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Sample records for root dentine irradiated

  1. Effects of Nd: YAG laser irradiation on the root canal wall dentin of human teeth: a SEM study.

    PubMed

    Kaitsas, V; Signore, A; Fonzi, L; Benedicenti, S; Barone, M

    2001-01-01

    The purpose of this study was to observe the morphological and histological changes on the root canal walls after Nd:YAG laser application. Twenty vital, recently extracted single-rooted human teeth were used for this study. Root canals were cleaned and shaped by a conventional step-back technique--by means of k files up to a 20 k-file type at working length--and subsequently shaped by Ni-Ti root-canal rotary instrumentation up to 30/06 and irrigated with 2.5% hypochlorite solution. Ten teeth (control group) were left unlased, while the other ten teeth were irradiated with Nd:YAG laser by means of a 320 microns fibre inserted in the root canal at 1 mm from the apex with a power of 1.5 Watt and a frequency of 15 pps for five seconds in retraction with rotating movements. The control specimen showed debris and smear layer on the root canal surface obscuring the dentin tubules. The root canal walls irradiated with Nd:YAG laser showed a clear glazed surface, some open dentinal tubules and some surface craters with cracks. Such results confirm that smear layer and debris are removable with Nd:YAG laser, however clearing all root canal walls is still difficult and, if the energy level and duration of application are inadequate, a certain degree of thermal damage and morphological changes in dentin structure are observable. PMID:11938590

  2. Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin.

    PubMed

    Archilla, José R F; Moreira, Maria S N A; Miyagi, Sueli P H; Bombana, Antônio C; Gutknecht, Norbert; Marques, Márcia M

    2012-11-01

    Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124  J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p≤0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

  3. Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin

    NASA Astrophysics Data System (ADS)

    Archilla, José R. F.; Moreira, Maria S. N. A.; Miyagi, Sueli P. H.; Bombana, Antônio C.; Gutknecht, Norbert; Marques, Márcia M.

    2012-11-01

    Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124 J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p≤0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

  4. Ecological Hypothesis of Dentin and Root Caries.

    PubMed

    Takahashi, Nobuhiro; Nyvad, Bente

    2016-01-01

    Recent advances regarding the caries process indicate that ecological phenomena induced by bacterial acid production tilt the de- and remineralization balance of the dental hard tissues towards demineralization through bacterial acid-induced adaptation and selection within the microbiota - from the dynamic stability stage to the aciduric stage via the acidogenic stage [Takahashi and Nyvad, 2008]. Dentin and root caries can also be partly explained by this hypothesis; however, the fact that these tissues contain a considerable amount of organic material suggests that protein degradation is involved in caries formation. In this review, we compiled relevant histological, biochemical, and microbiological information about dentin/root caries and refined the hypothesis by adding degradation of the organic matrix (the proteolytic stage) to the abovementioned stages. Bacterial acidification not only induces demineralization and exposure of the organic matrix in dentin/root surfaces but also activation of dentin-embedded and salivary matrix metalloproteinases and cathepsins. These phenomena initiate degradation of the demineralized organic matrix in dentin/root surfaces. While a bacterial involvement has never been confirmed in the initial degradation of organic material, the detection of proteolytic/amino acid-degrading bacteria and bacterial metabolites in dentin and root caries suggests a bacterial digestion and metabolism of partly degraded matrix. Moreover, bacterial metabolites might induce pulpitis as an inflammatory/immunomodulatory factor. Root and dentin surfaces are always at risk of becoming demineralized in the oral cavity, and exposed organic materials can be degraded by host-derived proteases contained in saliva and dentin itself. New approaches to the prevention and treatment of root/dentin caries are required. PMID:27458979

  5. How to bond to root canal dentin

    NASA Astrophysics Data System (ADS)

    Nica, Luminita; Todea, Carmen; Furtos, Gabriel; Baldea, Bogdan

    2014-01-01

    Bonding to root canal dentin may be difficult due to various factors: the structural characteristic of the root canal dentin, which is different from that of the coronal dentin; the presence of the organic tissue of the dental pulp inside the root canal, which has to be removed during the cleaning-shaping of the root canal system; the smear-layer resulted after mechanical instrumentation, which may interfere with the adhesion of the filling materials; the type of the irrigants used in the cleaning protocol; the type of the sealer and core material used in the obturation of the endodontic space; the type of the materials used for the restoration of the endodontically treated teeth. The influence of the cleaning protocol, of the root canal filling material, of the type of the adhesive system used in the restoration of the treated teeth and of the region of the root canal, on the adhesion of several filling and restorative materials to root canal dentin was evaluated in the push-out bond strength test on 1-mm thick slices of endodontically treated human teeth. The results showed that all these factors have a statistically significant influence on the push-out bond strength. Formation of resin tags between radicular dentin and the investigated materials was observed in some of the samples at SEM analysis.

