineralization of artificial dentinal caries lesions by biomimetically modified Mineral Trioxide Aggregate

PubMed Central

Qi, Yi-pin; Li, Nan; Niu, Li-na; Primus, Carolyn M.; Ling, Jun-Qi; Pashley, David H.; Tay, Franklin R.

2011-01-01

Fluoride-releasing restorative materials are available for remineralization of enamel and root caries. However, dentin remineralization is more difficult than enamel remineralization due to the paucity of apatite seed crystallites along the lesion surface for heterogeneous crystal growth. Extracellular matrix proteins play critical roles in controlling apatite nucleation/growth in collagenous tissues. This study examined the remineralization efficacy of mineral trioxide aggregate (MTA) in phosphate-containing simulated body fluid (SBF) by incorporating polyacrylic acid and sodium tripolyphosphate as biomimetic analogs of matrix proteins for remineralizing caries-like dentin. Artificial caries-like dentin lesions incubated in SBF were remineralized over a 6-week period using MTA or MTA containing biomimetic analogs in the absence or presence of dentin adhesive application. Lesion depths and integrated mineral loss were monitored with micro-computed tomography. Ultrastructure of baseline and remineralized lesions were examined by transmission electron microscopy. Dentin remineralization was best achieved using MTA containing biomimetic analogs regardless of whether an adhesive was applied; dentinal tubules within the remineralized dentin were occluded by apatite. It is concluded that the MTA version employed in the study may be doped with biomimetic analogs for remineralization of unbonded and bonded artificial caries-like lesions in the presence of SBF. PMID:22085925

Remineralization of artificial dentinal caries lesions by biomimetically modified mineral trioxide aggregate.

PubMed

Qi, Yi-pin; Li, Nan; Niu, Li-na; Primus, Carolyn M; Ling, Jun-Qi; Pashley, David H; Tay, Franklin R

2012-02-01

Fluoride-releasing restorative materials are available for remineralization of enamel and root caries. However, remineralization of dentin is more difficult than remineralization of enamel due to the paucity of apatite seed crystallites along the lesion surface for heterogeneous crystal growth. Extracellular matrix proteins play critical roles in controlling apatite nucleation/growth in collagenous tissues. This study examined the remineralization efficacy of mineral trioxide aggregate (MTA) in phosphate-containing simulated body fluid (SBF) by incorporating polyacrylic acid and sodium tripolyphosphate as biomimetic analogs of matrix proteins for remineralizing caries-like dentin. Artificial caries-like dentin lesions incubated in SBF were remineralized over a 6 week period using MTA alone or MTA containing biomimetic analogs in the absence or presence of dentin adhesive application. Lesion depths and integrated mineral loss were monitored with microcomputed tomography. The ultrastructure of baseline and remineralized lesions was examined by transmission electron microscopy. Dentin remineralization was best achieved using MTA containing biomimetic analogs regardless of whether an adhesive was applied; dentinal tubules within the remineralized dentin were occluded by apatite. It is concluded that the version of MTA employed in this study may be doped with biomimetic analogs for remineralization of unbonded and bonded artificial caries-like lesions in the presence of SBF. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The influence of the Q-switched and free-running Er:YAG laser beam characteristics on the ablation of root canal dentine

NASA Astrophysics Data System (ADS)

Papagiakoumou, Eirini; Papadopoulos, Dimitrios N.; Khabbaz, Marouan G.; Makropoulou, Mersini I.; Serafetinides, Alexander A.

2004-06-01

Laser based dental treatment is attractive to many researchers. Lasers in the 3 μm region, as the Er:YAG, are suitable especially for endodontic applications. In this study a pulsed free-running and Q-switched laser was used for the ablation experiments of root canal dentine. The laser beam was either directly focused on the dental tissue or delivered to it through an infrared fiber. For different spatial beam distributions, energies, number of pulses and both laser operations the quality characteristics (crater's shape formation, ablation efficiency and surface characteristics modification) were evaluated using scanning electron microscopy (SEM). The craters produced, generally, reflect the relevant beam profile. Inhomogeneous spatial beam profiles and short pulse duration result in cracks formation and lower tissue removal efficiency, while longer pulse durations cause hard dentine fusion. Any beam profile modification, due to laser characteristics variations and the specific delivering system properties, is directly reflected in the ablation crater shape and the tissue removal efficiency. Therefore, the laser parameters, as fluence, pulse repetition rate and number of pulses, have to be carefully adjusted in relation to the desirable result.

Mineral induction by immobilized phosphoproteins

NASA Technical Reports Server (NTRS)

Saito, T.; Arsenault, A. L.; Yamauchi, M.; Kuboki, Y.; Crenshaw, M. A.

1997-01-01

Dentin phosphoproteins are thought to have a primary role in the deposition of mineral on the collagen of dentin. In this study we determined the type of binding between collagen and phosphoproteins necessary for mineral formation onto collagen fibrils and whether the phosphate esters are required. Bovine dentin phosphophoryn or phosvitin from egg yolk were immobilized on reconstituted skin type I collagen fibrils by adsorption or by covalent cross-linking. In some samples the ester phosphate was removed from the covalently cross-linked phosphoproteins by treatment with acid phosphatase. All samples were incubated at 37 degrees C in metastable solutions that do not spontaneously precipitate. Reconstituted collagen fibrils alone did not induce mineral formation. The phosphoproteins adsorbed to the collagen fibrils desorbed when the mineralization medium was added, and mineral was not induced. The mineral induced by the cross-linked phosphoproteins was apatite, and the crystals were confined to the surface of the collagen fibrils. With decreasing medium saturation the time required for mineral induction increased. The interfacial tensions calculated for apatite formation by either phosphoprotein cross-linked to collagen were about the same as that for phosphatidic acid liposomes and hydroxyapatite. This similarity in values indicates that the nucleation potential of these highly phosphorylated surfaces is about the same. It is concluded that phosphoproteins must be irreversibly bound to collagen fibrils for the mineralization of the collagen network in solutions that do not spontaneously precipitate. The phosphate esters of phosphoproteins are required for mineral induction, and the carboxylate groups are not sufficient.

The Dentin Sialoprotein (DSP) Domain Regulates Dental Mesenchymal Cell Differentiation through a Novel Surface Receptor

PubMed Central

Wan, Chunyan; Yuan, Guohua; Luo, Daoshu; Zhang, Lu; Lin, Heng; Liu, Huan; Chen, Lei; Yang, Guobin; Chen, Shuo; Chen, Zhi

2016-01-01

Dentin sialophosphoprotein (DSPP) is a dentin extracellular matrix protein that is processed into dentin sialoprotein (DSP), dentin glycoprotein (DGP) and dentin phosphoprotein (DPP). DSP is mainly expressed in odontoblasts. We hypothesized that DSP interacts with cell surface receptors and subsequently activates intracellular signaling. Using DSP as bait for screening a protein library, we demonstrate that DSP acts as a ligand and binds to integrin β6. The 36 amino acid residues of DSP are sufficient to bind to integrin β6. This peptide promoted cell attachment, migration, differentiation and mineralization of dental mesenchymal cells. In addition, DSP aa183-219 stimulated phosphorylation of ERK1/2 and P38 kinases. This activation was inhibited by an anti-integrin β6 antibody and siRNA. Furthermore, we demonstrate that this DSP fragment induces SMAD1/5/8 phosphorylation and nuclear translocation via ERK1/2 and P38 signaling. SMAD1/5/8 binds to SMAD binding elements (SBEs) in the DSPP gene promoter. SBE mutations result in a decrease in DSPP transcriptional activity. Endogenous DSPP expression was up-regulated by DSP aa183-219 in dental mesenchymal cells. The data in the current study demonstrate for the first time that this DSP domain acts as a ligand in a RGD-independent manner and is involved in intracellular signaling via interacting with integrin β6. The DSP domain regulates DSPP expression and odontoblast homeostasis via a positive feedback loop. PMID:27430624

The Dentin Sialoprotein (DSP) Domain Regulates Dental Mesenchymal Cell Differentiation through a Novel Surface Receptor.

PubMed

Wan, Chunyan; Yuan, Guohua; Luo, Daoshu; Zhang, Lu; Lin, Heng; Liu, Huan; Chen, Lei; Yang, Guobin; Chen, Shuo; Chen, Zhi

2016-07-19

Dentin sialophosphoprotein (DSPP) is a dentin extracellular matrix protein that is processed into dentin sialoprotein (DSP), dentin glycoprotein (DGP) and dentin phosphoprotein (DPP). DSP is mainly expressed in odontoblasts. We hypothesized that DSP interacts with cell surface receptors and subsequently activates intracellular signaling. Using DSP as bait for screening a protein library, we demonstrate that DSP acts as a ligand and binds to integrin β6. The 36 amino acid residues of DSP are sufficient to bind to integrin β6. This peptide promoted cell attachment, migration, differentiation and mineralization of dental mesenchymal cells. In addition, DSP (aa183-219) stimulated phosphorylation of ERK1/2 and P38 kinases. This activation was inhibited by an anti-integrin β6 antibody and siRNA. Furthermore, we demonstrate that this DSP fragment induces SMAD1/5/8 phosphorylation and nuclear translocation via ERK1/2 and P38 signaling. SMAD1/5/8 binds to SMAD binding elements (SBEs) in the DSPP gene promoter. SBE mutations result in a decrease in DSPP transcriptional activity. Endogenous DSPP expression was up-regulated by DSP (aa183-219) in dental mesenchymal cells. The data in the current study demonstrate for the first time that this DSP domain acts as a ligand in a RGD-independent manner and is involved in intracellular signaling via interacting with integrin β6. The DSP domain regulates DSPP expression and odontoblast homeostasis via a positive feedback loop.

Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine.

PubMed

Pires, C W; Lenzi, T L; Soares, F Z M; Rocha, R O

2018-05-12

This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine. Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1 mm-thick layer of the pastes for 15 min at 37 °C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24 h of water storage at 37 °C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05). The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures. Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.

Short communication: pre- and co-curing effect of adhesives on shear bond strengths of composite resins to primary enamel and dentine: an in vitro study.

PubMed

Viswanathan, R; Shashibhushan, K K; Subba Reddy, V V

2011-12-01

To evaluate and compare shear bond strengths of composite resins to primary enamel and dentine when the adhesives are pre-cured (light cured before the application of the resin) or co-cured (adhesive and the resin light cured together). Buccal surfaces of 80 caries-free primary molars were wet ground to create bonding surfaces on enamel and dentine and specimens mounted on acrylic blocks. Two bonding agents (Prime and Bond NT® and Xeno III®) were applied to either enamel or dentine as per manufacturer's instructions. In 40 specimens, the bonding agent was light cured immediately after the application (pre-cured). The other 40 specimens were not light cured until the composite resin application (co-cured). Resin composite cylinders were made incrementally using acrylic moulds over the adhesives and light cured. Specimens were stored in deionised water for 24 hours at room temperature. Shear bond strength was measured using an Instron universal testing machine (in MPa) and was analysed with Student's unpaired t test. Light curing the adhesive separately produced significantly higher bond strengths to primary dentine than co-curing (p<0.001). At the same time light curing the adhesive separately did not produce significantly different bond strengths to primary enamel (p>0.05). Curing sequence had no significant effect on shear bond strength of adhesives on the primary enamel. Pre-curing adhesives before curing composite resins produced greater shear bond strength to primary dentine.

Improved degree of conversion of model self-etching adhesives through their interaction with dentin

PubMed Central

Zhang, Ying; Wang, Yong

2011-01-01

Objective To investigate the correlation of the chemical interaction between model self-etching adhesives and dentin with the degree of conversion (DC) of the adhesives. Methods The model self-etching adhesives contained bis[2-methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA) with a mass ratio of 1/1, and 0-40% water contents, respectively. The adhesives were applied either onto the prepared dentin surface or unreactive substrates (such as glass slides), agitated for 15s, then light-cured for 40s. The DCs of the adhesives were determined using micro-Raman spectral and mapping analysis. Results The DCs of the adhesives cured on the dentin substrate were found to be significantly higher than those on the unreactive glass substrate. Moreover, the DCs of the adhesives displayed a decreasing trend as the distance from the dentin surface became greater. The chemical interaction of the acidic 2MP/HEMA adhesives with the mineral apatite in dentin was proposed to play a significant role for the observations. The chemical interaction could be validated by the spectral comparison in the phosphate regions of 1100 cm−1 and 960 cm−1 in the Raman spectra. The results also revealed a notable influence of water content on the DC of adhesives. The DCs of the adhesive at 10% water content exhibited the highest DC level for both substrates. Conclusions Interaction with dentin dramatically improved the degree of conversion of self-etching adhesives. Our ability to chemically characterize the a/d interface including in situ detection of the DC distribution is very important in understanding self-etching adhesive bonding under in vivo conditions. PMID:22024375

Improved degree of conversion of model self-etching adhesives through their interaction with dentine.

PubMed

Zhang, Ying; Wang, Yong

2012-01-01

To investigate the correlation of the chemical interaction between model self-etching adhesives and dentine with the degree of conversion (DC) of the adhesives. The model self-etching adhesives contained bis[2-methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA) with a mass ratio of 1/1, and 0-40% water contents, respectively. The adhesives were applied either onto the prepared dentine surface or unreactive substrates (such as glass slides), agitated for 15s, then light-cured for 40s. The DCs of the adhesives were determined using micro-Raman spectral and mapping analysis. The DCs of the adhesives cured on the dentine substrate were found to be significantly higher than those on the unreactive glass substrate. Moreover, the DCs of the adhesives displayed a decreasing trend as the distance from the dentine surface became greater. The chemical interaction of the acidic 2MP/HEMA adhesives with the mineral apatite in dentine was proposed to play a significant role for the observations. The chemical interaction could be validated by the spectral comparison in the phosphate regions of 1100 cm(-1) and 960 cm(-1) in the Raman spectra. The results also revealed a notable influence of water content on the DC of adhesives. The DCs of the adhesive at 10% water content exhibited the highest DC level for both substrates. Interaction with dentine dramatically improved the degree of conversion of self-etching adhesives. Our ability to chemically characterise the a/d interface including in situ detection of the DC distribution is very important in understanding self-etching adhesive bonding under in vivo conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cariotester, a new device for assessment of dentin lesion remineralization in vitro.

PubMed

Utaka, Sachiko; Nakashima, Syozi; Sadr, Alireza; Ikeda, Masaomi; Nikaido, Toru; Shimizu, Akihiko; Tagami, Junji

2013-01-01

This study aimed to evaluate the potential of a new device (Cariotester) for monitoring of incipient carious lesion remineralization in root dentin by topical fluoride in vitro. Demineralized bovine dentin specimens were treated by fluoride solutions (APF or neutral NaF) and remineralized for 4 weeks. Cariotester was used to measure penetration depth (CTR depth) of the indenter into the de- and remineralized specimen surface. The specimens were assessed by transverse microradiography (TMR) to determine lesion parameters (depth: LD, mineral loss: ΔZ). Pearson's correlation analysis showed an overall significant relationship between CTR depth and both TMR parameters. CTR depth appeared to distinguish the positive effect that topical fluoride application had on the remineralization of the outer zone of dentin lesions. Cariotester had the potential to serve as a quantitative tool for monitoring of incipient carious lesion remineralization in root dentin.

Influence of dentin pretreatment on bond strength of universal adhesives.

PubMed

Poggio, Claudio; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Scribante, Andrea

2017-01-01

Objective: The purpose of the present study was to compare bond strength of different universal adhesives under three different testing conditions: when no pretreatment was applied, after 37% phosphoric acid etching and after glycine application. Materials and methods: One hundred and fifty bovine permanent mandibular incisors were used as a substitute for human teeth. Five different universal adhesives were tested: Futurabond M+, Scotchbond Universal, Clearfil Universal Bond, G-Premio BOND, Peak Universal Bond. The adhesive systems were applied following each manufacturer's instructions. The teeth were randomly assigned to three different dentin surface pretreatments: no pretreatment agent (control), 37% phosphoric acid etching, glycine pretreatment. The specimens were placed in a universal testing machine in order to measure and compare bond strength values. Results: The Kruskal-Wallis analysis of variance and the Mann-Whitney test were applied to assess significant differences among the groups. Dentin pretreatments provided different bond strength values for the adhesives tested, while similar values were registered in groups without dentin pretreatment. Conclusions: In the present report, dentin surface pretreatment did not provide significant differences in shear bond strength values of almost all groups. Acid pretreatment lowered bond strength values of Futurabond and Peak Universal Adhesives, whereas glycine pretreatment increased bond strength values of G Praemio Bond adhesive system.

Influence of dentin pretreatment on bond strength of universal adhesives

PubMed Central

Poggio, Claudio; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Scribante, Andrea

2017-01-01

Abstract Objective: The purpose of the present study was to compare bond strength of different universal adhesives under three different testing conditions: when no pretreatment was applied, after 37% phosphoric acid etching and after glycine application. Materials and methods: One hundred and fifty bovine permanent mandibular incisors were used as a substitute for human teeth. Five different universal adhesives were tested: Futurabond M+, Scotchbond Universal, Clearfil Universal Bond, G-Premio BOND, Peak Universal Bond. The adhesive systems were applied following each manufacturer’s instructions. The teeth were randomly assigned to three different dentin surface pretreatments: no pretreatment agent (control), 37% phosphoric acid etching, glycine pretreatment. The specimens were placed in a universal testing machine in order to measure and compare bond strength values. Results: The Kruskal–Wallis analysis of variance and the Mann–Whitney test were applied to assess significant differences among the groups. Dentin pretreatments provided different bond strength values for the adhesives tested, while similar values were registered in groups without dentin pretreatment. Conclusions: In the present report, dentin surface pretreatment did not provide significant differences in shear bond strength values of almost all groups. Acid pretreatment lowered bond strength values of Futurabond and Peak Universal Adhesives, whereas glycine pretreatment increased bond strength values of G Praemio Bond adhesive system. PMID:28642929

Shear Bond Strengths and Morphological Evaluation of Filled and Unfilled Adhesive Interfaces to Enamel and Dentine

PubMed Central

Mortazavi, Vajihesadat; Fathi, Mohammadhosein; Ataei, Ebrahim; Khodaeian, Niloufar; Askari, Navid

2012-01-01

In this laboratory study shear bond strengths of three filled and one unfilled adhesive systems to enamel and dentine were compared. Forty-eight extracted intact noncarious human mandibular molars were randomly assigned to two groups of 24 one for bonding to enamel and the other for bonding to dentine. Buccal and lingual surfaces of each tooth were randomly assigned for application of each one of filled (Prime & Bond NT (PBNT), Optibond Solo Plus (OBSP), and Clearfil SE Bond (CSEB)) and unfilled (Single Bond (SB)) adhesive systems (n = 12). A universal resin composite was placed into the translucent plastic cylinders (3 mm in diameter and 2 mm in length) and seated against the enamel and dentine surfaces and polymerized for 40 seconds. Shear bond strength was determined using a universal testing machine, and the results were statistically analyzed using two-way ANOVA, one-way ANOVA, t-test, and Tukey HSD post hoc test with a 5% level of significance.There were no statistically significant differences in bond strength between the adhesive systems in enamel, but CSEB and SB exhibited significantly higher and lower bond strength to dentine, respectively, than the other tested adhesive systems while there were no statistically significant differences between PBNT and OBSP. PMID:23209471

The effect of a manual instrumentation technique on five types of premolar root canal geometry assessed by microcomputed tomography and three-dimensional reconstruction

PubMed Central

2011-01-01

Background Together with diagnosis and treatment planning, a good knowledge of the root canal system and its frequent variations is a necessity for successful root canal therapy. The selection of instrumentation techniques for variants in internal anatomy of teeth has significant effects on the shaping ability and cleaning effectiveness. The aim of this study was to reveal the differences made by including variations in the internal anatomy of premolars into the study protocol for investigation of a single instrumentation technique (hand ProTaper instruments) assessed by microcomputed tomography and three-dimensional reconstruction. Methods Five single-root premolars, whose root canal systems were classified into one of five types, were scanned with micro-CT before and after preparation with a hand ProTaper instrument. Instrumentation characteristics were measured quantitatively in 3-D using a customized application framework based on MeVisLab. Numeric values were obtained for canal surface area, volume, volume changes, percentage of untouched surface, dentin wall thickness, and the thickness of dentin removed. Preparation errors were also evaluated using a color-coded reconstruction. Results Canal volumes and surface areas were increased after instrumentation. Prepared canals of all five types were straightened, with transportation toward the inner aspects of S-shaped or multiple curves. However, a ledge was formed at the apical third curve of the type II canal system and a wide range in the percentage of unchanged canal surfaces (27.4-83.0%) was recorded. The dentin walls were more than 0.3 mm thick except in a 1 mm zone from the apical surface and the hazardous area of the type II canal system after preparation with an F3 instrument. Conclusions The 3-D color-coded images showed different morphological changes in the five types of root canal systems shaped with the same hand instrumentation technique. Premolars are among the most complex teeth for root canal treatment and instrumentation techniques for the root canal systems of premolars should be selected individually depending on the 3-D canal configuration of each tooth. Further study is needed to demonstrate the differences made by including variations in the internal anatomy of teeth into the study protocol of clinical RCT for identifying the best preparation technique. PMID:21676233

Resin–dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding

PubMed Central

Sauro, Salvatore; Toledano, Manuel; Aguilera, Fatima Sánchez; Mannocci, Francesco; Pashley, David H.; Tay, Franklin R.; Watson, Timothy F.; Osorio, Raquel

2013-01-01

Objective To compare resin–dentin bond strengths and the micropermeability of hydrophobic vs. hydrophilic resins bonded to acid-etched or EDTA-treated dentin, using the ethanol wet-bonding technique. Methods Flat dentin surfaces from extracted human third molars were conditioned before bonding with: 37% H3PO4 (15 s) or 0.1 M EDTA (60 s). Five experimental resin blends of different hydrophilicities and one commercial adhesive (SBMP: Scotchbond Multi-Purpose) were applied to ethanol wet-dentin (1 min) and light-cured (20 s). The solvated resins were used as primers (50% ethanol/50% comonomers) and their respective neat resins were used as the adhesive. The resin-bonded teeth were stored in distilled water (24 h) and sectioned in beams for microtensile bond strength testing. Modes of failure were examined by stereoscopic light microscopy and SEM. Confocal tandem scanning microscopy (TSM) interfacial characterization and micropermeability were also performed after filling the pulp chamber with 1 wt% aqueous rhodamine-B. Results The most hydrophobic resin 1 gave the lowest bond strength values to acid-etched dentin and all beams failed prematurely when the resin was applied to EDTA-treated dentin. Resins 2 and 3 gave intermediate bond strengths to both conditioned substrates. Resin 4, an acidic hydrophilic resin, gave the highest bond strengths to both EDTA-treated and acid-etched dentin. Resin 5 was the only hydrophilic resin showing poor resin infiltration when applied on acid-etched dentin. Significance The ethanol wet-bonding technique may improve the infiltration of most of the adhesives used in this study into dentin, especially when applied to EDTA-treated dentin. The chemical composition of the resin blends was a determining factor influencing the ability of adhesives to bond to EDTA-treated or 37% H3PO4 acid-etched dentin, when using the ethanol wet-bonding technique in a clinically relevant time period. PMID:20074787

Effect of hydrostatic pressure on regional bond strengths of compomers to dentine.