  6. Clinical management of infected root canal dentin.

    PubMed

    Love, R M

    1996-08-01

    Several hundred different species of bacteria are present in the human intraoral environment. Bacterial penetration of root canal dentin occurs when bacteria invade the root canal system. These bacteria may constitute a reservoir from which root canal reinfection may occur during or after endodontic treatment. The learning objective of this article is to review endodontic microbiology, update readers on the role of bacteria in pulp and periapical disease, and discuss the principles of management of infected root canal dentin. Complete debridement, removal of microorganisms and affected dentin, and chemomechanical cleansing of the root canal are suggested as being the cornerstones of successful endodontic therapy, followed by intracanal medication to remove residual bacteria, when required. PMID:9242125

  7. Evaluation of the Morphological Characteristics of Laser-Irradiated Dentin

    PubMed Central

    Lilaj, Bledar; Franz, Alexander; Degendorfer, Daniela; Moritz, Andreas

    2015-01-01

    Abstract Objective: The aim of this study was to investigate the effect of different energy settings of Er:YAG laser irradiation on dentin surface morphology with respect to the number of opened dentinal tubules. Background data: An ideally prepared dentin surface with opened dentinal tubules is a prerequisite for adhesive fixation. No study, however, has yet compared the numbers of opened dentinal tubules with regard to statistical differences. Methods: Conventional preparations using a bur with or without additional acid etching acted as control groups. Dentin specimens were prepared from human third molars and randomly divided into eight groups according to the energy settings of the laser (1, 1.5, 4, 6, 7.5, and 8 W) and two controls (bur and bur plus acid etching). After surface preparation, dentin surfaces were analyzed with a scanning electron microscope, and the number of opened dentinal tubules in a defined area was counted. Results: The control groups showed smooth surfaces with (bur plus acid etching) and without opened dentinal tubules (bur), whereas all laser-irradiated surfaces showed rough surfaces. Using the energy setting of 4 W resulted in significantly more opened dentinal tubules than the conventional preparation technique using the bur with additional acid etching. In contrast, the energy setting of 8 W showed significantly fewer opened dentinal tubules, and also exhibited signs of thermal damage. Conclusions: The Er:YAG laser with an energy setting of 4 W generates a dentin surface with opened dentinal tubules, a prerequisite for adhesive fixation. PMID:26389986

  8. Bacterial penetration and proliferation in root canal dentinal tubules after applying dentin adhesives in vitro.

    PubMed

    Assouline, L S; Fuss, Z; Mazor, Y; Weiss, E I

    2001-06-01

    Endodontic treatment is aimed at eliminating infection and preventing bacterial regrowth in the root canal and dentinal tubules. In the present study the ability of two dentin adhesives to prevent bacterial penetration and subsequent proliferation in dentinal tubules was evaluated. Cylindrical root specimens prepared from freshly extracted bovine teeth were used in an in vitro model of dentinal tubule infection. After removal of the smear layer the intracanal dentinal tubules of the specimens were acid-etched and treated with either Gluma or EBS. Untreated specimens served as controls. Specimens were infected with Enterococcus faecalis and incubated in Brain Heart Infusion for 21 days. Powder dentin samples obtained from within the canal lumina, using ISO 025 to 033 burs, were examined for the presence of vital bacteria by inoculating on agar plates and counting colony-forming units. A significant difference was found between the experimental groups and the untreated group. After application with Gluma specimens showed the least viable bacteria in dentinal tubules. Data suggested that dentin adhesives reduced bacterial invasion into dentin and therefore have a potential role in endodontic treatment.