PubMed

Zheng, L; Pereira, P N; Somphone, P; Nikaido, T; Tagami, J

2000-09-01

The aim of this study was to evaluate the effect of hydrostatic pressure on the regional bond strengths of compomers to dentine. Thirty freshly extracted molars were ground flat to expose the dentine and randomly divided into two groups for bonding: no hydrostatic pressure and hydrostatic pressure of 15cm H(2)O. Xeno CF, Dyract AP and F 2000 were applied to dentine surfaces pretreated by the respective bonding systems following the manufactures' instructions, and then restored with Clearfil AP-X. After 24h storage in water, the teeth were sectioned into 0.7-mm thick slabs and visually divided into three regional subgroups: the region communicating with the pulp through dentinal tubules (pulp horn); the region between the pulp horns (center); and the region between the pulp horn and DEJ (periphery). The specimens were trimmed to a cross-sectional area of 1mm(2) and subjected to the micro-tensile bond test. The data were analyzed by one- and three-way ANOVA, and Fisher's PLSD (p<0.05). There were no significant regional differences of bond strengths for all the compomers tested (p>0.05). However, hydrostatic pressure significantly decreased the bond strength of F 2000 to all regions (p<0.05), while the bond strength of Dyract AP significantly decreased only at the pulp horn region (p<0.05). On the other hand, the bond strengths of Xeno CF seemed not to be affected by hydrostatic pressure (p>0.05). For Dyract AP and F 2000, the fracture modes were affected by hydrostatic pressure, while, for Xeno CF, there were no significant differences between the fracture modes with non- or positive hydrostatic pressure. Simulated pulpal pressure of 15cm H(2)O had a greater influence on the bond strengths of compomers to dentine than did dentine regions. Therefore, when measuring the bond strengths of compomers to dentine under the simulated in vivo conditions, the wetness of the dentine surface, as well as the intrinsic properties of each material should be seriously considered.

Enamel and dentin bond strengths of a new self-etch adhesive system.

PubMed

Walter, Ricardo; Swift, Edward J; Boushell, Lee W; Braswell, Krista

2011-12-01

statement of problem:  Self-etch adhesives typically are mildly acidic and therefore less effective than etch-and-rinse adhesives for bonding to enamel.   The purpose of this study was to evaluate the enamel and dentin shear bond strengths of a new two-step self-etch adhesive system, OptiBond XTR (Kerr Corporation, Orange, CA, USA).   The labial surfaces of 80 bovine teeth were ground to create flat, 600-grit enamel or dentin surfaces. Composite was bonded to enamel or dentin using the new two-step self-etch system or a three-step etch-and-rinse (OptiBond FL, Kerr), two-step self-etch (Clearfil SE Bond, Kuraray America, Houston, TX, USA), or one-step self-etch adhesive (Xeno IV, Dentsply Caulk, Milford, DE, USA). Following storage in water for 24 hours, shear bond strengths were determined using a universal testing machine. The enamel and dentin data sets were subjected to separate analysis of variance and Tukey's tests. Scanning electron microscopy was used to evaluate the effects of each system on enamel.   Mean shear bond strengths to enamel ranged from 18.1 MPa for Xeno IV to 41.0 MPa for OptiBond FL. On dentin, the means ranged from 33.3 MPa for OptiBond FL to 47.1 MPa for Clearfil SE Bond. OptiBond XTR performed as well as Clearfil SE Bond on dentin and as well as OptiBond FL on enamel. Field emission scanning electron microscope revealed that OptiBond XTR produced an enamel etch pattern that was less defined than that of OptiBond FL (37.5% phosphoric acid) but more defined than that of Clearfil SE Bond or Xeno IV.   The new two-step self-etch adhesive system formed excellent bonds to enamel and dentin in vitro. OptiBond XTR, a new two-step self-etch adhesive system, is a promising material for bonding to enamel as well as to dentin. © 2011 Wiley Periodicals, Inc.

Release of ICTP and CTX telopeptides from demineralized dentin matrices: Effect of time, mass and surface area.

PubMed

Turco, Gianluca; Cadenaro, Milena; Maravić, Tatjana; Frassetto, Andrea; Marsich, Eleonora; Mazzoni, Annalisa; Di Lenarda, Roberto; Tay, Franklin R; Pashley, David H; Breschi, Lorenzo

2018-03-01

The present study evaluated the influence of time, mass and surface area of demineralized dentin collagen matrices on telopeptides release. The hypotheses tested were that the rates of ICTP and CTX release by matrix bound endogenous proteases are 1) not time-dependent, 2) unrelated to specimen mass, 3) unrelated to specimen surface area. Non-carious human molars (N=24) were collected and randomly assigned to three groups. Dentin slabs with three different thicknesses: 0.37mm, 0.75mm, and 1.50mm were completely demineralized and stored in artificial saliva for one week. Collagen degradation was evaluated by sampling storage media for ICTP and CTX telopeptidases. Activity of MMPs in the aging medium was evaluated using fluorometric activity assay kit. A statistically significant (p<0.05) decrease in the release of both ICTP and CTX fragments over time was observed irrespective of the specimen thickness. When data were normalized by the specimen mass, no significant differences were observed. Releases of ICTP and CTX were significantly related to the aging time as a function of surface area for the first 12h. Total MMP activity, mainly related to MMP-2 and -9, decreased with time (p<0.05). Because the release of collagen fragments was influenced by specimen storage time and surface area, it is likely that cleaved collagen fragments closer to the specimen surface diffuse into the incubation medium; those further away from the exposed surface are still entrapped within the demineralized dentin matrix. Bound MMPs can only degrade the substrate within the limited zone of their molecular mobility. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Adipose tissue-deprived stem cells acquire cementoblast features treated with dental follicle cell conditioned medium containing dentin non-collagenous proteins in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wen, Xiujie; Nie, Xin; Zhang, Li

Highlights: {yields} In this study we examine the effects of dental follicle cell conditioned medium (DFCCM) containing dentin non-collagenous proteins (dNCPs) on differentiation of ADSCs. {yields} We examined that ADSCs treated with dNCPs/DFCCM underwent morphological changes and significantly lost their proliferative capacity. {yields} dNCPs/DFCCM enhanced the mineralization behaviour and mineralization-related marker expression of ADSCs. {yields} ADSCs acquired cementoblast features in vitro with dNCPs/DFCCM treatment. -- Abstract: Adipose tissue-derived stem cells (ADSCs), which are easily harvested and show excellent pluripotency potential, have generated considerable interest in regenerative medicine. In this study, the differentiation of ADSCs was assessed after treatment with dentalmore » follicle cell conditioned medium (DFCCM) containing dentin non-collagenous proteins (dNCPs). ADSCs exhibited a fibroblast-like morphology and high proliferative capacity. However, after treatment with dNCPs/DFCCM, ADSCs changed from a fibroblast-like to cementoblast-like morphology and significantly lost their proliferative capacity. Alkaline phosphatase activity and in vitro mineralization behaviour of ADSCs were significantly enhanced. Mineralization-related markers including cementum attachment protein, bone sialoprotein, osteocalcin, osteopontin and osteonectin were detected at mRNA or protein levels, whereas dentin sialophosphoprotein and dentin sialoprotein were not detected, implying a cementoblast-like phenotype. These results demonstrate that ADSCs acquired cementoblast features in vitro with dNCPs/DFCCM treatment and could be a potential source of cementogenic cells for periodontal regeneration.« less

Effect of Photo-Fenton Bleaching on Tetracycline-stained Dentin in vitro.

PubMed

Bennett, Zackary Yale; Walsh, Laurence James

2015-02-01

Tetracycline-stained tooth structure is difficult to bleach using nightguard tray methods. The possible benefits of in-office light-accelerated bleaching systems based on the photo-Fenton reaction are of interest as possible adjunctive treatments. This study was a proof of concept for possible benefits of this approach, using dentine slabs from human tooth roots stained in a reproducible manner with the tetracycline antibiotic demeclocycline hydrochloride. Color changes overtime in tetra-cycline stained roots from single rooted teeth treated using gel (Zoom! WhiteSpeed(®)) alone, blue LED light alone, or gel plus light in combination were tracked using standardized digital photography. Controls received no treatment. Changes in color channel data were tracked overtime, for each treatment group (N = 20 per group). Dentin was lighter after bleaching, with significant improvements in the dentin color for the blue channel (yellow shade) followed by the green channel and luminosity. The greatest changes occurred with gel activated by light (p < 0.0001), which was superior to effects seen with gel alone. Use of the light alone did not significantly alter shade. This proof of concept study demonstrates that bleaching using the photo-Fenton chemistry is capable of lightening tetracycline-stained dentine. Further investigation of the use of this method for treating tetracycline-stained teeth in clinical settings appears warranted. Because tetracycline staining may respond to bleaching treatments based on the photo-Fenton reaction, systems, such as Zoom! WhiteSpeed, may have benefits as adjuncts to home bleaching for patients with tetracycline-staining.

Adhesive sealing of dentin surfaces in vitro: A review

PubMed Central

Abu-Nawareg, Manar M; Zidan, Ahmed Z; Zhou, Jianfeng; Agee, Kelli; Chiba, Ayaka; Tagami, Jungi; Pashley, David H

2016-01-01

Purpose The purpose of this review is to describe the evolution of the use of dental adhesives to form a tight seal of freshly prepared dentin to protect the pulp from bacterial products, during the time between crown preparation and final cementum of full crowns. The evolution of these “immediate dentin sealants” follows the evolution of dental adhesives, in general. That is, they began with multiple-step, etch-and-rinse adhesives, and then switched to the use of simplified adhesives. Methods Literature was reviewed for evidence that bacteria or bacterial products diffusing across dentin can irritate pulpal tissues before and after smear layer removal. Smear layers can be solubilized by plaque organisms within 7–10 days if they are directly exposed to oral fluids. It is likely that smear layers covered by temporary restorations may last more than one month. As long as smear layers remain in place, they can partially seal dentin. Thus, many in vitro studies evaluating the sealing ability of adhesive resins use smear layer-covered dentin as a reference condition. Surprisingly, many adhesives do not seal dentin as well as do smear layers. Results Both in vitro and in vivo studies show that resin-covered dentin allows dentinal fluid to cross polymerized resins. The use of simplified single bottle adhesives to seal dentin was a step backwards. Currently, most authorities use either 3-step adhesives such as Scotchbond Multi-Purposea or OptiBond FLb or two-step self-etching primer adhesives, such as Clearfil SEc, Unifil Bondd or AdheSEe, respectfully. PMID:26846037

Fabrication and characterization of dendrimer-functionalized nano-hydroxyapatite and its application in dentin tubule occlusion.

PubMed

Lin, Xuandong; Xie, Fangfang; Ma, Xueling; Hao, Yuhong; Qin, Hejia; Long, Jindong

2017-06-01

The occlusion of dentinal tubules is an effective method to alleviate the symptoms of dentin hypersensitivity. In this paper, we successfully modified nano-hydroxyapatite (n-HAP) with carboxyl-terminated polyamidoamine dendrimers by an aqueous-based chemical method and verified by fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM). Then the demineralization dentin discs were randomly divided into 4 groups, corresponding to subsequent brushing experiments: deionized water and kept in artificial saliva (AS), dendrimer-functionalized n-HAP and stored in AS, n-HAP and saved in AS, dendrimer-functionalized n-HAP and stored in deionized water. After 7 days of simulated brushing, dentin discs followed the in vitro characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy and microhardness test. These data suggested that dendrimer-functionalized n-HAP could crosslink with collagen fibers and resulted in effective dentinal tubule occlusion. Moreover, the new material can induce the HAP formation with the help of superficial carboxyl and fill the spaces in dentinal tubules furtherly. The microhardness of dendrimer-functionalized n-HAP-treated specimens was significantly higher than others. In summary, dendrimer-functionalized n-HAP can be a new therapeutic material for the treatment of dentin hypersensitivity.

The influence of temporary cements on dental adhesive systems for luting cementation.

PubMed

Ribeiro, José C V; Coelho, Paulo G; Janal, Malvin N; Silva, Nelson R F A; Monteiro, André J; Fernandes, Carlos A O

2011-03-01

This study tested the hypothesis that bond strength of total- and self-etching adhesive systems to dentine is not affected by the presence of remnants from either eugenol-containing (EC) or eugenol-free (EF) temporary cements after standardized cleaning procedures. Thirty non-carious human third molars were polished flat to expose dentine surfaces. Provisional acrylic plates were fabricated and cemented either with EC, EF or no temporary cements. All specimens were incubated for 7 days in water at 37°C. The restorations were then taken out and the remnants of temporary cements were mechanically removed with a dental instrument. The dentine surfaces were cleaned with pumice and treated with either total-etching (TE) or self-etching (SE) dental adhesive systems. Atomic force microscopy was used to examine the presence of remnants of temporary cements before and after dentine cleaning procedures. Composite resin build-ups were fabricated and cemented to the bonded dentine surfaces with a resin luting cement. The specimens were then sectioned to obtain 0.9mm(2) beams for microtensile bond strength testing. Fractographic analysis was performed by optical and scanning electron microscopy. ANOVA showed lower mean microtensile bond strength in groups of specimens treated with EC temporary cement than in groups treated with either no cement or an EF cement (p<0.05). Mean microtensile bond strength was lower in groups employing the SE rather than the TE adhesive system (p<0.001). SE samples were also more likely to fail during initial processing of the samples. There was no evidence of interaction between cement and adhesive system effects on tensile strength. Fractographic analysis indicated different primary failure modes for SE and TE bonding systems, at the dentine-adhesive interface and at the resin cement-resin composite interface, respectively. The use of eugenol-containing temporary cements prior to indirect bonding restorations reduce, to a statistically similar extent, the bond strength of both total- and self-etching adhesive systems to dentine. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mechanical loading influences the viscoelastic performance of the resin-carious dentin complex.

PubMed

Toledano, Manuel; Osorio, Raquel; López-López, Modesto T; Aguilera, Fátima S; García-Godoy, Franklin; Toledano-Osorio, Manuel; Osorio, Estrella

2017-04-04

The aim of this study was to evaluate the changes in the mechanical behavior and bonding capability of Zn-doped resin-infiltrated caries-affected dentin interfaces. Dentin surfaces were treated with 37% phosphoric acid (PA) followed by application of a dentin adhesive, single bond (SB) (PA+SB) or by 0.5 M ethylenediaminetetraacetic acid (EDTA) followed by SB (EDTA+SB). ZnO microparticles of 10 wt. % or 2 wt. % ZnCl 2 was added into SB, resulting in the following groups: PA+SB, PA+SB-ZnO, PA+SB-ZnCl 2 , EDTA+SB, EDTA+SB-ZnO, EDTA+SB-ZnCl 2 . Bonded interfaces were stored for 24 h, and tested or submitted to mechanical loading. Microtensile bond strength was assessed. Debonded surfaces were evaluated by scanning electron microscopy and elemental analysis. The hybrid layer, bottom of the hybrid layer, and peritubular and intertubular dentin were evaluated using a nanoindenter. The load/displacement responses were used for the nanodynamic mechanical analysis III to estimate complex modulus, tan delta, loss modulus, and storage modulus. The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. Atomic force microscopy imaging was performed. Load cycling decreased the tan delta at the PA+SB-ZnCl 2 and EDTA+SB-ZnO interfaces. Tan delta was also diminished at peritubular dentin when PA+SB-ZnO was used, hindering the dissipation of energy throughout these structures. Tan delta increased at the interface after using EDTA+SB-ZnCl 2 , lowering the energy for recoil or failure. After load cycling, loss moduli at the interface decreased when using ZnCl 2 as doping agent, increasing the risk of fracture; but when using ZnO, loss moduli was dissimilarly affected if dentin was EDTA-treated. The border between intertubular and peritubular dentin attained the highest discrepancy in values of viscoelastic properties, meaning a risk for cracking and breakdown of the resin-dentin interface. PA used on dentin provoked differences in complex and storage modulus values at the intertubular and peritubular structures, and these differences were higher than when EDTA was employed. In these cases, the long-term performance of the restorative interface will be impaired.

Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives

PubMed Central

Piemjai, Morakot; Nakabayashi, Nobuo

2015-01-01

A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred. PMID:26539520

Highly concentrated EDTA gel improves cleaning efficiency of root canal preparation in vitro.

PubMed

Putzer, P; Hoy, L; Günay, H

2008-12-01

Debris and smear layer, as a product of mechanical root canal instrumentation, reduce the effectiveness of pharmacological substances to prevent post-treatment diseases and impair direct contact of filling materials with a clean dentinal surface. The aim of this in vitro study was to investigate the presence and localization of debris and smear layer via scanning electron microscope analysis after standardized root canal preparation with different chelating agents. Dentin surfaces received treatment with: (1) 15% ethylenediaminetetraacetic acid (EDTA), (2) 18.6% EDTA (3) and 24% EDTA or without any demineralizing chemicals as control. Forty vertically split human premolars were sputtered and divided into coronal, middle, and apical sections, followed by a randomized, blinded score evaluation using five scores. Pairwise comparisons of all treatment groups against a control group have been performed by Mann-Whitney U test and the Kruskal-Wallis test. Debris grades showed no significant difference between the three regions of the root canals, except for 18.6% EDTA in the central third. Smear layer and smear plug removal was concentration-dependent. Removal of the smear layer in the three areas showed that there was a statistically significant difference between all parts when using 18.6% and 24% EDTA concentrations compared with the control. The best smear layer removal in the apical region was observed using a 24% EDTA gel as chelating agent and lubricant. The usage of EDTA gel >/=18.6% presented a better cleaning regime when compared to the control group.

Thermal effects associated with the Nd/YAG dental laser.

PubMed

von Fraunhofer, J A; Allen, D J

1993-01-01

The heat produced at the dentinal pulpal wall opposite the irradiation site was measured during etching of dental enamel with an Nd:YAG laser in preparation for direct bonding of orthodontic appliances. Forty extracted human teeth were randomly divided into four groups of 10 teeth. Within each group, the buccal surfaces of 5 teeth and the lingual surfaces of the other 5 teeth were laser treated for 12 sec. Irradiation was performed with a commercial Nd:YAG laser at the power settings of 80mJ, 1W, 2W and 3W. Prior to irradiation, an occlusal access preparation was made into the pulp in order to facilitate the placement of a thermocouple for measurement of temperature changes at the dentinal pulpal wall opposite the irradiation site. The thermocouple was held against the dentinal pulpal wall and the resulting temperature changes were recorded. Heating effects at the dentinal pulpal wall on both buccal and lingual surfaces showed an increase in heat as a function of the increase in power output from the laser unit (p < 0.01). The temperatures measured at power levels 1-3W appeared to be of sufficient magnitude to cause at least localized pulpal inflammation and possible irreversible damage to the pulp tissue immediately opposite the site of laser irradiation.

Improving the efficiency of an Er:YAG laser on enamel and dentin.

PubMed

Rizcalla, Nicolas; Bader, Carl; Bortolotto, Tissiana; Krejci, Ivo

2012-02-01

To evaluate the influence of air pressure, water flow rate, and pulse frequency on the removal speed of enamel and dentin as well as on their surface morphology. Twenty-four bovine incisors were horizontally cut in slices. Each sample was mounted on an experimental assembly, allowing precise orientation. Eighteen cavities were prepared, nine in enamel and nine in dentin. Specific parameters for frequency, water flow rate, and air pressure were applied for each experimental group. Three groups were randomly formed according to the air pressure settings. Cavity depth was measured using a digital micrometer gauge, and surface morphology was checked by means of scanning electron microscopy. Data was analyzed with ANOVA and Duncan post hoc test. Irradiation at 25 Hz for enamel and 30 Hz for dentin provided the best ablation rates within this study, but efficiency decreased if the frequency was raised further. Greater tissue ablation was found with water flow rate set to low and dropped with higher values. Air pressure was found to have an interaction with the other settings, since ablation rates varied with different air pressure values. Fine-tuning of all parameters to get a good ablation rate with minimum surface damage seems to be key in achieving optimal efficiency for cavity preparation with an Er:YAG laser.

Shear bond strength of bulk-fill and nano-restorative materials to dentin.

PubMed

Colak, Hakan; Ercan, Ertugrul; Hamidi, Mehmet Mustafa

2016-01-01

Bulk-fill composite materials are being developed for preparation depths of up to 4 mm in an effort to simplify and improve the placement of direct composite posterior restorations. The aim of our study was to compare shear-bond strength of bulk-fill and conventional posterior composite resins. In this study, 60 caries free extracted human molars were used and sectioned parallel to occlusal surface to expose midcoronal dentin. The specimens were randomly divided into four groups. Total-etch dentine bonding system (Adper Scotchbond 1XT, 3M ESPE) was applied to dentin surface in all the groups to reduce variability in results. Then, dentine surfaces covered by following materials. Group I: SonicFill Bulk-Fill, Group II: Tetric EvoCeram (TBF), Group III: Herculite XRV Ultra, and Group IV: TBF Bulk-Fill, 2 mm × 3 mm cylindrical restorations were prepared by using application apparatus. Shear bond testing was measured by using a universal testing machine. Kruskal-Wallis and Mann-Whitney U-tests were performed to evaluate the data. The highest value was observed in Group III (14.42 ± 4.34) and the lowest value was observed in Group IV (11.16 ± 2.76) and there is a statistically significant difference between these groups (P = 0.046). However, there is no statistically significant difference between the values of other groups. In this study, Group III was showed higher strength values. There is a need for future studies about long-term bond strength and clinical success of these adhesive and bulk-fill systems.

Enzyme-catalyzed hydrolysis of dentin adhesives containing a new urethane-based trimethacrylate monomer

PubMed Central

Park, Jong-Gu; Ye, Qiang; Topp, Elizabeth M.; Spencer, Paulette

2009-01-01

A new trimethacrylate monomer with urethane-linked groups, 1,1,1-tri-[4-(methacryloxyethylamino-carbonyloxy)-phenyl]ethane (MPE), was synthesized, characterized, and used as a co-monomer in dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA, 45% w/w) and 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane (BisGMA, 30% w/w) in addition to MPE (25% w/w) were formulated with H2O at 0 (MPE0), 8 (MPE8) and 16 wt % water (MPE16) to simulate the wet demineralized dentin matrix and compared with controls [HEMA/BisGMA, 45/55 w/w, at 0 (C0), 8 (C8) and 16 wt% water (C16)]. The new adhesive showed a degree of double bond conversion and mechanical properties comparable with control, with good penetration into the dentin surface and a uniform adhesive/dentin interface. On exposure to porcine liver esterase, the net cumulative methacrylic acid (MAA) release from the new adhesives was dramatically (P < 0.05) decreased relative to the control, suggesting that the new monomer improves esterase resistance. PMID:19582843

Construction and in vitro test of a new electrode for dentin resistance measurement.

PubMed

Stein, Steffen; Gente, Michael

2013-10-01

It is necessary to reduce the tooth substance before treating a tooth with a dental crown. The preparation often requires reduction of the dentin. This results in a dentin wound and a thinner substance over the pulp, increases the risk of inflammation, and could result in necrosis of the pulp. To give the dentist information about the amount of dentin over the pulp during preparation, the Prepometer was developed. The function of this device is based on the measurement of the electric resistance of the tooth substance. The measuring behavior of the first-generation Prepometer is characterized by smaller values of electric resistance before reaching full contact of the measuring head to the dentin surface and the actual value RT. This measuring behavior can mislead inexperienced therapists with inaccurate values that suggest thinner dentin than the reality. In this study, a new electrode based on the technology of active guard drive was constructed to overcome this issue. The results show that improvement in the measuring behavior of the new electrode could be achieved, eliminating the earlier disadvantage of the Prepometer.

Effects of attrition, prior acid-etching, and cyclic loading on the bond strength of a self-etching adhesive system to dentin.

PubMed

Shinkai, Koichi; Ebihara, Takashi; Shirono, Manabu; Seki, Hideaki; Wakaki, Suguru; Suzuki, Masaya; Suzuki, Shiro; Katoh, Yoshiroh

2009-03-01

The purpose of this study was to evaluate the effects of dentin attrition, phosphoric acid etching, and cyclic loading on the microtensile bond strength (microTBS) of a self-etching adhesive system to dentin. Flat dentin surfaces of human molars were assigned to eight experimental groups based on those with or without attrition, prior acid-etching, and cyclic loading. Resin composite paste was placed and polymerized after the bonding procedure according to manufacturer's instructions. The specimens were subjected to microTBS testing at a crosshead speed of 0.5 mm/min. Results showed that the minimum mean value of microTBS was 14.9 MPa in the group without attrition and acid-etching but with loading, while the maximum mean value of microTBS was 40.0 MPa in the group without attrition and loading but with acid etching. Therefore, the value of microTBS to dentin without attrition was significantly decreased by cyclic loading but that to dentin with attrition was not affected.

Microtensile bond strength of indirect resin composite to resin-coated dentin: interaction between diamond bur roughness and coating material.

PubMed

Kameyama, Atsushi; Oishi, Takumi; Sugawara, Toyotarou; Hirai, Yoshito

2009-02-01

This aim of this study was to determine the effect of type of bur and resin-coating material on microtensile bond strength (microTBS) of indirect composite to dentin. Dentin surfaces were first ground with two types of diamond bur and resin-coated using UniFil Bond (UB) or Adper Single Bond (SB), and then bonded to a resin composite disc for indirect restoration with adhesive resin cement. After storage for 24 hr in distilled water at 37 degrees C, microTBS was measured (crosshead speed 1 mm/min). When UB was applied to dentin prepared using the regular-grit diamond bur, microTBS was significantly lower than that in dentin prepared using the superfine-grit bur. In contrast, no significant difference was found between regular-grit and superfine-grit bur with SB. However, more than half of the superfine-grit specimens failed before microTBS testing. These results indicate that selection of bur type is important in improving the bond strength of adhesive resin cement between indirect resin composite and resin-coated dentin.

Effects of various final irrigants on the shear bond strength of resin-based sealer to dentin

PubMed Central

Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu; Arathi, Ganesh; Roohi, Riaz; Anand, Suresh

2011-01-01

Aim: This study has been designed to evaluate the effect of strong (MTAD) or soft (1- hydroxyethylidene – 1, 1-bisphosphonate (HEBP) final irrigating solution on the shear bond strength of AH plus sealer to coronal dentin. 17% EDTA was used as the reference. Materials and Methods: Forty freshly extracted human maxillary first premolars were prepared using different irrigation protocols (n=10). All the test groups had 1.3% NaOCl as initial rinse and followed by specific final rinse for each group: G1 – distilled water(control), G2 – 17% EDTA, G3- 18% HEBP and G4 – MTAD. Sections of polyethylene tubes that are 3mm long were filled with freshly mixed sealer and placed on the dentin surfaces. The bonding between the sealer and dentine surface was evaluated using shear bond testing. The values were statistically evaluated using one-way ANOVA followed by Tukey's test. Result: Significant difference was found among the irrigating regimes. EDTA showed highest bond strength followed by HEBP and MTAD PMID:21691504

Pulp-dentin biology in restorative dentistry. Part 1: normal structure and physiology.

PubMed

Mjör, I A; Sveen, O B; Heyeraas, K J

2001-06-01

Considerable knowledge has accumulated over the years on the structure and function of the dental pulp and dentin. Some of this knowledge has important clinical implications. This review, which is the first of seven articles, will be limited to those parts of the normal structure and physiology of the pulp and dentin that have been shown to result in, or are likely lead to, tissue reactions associated with the clinical treatment of these tissues. Although certain normal structures will be highlighted in some detail, a basic knowledge of pulpal and dentinal development and structure is a prerequisite for an understanding of this text.

Developing a tooth restorability index.

PubMed

McDonald, Ailbhe; Setchell, Derrick

2005-01-01

It is generally agreed that the inherent strength of a tooth is dependent on the remaining dentine. It therefore seems logical that preservation of coronal dentine is important to the survival of intra- and extra-coronal restorations. The clinical assessment of the amount of dentine needed for functional requirements and the strategic value of remaining tooth structure is currently based on clinical opinion. This paper discusses what recommendations have been published and proposes an index that may be useful in assessing the restorability of a tooth. An index used to assess the amount and contribution of remaining coronal dentine to resistance and retention form could be of value in treatment planning.

Repair dentinogenesis following transplantation into normal and germ-free animals.

PubMed

Inoue, T; Shimono, M

1992-01-01

The purpose of this study was to investigate the dentinogenesis of dental pulp tissue following transplantation and during regeneration in normal and germ free animals, as well as in vitro experiments. (1) Partial and complete exposure of dental pulp in germ free rats by removing the enamel and dentin of molars. (2) The central portion of rat incisor which consisted of pulp and pulp chamber were autografted into various tissues. (3) Explants of rat pulp tissue were cultured on dentin matrix. (4) Resin bonding agent, 4-META/MMA-TBB-O (Superbond), was placed directly on surgically-exposed dental pulp. (1) Dentin bridge formation was recognized at 5 days after operation in germ free rat. (2) The cut surface of the transplant exhibited dentin bridge at 7 days after implantation, and the thickness of the newly formed dentin increased gradually thereafter up to 30 days. (3) Cultured pulp cells had high alkaline phosphatase activity and bone- or dentin-like hard tissue was synthesized on the dentin matrix in vitro. (4) Dentin bridge formation was evident on the surgically-exposed dental pulp even after application of Superbond. From these results, it is suggested that pulp tissue has a high activity of dentinogenesis both in vivo and in vitro and 3 days is enough for pulp cells to express the odontoblast phenotype when inflammatory factors are not present.

Microorganism penetration in dentinal tubules of instrumented and retreated root canal walls. In vitro SEM study.

PubMed

Al-Nazhan, Saad; Al-Sulaiman, Alaa; Al-Rasheed, Fellwa; Alnajjar, Fatimah; Al-Abdulwahab, Bander; Al-Badah, Abdulhakeem

2014-11-01

This in vitro study aimed to investigate the ability of Candida albicans (C. albicans) and Enterococcus faecalis (E. faecalis) to penetrate dentinal tubules of instrumented and retreated root canal surface of split human teeth. Sixty intact extracted human single-rooted teeth were divided into 4 groups, negative control, positive control without canal instrumentation, instrumented, and retreated. Root canals in the instrumented group were enlarged with endodontic instruments, while root canals in the retreated group were enlarged, filled, and then removed the canal filling materials. The teeth were split longitudinally after canal preparation in 3 groups except the negative control group. The teeth were inoculated with both microorganisms separately and in combination. Teeth specimens were examined by scanning electron microscopy (SEM), and the depth of penetration into the dentinal tubules was assessed using the SMILE view software (JEOL Ltd). Penetration of C. albicans and E. faecalis into the dentinal tubules was observed in all 3 groups, although penetration was partially restricted by dentin debris of tubules in the instrumented group and remnants of canal filling materials in the retreated group. In all 3 groups, E. faecalis penetrated deeper into the dentinal tubules by way of cell division than C. albicans which built colonies and penetrated by means of hyphae. Microorganisms can easily penetrate dentinal tubules of root canals with different appearance based on the microorganism size and status of dentinal tubules.

Effect of reducing acid etching time on bond strength to noncarious and caries-affected primary and permanent dentin.

PubMed

Scheffel, Débora Lopes Salles; Ricci, Hérica Adad; de Souza Costa, Carlos Alberto; Pashley, David Henry; Hebling, Josimeri

2013-01-01

The purpose was to evaluate the effect of acid etching time on the bond strength of a simplified etch-and-rinse adhesive system to noncarious and caries-affected dentin of primary and permanent teeth. Twenty-four extracted primary and permanent teeth were divided into three groups, according to the acid etching time. Four teeth from each group were exposed to a microbiological caries-inducing protocol. After caries removal, noncarious and caries-affected dentin surfaces were etched with 37 percent phosphoric acid for five, 10, or 15 seconds prior to the application of Prime & Bond NT adhesive. Crowns were restored with resin composite and prepared for microtensile testing. Data were submitted to Kruskal-Wallis and Mann-Whitney tests (α=0.05). Higher bond strengths were obtained for noncarious dentin vs. caries-affected dentin for both primary and permanent teeth. Reducing the acid etching time from 15 to five seconds did not affect the bond strength to caries-affected or noncarious dentin in primary teeth. For permanent teeth, lower bond strength values were observed when the noncarious dentin was etched for five seconds, while no difference was seen between 10 and 15 seconds. For Prime & Bond NT, the etching of dentin for five seconds could be recommended for primary teeth, while 10 seconds would be the minimum time for permanent teeth.

Changes in deciduous and permanent dentinal tubules diameter after several conditioning protocols: In vitro study.

PubMed

de Los Angeles Moyaho-Bernal, María; Contreras-Bulnes, Rosalía; Rodríguez-Vilchis, Laura Emma; Rubio-Rosas, Efraín

2018-05-08

Innovators conditioning protocols are emerged in permanent dentin, however for deciduous dentin the information is limited; the aim of this study was to evaluate in vitro diameter of deciduous and permanent dentinal tubules after several conditioning protocols. Eighty dentin samples were distributed in sixteen groups (n = 5 p/g) and dentin surface was conditioned as follow: G1D/G1P acid etching; G2D/G2P, self-etch adhesive; G3D/G3P, G4D/G4P, Er: YAG laser irradiation at 200 mJ-25.5 J/cm 2 and 300 mJ-38.2 J/cm 2 , at 10 Hz under water spray respectively; G5D/G5P, G6D/G6P, G7D/G7P, and G8D/G8P were irradiated under the same energy densities followed phosphoric acid or self-etch adhesive conditioning. The sample dentin of deciduous and permanent teeth was analyzed with scanning electron microscopy and tubule diameter was evaluated by Image Tools Scandium program. Data were subjected to one-way analysis ANOVA to compare among groups with a level of significance at p ≤ .05. For deciduous dentin, diameters were from 1.52 ± 0.32 µm in G3D to 3.88 ± 0.37 µm in G1D; narrowest and widest diameter, respectively (p < .000). While permanent dentin tubules exhibited diameters from 1.16 ± 0.16/1.19 ± 0.12 µm in G7P/G8P to 2.76 ± 0.28 µm in G6P; narrowest and widest diameter, respectively (p < .000). All dentin conditioning protocols produced more open dentin tubules (diameter size) in deciduous dentin than permanent, specific conditioning protocols are required for each tissue (deciduous or permanent dentin), since same protocol produced stronger effects on primary dentin, which is important for dental clinical success in children and adolescents. © 2018 Wiley Periodicals, Inc.

Effect of dentin powder on the antimicrobial properties of hyperpure chlorine-dioxide and its comparison to conventional endodontic disinfecting agents.

PubMed

Herczegh, Anna; Gyurkovics, Milán; Ghidan, Ágoston; Megyesi, Marianna; Lohinai, Zsolt

2014-06-01

Previously we found that the high purity chlorine-dioxide(ClO2) has a very potent disinfectant efficacy on oral pathogenic microorganisms and as a root canal irrigant it is able to eliminate the experimental Enterococcus faecalis(E. faecalis) infection from the root canal system. This study examines whether the presence of dentin powder influences the antibacterial efficacy of ClO 2. In an in vitro dentin powder model the following irrigants were tested against planktonic E. faecalis: 2% chlorhexidine (CHX), 2.5% sodium hypochlorite (NaOCl), 0.12%ClO2 (Solumium) and one local root canal medicament: saturated Ca(OH)2. Survival of bacteria exposed to agents without and with human dentin powder or preincubated with dentin powder was investigated. The effect of the dentin powder on ClO2 concentration was investigated by titrations. Without dentin powder ClO 2 killed all E. faecalis and delivered the best result already after 1 minute; however, after longer contact time with dentin the difference between the disinfectants disappeared. The presence of dentin powder decreased the concentration of ClO 2 and attenuated the antibacterial efficiency of ClO2 and Ca(OH)2, but did not decrease of CHX and NaOCl.Preincubation with dentin powder caused significant loss of antibacterial activity of all investigated agents, ClO2 and Ca(OH)2 having the highest reduction. As the presence of dentin powder had a negative effect on the efficacy of disinfectants, the importance of elimination of dentin scrapings and smear layer from the root canal system during endodontic treatments is highly recommended. ClO 2 can be effective for a final rinse.

Impact of combined CO2 laser irradiation and fluoride on enamel and dentin biofilm-induced mineral loss.

PubMed

Esteves-Oliveira, Marcella; El-Sayed, Karim Fawzy; Dörfer, Christof; Schwendicke, Falk

2017-05-01

The caries-protective effects of CO 2 laser irradiation on dental enamel have been demonstrated using chemical demineralization models. We compared the effect of CO 2 laser irradiation, sodium fluoride, or both on biofilm-induced mineral loss (∆Z) and Streptococcus mutans adhesion to enamel and dentin in vitro. Ground, polished bovine enamel, and dentin samples were allocated to four groups (n = 12/group): no treatment (C); single 22,600-ppm fluoride (F) varnish (5 % NaF) application; single CO 2 laser treatment (L) with short pulses (5 μs/λ = 10.6 μm); and laser and subsequent fluoride treatment (LF). Samples were sterilized and submitted to an automated mono-species S. mutans biofilm model. Brain heart infusion plus 5 % sucrose medium was provided eight times daily, followed by rinses with artificial saliva. After 10 days, bacterial numbers in biofilms were enumerated as colony-forming units/ml (CFU/ml) (n = 7/group). ∆Z was assessed using transversal microradiography (n = 12/group). Univariate ANOVA with post hoc Tukey honestly-significant-difference test was used for statistical analysis. Bacterial numbers were significantly higher on dentin than enamel (p < 0.01/ANOVA). On dentin, LF yielded significantly lower CFUs than other groups (p = 0.03/Tukey), while no differences between groups were found for enamel. The lowest ∆Z in enamel was observed for L (mean/SD 2036/1353 vol%×μm), which was not only significantly lower than C (9642/2452 vol%×μm) and F (7713/1489 vol%×μm) (p < 0.05) but also not significantly different from LF (3135/2628 vol%×μm) (p > 0.05). In dentin, only LF (163/227) significantly reduced ∆Z (p < 0.05). CO 2 laser irradiation did not increase adhesion of S. mutans in vitro. Laser treatment alone protected enamel against biofilm-induced demineralization, while a combined laser-fluoride application was required to protect dentin.

Penetration pattern of rhodamine dyes into enamel and dentin: confocal laser microscopy observation.

PubMed

Kwon, S R; Wertz, P W; Li, Y; Chan, D C N

2012-02-01

Enamel and dentin are susceptible to extrinsic and intrinsic stains. The purposes of this study were to determine the penetration pattern of Rhodamine B and dextran-conjugated Rhodamine B into the enamel and dentin as observed by confocal laser microscopy and to relate it to the penetration pattern of hydrogen peroxide commonly used as an active ingredient in tooth-whitening agents and high-molecular-weight staining molecules. Eighteen recently extracted human maxillary anterior teeth were used. Teeth were cleaned and painted with nail varnish except for the crown area above the cemento-enamel junction (CEJ). The painted teeth were then immersed in Rhodamine B and dextran-conjugated Rhodamine B (70 000 MW) for 4, 7, 10 and 15 days. Teeth were sliced to 3 mm thickness in transverse plane and mounted on a glass slide just prior to observation with confocal laser microscopy. Rhodamine B and dextran-conjugated Rhodamine B readily penetrated into the enamel and dentin when exposed for 4 and 7 days, respectively. Rhodamine B penetrated along the interprismatic spaces of the enamel into the dentin. The penetration was accentuated in sections with existing crack lines in the enamel. Rhodamine B was readily absorbed into the dentinal tubules at the dentino-enamel junction and continued to penetrate through the dentin via the dentinal tubules into the pre-dentin. Within the limitations of this study, it is concluded that Rhodamine B and dextran-conjugated Rhodamine B when applied to the external surface of the tooth readily penetrate into the enamel and dentin via the interprismatic spaces in the enamel and dentinal tubules in the dentin, suggesting that stain molecules and bleaching agents possibly exhibit similar penetration pathways. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Nanoindentation hardness of intertubular dentin in sound, demineralized and natural caries-affected dentin.

PubMed

Joves, Gerardo José; Inoue, Go; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

2014-04-01

The purpose of this study was to investigate the mechanical properties of intertubular dentin in sound, natural caries-affected (NCAD) and artificial caries-affected dentin (ACAD) using nanoindentation. Non-caries molars and caries molars with International Caries Detection and Assessment System (ICDAS II) score 5 at the occlusal site were used and caries was excavated using a spoon excavator, a round bur at low speed without water and a dye solution as guidance to detect the infected tissue. Specimens with remaining dentin thickness (RDT) >2mm were selected. ACAD teeth were created from sound teeth over 7 days in a demineralizing solution. Specimens were embedded into plastic rings with acrylic resin and then sagittal mesial-distal sectioned from crown to the long axis of the root under cooling water using a low-speed diamond blade. The surface of interest was fine polished sequentially. Hardness measurement was performed within an axial depth of 1000μm with at least of 320 indentations on each sample. Mann-Whitney U Test was used to compare the hardness as the variable among different dentin types (SOUND, NCAD and ACAD) at each dentin depth level. There was no significant difference in nanohardness between NCAD and ACAD up to a depth of 130μm (p>0.05). NCAD consistently showed lower hardness. ACAD showed no significant difference in hardness with SOUND dentin beyond 190μm (p<0.05). The lesion front in ACAD was considered to be located around the depth of 180μm. Natural and artificial caries-affected dentin tissues were superficially comparable in intertubular nanohardness. There is a certain layer within the natural caries-affected dentin with higher hardness; however the long-term effects of caries beneath the lesion extend deeply through intertubular dentin. Sound dentin at deep areas (close to the pulp chamber) is considered to be soft. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ethanol wet-bonding technique sensitivity assessed by AFM.

PubMed

Osorio, E; Toledano, M; Aguilera, F S; Tay, F R; Osorio, R

2010-11-01

In ethanol wet bonding, water is replaced by ethanol to maintain dehydrated collagen matrices in an extended state to facilitate resin infiltration. Since short ethanol dehydration protocols may be ineffective, this study tested the null hypothesis that there are no differences in ethanol dehydration protocols for maintaining the surface roughness, fibril diameter, and interfibrillar spaces of acid-etched dentin. Polished human dentin surfaces were etched with phosphoric acid and water-rinsed. Tested protocols were: (1) water-rinse (control); (2) 100% ethanol-rinse (1-min); (3) 100% ethanol-rinse (5-min); and (4) progressive ethanol replacement (50-100%). Surface roughness, fibril diameter, and interfibrillar spaces were determined with atomic force microscopy and analyzed by one-way analysis of variance and the Student-Newman-Keuls test (α = 0.05). Dentin roughness and fibril diameter significantly decreased when 100% ethanol (1-5 min) was used for rinsing (p < 0.001). Absolute ethanol produced collapse and shrinkage of collagen fibrils. Ascending ethanol concentrations did not collapse the matrix and shrank the fibrils less than absolute ethanol-rinses.

Impact of dentifrice abrasivity and remineralization time on erosive tooth wear in vitro.

PubMed

Buedel, Sarah; Lippert, Frank; Zero, Domenick T; Eckert, George J; Hara, Anderson T

2018-02-01

To investigate the in vitro effects of simulated dentifrice slurry abrasivity (L-low, M-medium and H-high) and remineralization time (0, 30, 60 and 120 minutes) on erosive tooth wear. Enamel and root dentin specimens were prepared from bovine incisors (n= 8) and submitted to a cycling protocol including erosion, remineralization at the test times, and brushing with each of the tested slurries, for 5 days. Dental surface loss (SL) was determined by optical profilometry. Data was analyzed using mixed-model ANOVA and Fisher's PLSD tests (alpha= 0.05). SL generally increased along with the increase in slurry abrasive level, with significance dependent upon the specific substrate and remineralization times. H showed the highest SL on both enamel and dentin; remineralization for 30 minutes reduced SL significantly (P< 0.05), but only for enamel. M showed intermediate SL values, with remineralization benefit clearly seen only after 120 minutes of remineralization (P< 0.05). L caused the least SL for both enamel and dentin, which was further reduced after remineralization for 120 and 30 minutes, respectively (both P< 0.05). Overall, root dentin had significantly higher SL than enamel. Less abrasive dentifrice slurries were able to reduce toothbrushing abrasion on both enamel and root dentin. This protection was enhanced by remineralization for all abrasive levels on enamel, but only for L on root dentin. High-risk erosion patients should avoid highly abrasive toothpastes, as remineralization can only partially compensate for their deleterious effects on eroded dental surfaces. Lower abrasive toothpastes are recommended. Copyright©American Journal of Dentistry.

Antimicrobial effect of chlorhexidine digluconate in dentin: In vitro and in situ study.

PubMed

Borges, Fátima Maria Cavalcante; de Melo, Mary Anne Sampaio; Lima, Juliana Paiva Marques; Zanin, Iriana Carla Junqueria; Rodrigues, Lidiany Karla Azevedo

2012-01-01

The aim of this study was to evaluate a very short-term in vitro and in situ effect of 2% chlorhexidine-digluconate-based (CHX) cavity cleanser on the disinfection of dentin demineralized by cariogenic bacteria. Human dentin slabs were randomly allocated and used in 2 distinct phases, in vitro and in situ, for obtaining demineralized dentin. In vitro, the slabs (n=15) were immersed for 5 days in BHI broth inoculated with Streptococcus mutans CTT 3440. In situ, a double-blind design was conducted in one phase of 14 days, during which 20 volunteers wore palatal devices containing two human dental dentin slabs. On 5(th) day in vitro and 14(th) day in situ, the slabs were allocated to the two groups: Control group (5 μl of 0.9% NaCl solution) and CHX group (5 μl of 2% chlorhexidine digluconate solution, Cavity Cleanser™ BISCO, Schaumburg, IL, EUA), for 5 minutes. The microbiological analyses were performed immediately before and after the treatments. The log reductions means found for CHX treatment on tested micro organisms were higher when compared to Control group either in vitro or in situ conditions. Our results showed that CHX was effective in reducing the cultivable microbiota in contaminated dentin. Furthermore, although the use of chlorhexidine-digluconate-based cavity disinfectant did not completely eliminate the viable microorganisms, it served as a suitable agent to disinfect tooth preparations.

Residual antibiofilm effects of various concentrations of double antibiotic paste used during regenerative endodontics after different application times.

PubMed

Jenks, Daniel B; Ehrlich, Ygal; Spolnik, Kenneth; Gregory, Richard L; Yassen, Ghaeth H

2016-10-01

We investigated the residual antibiofilm effects of different concentrations of double antibiotic paste (DAP) applied on radicular dentin for 1 or 4 weeks. Dentin samples were prepared (n=120), sterilized and pretreated for 1 or 4 weeks with the clinically used concentration of DAP (500mg/mL), low concentrations of DAP (1, 5 or 50mg/mL) loaded into a methylcellulose system, calcium hydroxide (Ca(OH) 2 ), or placebo paste. After the assigned treatment time, treatment pastes were rinsed off and the samples were kept independently in phosphate buffered saline for 3 weeks. Pretreated dentin samples were then inoculated with Enterococcus faecalis and bacterial biofilms were allowed to grow for an additional 3 weeks. Biofilms were then retrieved from dentin using biofilm disruption assays, diluted, spiral plated, and quantified. Fisher's Exact and Wilcoxon rank sum tests were used for statistical comparisons (α=0.05). Dentin pretreatment for 4 weeks with 5, 50 or 500mg/mL of DAP demonstrated significantly higher residual antibiofilm effects and complete eradication of E. faecalis biofilms in comparison to a 1 week pretreatment with similar concentrations. However, dentin pretreated with 1mg/mL of DAP or Ca(OH) 2 did not provide a substantial residual antibiofilm effect regardless of the application time. Dentin pretreatment with 5mg/mL of DAP or higher for 4 weeks induced significantly higher residual antibiofilm effects in comparison to a 1 week pretreatment with the same concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling micromechanical measurements of depth-varying properties with scanning acoustic microscopy

NASA Astrophysics Data System (ADS)

Marangos, Orestes; Misra, Anil

2018-02-01

Scanning acoustic microscopy (SAM) has been applied to measure the near-surface elastic properties of materials. For many substrates, the near-surface property is not constant but varies with depth. In this paper, we aim to interpret the SAM data from such substrates by modeling the interaction of the focused ultrasonic field with a substrate having a near-surface graded layer. The focused ultrasonic field solutions were represented as spherical harmonic expansions while the substrate solutions were represented as plane wave expansions. The bridging of the two solutions was achieved through the decomposition of the ultrasonic pressure fields in their angular spectra. Parametric studies were performed, which showed that near-surface graded layers exhibit distinctive frequency dependence of their reflectance functions. This behavior is characteristic to the material property gradation profile as well as the extent of the property gradation. The developed model was used to explain the frequency-dependent reflection coefficients measured from an acid-etched dentin substrate. Based on the model calculations, the elastic property variations of the acid-etched dentin near-surface indicate that the topmost part of the etched layer is very soft (3-6 GPa) and transitions to the native dentin through a depth of 27 and 36 microns.

Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope - Part 1

NASA Astrophysics Data System (ADS)

El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; Maghraby, Ahmed; El-Zainy, Medhat

2011-12-01

In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope. For doses up to 0.5 Gy, there was no evidence of the existence of cracks on the enamel surface. With 1 Gy irradiation dose, cracks were clearly observed with localized erosive areas. At 2 Gy irradiation dose, the enamel showed morphological alterations as disturbed prismatic and interprismatic areas. An increase in dentinal tubules diameter and a contemporary inter-tubular dentine volume decrease were observed with higher irradiation dose. Concerning cementum, low doses,<0.5 Gy, showed surface irregularities and with increase in the irradiation dose to≥1 Gy, noticeable surface irregularities and erosive areas with decrease in Sharpey's fiber sites were observed. These observations could shed light on the hazardous effects of irradiation fields to the functioning of the human teeth.

Clinical and radiographic comparison of indirect pulp treatment using light-cured calcium silicate and mineral trioxide aggregate in primary molars: A randomized clinical trial.

PubMed

Menon, Navya P; Varma, Balagopal R; Janardhanan, Sureshkumar; Kumaran, Parvathy; Xavier, Arun Mamachan; Govinda, Bhat Sangeetha

2016-01-01

To clinically and radiographically evaluate the reparative dentin formation in indirect pulp treatment (IPT) using mineral trioxide aggregate (MTA) and light cured calcium silicate (TheraCal) in primary molars over a period of 6 months. A clinical trial on IPT on 43 primary molars in 21 patients between the age of 4-7 years, divided into two groups: 22 teeth in MTA group and 21 in TheraCal group. Measurement of the variation in dentin thickness was done on the digitalized radiograph at baseline, 3 months and 6 months using CorelDRAW X3 software. Statistical analysis using an independent t -test for intragroup and intergroup comparison showed a significant increase in dentin thickness in both the MTA and TheraCal group (intragroup comparison [ P < 0.05]). However, intergroup comparison between MTA and TheraCal showed no statistical difference in reparative dentin formation ( P > 0.05). Clinically and radiographically, both MTA and TheraCal are good IPT materials. The better handling characteristics and comparable reparative dentin-forming ability of TheraCal make this material an alternative to MTA in pediatric restorative procedures.

Dental Pulp Defence and Repair Mechanisms in Dental Caries

PubMed Central

Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J.; Cooper, Paul R.

2015-01-01

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo. PMID:26538821

Dental Pulp Defence and Repair Mechanisms in Dental Caries.

PubMed

Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J; Cooper, Paul R

2015-01-01

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

Penetration of sub-micron particles into dentinal tubules using ultrasonic cavitation.

PubMed

Vyas, N; Sammons, R L; Pikramenou, Z; Palin, W M; Dehghani, H; Walmsley, A D

2017-01-01

Functionalised silica sub-micron particles are being investigated as a method of delivering antimicrobials and remineralisation agents into dentinal tubules. However, their methods of application are not optimised, resulting in shallow penetration and aggregation. The aim of this study is to investigate the impact of cavitation occurring around ultrasonic scalers for enhancing particle penetration into dentinal tubules. Dentine slices were prepared from premolar teeth. Silica sub-micron particles were prepared in water or acetone. Cavitation from an ultrasonic scaler (Satelec P5 Newtron, Acteon, France) was applied to dentine slices immersed inside the sub-micron particle solutions. Samples were imaged with scanning electron microscopy (SEM) to assess tubule occlusion and particle penetration. Qualitative observations of SEM images showed some tubule occlusion. The particles could penetrate inside the tubules up to 60μm when there was no cavitation and up to ∼180μm when there was cavitation. The cavitation bubbles produced from an ultrasonic scaler may be used to deliver sub-micron particles into dentine. This method has the potential to deliver such particles deeper into the dentinal tubules. Cavitation from a clinical ultrasonic scaler may enhance penetration of sub-micron particles into dentinal tubules. This can aid in the development of novel methods for delivering therapeutic clinical materials for hypersensitivity relief and treatment of dentinal caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of application mode on interfacial morphology and chemistry between dentin and self-etch adhesives

PubMed Central

Zhang, Ying; Wang, Yong

2012-01-01

Objective To investigate the influence of application mode on the interfacial morphology and chemistry between dentin and self-etch adhesives with different aggressiveness. Methods The occlusal one-third of the crown was removed from un-erupted human third molars, followed by abrading with 600 grit SiC under water. Rectangular dentin slabs were prepared by sectioning the tooth specimens perpendicular to the abraded surfaces. The obtained dentin slabs were treated with one of the two one-step self-etch adhesives: Adper Easy Bond (AEB, PH~2.5) and Adper Prompt L-Pop (APLP, PH~0.8) with (15s, active application) or without (15s, inactive application) agitation. The dentin slabs were fractured and the exposed adhesive/dentin (A/D) interfaces were examined with micro-Raman spectroscopy and scanning electron microscopy (SEM). Results The interfacial morphology, degree of dentin demineralization (DD) and degree of conversion (DC) of the strong self-etch adhesive APLP showed more significant dependence on the application mode than the mild AEB. APLP exhibited inferior bonding at the A/D interface if applied without agitation, evidenced by debonding from the dentin substrate. The DDs and DCs of the APLP with agitation were higher than those of without agitation in the interface, in contrast to the comparable DD and DC values of two AEB specimen groups with different application modes. Raman spectral analysis revealed the important role of chemical interaction between acid monomers of self-etch adhesives and dentin in the above observations. Conclusion The chemical interaction with dentin is especially important for improving the DC of the strong self-etching adhesive at the A/D interface. Agitation could benefit polymerization efficacy of the strong self-etch adhesive through enhancing the chemical interaction with tooth substrate. PMID:23153573

Effect of additional etching and ethanol-wet bonding on the dentin bond strength of one-step self-etch adhesives

PubMed Central

Ahn, Joonghee; Jung, Kyoung-Hwa; Son, Sung-Ae; Hur, Bock; Kwon, Yong-Hoon

2015-01-01

Objectives This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Materials and Methods Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. Results In GB, XV and SE (pH ≤ 2), the bond strength was decreased significantly when the dentin was etched (p < 0.05). In BB, AE and SU (pH 2.4 - 2.7), additional etching did not affect the bond strength (p > 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p < 0.05). When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. Conclusions The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin. PMID:25671215

Influence of the dentinal wall on the pH of sodium hypochlorite during root canal irrigation.

PubMed

Macedo, Ricardo Gomes; Herrero, Noemi Pascual; Wesselink, Paul; Versluis, Michel; van der Sluis, Luc

2014-07-01

The purpose of this study was to evaluate the influence of dentin on the pH levels of different concentrations of sodium hypochlorite (NaOCl) solutions over time and to evaluate if preconditioning of dentin with 17% EDTA or agitation of the NaOCl solution influences these pH levels. A novel clinically representative model that scales with the ratio of the irrigant volume to the dentin surface area of a human root canal was used. Three standardized bovine dentin bars (2 × 2 × 10 mm) were placed in a plastic test tube. A total of 150 tubes were distributed in 29 groups. In the first experiment, the pH of various NaOCl solutions, with different concentrations (3%, 6%, and 9%) and starting pH levels (5 and 12), was monitored during exposure to dentin between 10 and 300 seconds. In a second experiment, the effect of agitation (45 Hz) and pretreatment of dentin with 17% EDTA on the pH levels of various NaOCl solutions was studied after 30 seconds of exposure to dentin. The short-term chemical stability of the tested solutions was assessed for both the concentration and the pH. The exposure time (P < .001) and concentration of the NaOCl solution (P < .011) significantly influence the pH level after exposure to dentin. However, the change in pH is too small to induce a change in the irrigant antimicrobial/tissue dissolution capacity. Agitation of the irrigant and preconditioning of the dentin did not alter the pH (P > .05). Both the pH 5 and pH 12 solutions were chemically stable for 1 hour. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effect of tooth substrate and porcelain thickness on porcelain veneer failure loads in vitro.

PubMed

Ge, Chunling; Green, Chad C; Sederstrom, Dalene A; McLaren, Edward A; Chalfant, James A; White, Shane N

2017-12-19

Bonded porcelain veneers are widely used esthetic restorations. High success and survival rates have been reported, but failures do occur. Fractures are the commonest failure mode. Minimally invasive or thin veneers have gained popularity. Increased enamel and porcelain thickness improve the strength of veneers bonded to enamel, but less is known about dentin or mixed substrates. The purpose of this in vitro study was to measure the influences of tooth substrate type (all-enamel, all-dentin, or half-dentin-half-enamel) and veneer thickness on the loads needed to cause initial and catastrophic porcelain veneer failure. Model discoid porcelain veneer specimens of varying thicknesses were bonded to the flattened facial surfaces of incisors with different enamel and dentin tooth substrates, artificially aged, and loaded to failure with a small sphere. Initial and catastrophic fracture events were identified and analyzed statistically and fractographically. Fracture events included initial Hertzian cracks, intermediate radial cracks, and catastrophic gross failure. All specimens retained some porcelain after catastrophic failure. Cement failure occurred at the cement-porcelain interface not at the cement-tooth interface. Porcelain veneers bonded to enamel were substantially stronger and more damage-tolerant than those bonded to dentin or mixed substrates. Increased porcelain thickness substantially raised the loads to catastrophic failure on enamel substrates but only moderately raised the loads to catastrophic failure on dentin or mixed substrates. The veneers bonded to half-dentin-half-enamel behaved remarkably like those bonded wholly to dentin. Porcelain veneers bonded to enamel were substantially stronger and more damage-tolerant than those bonded to dentin or half-enamel-half dentin. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effect of Minocycline on the Durability of Dentin Bonding Produced with Etch-and-Rinse Adhesives.

PubMed

Loguercio, A D; Stanislawczuk, R; Malaquias, P; Gutierrez, M F; Bauer, J; Reis, A

2016-01-01

To evaluate the effect of minocycline and chlorhexidine pretreatment of acid-etched dentin on the longevity of resin-dentin bond strength (μTBS) and nanoleakage of two-step etch-and-rinse adhesives. Before application of Prime & Bond NT and Adper Single Bond 2 in occlusal dentin, the dentin surfaces were treated with 37% phosphoric acid, rinsed, air-dried, and rewetted with water (control group), 2% minocycline, or 2% chlorexidine digluconate. Composite buildups were constructed incrementally, and specimens were longitudinally sectioned to obtain bonded sticks (0.8 mm 2 ) to be tested in tension (0.5 mm/min) immediately or after 24 months of water storage. For nanoleakage, two specimens of each tooth/period were immersed in the silver nitrate solution, photo-developed, and polished with SiC paper for analysis under energy-dispersive X-ray spectroscopy/scanning electron microscopy. Reductions of the μTBS and increases in the nanoleakage were observed for both adhesives when the rewetting procedure was performed with water. Stable bonds were observed for the 2% minocycline and 2% chlorexidine digluconate groups after 24 months. The use of 2% minocycline as pretreatment of acid-etched dentin is one alternative to retard the degradation of resin-dentin interfaces over a 24-month period as well as 2% chlorexidine digluconate.

Effect of sonic application mode on the resin-dentin bond strength and dentin permeability of self-etching systems.

PubMed

Mena-Serrano, Alexandra; Costa, Thays Regina Ferreira da; Patzlaff, Rafael Tiago; Loguercio, Alessandro Dourado; Reis, Alessandra

2014-10-01

To compare manual and sonic adhesive application modes in terms of the permeability and microtensile bond strength of a self-etching adhesive applied in the one-step or two-step protocol. Self-etching All Bond SE (Bisco) was applied as a one- or a two-step adhesive under manual or sonic vibration modes on flat occlusal dentin surfaces of 64 human molars. Half of the teeth were used to measure the hydraulic conductance of dentin at 200 cm H₂O hydrostatic pressure for 5 min immediately after the adhesive application. In the other half, composite buildups (Opallis) were constructed incrementally to create resin-dentin sticks with a cross-sectional area of 0.8 mm² to be tested in tension (0.5 mm/min) immediately after restoration placement. Data were analyzed using a two-way ANOVA and Tukey's test (α = 0.05). The fluid conductance of dentin was significantly reduced by the sonic vibration mode for both adhesives, but no effect on the bond strength values was observed for either adhesive. The sonic application mode at an oscillating frequency of 170 Hz can reduce the fluid conductance of the one- and two-step All Bond SE adhesive when applied on dentin.

Effect of a New Surface Treatment Solution on the Bond Strength of Composite to Enamel

DTIC Science & Technology

2016-06-01

enamel ( Erickson et al., 2005). More significantly, clinical studies have shown significantly less marginal defects and staining with selective...using phosphoric acid. Erickson et al., (2009) also found improved bond strengths with a selective-etch step and attributed this to the degree of...cut enamel and dentin. Oper Dent 2005;30(1):39-49. Erickson RL, Barkmeier WW, Kimmes NS. Bond strength of self-etch adhesives to pre-etched

Microtensile bond strength of etch and rinse versus self-etch adhesive systems.

PubMed

Hamouda, Ibrahim M; Samra, Nagia R; Badawi, Manal F

2011-04-01

The aim of this study was to compare the microtensile bond strength of the etch and rinse adhesive versus one-component or two-component self-etch adhesives. Twelve intact human molar teeth were cleaned and the occlusal enamel of the teeth was removed. The exposed dentin surfaces were polished and rinsed, and the adhesives were applied. A microhybride composite resin was applied to form specimens of 4 mm height and 6 mm diameter. The specimens were sectioned perpendicular to the adhesive interface to produce dentin-resin composite sticks, with an adhesive area of approximately 1.4 mm(2). The sticks were subjected to tensile loading until failure occurred. The debonded areas were examined with a scanning electron microscope to determine the site of failure. The results showed that the microtensile bond strength of the etch and rinse adhesive was higher than that of one-component or two-component self-etch adhesives. The scanning electron microscope examination of the dentin surfaces revealed adhesive and mixed modes of failure. The adhesive mode of failure occurred at the adhesive/dentin interface, while the mixed mode of failure occurred partially in the composite and partially at the adhesive/dentin interface. It was concluded that the etch and rinse adhesive had higher microtensile bond strength when compared to that of the self-etch adhesives. Copyright © 2010 Elsevier Ltd. All rights reserved.

Micro-shear bond strength of resin cement to dentin after application of desensitizing toothpastes.

PubMed

Bavbek, Andac Barkin; Goktas, Baris; Cekic-Nagas, Isil; Egilmez, Ferhan; Ergun, Gulfem; Eskitascioglu, Gurcan

2013-01-01

The aim of the study was to evaluate the effect of three desensitizing toothpastes on bonding of resin cements to dentin. The occlusal surfaces of 72 maxillary third molars were ground to obtain flat dentin surfaces and then divided into three groups according to three desensitizing toothpastes used: Sensodyne Rapid Relief (GlaxoSmithKline, SmithKline Beecham Ltd., Slough, UK), Signal Sensitive Expert (Unilever Sanayi ve Ticaret Türk A.Ş., Ümraniye, İstanbul, Turkey) and Colgate Sensitive Pro-Relief (Colgate Palmolive, New York, NY). Following bonding of the resin cement (Clearfil™ SA Cement, Kuraray Co, Osaka, Japan) to dentin, the specimens were light cured for 40 s with a LED (Elipar S10, 3M Espe, St. Paul, MN). The strength measurements were accomplished with a micro-shear testing machine (Bisco, Schaumburg, IL) at a cross-head speed of 0.5 mm/min until the failure occurs. Failure modes were examined using a stereomicroscope and scanning electron microscope. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey HSD test (α = 0.05). ANOVA revealed that the application of desensitizing toothpastes had significant effects on bond strength of the resin cement tested to dentin (p < 0.05). Mixed failures were observed in all of the groups. The use of a desensitizing toothpaste before cementation might alter the bond strength of adhesively luted restorations.

Characterization of dental pulp defect and repair in a canine model.

PubMed

Yildirim, Sibel; Can, Alp; Arican, Mustafa; Embree, Mildred C; Mao, Jeremy J

2011-12-01

To explore a relationship between the size of pulp chamber perforation and reparative dentin formation in a canine model. Pulp defects were created in the pulp chambers of maxillary and mandibular premolars (N = 64) in 17 healthy mongrel dogs in three different sizes (diameter/depth: 1/1, 2/1, and 2/2 mm3) with sterile round burs under general anesthesia. The perforations were immediately capped with hard-setting calcium hydroxide (CH) in the control group or sealed with Teflon membrane (TM) in the experimental group, followed by restoration with reinforced zinc oxide eugenol cement in vivo. Seven and 30 days after pulp chamber perforation and restoration all treated and control premolars were extracted and prepared for histomorphometric and statistical analyses. Reparative dentin formation was more pronounced for defect sizes up to 2/1 mm3 when treated with CH, and completely bridged the surgically created dentin defects only after 30 days. However, reparative dentin upon CH treatment failed to completely bridge pulp chamber exposure for 2/2 defects. By contrast, TM treatment only yielded mild reparative dentin bridging for defects up to 1/1, but not for either 2/1 or 2/2 defects at 30 days. Inflammatory responses of the exposed dental pulp tissue were more robust with the TM group than with the CH group. Thus, dental pulp tissue possesses a capacity for spontaneous repair by the formation of reparative dentin in this preclinical model, but only up to a defect size of -2 mm in diameter and 1 mm in depth. All observations are based on 30 days post-treatment in the canine model. These findings may serve as baseline for regenerative endodontic studies.

Effect of tooth whitening strips on fatigue resistance and flexural strength of bovine dentin in vitro

PubMed Central

Kim, Namhee; De Souza, Grace M.

2017-01-01

Objective To determine the effects of whitening strips on bovine dentin fatigue resistance and flexural strength in vitro. Materials and methods A total of eighty bovine dentin specimens (2x2x17mm) were treated with either: control glycerine gel on plastic film wrap or whitening strips containing 9.5% hydrogen peroxide. Treatment was applied for 30 minutes, twice a day, for 1- or 4-weeks. After the last treatment, ten specimens per group were randomly selected to undergo fatigue testing (106 cycles, 3Hz, 20N) while the other ten were subjected to flexural strength testing after ten days of storage in artificial saliva. Kaplan-Meier method with a log rank test, Wilcoxon test and Cox regression were used to assess fatigue test results (p<0.05). One-way ANOVA and Tukey’s tests were used to compare the flexural strength results (p<0.05). Results There were significant differences in survival during the fatigue test among the groups (p<0.001). Treatment (control or bleach) was a significant factor for specimen survival (p<0.001, Exp(B) = 33.45). There were significant differences in mean flexural strength (p<0.001). No significant difference was found between “1-wk control” and “4-wk control”. The mean flexural strength and fatigue resistance of the “4-wk bleach” were significantly lower than all the other groups. Conclusions The use of whitening strips reduced the fatigue resistance and flexural strength of bovine dentin in vitro. Until the effect of whitening strips on mechanical properties of human dentin is fully elucidated, it remains prudent to advise patients to avoid excessive direct use of whitening strips on dentin. PMID:28278191

PLGA nanoparticles as chlorhexidine-delivery carrier to resin-dentin adhesive interface.

PubMed

Priyadarshini, Balasankar Meera; Mitali, Kakran; Lu, Thong Beng; Handral, Harish K; Dubey, Nileshkumar; Fawzy, Amr S

2017-07-01

To characterize and deliver fabricated CHX-loaded PLGA-nanoparticles inside micron-sized dentinal-tubules of demineralized dentin-substrates and resin-dentin interface. Nanoparticles fabricated by emulsion evaporation were assessed in-vitro by different techniques. Delivery of drug-loaded nanoparticles to demineralized dentin substrates, interaction with collagen matrix, and ex-vivo CHX-release profiles using extracted teeth connected to experimental setup simulating pulpal hydrostatic pressure were investigated. Furthermore, nanoparticles association/interaction with a commercial dentin-adhesive applied to demineralized dentin substrates were examined. The results showed that the formulated nanoparticles demonstrated attractive physicochemical properties, low cytotoxicity, potent antibacterial efficacy, and slow degradation and gradual CHX release profiles. Nanoparticles delivered efficiently inside dentinal-tubules structure to sufficient depth (>10μm) against the simulated upward pulpal hydrostatic-pressure, even after bonding-resins infiltration and were attached/retained on collagen-fibrils. These results verified the potential significance of this newly introduced drug-delivery therapeutic strategy for future clinical applications and promote for a new era of future dental research. This innovative drug-delivery strategy has proven to be a reliable method for delivering treatments that could be elaborated for other clinical applications in adhesive and restorative dentistry. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of conditioning solutions containing ferric chloride on dentin bond strength and collagen degradation.

PubMed

Rodrigues, Raquel Viana; Giannini, Marcelo; Pascon, Fernanda Miori; Panwar, Preety; Brömme, Dieter; Manso, Adriana Pigozzo; Carvalho, Ricardo Marins

2017-10-01

To investigate the effects of conditioning solutions containing ferric chloride (FeCl 3 ) on resin-dentin bond strength; on protection of dentin collagen against enzymatic degradation and on cathepsin-K (CT-K) activity. Conditioning solutions were prepared combining citric acid (CA) and anhydrous ferric chloride (FeCl 3 ) in different concentrations. The solutions were applied to etch flat dentin surfaces followed by bonding with adhesive resin. Phosphoric acid (PA) gel etchant was used as control. The microtensile bond strength (μTBS) was tested after 24h of storage in water and after 9 months of storage in phosphate buffer saline. Dentin slabs were demineralized in 0.5M EDTA, pre-treated or not with FeCl 3 and incubated with CT-K. The collagenase activity on dentin collagen matrix was examined and characterized by SEM. Additional demineralized dentin slabs were treated with the conditioning solutions, and the amount of Fe bound to collagen was determined by EDX. The activity of CT-K in the presence of FeCl 3 was monitored fluorimetrically. Data were analyzed by ANOVA followed by post-hoc tests as required (α=5%). Slightly higher bond strengths were obtained when dentin was conditioned with 5% CA/0.6% FeCl 3 and 5% CA-1.8%FeCl 3 regardless of storage time. Bond strengths reduced significantly for all tested conditioners after 9 months of storage. Treating dentin with 1.8% FeCl 3 was effective to preserve the structure of collagen against CT-K. EDX analysis revealed binding of Fe-ions to dentin collagen after 15s immersion of demineralized dentin slabs into FeCl 3 solutions. FeCl 3 at concentration of 0.08% was able to suppress CT-K activity. This study shows that FeCl 3 binds to collagen and offers protection against Cat-K degradation. Mixed solutions of CA and FeCl 3 may be used as alternative to PA to etch dentin in resin-dentin bonding with the benefits of preventing collagen degradation. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Pulpal reaction to a dental adhesive in deep human cavities.

PubMed

Torstenson, B

1995-08-01

In the last years several dental adhesives have been developed. They are supposed to chemically adhere to dentin and a liner to protect the pulp is not used. The aim of this study was to compare the short-term pulpal reaction, in an intra-toothpair study, between a dental adhesive, Scotchbond 2, and a lining system, Tubulitec, in combination with P-50 in surface-sealed cavities. Deep buccal cavities in 16 human pairs of premolars, 32 teeth, were restored in vivo with a light cured composite resin, P-50. To minimize bacterial contamination all cavities were treated with a cleanser, Tubulicid, and the cavities were surface-sealed with temporary cement, Coltosol. One tooth in each pair, the test, was treated with Scotchprep Dentin Primer and Scotchbond 2 Light Cure Dental Adhesive. In the other tooth in the pair, the control, Tubulitec Primer and Liner were used. The teeth were extracted after 6-14 days. The sections were evaluated for degree of inflammation and the presence of bacteria. Irrespective of treatment of dentin the majority of teeth, 23, including one pulpal exposure, revealed no inflammation or a few inflammatory cells. In four test teeth, including one pulpal exposure, and two controls, growth of bacteria was found on the cavity walls and slight or moderate inflammation was seen in the corresponding pulps. In one test and two control teeth slight inflammation was seen but no bacteria could be detected. In the absence of bacteria Scotchbond 2 did not seem to irritate the pulp.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring of copper nanoparticle penetration into dentin of human tooth in vitro

NASA Astrophysics Data System (ADS)

Selifonov, Alexey A.; Glukhovskoy, Evgeny G.; Skibina, Yulia S.; Zakharevich, Andrey M.; Begletsova, Nadezhda N.; Tuchin, Valery V.

2018-04-01

Study of the penetration depth of synthesized copper nanoparticles into cut samples of human dentin was conducted. The scanning electron microscopy was used to determine the elemental composition of fresh transverse cleavage of the dentin cut for determination of the copper nanoparticles penetration with an effective antiseptic effect. The morphology of the cut surface of the dentin of a human tooth was studied and the lower limit of the diffusion boundary was determined. It was found that copper nanoparticles penetrate into the dentin cut to a depth of 1.8 μm with the diffusion coefficient of 1.8×10-11 cm2/s. Despite the rather small size of the synthesized copper nanoparticles (20-80 nm), a rather small penetration depth can be explained by the high aggregation ability of copper nanoparticles, as well as the ability of a micellar solution of sodium dodecyl sulfate, in which nanoparticles were stabilized, to form conglomerates in micelles of much larger sizes.

Effect of Er,Cr:YSGG laser on human dentin fluid flow.

PubMed

Al-Omari, Wael M; Palamara, Joseph E

2013-11-01

The aim of the current investigation was to assess the rate and magnitude of dentin fluid flow of dentinal surfaces irradiated with Er,Cr:YSGG laser. Twenty extracted third molars were sectioned, mounted, and irradiated with Er,Cr:YSGG laser at 3.5 and 4.5 W power settings. Specimens were connected to an automated fluid flow measurement apparatus (Flodec). The rate, magnitude, and direction of dentin fluid flow were recorded at baseline and after irradiation. Nonparametric Wilcoxon signed ranks repeated measure t test revealed a statistically significant reduction in fluid flow for all the power settings. The 4.5-W power output reduced the flow significantly more than the 3.5 W. The samples showed a baseline outward flow followed by inward flow due to irradiation then followed by decreased outward flow. It was concluded that Er,Cr:YSGG laser irradiation at 3.5 and 4.5 W significantly reduced dentinal fluid flow rate. The reduction was directly proportional to power output.

Elemental content of enamel and dentin after bleaching of teeth (a comparative study between laser-induced breakdown spectroscopy and x-ray photoelectron spectroscopy)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imam, H.; Ahmed, Doaa; Eldakrouri, Ashraf

2013-06-21

The elemental content of the superficial and inner enamel as well as that of dentin was analyzed using laser-induced breakdown spectroscopy (LIBS) and x-ray photoelectron spectroscopy (XPS) of bleached and unbleached tooth specimens. It is thus clear from the spectral analysis using both the LIBS and XPS technique that elemental changes (though insignificant within the scopes of this study) of variable intensities do occur on the surface of the enamel and extend deeper to reach dentin. The results of the LIBS revealed a slight reduction in the calcium levels in the bleached compared to the control specimens in all themore » different bleaching groups and in both enamel and dentin. The good correlation found between the LIBS and XPS results demonstrates the possibility of LIBS technique for detection of minor loss in calcium and phosphorus in enamel and dentin.« less

Pulpal and periradicular response to caries: current management and regenerative options.

PubMed

Chogle, Sami M A; Goodis, Harold E; Kinaia, Bassam Michael

2012-07-01

The pulp-dentin complex is a strategic and dynamic barrier to various insults that plague the dentition. Researchers have yet to understand the complete potential of this shifting junction and its components. The most common cause of injury to the pulp-dentin complex is carious breakdown of enamel and dentin. In recent years, there has been a change in restorative management of caries. The emphasis is on strategies to preserve dentin and protect the pulp. This article provides a brief review of the effect of caries on the pulp, of subsequent events on the periradicular tissues, and of current understanding of treatment modalities. Copyright © 2012 Elsevier Inc. All rights reserved.

MicroCT analysis of a retrieved root restored with a bonded fiber-reinforced composite dowel: a pilot study.

PubMed

Lorenzoni, Fabio Cesar; Bonfante, Estevam A; Bonfante, Gerson; Martins, Leandro M; Witek, Lukasz; Silva, Nelson R F A

2013-08-01

This evaluation aimed to (1) validate micro-computed tomography (microCT) findings using scanning electron microscopy (SEM) imaging, and (2) quantify the volume of voids and the bonded surface area resulting from fiber-reinforced composite (FRC) dowel cementation technique using microCT scanning technology/3D reconstructing software. A fiberglass dowel was cemented in a condemned maxillary lateral incisor prior to its extraction. A microCT scan was performed of the extracted tooth creating a large volume of data in DICOM format. This set of images was imported to image-processing software to inspect the internal architecture of structures. The outer surface and the spatial relationship of dentin, FRC dowel, cement layer, and voids were reconstructed. Three-dimensional spatial architecture of structures and volumetric analysis revealed that 9.89% of the resin cement was composed of voids and that the bonded area between root dentin and cement was 60.63% larger than that between cement and FRC dowel. SEM imaging demonstrated the presence of voids similarly observed using microCT technology (aim 1). MicroCT technology was able to nondestructively measure the volume of voids within the cement layer and the bonded surface area at the root/cement/FRC interfaces (aim 2). The interfaces at the root dentin/cement/dowel represent a timely and relevant topic where several efforts have been conducted in the past few years to understand their inherent features. MicroCT technology combined with 3D reconstruction allows for not only inspecting the internal arrangement rendered by fiberglass adhesively bonded to root dentin, but also estimating the volume of voids and contacted bond area between the dentin and cement layer. © 2013 by the American College of Prosthodontists.

Cariogenicity of different commercially available bovine milk types in a biofilm caries model.

PubMed

Giacaman, Rodrigo A; Muñoz-Sandoval, Cecilia

2014-01-01

This study's purpose was to assess the cariogenicity of commercial bovine milk types in an experimental biofilm/caries model. Enamel and dentin slabs were used to grow biofilms of Streptococcus mutans UA159. Slabs/biofilms were exposed three times per day to commercial skim, semi-skim, whole, whole lactose-free, and whole with 10 percent sucrose-added bovine milk and to 10 percent sucrose and 0.9 percent sodium chloride as positive and negative caries-control, respectively. Biofilms were analyzed for bacterial counts, biomass, proteins, and polysaccharide production. Slab's demineralization was assessed by loss of surface microhardness and the biofilm acidogenicity by medium pH. Only whole and whole lactose-free milk kept pH above the demineralization threshold, inducing the lowest demineralization in both enamel and dentin (P<.05). Skim and semi-skim milk induced similar demineralization to the sucrose control, albeit slightly lower for semi-skim milk (P<.05). Whole and whole lactose-free milk produced lower biomass and less insoluble polysaccharides than the other treatments in enamel and dentin (P<.05). Adding 10 percent sucrose to whole milk turned it as cariogenic as 10 percent sucrose solution. Bovine whole milk seemed less cariogenic than sucrose and the other commercial milk types, but not anticariogenic. Fat content in milk seemed to reduce cariogenicity of the fluid.

Resin-dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding. Part II: Effects of mechanical cycling load on microtensile bond strengths.

PubMed

Sauro, Salvatore; Toledano, Manuel; Aguilera, Fatima Sánchez; Mannocci, Francesco; Pashley, David H; Tay, Franklin R; Watson, Timothy F; Osorio, Raquel

2011-06-01

To compare microtensile bond strengths (MTBS) subsequent to load cycling of resin bonded acid-etched or EDTA-treated dentin using a modified ethanol wet-bonding technique. Flat dentin surfaces were obtained from extracted human molars and conditioned using 37% H(3)PO(4) (PA) (15s) or 0.1M EDTA (60s). Five experimental adhesives and one commercial bonding agent were applied to the dentin and light-cured. Solvated experimental resins (50% ethanol/50% comonomers) were used as primers and their respective neat resins were used as the adhesives. The resin-bonded teeth were stored in distilled water (24h) or submitted to 5000 loading cycles of 90N. The bonded teeth were then sectioned in beams for MTBS. Modes of failure were examined by scanning electron microscopy. The most hydrophobic resin 1 gave the lowest bond strength values to both acid and EDTA-treated dentin. The hydrophobic resin 2 applied to EDTA-treated dentin showed lower bond strengths after cycling load but this did not occur when it was bonded to PA-etched dentin. Resins 3 and 4, which contained hydrophilic monomers, gave higher bond strengths to both EDTA-treated or acid-etched dentin and showed no significant difference after load cycling. The most hydrophilic resin 5 showed no significant difference in bond strengths after cycling loading when bonded to EDTA or phosphoric acid treated dentin but exhibited low bond strengths. The presence of different functional monomers influences the MTBS of the adhesive systems when submitted to cyclic loads. Adhesives containing hydrophilic comonomers are not affected by cycling load challenge especially when applied on EDTA-treated dentin followed by ethanol wet bonding. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Antibacterial effects of Nd:YAG laser irradiation within root canal dentin.

PubMed

Klinke, T; Klimm, W; Gutknecht, N

1997-02-01

The microbial flora of the root canal dentin can cause failures in the conventional treatment of infected root canals if it cannot be sufficiently removed by preparation and chemical disinfection of the root canal. The aim of this study is to examine the bactericidal effects of neodymium:yttriumaluminum garnet (Nd:YAG) laser irradiation in the depth of the root canal dentin. Following sterilization, longitudinal section dentin slices of different thicknesses (100-1000 microns) were inoculated on one side with 4 microliters of a Streptococcus mutans suspension. The opposite sides of the dentin slices were then irradiated four times for 10-20 sec (according to the sample area) using the Nd:YAG laser at a setting of 1.5 W, 15 pps with a 200 microns glass fiber from an angle of about 5 degrees. The bacteria were then removed from the dentin using vibration and plated out on culture dishes that were selective for Streptococcus mutans. When compared with untreated control slices, counting of the colonies revealed a highly significant elimination of bacteria for all thicknesses following laser irradiation. Although the intensity of the laser irradiation decreased after penetration of a 1000-micron dentin slice, the bactericidal mode of action was still effective.

Microorganism penetration in dentinal tubules of instrumented and retreated root canal walls. In vitro SEM study

PubMed Central

Al-Sulaiman, Alaa; Al-Rasheed, Fellwa; Alnajjar, Fatimah; Al-Abdulwahab, Bander; Al-Badah, Abdulhakeem

2014-01-01

Objectives This in vitro study aimed to investigate the ability of Candida albicans (C. albicans) and Enterococcus faecalis (E. faecalis) to penetrate dentinal tubules of instrumented and retreated root canal surface of split human teeth. Materials and Methods Sixty intact extracted human single-rooted teeth were divided into 4 groups, negative control, positive control without canal instrumentation, instrumented, and retreated. Root canals in the instrumented group were enlarged with endodontic instruments, while root canals in the retreated group were enlarged, filled, and then removed the canal filling materials. The teeth were split longitudinally after canal preparation in 3 groups except the negative control group. The teeth were inoculated with both microorganisms separately and in combination. Teeth specimens were examined by scanning electron microscopy (SEM), and the depth of penetration into the dentinal tubules was assessed using the SMILE view software (JEOL Ltd). Results Penetration of C. albicans and E. faecalis into the dentinal tubules was observed in all 3 groups, although penetration was partially restricted by dentin debris of tubules in the instrumented group and remnants of canal filling materials in the retreated group. In all 3 groups, E. faecalis penetrated deeper into the dentinal tubules by way of cell division than C. albicans which built colonies and penetrated by means of hyphae. Conclusions Microorganisms can easily penetrate dentinal tubules of root canals with different appearance based on the microorganism size and status of dentinal tubules. PMID:25383343

Effect of Storage Time on Bond Strength and Nanoleakage Expression of Universal Adhesives Bonded to Dentin and Etched Enamel.

PubMed

Makishi, P; André, C B; Ayres, Apa; Martins, A L; Giannini, M

2016-01-01

To investigate bond strength and nanoleakage expression of universal adhesives (UA) bonded to dentin and etched enamel. Extracted human third molars were sectioned and ground to obtain flat surfaces of dentin (n = 36) and enamel (n = 48). Dentin and etched enamel surfaces were bonded with one of two UAs, All-Bond Universal (ABU) or Scotchbond Universal (SBU); or a two-step self-etching adhesive, Clearfil SE Bond (CSEB). A hydrophobic bonding resin, Adper Scotchbond Multi-Purpose Bond (ASMP Bond) was applied only on etched enamel. Following each bonding procedure, resin composite blocks were built up incrementally. The specimens were sectioned and subjected to microtensile bond strength (MTBS) testing after 24 hours or one year water storage, or immersed into ammoniacal silver nitrate solution after aging with 10,000 thermocycles and observed using scanning electron microscopy. The percentage distribution of silver particles at the adhesive/tooth interface was calculated using digital image-analysis software. The MTBS (CSEB = SBU > ABU, for dentin; and CSEB > ABU = SBU = ASMP Bond, for etched enamel) differed significantly between the adhesives after 24 hours. After one year, MTBS values were reduced significantly within the same adhesive for both substrates (analysis of variance, Bonferroni post hoc, p<0.05), and no significant differences were found among the adhesives for etched enamel. Silver particles could be detected within the adhesive/dentin interface of all specimens tested. Kruskal-Wallis mean ranks for nanoleakage in ABU, SBU, and CSEB were 16.9, 18.5 and 11, respectively (p>0.05). In the short term, MTBS values were material and dental-substrate dependent. After aging, a decrease in bonding effectiveness was observed in all materials, with nanoleakage at the adhesive/dentin interface. The bonding of the UAs was equal or inferior to that of the conventional restorative systems when applied to either substrate and after either storage period.

Bond strength to dentin with artificial carious lesions: influence of caries detecting dye.

PubMed

Palma, R G; Turbino, M L; Matson, E; Powers, J M

1998-06-01

To evaluate the influence of dyes for caries detection on tensile bond strength of adhesive materials to artificial carious dentin. Buccal and lingual enamel of human molars were removed leaving intact dentin surfaces. The entire surface of each specimen was covered with nail varnish, keeping a window area of 4 x 4 mm. Artificial carious lesions were induced with acidified gel. Three dyes (0.5% basic fuchsin; Caries Finder and Cari-D-Tect) were used according to manufacturers' recommendations. Specimens were etched with 35% phosphoric acid for 20 s, washed and dried, leaving a wet dentin surface. The adhesive system (Prime & Bond 2.0) was applied in two layers and light-cured. Restorative materials (TPH Spectrum, Dyract, Advance) were bonded using a 3-mm diameter inverted-cone mold. Control groups were made without dye. Eight samples were tested for each group. After 24 hrs of storage in distilled water, the samples were debonded using a testing machine at 0.5 mm/min crosshead speed. ANOVA and Tukey-Kramer test showed that TPH Spectrum (0.73 MPa) and Dyract (0.74 MPa) had similar bond strengths, and both were higher than Advance (0.0 MPa), which was statistically different (P < 0.01). The use of the dyes did not cause any changes in tensile bond strength for any tested materials.

The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate

PubMed Central

Pilo, Raphael; Harel, Noga; Nissan, Joseph; Levartovsky, Shifra

2016-01-01

The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP) crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC) or Self Adhesive Resin Cement (SARC)). Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa) were significantly higher than those for SARC (2.28 ± 0.58 MPa). The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns. PMID:27023532

The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate.

PubMed

Pilo, Raphael; Harel, Noga; Nissan, Joseph; Levartovsky, Shifra

2016-03-25

The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP) crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC) or Self Adhesive Resin Cement (SARC)). Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa) were significantly higher than those for SARC (2.28 ± 0.58 MPa). The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns.

Randomized in vivo evaluation of photodynamic antimicrobial chemotherapy on deciduous carious dentin

NASA Astrophysics Data System (ADS)

Steiner-Oliveira, Carolina; Longo, Priscila Larcher; Aranha, Ana Cecília Corrêa; Ramalho, Karen Müller; Mayer, Marcia Pinto Alves; de Paula Eduardo, Carlos

2015-10-01

The aim of this randomized in vivo study was to compare antimicrobial chemotherapies in primary carious dentin. Thirty-two participants ages 5 to 7 years underwent partial caries removal from deep carious dentin lesions in primary molars and were subsequently divided into three groups: control [chlorhexidine and resin-modified glass ionomer cement (RMGIC)], LEDTB [photodynamic antimicrobial chemotherapy (PACT) with light-emitting diode associated with toluidine blue solution and RMGIC], and LMB [PACT with laser associated with methylene blue solution and RMGIC]. The participants were submitted to initial clinical and radiographic examinations. Demographic features and biofilm, gingival, and DMFT/DMFS indexes were evaluated, in addition to clinical and radiographic followups at 6 and 12 months after treatments. Carious dentin was collected before and after each treatment, and the number of Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Fusobacterium nucleatum, Atopobium rimae, and total bacteria was established by quantitative polymerase chain reaction. No signs of pain or restoration failure were observed. All therapies were effective in reducing the number of microorganisms, except for S. sobrinus. No statistical differences were observed among the protocols used. All therapies may be considered as effective modern approaches to minimal intervention for the management of deep primary caries treatment.

Femtosecond laser ablation of dentin and enamel: relationship between laser fluence and ablation efficiency.

PubMed

Chen, Hu; Liu, Jing; Li, Hong; Ge, Wenqi; Sun, Yuchun; Wang, Yong; Lü, Peijun

2015-02-01

The objective was to study the relationship between laser fluence and ablation efficiency of a femtosecond laser with a Gaussian-shaped pulse used to ablate dentin and enamel for prosthodontic tooth preparation. A diode-pumped thin-disk femtosecond laser with wavelength of 1025 nm and pulse width of 400 fs was used for the ablation of dentin and enamel. The laser spot was guided in a line on the dentin and enamel surfaces to form a groove-shaped ablation zone under a series of laser pulse energies. The width and volume of the ablated line were measured under a three-dimensional confocal microscope to calculate the ablation efficiency. Ablation efficiency for dentin reached a maximum value of 0.020 mm3∕J when the laser fluence was set at 6.51 J∕cm2. For enamel, the maximum ablation efficiency was 0.009 mm3∕J at a fluence of 7.59 J∕cm2.Ablation efficiency of the femtosecond laser on dentin and enamel is closely related to the laser fluence and may reach a maximum when the laser fluence is set to an appropriate value. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)

Bonding effectiveness and interfacial characterization of a nano-filled resin-modified glass-ionomer.

PubMed

Coutinho, E; Cardoso, M V; De Munck, J; Neves, A A; Van Landuyt, K L; Poitevin, A; Peumans, M; Lambrechts, P; Van Meerbeek, B

2009-11-01

Glass-ionomers (GIs) exhibit excellent clinical bonding effectiveness, but still have shortcomings such as polishability and general aesthetics. The aims of this study were (1) to determine the micro-tensile bond strength (microTBS) to enamel and dentin of a nano-filled resin-modified GI (nano-RMGI; Ketac N100, 3M-ESPE), and (2) to characterize its interfacial interaction with enamel and dentin using transmission electron microscopy (TEM). The nano-RMGI was used both with and without its primer, while a conventional RMGI restorative material (conv-RMGI; Fuji II LC, GC) and a packable conventional GI cement (conv-GI; Fuji IX GP, GC) were used as controls. After bonding to freshly extracted human third molars, microspecimens of the interfaces were machined into a cylindrical hourglass shape and tested to failure in tension. Non-demineralized TEM sections were prepared and examined from additional teeth. The microTBS to both enamel and dentin of nano-RMGI and conv-GI were not statistically different; the microTBS of non-primed nano-RMGI was significantly lower, while that of conv-RMGI was significantly higher than that of all other groups. TEM of nano-RMGI disclosed a tight interface at enamel and dentin without surface demineralization and hybrid-layer formation. A thin filler-free zone (<1 microm) was formed at dentin. A high filler loading and effective filler distribution were also evident, with localized areas exhibiting nano-filler clustering. The nano-RMGI bonded as effectively to enamel and dentin as conv-GI, but bonded less effectively than conv-RMGI. Its bonding mechanism should be attributed to micro-mechanical interlocking provided by the surface roughness, most likely combined with chemical interaction through its acrylic/itaconic acid copolymers.

Inhibitory effect of silver diamine fluoride on dentine demineralisation and collagen degradation.

PubMed

Mei, May L; Ito, L; Cao, Y; Li, Q L; Lo, Edward C M; Chu, C H

2013-09-01

To investigate the inhibitory effects of 38% silver diamine fluoride (SDF) on demineralised dentine. Human dentine blocks were demineralised and allocated to four groups: SF, F, S and W. The blocks in group SF received a topical application of 38% SDF solution (253,900ppm Ag, 44,800ppm F), group F received a 10% sodium fluoride solution (44,800ppm F), group S received a 42% silver nitrate solution (253,900ppm Ag) and group W received deionised water (control). They were subjected to pH cycling using demineralisation solution (pH 5) and remineralisation solution (pH 7) for 8 days. The surface morphology, crystal characteristics, lesion depth and collagen matrix degradation of the specimens were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-CT testing and spectrophotometry with a hydroxyproline assay. The surface morphology under SEM showed evident demineralisation with exposed collagen in groups S and W, but not in group SF. Clusters of granular spherical grains were observed in the cross-sections of specimens in groups SF and F. XRD revealed precipitates of silver chloride in groups SF and S. The mean lesion depths (±SD) of groups SF, F, S and W were 182 ± 32μm, 204 ± 26μm, 259 ± 42μm and 265 ± 40μm, respectively (SDF, F

Development of a multifunctional adhesive system for prevention of root caries and secondary caries

PubMed Central

Zhang, Ning; Melo, Mary A. S.; Chen, Chen; Liu, Jason; Weir, Michael D.; Bai, Yuxing; Xu, Hockin H. K.

2015-01-01

Objectives The objectives of this study were to: (1) develop a novel adhesive for prevention of tooth root caries and secondary caries by possessing a combination of protein-repellent, antibacterial, and remineralization capabilities for the first time; and (2) investigate the effects of 2-methacryloyloxyethyl phosphorylcholine (MPC), dimethylaminohexadecyl methacrylate (DMAHDM), and nanoparticles of amorphous calcium phosphate (NACP) on dentine bond strength, protein-repellent properties, and dental plaque microcosm biofilm response. Methods MPC, DMAHDM and NACP were added into Scotchbond Multi-Purpose primer and adhesive. Dentine shear bond strengths were measured. Adhesive coating thickness, surface texture and dentine-adhesive interfacial structure were examined. Protein adsorption onto adhesive resin surface was determined by the micro bicinchoninic acid method. A human saliva microcosm biofilm model was used to investigate biofilm metabolic activity, colony-forming unit (CFU) counts, and lactic acid production. Results The resin with 7.5% MPC + 5% DMAHDM + 30% NACP did not adversely affect dentine shear bond strength (p > 0.1). The resin with 7.5% MPC + 5% DMAHDM + 30% NACP produced a coating on root dentine with a thickness of approximately 70 μm and completely sealed all the dentinal tubules. The resin with 7.5% MPC + 5% DMAHDM + 30% NACP had 95% reduction in protein adsorption, compared to SBMP control (p < 0.05). The resin with 7.5% MPC + 5% DMAHDM + 30% NACP was strongly antibacterial, with biofilm CFU being four orders of magnitude lower than that of SBMP control. Significance The novel multifunctional adhesive with strong protein-repellent, antibacterial and remineralization properties is promising to coat tooth roots to prevent root caries and secondary caries. The combined use of MPC, DMAHDM and NACP may have wide applicability to bonding agents, cements, sealants and composites to inhibit caries. PMID:26187532

The effect of increasing sodium fluoride concentrations on erosion and attrition of enamel and dentine in vitro.

PubMed

Austin, R S; Rodriguez, J M; Dunne, S; Moazzez, R; Bartlett, D W

2010-10-01

To investigate the effect of an aqueous sodium fluoride solution of increasing concentration on erosion and attrition of enamel and dentine in vitro. Enamel and dentine sections from caries-free human third molars were polished flat and taped (exposing a 3 mm x 3 mm area) before being randomly allocated to 1 of 5 groups per substrate (n=10/gp): G1 (distilled water control); G2 (225 ppm NaF); G3 (1450 ppm NaF); G4 (5000 ppm NaF); G5 (19,000 ppm NaF). All specimens were subjected to 5, 10 and 15 cycles of experimental wear [1 cycle=artificial saliva (2h, pH 7.0)+erosion (0.3% citric acid, pH 3.2, 5 min)+fluoride/control (5 min)+attrition (60 linear strokes in artificial saliva from enamel antagonists loaded to 300 g)]. Following tape removal, step height (SH) in mum was measured using optical profilometry. When the number of cycles increased the amount of tooth surface loss increased significantly in enamel and dentine after attrition and erosion and for dentine after attrition. Attrition and erosion resulted in greater surface loss than attrition alone after 15 cycles of experimental wear of enamel. 5000 ppm and 19,000 ppm sodium fluoride solutions had a protective effect on erosive and attritional enamel tooth wear in vitro, however no other groups showed significant differences. The more intensive the fluoride regime the more protection was afforded to enamel from attrition and erosion. However, in this study no such protective effect was demonstrated for dentine. Copyright 2010 Elsevier Ltd. All rights reserved.

The role of erosion, abrasion and attrition in tooth wear.

PubMed

Barbour, Michele E; Rees, Gareth D

2006-01-01

There is increasing clinical awareness of erosion of enamel and dentine by dietary acids and the consequent increased susceptibility to physical wear. Enamel erosion is characterized by acid-mediated surface softening that, if unchecked, will progress to irreversible loss of surface tissue, potentially exposing the underlying dentine. In comparison, dentine erosion is less well understood as the composition and microstructure are more heterogeneous. Factors which affect the erosive potential of a solution include pH, titratable acidity, common ion concentrations, and frequency and method of exposure. Abrasion and attrition are sources of physical wear and are commonly associated with tooth brushing and tooth-to-tooth contact, respectively. A combination of erosion and abrasion or attrition exacerbates wear; however, further research is required to understand the role of fluoride in protecting mineralized tissues from such processes. Abrasive wear may be seen in a wide range of patients, whereas attritive loss is usually seen in individuals with bruxism. Wear processes are implicated in the development of dentine hypersensitivity. Saliva confers the major protective function against wear due to its role in pellicle formation, buffering, acid clearance, and hard tissue remineralization. This review focuses on the physiochemical factors impacting tooth wear.

Effect of calcium phosphate nanocomposite on in vitro remineralization of human dentin lesions.

PubMed

Weir, Michael D; Ruan, Jianping; Zhang, Ning; Chow, Laurence C; Zhang, Ke; Chang, Xiaofeng; Bai, Yuxing; Xu, Hockin H K

2017-09-01

Secondary caries is a primary reason for dental restoration failures. The objective of this study was to investigate the remineralization of human dentin lesions in vitro via restorations using nanocomposites containing nanoparticles of amorphous calcium phosphate (NACP) or NACP and tetracalcium phosphate (TTCP) for the first time. NACP was synthesized by a spray-drying technique and incorporated into a resin consisting of ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM). After restoring the dentin lesions with nanocomposites as well as a non-releasing commercial composite control, the specimens were treated with cyclic demineralization (pH 4, 1h per day) and remineralization (pH 7, 23h per day) for 4 or 8 weeks. Calcium (Ca) and phosphate (P) ion releases from composites were measured. Dentin lesion remineralization was measured at 4 and 8 weeks by transverse microradiography (TMR). Lowering the pH increased ion release of NACP and NACP-TTCP composites. At 56 days, the released Ca concentration in mmol/L (mean±SD; n=3) was (13.39±0.72) at pH 4, much higher than (1.19±0.06) at pH 7 (p<0.05). At 56 days, P ion concentration was (5.59±0.28) at pH 4, much higher than (0.26±0.01) at pH 7 (p<0.05). Quantitative microradiography showed typical subsurface dentin lesions prior to the cyclic demineralization/remineralization treatment, and dentin remineralization via NACP and NACP-TTCP composites after 4 and 8 weeks of treatment. At 8 weeks, NACP nanocomposite achieved dentin lesion remineralization (mean±SD; n=15) of (48.2±11.0)%, much higher than (5.0±7.2)% for dentin in commercial composite group after the same cyclic demineralization/remineralization regimen (p<0.05). Novel NACP-based nanocomposites were demonstrated to achieve dentin lesion remineralization for the first time. These results, coupled with acid-neutralization and good mechanical properties shown previously, indicate that the NACP-based nanocomposites are promising for restorations to inhibit caries and protect tooth structures. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Prevention of root caries with dentin adhesives.

PubMed

Grogono, A L; Mayo, J A

1994-04-01

This in vitro investigation determined the feasibility of using dentin adhesives to protect root surfaces against caries. The roots of 22 recently extracted human teeth were all painted with a protective lacquer leaving two unprotected small windows. On each specimen, one window (control) was left untreated and the other window (experimental) was treated using a dentin adhesive (Scotchbond Multi-Purpose). The roots were then immersed in an in vitro acetate/calcium/phosphate demineralization model at pH 4.3. After 70 days, the samples were removed and sectioned through the windows. The undecalcified ground sections were examined under transmitted and polarized light. Lesions characteristic of natural root caries were seen in the untreated control windows. No such lesions were apparent in the experimental windows. The results of this preliminary study suggest that dentin adhesives may provide protection against root caries.

Ions-modified nanoparticles affect functional remineralization and energy dissipation through the resin-dentin interface.

PubMed

Toledano, Manuel; Osorio, Raquel; Osorio, Estrella; Medina-Castillo, Antonio Luis; Toledano-Osorio, Manuel; Aguilera, Fátima S

2017-04-01

The aim of this study was to evaluate changes in the mechanical and chemical behavior, and bonding ability at dentin interfaces infiltrated with polymeric nanoparticlesstandard deviations and modes of failure are (NPs) prior to resin application. Dentin surfaces were treated with 37% phosphoric acid followed by application of an ethanol suspension of NPs, Zn-NPs or Ca-NPs followed by the application of an adhesive, Single Bond (SB). Bonded interfaces were stored for 24h, submitted to microtensile bond strength test, and evaluated by scanning electron microscopy. After 24h and 21 d of storage, the whole resin-dentin interface adhesive was evaluated using a Nano-DMA. Complex modulus, storage modulus and tan delta (δ) were assessed. AFM imaging and Raman analysis were performed. Bond strength was not affected by NPs infiltration. After 21 d of storage, tan δ generally decreased at Zn-NPs/resin-dentin interface, and augmented when Ca-NPs or non-doped NPs were used. When both Zn-NPs and Ca-NPs were employed, the storage modulus and complex modulus decreased, though both moduli increased at the adhesive and at peritubular dentin after Zn-NPs infiltration. The phosphate and the carbonate peaks, and carbonate substitution, augmented more at interfaces promoted with Ca-NPs than with Zn-NPs after 21 d of storage, but crystallinity did not differ at created interfaces with both ions-doped NPs. Crosslinking of collagen and the secondary structure of collagen improved with Zn-NPs resin-dentin infiltration. Ca-NPs-resin dentin infiltration produced a favorable dissipation of energy with minimal stress concentration trough the crystalline remineralized resin-dentin interface, causing minor damage at this structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of double-coating and times on the immediate and 6-month dentin bonding of universal adhesives.

PubMed

Pashaev, Diial; Demirci, Mustafa; Tekçe, Neslihan; Tuncer, Safa; Baydemir, Canan

2017-01-01

The purpose of this study was to evaluate the effect of double-application coats and times on microtensile bond strength (μTBS) and adhesive-dentin interfaces created by dentin adhesive systems after 6 months of storage in water. Two-hundred sixteen extracted non-carious human third molars were selected for the study. Single-Bond Universal (SU) and All-Bond Universal (AU), Adper Easy One (Eo) Self-Etch adhesive and Adper Single-Bond 2 (Sb) etch-and-rinse adhesive were applied to a flat dentin surface using three methods (1): dentin adhesives were applied as recommended by the manufacturers; (2): two consecutive coats of dentin adhesives were applied before photo-polymerization; and (3): a single coat of adhesive was applied but with twice the manufacturers recommended application time. Microtensile bond strength was determined either immediately or after 6 months of water storage. Data were analyzed using one-way analysis of variance and Tukey's post-hoc tests. At 24 h, groups 1, 2, and 3 exhibited statistically similar results for all dentin adhesive systems. For AU-Er, group 3 showed significantly higher bond strength than all group of AU-Se after 6 months. Universal adhesives seemed more stable against water degradation than traditional two-step etch-and-rinse and all-in-one systems within the 6-month period.

Imperfect hybrid layers created by an aggressive one-step self-etch adhesive in primary dentin are amendable to biomimetic remineralization in vitro

PubMed Central

Kim, Jongryul; Vaughn, Ryan M.; Gu, Lisha; Rockman, Roy A.; Arola, Dwayne D.; Schafer, Tara E.; Choi, Kyungkyu; Pashley, David H.; Tay, Franklin R.

2009-01-01

Degradation of hybrid layers created in primary dentin occurs as early as 6 months in vivo. Biomimetic remineralization utilizes “bottom-up” nanotechnology principles for interfibrillar and intrafibrillar remineralization of collagen matrices. This study examined whether imperfect hybrid layers created in primary dentin can be remineralized. Coronal dentin surfaces were prepared from extracted primary molars and bonded using Adper Prompt L-Pop and a composite. One millimeter-thick specimen slabs of the resin-dentin interface were immersed in a Portland cement-based remineralization medium that contained two biomimetic analogs to mimic the sequestration and templating functions of dentin noncollagenous proteins. Specimens were retrieved after 1–6 months. Confocal laser scanning microscopy was employed for evaluating the permeability of hybrid layers to Rhodamine B. Transmission electron microscopy was used to examine the status of remineralization within hybrid layers. Remineralization at different locations of the hybrid layers corresponded with quenching of fluorescence within similar locations of those hybrid layers. Remineralization was predominantly intrafibrillar in nature as interfibrillar spaces were filled with adhesive resin. Biomimetic remineralization of imperfect hybrid layers in primary human dentin is a potential means for preserving bond integrity. The success of the current proof-of-concept, laterally-diffusing remineralization protocol warrants development of a clinically-applicable biomimetic remineralization delivery system. PMID:19768792

Evaluation of ex vivo effectiveness of commercial desensitizing dentifrices

PubMed Central

Mockdeci, Hanny; Polonini, Hudson; Granato, Ana-Paula; Raposo, Nádia; Chaves, Maria-das Graças

2017-01-01

Background Dentin hypersensitivity is a short, severe pain with fast onset. Therapy aims to either prevent or decrease neural transmission or physically occlude the dentinal tubules. This study aimed to evaluate the effectiveness of commercial desensitizing dentifrice by means of an ex vivo method. Material and Methods Samples (n=8 lower human premolars for each group) were randomly allocated into: G1- brushing with Colgate®Sensitive Pro-Relief; G2- brushing with Sensodyne®Rapid Relief; G3- brushing with Sensodyne®Repair & Protect; and G4- brushing with Colgate®Maximum Cavity Protection. The test bodies were submitted to simulated toothbrushing and dentifrices were analyzed regarding their hydrodynamic size, polydispersity index (PI) and zeta potential. Specimens were evaluated using: scanning electron microscopy (SEM); spectroscopy energy dispersive X-ray (EDS); and profilometry. A qualitative analysis of the photomicrographs and topographies was performed. Results The dentifrices showed statistical similar physical and chemical characteristics. They also demonstrated obliteration of dentinal tubules when micrographs were observed. Regarding the chemical elements present in the dentin samples, there was a statistically significant difference between the control and experimental surfaces in the four groups. Conclusions Joint data analysis shows that the desensitizing dentifrice showed better results with regards to the obliteration of dentinal tubules compared to positive and negative controls. Key words:Dentin hypersensitivity, dentin desensitizing agents, toothpastes. PMID:28469813

Selective treatment of carious dentin using a mid-infrared tunable pulsed laser at 6 μm wavelength range

NASA Astrophysics Data System (ADS)

Saiki, Masayuki; Ishii, Katsunori; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

2011-03-01

Optical technologies have good potential for caries detection, prevention, excavation, and the realization of minimal intervention dentistry. This study aimed to develop a selective excavation technique of carious tissue using the specific absorption in 6 μm wavelength range. Bovine dentin demineralized with lactic acid solution was used as a carious dentin model. A mid-infrared tunable pulsed laser was obtained by difference-frequency generation technique. The wavelength was tuned to 6.02 and 6.42 μm which correspond to absorption bands called amide I and amide II, respectively. The laser delivers 5 ns pulse width at a repetition rate of 10 Hz. The morphological change after irradiation was observed with a scanning electron microscope, and the measurement of ablation depth was performed with a confocal laser microscope. At λ = 6.02 μm and the average power density of 15 W/cm2, demineralized dentin was removed selectively with less-invasive effect on sound dentin. The wavelength of 6.42 μm also showed the possibility of selective removal. High ablation efficiency and low thermal side effect were observed using the nanosecond pulsed laser with λ = 6.02 μm. In the near future, development of compact laser device will open the minimal invasive laser treatment to the dental clinic.

Effects of acidification on the isotopic ratios of Neotropical otter tooth dentin.

PubMed

Carrasco, Thayara S; Botta, Silvina; Machado, Rodrigo; Colares, Elton P; Secchi, Eduardo R

2018-05-30

Stable carbon and nitrogen isotope ratios are widely used in ecological studies providing important information on the trophic ecology and habitat use of consumers. However, some factors may lead to isotopic variability, which makes difficult the interpretation of data, such as the presence of inorganic carbon in mineralized tissues. In order to remove the inorganic carbon, acidification is a commonly used treatment. The effects of two methods of acidification were tested: (i) dentin acidification with 10% HCl using the 'drop-by-drop' technique, and (ii) dentin acidification in an 'HCl atmosphere', by exposing the dentin to vaporous 30% hydrochloric acid. Results were compared with untreated subsamples. The stable carbon and nitrogen ratios of untreated and acidified subsamples were measured using an elemental analyzer coupled to an isotope ratio mass spectrometer. The nitrogen isotopic ratios were statistically different between the two acidification treatments, but no significant changes in carbon isotopic ratios were found in acidified and untreated samples. The results indicated that acidification had no effect on carbon isotopic ratios of Neotropical otter tooth dentin, while introducing a source of error in nitrogen isotopic ratios. Therefore, we conclude that acidification is an unnecessary step for C and N stable isotope analysis. Copyright © 2018 John Wiley & Sons, Ltd.

Assessment of the amount of remaining coronal dentine in root-treated teeth.

PubMed

Bandlish, R B; McDonald, A V; Setchell, D J

2006-10-01

There is currently no standardised technique to measure the amount of coronal dentine remaining in a root-treated tooth after crown preparation. The aim of this study was to develop a method of measuring remaining coronal dentine in root-treated teeth and to propose an index for grading tooth restorability. The study recruited 20 patients who had completed molar endodontic treatment at the Eastman Dental Hospital and had been prescribed an amalgam coronal-radicular core with a full coverage cast restoration. Using a series of interlocking special trays and impressions, a method was devised to produce a cast of the amount of remaining dentine coronal to the finish line after crown preparation. This cast was scanned using a laser profilometer and the volume of remaining dentine was calculated. A tooth restorability index (TRI) was developed to assess the strategic value of the remaining dentine. The TRI allowed scores of 0-3 in each sextant with a maximum score of 18 per tooth. Twenty teeth were scored by three examiners and the TRI scores varied from 2 to 13. The volume of coronal dentine varied from 61.73 to 232.22 mm(3). A tooth restorability index has been devised to assess the strategic value of remaining dentine. A Kappa statistic was calculated to produce values of 0.584, 0.688 and 0.720, giving moderate-good agreement between the examiners.

Optical coherence tomography guided dental drill

DOEpatents

DaSilva, Luiz B.; Colston, Jr., Bill W.; James, Dale L.

2002-01-01

A dental drill that has one or multiple single mode fibers that can be used to image in the vicinity of the drill tip. It is valuable to image below the surface being drilled to minimize damage to vital or normal tissue. Identifying the boundary between decayed and normal enamel (or dentine) would reduce the removal of viable tissue, and identifying the nerve before getting too close with the drill could prevent nerve damage. By surrounding a drill with several optical fibers that can be used by an optical coherence domain reflectometry (OCDR) to image several millimeters ahead of the ablation surface will lead to a new and improved dental treatment device.

[Dentinopulpar organ: biological basis of clinical response to Ca(OH)2 application].

PubMed

Gani, O; Crosa, M E

1989-01-01

We have studied the changes presented by mediate and immediate roentgenographic images of indirect pulp capping and pulpotomies. In the cases of indirect pulp capping it was observed an increase of radiolucidity in the places occupied by Ca(OH)2, and sclerotic dentin was present. In pulpotomies, it was found the dentin bridge, which thickness increases with time. The radiolucidity of pulp chamber occupied by Ca(OH)2 was greater in the long time treatment. The radiopacity of non-vital dentin of walls and floor chamber was increased too. It has suggested that Ca++ ion would have migrated from its place and probably would take part in the synthesis of sclerotic dentin, independently of the vitality of the tissue.

Violet and blue light-induced green fluorescence emissions from dental caries.

PubMed

Shakibaie, F; Walsh, L J

2016-12-01

The objective of this laboratory study was to compare violet and visible blue LED light-elicited green fluorescence emissions from enamel and dentine in healthy or carious states. Microscopic digital photography was undertaken using violet and blue LED illumination (405 nm and 455 nm wavelengths) of tooth surfaces, which were photographed through a custom-made stack of green compensating filters which removed the excitation light and allowed green fluorescence emissions to pass. Green channel pixel data were analysed. Dry sound enamel and sound root surfaces showed strong green fluorescence when excited by violet or blue lights. Regions of cavitated dental caries gave lower green fluorescence, and this was similar whether the dentine in the lesions was the same colour as normal dentine or was darkly coloured. The presence of saliva on the surface did not significantly change the green fluorescence, while the presence of blood diluted in saliva depressed green fluorescence. Using violet or blue illumination in combination with green compensating filters could potentially aid in the assessment of areas of mineral loss. © 2016 Australian Dental Association.

Efficacy of removal of cariogenic bacteria and carious dentin by ablation using different modes of Er:YAG lasers

PubMed Central

Baraba, A.; Kqiku, L.; Gabrić, D.; Verzak, Ž.; Hanscho, K.; Miletić, I.

2018-01-01

The primary objective of this in vitro study was to evaluate the efficiency of removal of cariogenic bacteria and carious dentin by ablation using two lasers: fluorescence-feedback controlled (FFC) Er:YAG laser and different pulses of Er:YAG laser based on variable square pulse technology (VSPt). The secondary objective was to measure the temperature during laser ablation of carious tissue. Seventy-two extracted human molars were used in this study. Sixty teeth with carious dentin were randomly divided into four experimental groups according to the treatment for caries removal: group 1: 400 µs (FFC group); group 2: super short pulse (SSP group, 50 µs pulse); group 3: medium short pulse (MSP group, 100 µs pulse); group 4: short pulse (SP group, 300 µs pulse) and one positive control group with no treatment. Twelve teeth without carious lesion were used as a negative control group. After caries removal, swabs were taken with cotton pellets and real-time PCR analysis was performed. During caries ablation, a thermal infrared camera was used to measure the temperature changes. In all experimental groups, specimens were free of bacterial contamination after the treatment. In the SSP, MSP and SP groups, temperatures measured during caries ablation were significantly higher compared to temperatures in the FFC group (P<0.001). In this in vitro study, laser treatment for removal of carious dentin and cariogenic bacteria was an efficient treatment modality without causing excessive temperatures that might adversely affect pulp vitality. PMID:29340524

Efficacy of removal of cariogenic bacteria and carious dentin by ablation using different modes of Er:YAG lasers.

PubMed

Baraba, A; Kqiku, L; Gabrić, D; Verzak, Ž; Hanscho, K; Miletić, I

2018-01-11

The primary objective of this in vitro study was to evaluate the efficiency of removal of cariogenic bacteria and carious dentin by ablation using two lasers: fluorescence-feedback controlled (FFC) Er:YAG laser and different pulses of Er:YAG laser based on variable square pulse technology (VSPt). The secondary objective was to measure the temperature during laser ablation of carious tissue. Seventy-two extracted human molars were used in this study. Sixty teeth with carious dentin were randomly divided into four experimental groups according to the treatment for caries removal: group 1: 400 µs (FFC group); group 2: super short pulse (SSP group, 50 µs pulse); group 3: medium short pulse (MSP group, 100 µs pulse); group 4: short pulse (SP group, 300 µs pulse) and one positive control group with no treatment. Twelve teeth without carious lesion were used as a negative control group. After caries removal, swabs were taken with cotton pellets and real-time PCR analysis was performed. During caries ablation, a thermal infrared camera was used to measure the temperature changes. In all experimental groups, specimens were free of bacterial contamination after the treatment. In the SSP, MSP and SP groups, temperatures measured during caries ablation were significantly higher compared to temperatures in the FFC group (P<0.001). In this in vitro study, laser treatment for removal of carious dentin and cariogenic bacteria was an efficient treatment modality without causing excessive temperatures that might adversely affect pulp vitality.

Efficacy of Modified Bioactive Glass for Dentin Remineralization and Obstruction of Dentinal Tubules.

PubMed

Saffarpour, Mahshid; Mohammadi, Maryam; Tahriri, Mohammadreza; Zakerzadeh, Azadeh

2017-07-01

This study assessed the efficacy of modified bioactive glass (MBG) for dentin remineralization and obstruction of dentinal tubules. Thirty-six dentin discs were made from 20 third molars and were stored in 12% lactic acid solution for two weeks to induce demineralization. The samples were divided into three groups (n=12): 1- BG, 2- BG modified with 5% strontium (Sr) and 3- BG modified with 10% Sr. After applying the BG, the samples were stored in artificial saliva for 7, 14 and 21 days. Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray (EDX) analysis were used to assess remineralization. Also, 6 dentin discs were divided into three groups of BG, BG modified with 5% Sr and BG modified with 10% Sr, to examine tubular occlusion. The discs were etched using 0.5M of EDTA for two minutes and were stored in artificial saliva for 7 days. Changes in dentin surface morphology were evaluated under SEM. Group 3 showed high rates of remineralization at days 7 and 14, although the rate decreased at day 21. Group 2 exhibited high rates of remineralization at days 7, 14 and 21. Dentinal tubules were partially occluded by BG and BG modified with 5% Sr, while they were almost completely obstructed after the use of BG modified with 10% Sr. Strontium increases remineralization. Addition of 10% Sr to BG enhances apatite formation; however, the apatite dissolves over time. Addition of 5% Sr to BG stabilizes the apatite lattice and increases the remineralization.

Clinical status of ten dentin adhesive systems.

PubMed

Van Meerbeek, B; Peumans, M; Verschueren, M; Gladys, S; Braem, M; Lambrechts, P; Vanherle, G

1994-11-01

Laboratory testing of dentin adhesive systems still requires corroboration by long-term clinical trials for their ultimate clinical effectiveness to be validated. The objective of this clinical investigation was to evaluate, retrospectively, the clinical effectiveness of earlier-investigated dentin adhesive systems (Scotchbond, Gluma, Clearfil New Bond, Scotchbond 2, Tenure, and Tripton), and to compare their clinical results with those obtained with four modern total-etch adhesive systems (Bayer exp. 1 and 2, Clearfil Liner Bond System, and Scotchbond Multi-Purpose). In total, 1177 Class V cervical lesions in the teeth of 346 patients were restored following two cavity designs: In Group A, enamel was neither beveled nor intentionally etched, as per ADA guidelines; in Group B, adjacent enamel was beveled and conditioned. Clinical retention rates definitely indicated the improved clinical efficacy of the newest dentin adhesives over the earlier systems. With regard to adhesion strategy, adhesive systems that removed the smear layer and concurrently demineralized the dentin surface layer performed clinically better than systems that modified the disorderly layer of smear debris without complete removal. Hybridization by resin interdiffusion into the exposed dentinal collagen layer, combined with attachment of resin tags into the opened dentin tubules, appeared to be essential for reliable dentin bonding but might be insufficient by itself. The additional formation of an elastic bonding area as a polymerization shrinkage absorber and the use of a microfine restorative composite apparently guaranteed an efficient clinical result. The perfect one-year retention recorded for Clearfil Liner Bond System and Scotchbond Multi-Purpose must be confirmed at later recalls.

Effects of Dentin Debris on the Antimicrobial Properties of Sodium Hypochlorite and Etidronic Acid.

PubMed

Arias-Moliz, Maria Teresa; Morago, Ana; Ordinola-Zapata, Ronald; Ferrer-Luque, Carmen María; Ruiz-Linares, Matilde; Baca, Pilar

2016-05-01

The purpose of this study was to determine the influence of dentin powder on the concentration, pH, and antimicrobial activity of sodium hypochlorite (NaOCl) alone and combined with etidronic acid (HEBP). Biofilms of Enterococcus faecalis were grown on the surface of dentin blocks for 5 days and then exposed to 1% and 2.5% NaOCl alone or combined with 9% HEBP for 3 minutes in the absence and presence of dentin powder. The biovolumes of the biofilm were measured using confocal microscopy and the live/dead technique. The available chlorine and pH of the solutions were also measured. Nonparametric tests were used to determine statistical differences (P < .05). The presence of dentin powder resulted in a reduction of the free available chlorine and pH in all the irrigating solutions; 1% NaOCl lost its antimicrobial activity completely in the presence of dentin powder. The antimicrobial activity was significantly reduced in the 2.5% NaOCl and 1% NaOCl/HEBP groups, and it was not affected in the 2.5% NaOCl/HEBP group. The presence of dentin powder significantly decreased the available chlorine and antimicrobial activity of 1% NaOCl, 2.5% NaOCl, and 1% NaOCl/HEBP irrigating solutions. The antimicrobial activity of 2.5% NaOCl/HEBP was not affected by the dentin powder after a 3-minute contact time against E. faecalis biofilms. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Dentine tubule infection and endodontic therapy implications.

PubMed

Oguntebi, B R

1994-07-01

A critical review of the literature suggests that the microenvironment of dentinal tubules appears to favour the selection of relatively few bacterial types irrespective of the aetiology of the infection process; coronal dental caries or pulpar necrosis. These bacteria may constitute an important reservoir from which root canal infection and reinfection may occur following pulp necrosis or during and after endodontic treatment. Previous studies of this microflora have utilized microbiological culture techniques which need to be supplemented by those that allow in situ demonstration as well as identification of the bacteria. Newer treatment strategies that are designed to eliminate this microflora must include agents that can penetrate the dentinal tubules and destroy these microorganisms, since they are located in an area beyond the host defence mechanisms where they cannot be reached by systemically administered antimicrobial agents.

Effect of desensitizing agents on dentin permeability.

PubMed

Ishihata, Hiroshi; Kanehira, Masafumi; Nagai, Tomoko; Finger, Werner J; Shimauchi, Hidetoshi; Komatsu, Masashi

2009-06-01

To investigate the in vitro efficacy of two dentin desensitizing products at reducing liquid permeability through human dentin discs. The tested hypothesis was that the products, in spite of different chemical mechanisms were not different at reducing or eliminating flow through dentin discs. Dentin slices (1 mm thick) were prepared from 16 extracted human third molars and their permeability was indirectly recorded in a split chamber model, using a chemiluminescence technique, after EDTA treatment (control), after soaking with albumin, and after desensitizer application. Two products were studied: MS Coat, a self-curing resin-containing oxalate product, and Gluma Desensitizer, a glutaraldehyde/HEMA-based agent without initiator. The dentin slices were mounted between an upper chamber, filled with an aqueous solution of 1% potassium ferricyanide and 0.3% hydrogen peroxide, and a lower chamber filled with 1% sodium hydroxide solution and 0.02% luminol. The upper solution was pressurized, and upon contact with the luminol solution a photochemical signal was generated and recorded as a measure of permeability throughout two consecutive pressurizing cycles at 2.5 and 13 kPa (26 and 133 cm H2O), respectively. The permeability of the control and albumin-soaked samples was similarly high. After application of the desensitizing agents, dentin permeability was reduced to virtually zero at both pressure levels (P < 0.001).

Viscoelasticity and plasticity mechanisms of human dentin

NASA Astrophysics Data System (ADS)

Borodin, E. N.; Seyedkavoosi, S.; Zaitsev, D.; Drach, B.; Mikaelyan, K. N.; Panfilov, P. E.; Gutkin, M. Yu.; Sevostianov, I.

2018-01-01

Theoretical models of viscoelastic behavior and plastic deformation mechanisms of human dentin are considered. Using the linear viscoelasticity theory in which creep and relaxation kernels have the form of fraction-exponential functions, numerical values of instantaneous and long-time Young's moduli and other characteristics of dentin viscoelasticity under uniaxial compression are found. As dentin plastic deformation mechanisms, mutual collagen fiber sliding in the region of contact of their side surfaces, separation of these fibers from each other, and irreversible tension of some collagen fibers, are proposed. It is shown that the second mechanism activation requires a smaller stress than that for activating others. The models of plastic zones at the mode I crack tip, which correspond to these mechanisms, are studied. It is shown that the plastic zone size can increase from a few hundreds of nanometers to hundreds of micrometers with increasing applied stress.

Molecular energy dissipation in nanoscale networks of dentin matrix protein 1 is strongly dependent on ion valence

NASA Astrophysics Data System (ADS)

Adams, J.; Fantner, G. E.; Fisher, L. W.; Hansma, P. K.

2008-09-01

The fracture resistance of biomineralized tissues such as bone, dentin, and abalone is greatly enhanced through the nanoscale interactions of stiff inorganic mineral components with soft organic adhesive components. A proper understanding of the interactions that occur within the organic component, and between the organic and inorganic components, is therefore critical for a complete understanding of the mechanics of these tissues. In this paper, we use atomic force microscope (AFM) force spectroscopy and dynamic force spectroscopy to explore the effect of ionic interactions within a nanoscale system consisting of networks of dentin matrix protein 1 (DMP1) (a component of both bone and dentin organic matrix), a mica surface and an AFM tip. We find that DMP1 is capable of dissipating large amounts of energy through an ion-mediated mechanism, and that the effectiveness increases with increasing ion valence.

Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

PubMed

Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

2012-01-01

The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (p<0.01). The GC group presented a significantly lower peroxide passage than did GD and GE (p<0.01). It can be concluded that the hydrogen peroxide placed into the pulp chamber passed through the dental hard tissues, reaching the external surface and the periodontal tissue. The cementum surface was less permeable than were the dentin and enamel surfaces.

A prospective, randomized, comparative clinical study of resin composite and glass ionomer cement for retrograde root filling.

PubMed

Jensen, S S; Nattestad, A; Egdø, P; Sewerin, I; Munksgaard, E C; Schou, S

2002-12-01

To compare the clinical and radiographic treatment outcome of retrograde root filling with either dentin-bonded resin composite (Retroplast, RP) or glass ionomer cement (Chelon-Silver, CS). A prospective, randomized clinical study of 134 consecutive patients with indication of retrograde root filling of an incisor, canine, premolar, or first molar. Either RP or CS was chosen at random as retrograde filling material. Either material was applied onto the entire resection surface after prepared slightly concave. This preparation technique makes a sealing of the entire resection surface possible and prevents marginal contraction gaps during polymerization. A total of 122 patients were available for 1-year follow-up. After 1 year the proportion of successful cases was significantly higher in the RP group (73%) than in the CS group (31%) (p<0.001). Doubtful healing with a need for a longer observation period was seen in 17% of the RP cases and 19% of the CS cases. The proportion of failures in the RP group (10%) was significantly lower than that in the CS group (50%) (p<0.001). Most of the unsuccessful CS cases failed due to loosening of the retrograde filling. Dentin-bonded RP applied onto the entire, slightly concave resection surface is a predictable apical sealant characterized by a high success rate. In contrast, retrograde root filling with CS results in an unacceptably high failure rate due to insufficient bonding strength to the concave resection surface.

Dental Stem Cell Migration on Pulp Ceiling Cavities Filled with MTA, Dentin Chips, or Bio-Oss

PubMed Central

Lymperi, Stefania; Taraslia, Vasiliki; Tsatsoulis, Ioannis N.; Samara, Athina; Agrafioti, Anastasia; Anastasiadou, Ema; Kontakiotis, Evangelos

2015-01-01

MTA, Bio-Oss, and dentin chips have been successfully used in endodontics. The aim of this study was to assess the adhesion and migration of dental stem cells on human pulp ceiling cavities filled with these endodontic materials in an experimental model, which mimics the clinical conditions of regenerative endodontics. Cavities were formed, by a homemade mold, on untouched third molars, filled with endodontic materials, and observed with electron microscopy. Cells were seeded on cavities' surface and their morphology and number were analysed. The phenomenon of tropism was assessed in a migration assay. All three materials demonstrated appropriate microstructures for cell attachment. Cells grew on all reagents, but they showed a differential morphology. Moreover, variations were observed when comparing cells numbers on cavity's filling versus the surrounding dentine disc. The highest number of cells was recorded on dentin chips whereas the opposite was true for Bio-Oss. This was confirmed in the migration assay where a statistically significant lower number of cells migrated towards Bio-Oss as compared to MTA and dentin chips. This study highlights that MTA and dentin chips have a greater potential compared to Bio-Oss regarding the attraction of dental stem cells and are good candidates for bioengineered pulp regeneration. PMID:26146613

[The effects of the processing technic on dentinal adhesion].

PubMed

Krejci, I; Lutz, F; Perisic, U

1992-01-01

In this in vitro study, the effect of application techniques on marginal adaptation of thermal cycled class V restorations restored with an actual dentinal adhesive were quantitated using SEM and dye penetration. Under optimal application conditions, excellent results were generated: though a simple bulk insertion technique was used, no difference was found between enamel and dentin margins before and after thermal loading. On the other hand, contamination of the bonding agent with saliva before composite resin insertion dramatically decreased the percentage of "excellent margin" in dentin and in enamel. Similar effects were found after protecting the bonding agent with an insulating gel. No improvement in marginal adaptation was found after reapplication of the bonding agent. The class V inlay did not show better results than the direct filling technique. However, postcured inlays performed better than their non-postcured counterparts. Without etching enamel with a phosphoric acid gel, but by priming its surface, approximately 80% of "excellent margin" were found in enamel before thermal cycling. This percentage decreased significantly after thermal loading. Restorations totally confined to dentin had slightly lower percentages of "excellent margin" than the mixed class V fillings. The results of this study indicated, that by using dentinal adhesives, little changes and deviations from the correct procedure result in significant alterations in marginal adaptation.

Inhibitory effects of acid water prepared by an electrolysis apparatus on early plaque formation on specimens of dentine.

PubMed

Ito, K; Nishida, T; Murai, S

1996-05-01

The aim of this study was to compare the effects of acid water prepared by an electrolysis apparatus with placebo treatment on the ultrastructure of early plaque formed on dentine specimens attached to retainers in the oral cavity. Dentine specimens were taken from 12 healthy extracted human 3rd molars. 4 dentine specimens were placed in the both the right and left buccal flanges of retainers fabricated from self-setting acrylic resin. The retainers were placed on both maxillary buccal sites in 6 subjects. The test solution was acid water (AW) prepared by an electrolysis apparatus with a pH of 2.7 and an oxidation-reduction potential of more than 1100 mV. As a positive control, 0.2% chlorhexidine digluconate (CHX) solution was used and normal saline solution as a negative control. 4 specimens placed in the right and left retainers were randomly allocated to 4 treatments as follows: treatment A, washing with AW; treatment B, washing with CHX solution; treatment C, washing with normal saline; treatment D, no washing. Washing was carried out in a plastic beaker containing 30 ml of each solution for 30s 2X daily over a 7-day period. The specimens were then carefully removed from the retainers, the morphology and thickness of the plaque formed examined by SEM, and the developmental condition of the plaque analyzed statistically. The plaque on the specimens in treatments A and B consisted mainly of coccoid forms. Mature plaque formation with complex flora was seen on the specimens in treatments C and D. The mean thickness of the plaque deposits on the dentin specimens as measured on SEM photographs magnified 2000 times was 8.80 mm for treatment. A, while in treatment B it was 3.90 mm. Plaque thickness for treatment C was 24.97 mm, and for treatment D 25.67 mm. The thickness of plaque formed on the sectioned specimens was significantly less for treatments A and B than for treatments C and D. However, there was no statistically significant difference between treatments A and B, and between treatments C and D (p < 0.0001). The results of this short-term study indicate that AW washing has almost the same potential for inhibition of plaque formation as CHX washing, and is more effective for inhibiting plaque formation than washing with sterile saline. It is therefore concluded that AW may be useful as an anti-plaque agent.

Effects of fluoride and epigallocatechin gallate on soft-drink-induced dental erosion of enamel and root dentin.

PubMed

Wang, Yin-Lin; Chang, Hao-Hueng; Chiang, Yu-Chih; Lu, Yu-Chen; Lin, Chun-Pin

2018-04-01

Fluoride and epigallocatechin gallate (EGCG) have been proven to prevent dental caries. The purpose of this study was to evaluate the effects of fluoride and EGCG on soft-drink-induced dental erosion in vitro. Forty enamel and dentin specimens were prepared from extracted human teeth. The specimens were divided into 4 groups and treated separately with distilled water (as control), 0.5 M sodium fluoride (NF), 400 μM EGCG (EG), and a solution containing 0.5 M NaF and 400 μM EGCG (FG). Cyclic erosive treatment was performed according to the experimental procedures. The specimens were analyzed using laser scanning confocal microscopy, scanning electron microscopy, and a microhardness tester. The data were analyzed using ANOVA and Bonferroni's post hoc test. The significance level was set at 5%. The amount of substance loss was lower in the NF and EG groups than in the control group (p < 0.05). The erosion-caused substance loss was more pronounced in the dentin than in the enamel specimens. Surface microhardness loss was lower in the NF and EG groups than in the control group (p < 0.05). The diameter of the dentinal tubule was wider in the control group than in the NF and EG groups (p < 0.05). No combined effects were observed in the FG group. Both fluoride and EGCG are effective in preventing soft-drink-induced erosion compared with the control group. Fluoride and EGCG may interfere with each other. The mechanisms of the anti-erosive effect need to be explored in the future. Copyright © 2018. Published by Elsevier B.V.

Marginal adaptation and retention of a glass-ionomer, resin-modified glass-ionomers and a polyacid-modified resin composite in cervical Class-V lesions.

PubMed

Gladys, S; Van Meerbeek, B; Lambrechts, P; Vanherle, G

1998-07-01

An 18-month follow-up clinical trial of one conventional glass-ionomer (HIFI Master Palette), three resin-modified glass-ionomers (Fuji II LC, Vitremer, 3M Exp. 155) and one polyacid-modified resin composite (Dyract) was conducted to evaluate their clinical effectiveness in Class-V cervical lesions. In addition, the interface between dentin and two resin-modified glass-ionomers and one polyacid-modified resin composite was examined by scanning electron microscopy (SEM). After evaluation of the restorations immediately following placement (baseline), all patients were subjected to a strict recall schedule with controls at 6, 12 and 18 months. The clinical effectiveness was recorded in terms of retention and marginal integrity, clinical microleakage, caries recurrence, and tooth vitality. A chi 2-test (p < 0.05) was used to test for significant differences between materials. In case of restoration loss or special defects, a replica was made to examine the surface texture and restoration margins by SEM. In vitro, the interface was examined by SEM after an argon-ion-beam etching technique was used to enhance surface relief and disclose interfacial substructures. Retention appeared to be good for all the materials tested. Marginal discrepancies were localized at the incisal enamel and/or the cervical dentin margin, except for the polyacid-modified resin composite that showed most of the defects at the incisal enamel margin. None of the systems could guarantee margins free of microleakage for a long time. In vitro, the type of dentin pre-treatment defines to a great extent the morphology of the resultant interface between dentin and the restorative material tested. In this clinical study, the retention rate of the tested materials was good and even excellent for some products. Perfect marginal adaptation deteriorated too fast. The marginal adaptation of the polyacid-modified resin composite at the enamel site would probably have been better by the use of selective enamel or total acid etching. Marginal sealing remains a problem. Future research should concentrate on improving the marginal adaptation and sealing capacities before a broader clinical use can be advocated.

Periodontal ligament stem/progenitor cells with protein-releasing scaffolds for cementum formation and integration on dentin surface.

PubMed

Cho, Hankyu; Tarafder, Solaiman; Fogge, Michael; Kao, Kristy; Lee, Chang H

2016-11-01

Purpose/Aim: Cementogenesis is a critical step in periodontal tissue regeneration given the essential role of cementum in anchoring teeth to the alveolar bone. This study is designed to achieve integrated cementum formation on the root surfaces of human teeth using growth factor-releasing scaffolds with periodontal ligament stem/progenitor cells (PDLSCs). Human PDLSCs were sorted by CD146 expression, and characterized using CFU-F assay and induced multi-lineage differentiation. Polycaprolactone scaffolds were fabricated using 3D printing, embedded with poly(lactic-co-glycolic acids) (PLGA) microspheres encapsulating connective tissue growth factor (CTGF), bone morphogenetic protein-2 (BMP-2), or bone morphogenetic protein-7 (BMP-7). After removing cementum on human tooth roots, PDLSC-seeded scaffolds were placed on the exposed dentin surface. After 6-week culture with cementogenic/osteogenic medium, cementum formation and integration were evaluated by histomorphometric analysis, immunofluorescence, and qRT-PCR. Periodontal ligament (PDL) cells sorted by CD146 and single-cell clones show a superior clonogenecity and multipotency as compared with heterogeneous populations. After 6 weeks, all the growth factor-delivered groups showed resurfacing of dentin with a newly formed cementum-like layer as compared with control. BMP-2 and BMP-7 showed de novo formation of tissue layers significantly thicker than all the other groups, whereas CTGF and BMP-7 resulted in significantly improved integration on the dentin surface. The de novo mineralized tissue layer seen in BMP-7-treated samples expressed cementum matrix protein 1 (CEMP1). Consistently, BMP-7 showed a significant increase in CEMP1 mRNA expression. Our findings represent important progress in stem cell-based cementum regeneration as an essential part of periodontium regeneration.

The effect of immediate dentin sealing and optical powder removal method on the fracture resistance of CAD/CAM-fabricated endocrowns.

PubMed

El-Damanhoury, Hatem M; Gaintantzopoulou, Marianna

2016-01-01

To evaluate the effect of immediate dentin sealing and optical powder removal method on the fracture resistance of CAD/CAM-fabricated ceramic endocrowns. Seventy-eight extracted premolars were endodontically treated. Standardized endocrown preparations were done in 60 teeth. Teeth were divided equally (n = 10) depending on the treatment of dentin (delayed sealing [DS] or immediate sealing [IS]), and the methods of optical powder removal (air-water spray washing [AW]; microabrasion [MA]; or aqueous suspension of pumice [PB], followed by air-water spray washing). After cementation, specimens were thermocycled (5,000 cycles, 5°C/50°C) and stored in distilled water for 1 week. Specimens were loaded in compression using a universal testing machine until failure. Failure load was recorded, and modes of failure were examined under a stereomicroscope. Micromorphological evaluation of different dentin treatments was done under SEM (n = 3). Results were analyzed using two-way ANOVA and Bonferroni post hoc multiple comparison tests (α = 0.05). Fracture resistance of all IS groups was significantly lower than DS groups, except for AW. There was no statistically significant difference between powder removal methods. Immediate dentin sealing does not improve the fracture resistance of endocrown restorations. Air-water spray washing is adequate to remove the optical powder after optical scanning impression taking.

Morphology of the cemento-enamel junction in premolar teeth.

PubMed

Arambawatta, Kapila; Peiris, Roshan; Nanayakkara, Deepthi

2009-12-01

The present study attempted to describe the distribution of the mineralized tissues that compose the cemento-enamel junction, with respect to both the different types of permanent premolars of males and females and the various surfaces of individual teeth. The cervical region of ground sections of 67 premolars that had been extracted for orthodontic reasons were analyzed using transmitted light microscopy to identify which of the following tissue interrelationships was present at the cemento-enamel junction: cementum overlapping enamel; enamel overlapping cementum; edge-to-edge relationship between cementum and enamel; or the presence of gaps between the enamel and cementum with exposed dentin. An edge-to-edge interrelation between root cementum and enamel was predominant (55.1%). In approximately one-third of the sample, gaps between cementum and enamel with exposed dentin were observed. Cementum overlapping enamel was less prevalent than previously reported, and enamel overlapping cementum was seen in a very small proportion of the sample. In any one tooth, the distribution of mineralized tissues at the cemento-enamel junction was irregular and unpredictable. The frequency of gaps between enamel and cementum with exposure of dentin was higher than previously reported, which suggests that this region is fragile and strongly predisposed to pathological changes. Hence, this region should be protected and carefully managed during routine clinical procedures such as dental bleaching, orthodontic treatment, and placement of restorative materials.

Effect of Airborne Particle Abrasion on Microtensile Bond Strength of Total-Etch Adhesives to Human Dentin

PubMed Central

Piccioni, Chiara; Di Carlo, Stefano; Capogreco, Mario

2017-01-01

Aim of this study was to investigate a specific airborne particle abrasion pretreatment on dentin and its effects on microtensile bond strengths of four commercial total-etch adhesives. Midcoronal occlusal dentin of extracted human molars was used. Teeth were randomly assigned to 4 groups according to the adhesive system used: OptiBond FL (FL), OptiBond Solo Plus (SO), Prime & Bond (PB), and Riva Bond LC (RB). Specimens from each group were further divided into two subgroups: control specimens were treated with adhesive procedures; abraded specimens were pretreated with airborne particle abrasion using 50 μm Al2O3 before adhesion. After bonding procedures, composite crowns were incrementally built up. Specimens were sectioned perpendicular to adhesive interface to produce multiple beams, which were tested under tension until failure. Data were statistically analysed. Failure mode analysis was performed. Overall comparison showed significant increase in bond strength (p < 0.001) between abraded and no-abraded specimens, independently of brand. Intrabrand comparison showed statistical increase when abraded specimens were tested compared to no-abraded ones, with the exception of PB that did not show such difference. Distribution of failure mode was relatively uniform among all subgroups. Surface treatment by airborne particle abrasion with Al2O3 particles can increase the bond strength of total-etch adhesives. PMID:29392128

Fourier transform infrared photoacoustic spectroscopy study of physicochemical interaction between human dentin and etch-&-rinse adhesives in a simulated moist bond technique.

PubMed

Ubaldini, Adriana L M; Baesso, Mauro L; Sehn, Elizandra; Sato, Francielle; Benetti, Ana R; Pascotto, Renata C

2012-06-01

The purpose of this study was to provide the physicochemical interactions at the interfaces between two commercial etch-&-rinse adhesives and human dentin in a simulated moist bond technique. Six dentin specimens were divided into two groups (n=3) according to the use of two different adhesive systems: (a) 2-hydroxyethylmethacrylate (HEMA) and 4-methacryloxyethyl trimellitate anhydrate (4-META), and (b) HEMA. The Fourier transform infrared photoacoustic spectroscopy was performed before and after dentin treatment with 37% phosphoric acid, with adhesive systems and also for the adhesive systems alone. Acid-conditioning resulted in a decalcification pattern. Adhesive treated spectra subtraction suggested the occurrence of chemical bonding to dentin expressed through modifications of the OH stretching peak (3340 cm(-1)) and symmetric CH stretching (2900 cm(-1)) for both adhesives spectra; a decrease of orthophosphate absorption band (1040 to 970 cm(-1)) for adhesive A and a better resolved complex band formation (1270 to 970 cm(-1)) for adhesive B were observed. These results suggested the occurrence of chemical bonding between sound human dentin and etch-&-rinse adhesives through a clinical typical condition.

Effect of air-blowing duration on the bond strength of current one-step adhesives to dentin.

PubMed

Fu, Jiale; Saikaew, Pipop; Kawano, Shimpei; Carvalho, Ricardo M; Hannig, Matthias; Sano, Hidehiko; Selimovic, Denis

2017-08-01

To evaluate the influence of different air-blowing durations on the micro-tensile bond strength (μTBS) of five current one-step adhesive systems to dentin. One hundred and five caries-free human molars and five current one-step adhesive systems were used: ABU (All Bond Universal, Bisco, Inc.), CUB (CLEARFIL™ Universal Bond, Kuraray), GPB (G-Premio BOND, GC), OBA (OptiBond All-in-one, Kerr) and SBU (Scotchbond Universal, 3M ESPE). The adhesives were applied to 600 SiC paper-flat dentin surfaces according to each manufacturer's instructions and were air-dried with standard, oil-free air pressure of 0.25MPa for either 0s, 5s, 15s or 30s before light-curing. Bond strength to dentin was determined by using μTBS test after 24h of water storage. The fracture pattern on the dentin surface was analyzed by SEM. The resin-dentin interface of untested specimens was visualized by panoramic SEM image. Data from μTBS were analyzed using two-way ANOVA (adhesive vs. air-blowing time), and Games-Howell (a=0.05). Two-way ANOVA revealed a significant effect of materials (p=0.000) and air-blowing time (p=0.000) on bond strength to dentin. The interaction between factors was also significantly different (p=0.000). Maximum bond strength for each system were recorded, OBA/15s (76.34±19.15MPa), SBU/15s (75.18±12.83MPa), CUB/15s (68.23±16.36MPa), GPB/30s (55.82±12.99MPa) and ABU/15s (44.75±8.95MPa). The maximum bond strength of OBA and SUB were significantly higher than that of GPB and ABU (p<0.05). The bond strength of the current one-step adhesive systems is material-dependent (p=0.000), and was influenced by air-blowing duration (p=0.000). For the current one-step adhesive systems, higher bond strengths could be achieved with prolonged air-blowing duration between 15-30s. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Comparison of shear bond strength of self-etch and self-adhesive cements bonded to lithium disilicate, enamel and dentin.

PubMed

Naranjo, Jennifer; Ali, Mohsin; Belles, Donald

2015-11-01

Comparison of shear bond strength of self-etch and self-adhesive cements bonded to lithium disilicate, enamel and dentin. With several self-adhesive resin cements currently available, there is confusion about which product and technique is optimal for bonding ceramic restorations to teeth. The objective of this study was to compare the shear bond strength of lithium disilicate cemented to enamel and dentin using 5 adhesive cements. 100 lithium disilicate rods were pretreated with 5% hydrofluoric acid, silane, and cemented to 50 enamel and 50 dentin surfaces using five test cements: Variolink II (etch-and-rinse) control group, Clearfil Esthetic (two step self-etch), RelyX Unicem, SpeedCEM, and BifixSE (self-adhesive). All specimens were stored (37 degrees C, 100% humidity) for 24 hours before testing their shear bond strength using a universal testing machine (Instron). Debonded surfaces were observed under a low-power microscope to assess the location and type of failure. The highest bond strength for both enamel and dentin were recorded for Variolink II, 15.1MPa and 20.4MPa respectively, and the lowest were recorded for BifixSE, 0.6MPa and 0.9MPa respectively. Generally, higher bond strengths were found for dentin (7.4MPa) than enamel (5.3MPa). Tukey's post hoc test showed no significant difference between Clearfil Esthetic and SpeedCem (p = 0.059), Unicem and SpeedCem (p = 0.88), and Unicem and BifixSE (p = 0.092). All cements bonded better to lithium disilicate than to enamel or dentin, as all bond failures occurred at the tooth/adhesive interface except for Variolink II. Bond strengths recorded for self-adhesive cements were very low compared to the control "etch and rinse" and self-etch systems. Further improvements are apparently needed in self-adhesive cements for them to replace multistep adhesive systems. The use of conventional etch and rinse cements such as Veriolink II should be preferred for cementing all ceramic restorations over self-adhesive cements until the bond strengths are improved.

The variation in surface morphology and hardness of human deciduous teeth samples after laser irradiation

NASA Astrophysics Data System (ADS)

Khalid, Arooj; Bashir, Shazia; Akram, Mahreen; Salman Ahmed, Qazi

2017-11-01

The variation in surface morphology and hardness of human deciduous teeth samples has been investigated after laser irradiation at different wavelengths and energies. Nd:YAG was employed as a source of irradiation for IR (1064 nm) and visible (532 nm) radiation, whereas an excimer laser was used as the source of UV (248 nm) radiation. Scanning electron microscope (SEM) analysis was carried out to reveal the surface morphological evolution of teeth samples. Vickers microhardness tester was employed to investigate the modifications in the hardness of the laser-treated samples. It is observed from SEM analysis that IR wavelength is responsible for ablation of collagen matrix and intertubular dentine. For visible radiation, the ablation of collagen along with hydroxypatite is observed. With UV radiation, the ablation of peritubular dentine is dominant and is responsible for the sealing of tubules. The decrease in hardness at lower energy for both wavelengths is due to the evaporation of carbon content. With increasing energy, evaporation of water along with carbon content, and resolidification and re-organization of inorganic content causes the increase in hardness of the treated dentine. SEM as well as microhardness analyses reveal that laser wavelengths and energy of laser radiation significantly influence the surface morphology and hardness of samples.

Adhesion of multimode adhesives to enamel and dentin after one year of water storage.

PubMed

Vermelho, Paulo Moreira; Reis, André Figueiredo; Ambrosano, Glaucia Maria Bovi; Giannini, Marcelo

2017-06-01

This study aimed to evaluate the ultramorphological characteristics of tooth-resin interfaces and the bond strength (BS) of multimode adhesive systems to enamel and dentin. Multimode adhesives (Scotchbond Universal (SBU) and All-Bond Universal) were tested in both self-etch and etch-and-rinse modes and compared to control groups (Optibond FL and Clearfil SE Bond (CSB)). Adhesives were applied to human molars and composite blocks were incrementally built up. Teeth were sectioned to obtain specimens for microtensile BS and TEM analysis. Specimens were tested after storage for either 24 h or 1 year. SEM analyses were performed to classify the failure pattern of beam specimens after BS testing. Etching increased the enamel BS of multimode adhesives; however, BS decreased after storage for 1 year. No significant differences in dentin BS were noted between multimode and control in either evaluation period. Storage for 1 year only reduced the dentin BS for SBU in self-etch mode. TEM analysis identified hybridization and interaction zones in dentin and enamel for all adhesives. Silver impregnation was detected on dentin-resin interfaces after storage of specimens for 1 year only with the SBU and CSB. Storage for 1 year reduced enamel BS when adhesives are applied on etched surface; however, BS of multimode adhesives did not differ from those of the control group. In dentin, no significant difference was noted between the multimode and control group adhesives, regardless of etching mode. In general, multimode adhesives showed similar behavior when compared to traditional adhesive techniques. Multimode adhesives are one-step self-etching adhesives that can also be used after enamel/dentin phosphoric acid etching, but each product may work better in specific conditions.

Efficacy of Modified Bioactive Glass for Dentin Remineralization and Obstruction of Dentinal Tubules

PubMed Central

Saffarpour, Mahshid; Tahriri, Mohammadreza; Zakerzadeh, Azadeh

2017-01-01

Objectives: This study assessed the efficacy of modified bioactive glass (MBG) for dentin remineralization and obstruction of dentinal tubules. Materials and Methods: Thirty-six dentin discs were made from 20 third molars and were stored in 12% lactic acid solution for two weeks to induce demineralization. The samples were divided into three groups (n=12): 1- BG, 2- BG modified with 5% strontium (Sr) and 3- BG modified with 10% Sr. After applying the BG, the samples were stored in artificial saliva for 7, 14 and 21 days. Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray (EDX) analysis were used to assess remineralization. Also, 6 dentin discs were divided into three groups of BG, BG modified with 5% Sr and BG modified with 10% Sr, to examine tubular occlusion. The discs were etched using 0.5M of EDTA for two minutes and were stored in artificial saliva for 7 days. Changes in dentin surface morphology were evaluated under SEM. Results: Group 3 showed high rates of remineralization at days 7 and 14, although the rate decreased at day 21. Group 2 exhibited high rates of remineralization at days 7, 14 and 21. Dentinal tubules were partially occluded by BG and BG modified with 5% Sr, while they were almost completely obstructed after the use of BG modified with 10% Sr. Conclusions: Strontium increases remineralization. Addition of 10% Sr to BG enhances apatite formation; however, the apatite dissolves over time. Addition of 5% Sr to BG stabilizes the apatite lattice and increases the remineralization. PMID:29285031

TEM characterization of a silorane composite bonded to enamel/dentin.

PubMed

Mine, Atsushi; De Munck, Jan; Van Ende, Annelies; Cardoso, Marcio Vivan; Kuboki, Takuo; Yoshida, Yasuhiro; Van Meerbeek, Bart

2010-06-01

The low-shrinking composite composed of combined siloxane-oxirane technology (Filtek Silorane, 3M ESPE, Seefeld, Germany) required the development of a specific adhesive (Silorane System Adhesive, 3M ESPE), in particular because of the high hydrophobicity of the silorane composite. The purpose of this study was to characterize the interfacial ultra-structure at enamel and dentin using transmission electron microscopy (TEM). Non-demineralized/demineralized 70-90 nm sections were prepared following common TEM specimen processing procedures. TEM revealed a typical twofold build-up of the adhesive resin, resulting in a total adhesive layer thickness of 10-20 microm. At bur-cut enamel, a tight interface without distinct dissolution of hydroxyapatite was observed. At bur-cut dentin, a relatively thin hybrid layer of maximum a few hundreds of nanometer was formed without clear surface demineralization. No clear resin tags were formed. At fractured dentin, the interaction appeared very superficial (100-200 nm). Distinct resin tags were formed due to the absence of smear plugs. Silver-nitrate infiltration showed a varying pattern of both spot- and cluster-like appearance of nano-leakage. Traces of Ag were typically detected along some part of the enamel-adhesive interface and/or between the two adhesive resin layers. Substantially more Ag-infiltration was observed along the dentin-adhesive interface of bur-cut dentin, as compared to that of fractured dentin. The nano-interaction of Silorane System Adhesive should be attributed to its relatively high pH of 2.7. The obtained tight interface at both enamel and dentin indicates that the two-step self-etch adhesive effectively bridged the hydrophilic tooth substrate with the hydrophobic silorane composite. Copyright (c) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Does Acid Challenge Affect the Properties and Bond Stability of Restorative Materials on Primary Teeth?

PubMed

Tedesco, Tamara K; Calvo, Ana F B; Yoshioka, Laysa; Fukushima, Karen A; Cesar, Paulo F; Raggio, Daniela P

2018-05-31

To evaluate the effect of acidic challenge (AC) on the properties and bond stability of restorative materials to primary enamel and dentin. One hundred twenty primary molars were assigned to 12 groups according to substrate (enamel or dentin), restorative material (composite, high-viscosity glass ionomer cement [HV-GIC] or resin-modified glass-ionomer cement [RM-GIC]), and immersion after restoration (control [saline solution/7 days] or AC [cola-based drink/5 min/3x per day/7 days]). Twenty-four hours after the restorative procedure, specimens were submitted to one of the proposed challenges. Half of the specimens were immediately subjected to the microshear bond strength test, and the other half after 12 months. To determine flexural strength flexural strength and superficial roughness (SR), 30 specimens were built up. After 24 h, the first measurement of SR from 10 specimens was performed. Specimens were then immersed in one of proposed challenges and SR was measured again. Subsequently, flexural strength testing was performed. Bond strength, surface roughness, and flexural strength data were subjected to ANOVA and Tukey's test. Composite showed the highest bond strengths compared to the others materials on both substrates. The storage period negatively influenced the bond strength only for composite groups in dentin. AC after restoration negatively influenced bond strength when the materials were evaluated in eroded dentin. AC affected the second SR measurement, showing increased SR for all restorative materials. AC did not affect flexural strength. The acidic challenge jeopardizes the surface roughness and bond strength of restorations to eroded dentin.

Effects of increased apical enlargement on the amount of unprepared areas and coronal dentine removal: a micro-computed tomography study.

PubMed

Pérez, A R; Alves, F R F; Marceliano-Alves, M F; Provenzano, J C; Gonçalves, L S; Neves, A A; Siqueira, J F

2018-06-01

To evaluate the effects of progressive apical enlargement on the amount of unprepared root canal surface area and remaining dentine thickness. The root canals of 30 extracted mandibular incisors with Vertucci's type I configuration were instrumented with rotary HyFlex CM instruments (Coltene-Whaledent, Altstätten, Switzerland) up to 4 instruments larger than the first one that bound at the working length (WL). Teeth were scanned in a micro-computed tomography (micro-CT) device before canal preparation and after instrumentation with the 2nd, 3rd and 4th larger instruments. The amount of unprepared surface area in the full canal or in the apical 4 mm as well as the remaining dentine thickness at 10 mm from the WL were calculated and compared. The general linear model for repeated measures adjusted by Bonferroni's post hoc test was used for statistic analysis. There was a significant reduction in the amount of unprepared areas after each increase in preparation size (P < 0.01). This was observed for both the full canal length and the 4-mm apical segment. The amount of remaining dentine was also significantly reduced after each file size (P < 0.01). However, dentine thickness always remained greater than 1 mm, even after using the largest instrument. Apical preparations up to 4 instruments larger than the first one to bind at the WL caused a significant progressive reduction in the unprepared canal area. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

ADHESION OF AN ENDODONTIC SEALER TO DENTIN AND GUTTA-PERCHA: SHEAR AND PUSH-OUT BOND STRENGTH MEASUREMENTS AND SEM ANALYSIS

PubMed Central

Teixeira, Cleonice Silveira; Alfredo, Edson; Thomé, Luis Henrique de Camargo; Gariba-Silva, Ricardo; Silva-Sousa, Yara T. Correa; Sousa, Manoel Damião

2009-01-01

The use of an adequate method for evaluation of the adhesion of root canal filling materials provides more reliable results to allow comparison of the materials and substantiate their clinical choice. The aims of this study were to compare the shear bond strength (SBS) test and push-out test for evaluation of the adhesion of an epoxy-based endodontic sealer (AH Plus) to dentin and guttapercha, and to assess the failure modes on the debonded surfaces by means of scanning electron microscopy (SEM). Three groups were established (n=7): in group 1, root cylinders obtained from human canines were embedded in acrylic resin and had their canals prepared and filled with sealer; in group 2, longitudinal sections of dentin cylinders were embedded in resin with the canal surface smoothed and turned upwards; in group 3, gutta-percha cylinders were embedded in resin. Polyethylene tubes filled with sealer were positioned on the polished surface of the specimens (groups 2 and 3). The push-out test (group 1) and the SBS test (groups 2 and 3) were performed in an Instron universal testing machine running at crosshead speed of 1 mm/min. Means (±SD) in MPa were: G1 (8.8±1.13), G2 (5.9±1.05) and G3 (3.8±0.55). Statistical analysis by ANOVA and Student's t-test (α=0.05) revealed statistically significant differences (p<0.01) among the groups. SEM analysis showed a predominance of adhesive and mixed failures of AH Plus sealer. The tested surface affected significantly the results with the sealer reaching higher bond strength to dentin than to guttapercha with the SBS test. The comparison of the employed methodologies showed that the SBS test produced significantly lower bond strength values than the push-out test, was skilful in determining the adhesion of AH Plus sealer to dentin and gutta-percha, and required specimens that could be easily prepared for SEM, presenting as a viable alternative for further experiments. PMID:19274399

A scanning electron microscopy study of diseased root surfaces conditioned with EDTA gel plus Cetavlon after scaling and root planing.

PubMed

Martins Júnior, Walter; De Rossi, Andiara; Samih Georges Abi Rached, Ricardo; Rossi, Marcos Antonio

2011-01-01

In the present investigation, a scanning electron microscopy analysis was performed to evaluate the effects of the topical application of ethylenediaminetetraacetic acid (EDTA) gel associated with Cetavlon (EDTAC) in removing the smear layer and exposing collagen fibers following root surface instrumentation. Twenty-eight teeth from adult humans, single rooted and scheduled for extraction due to periodontal reasons, were selected. Each tooth was submitted to manual (scaling and root planing) instrumentation alone or combined with ultrasonic instruments, with or without etching using a 24% EDTAC gel. Following extraction, specimens were processed and examined under a scanning electron microscope. A comparative morphological semi-quantitative analysis was performed; the intensity of the smear layer and the decalcification of cementum and dentinal surfaces were graded in 12 sets using an arbitrary scale ranging from 1 (area covered by a smear layer) to 4 (no smear layer). Root debridement with hand instruments alone or combined with ultrasonic instruments resulted in a similar smear layer covering the root surfaces. The smear layer was successfully removed from the surfaces treated with EDTAC, which exhibited numerous exposed dentinal tubules and collagen fibers. This study supports the hypothesis that manual instrumentation alone or instrumentation combined with ultrasonic instrumentation is unable to remove the smear layer, whereas the subsequent topical application of EDTAC gel effectively removes the smear layer, uncovers dentinal openings and exposes collagen fibers.

Combined Antibacterial Effect of Sodium Hypochlorite and Root Canal Sealers against Enterococcus faecalis Biofilms in Dentin Canals.

PubMed

Du, Tianfeng; Wang, Zhejun; Shen, Ya; Ma, Jingzhi; Cao, Yingguang; Haapasalo, Markus

2015-08-01

The present study aimed to evaluate the antibacterial effect of the combined use of sodium hypochlorite (NaOCl) and root canal sealers on Enterococcus faecalis biofilms using a dentin infection model. Cells of E. faecalis were introduced into the dentinal tubules by centrifugation and incubated in brain-heart infusion for 3 weeks. The biofilms in dentin were first subjected to 5% NaOCl or sterile water for 10 minutes followed by an equal thickness of AH Plus (Dentsply International Inc, York, PA), Endosequence BC Sealer (Brasseler USA, Savannah, GA), or MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, Brazil) placed on the root canal wall of the dentin specimens for 7, 30, and 60 days. Gutta-percha and water were used in a similar manner as controls. The proportions of dead and live bacteria inside the dentinal tubules were assessed by confocal laser scanning microscopy and viability staining. The combined use of NaOCl and sealers (30 and 60 days) killed significantly more bacteria than NaOCl or sealers alone (P < .05). NaOCl + MTA Fillapex was the most effective antibacterial combination by killing 83% bacteria in dentin tubules in 60 days. Thirty and 60 days of exposure to the sealers resulted in significantly more dead bacteria in dentin biofilms than 7-day exposures (P < .05). The placement of root canal sealer after NaOCl treatment enhanced antibacterial effects against E. faecalis in the dentinal tubules. Little additional effect was obtained after 30 days of exposure to sealers. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.