  9. Abrasion of eroded root dentine brushed with different toothpastes.

    PubMed

    De Menezes, Márcio; Turssi, Cecilia Pedroso; Hara, Anderson Takeo; Messias, Danielle Cristine Furtado; Serra, Mônica Campos

    2004-09-01

    This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6 x 3 x 2 mm) were ground flat and polished. In an area of 4 x 3 mm on the dentine surface, specimens were submitted to five erosive/abrasive events, each one composed by: exposure to Sprite Diet or distilled water for 5 min, then to a remineralizing solution for 1 min, and simulation of 5,000 brushing strokes. Four dentifrices--regular (RE), baking soda (BS), whitening (WT) and tartar control (TC)--and distilled water (CO), used as control, were compared. Final texture and the wear depth were evaluated using a profilometer. ANOVA did not show significant interaction, indicating that the effect of dentifrices on both surface roughness change and wear did not depend on whether or not the dentine was eroded ( p>0.05). There was no difference between abrasion of eroded and sound dentine. The Tukey's test revealed that WT, BS and TC provided the highest increase in surface roughness differing from RE and CO. TC yielded the deepest wear of root dentine, whereas RE and CO, the shallowest. No significant difference in wear among BS, TC and WT were observed. Within the limitations of this study, the data showed that abrasion of both eroded and sound root dentine was dependent on the dentifrice used. PMID:15146320

  10. Effect of two restorative materials on root dentine erosion.

    PubMed

    Domiciano, Silvia Jorge; Colucci, Vivian; Serra, Mônica Campos

    2010-05-01

    This study sought to evaluate the microhardness of root dentine adjacent to glass-ionomer and composite resin restorations after erosive challenge. A crossover study was performed in two phases of 4 consecutive days each. One hundred twelve bovine root dentine slabs were obtained, and standardized box-shaped cavities were prepared at center of each specimen. The prepared cavities were randomly restored with glass-ionomer cement or composite resin. The slabs were randomly assigned among 14 volunteers, which wore intraoral palatal device containing four restored root dentin slabs. Starting on the second day, half of the palatal acrylic devices were immersed extraorally in a lemonade-like carbonated soft drink for 90 s, four times daily for 3 days. After 3-day wash-out, dentine slabs restored with the alternative material were placed into palatal appliance and the volunteers started the second phase of this study. After erosive challenges, microhardness measurements were performed. Regardless of the restorative material employed, eroded specimens demonstrated lower microhardness value (p < 0.0001). At eroded condition examined in this study, dentine restored with glass-ionomer cement showed higher microhardness values (p < 0.0001). It may be concluded that the glass-ionomer cement decreases the progression of root dentine erosion at restoration margin.

  11. Penetration of varnishes into demineralized root dentine in vitro.

    PubMed

    Arends, J; Duschner, H; Ruben, J L

    1997-01-01

    In this paper the penetration of three different varnishes employed in caries prevention (Duraphat, Fluor Protector and Cervitec) into demineralized dentine is quantified using confocal laser scanning microscopy. The results show that the varnish penetration into lesions about 85 microns in depth if for Cervitec about 35 microns and considerably less for Duraphat and Fluor Protector. The penetration is into the dentinal tubules and is influenced by dentinal tubule direction. The drying procedure--pretreatment of the dentine--influences the penetration, though sizeably only for Cervitec applications. This paper shows that varnish penetration into the tissue and presumably 'sealing' tubules completely or partly is valuable with respect to root caries prevention and hypersensitivity. PMID:9165191

  12. Lack of dentin acid resistance following 9.3 um CO2 laser irradiation

    NASA Astrophysics Data System (ADS)

    Le, Charles Q.; Fried, Daniel; Featherstone, John D. B.

    2008-02-01

    Previous studies have shown that laser irradiation of dental enamel by specific carbon dioxide laser conditions can inhibit subsequent acid dissolution of the dental enamel surface. The purpose of this study was to determine whether similar carbon dioxide laser conditions would have a protective effect on dentin. Blocks of human dentin roots (3x3 mm2) were irradiated at 9.3 µm wavelength with a 15-18 µs pulse duration laser and fluences of 0.50-1.50 J/cm2. A motion controller system was used to ensure uniform irradiation of the entire dentin surface. Surface acid dissolution profiles following irradiation were acquired for the five study groups, control group (Non-irradiated) and four laser-treated groups. Dissolution profiles of low fluence groups (0.50 and 0.75 J/cm2) exhibited similar profiles to the control group. Dissolution profiles of higher fluence groups (1.0 and 1.5 J/cm2) showed an increased dissolution rate over the control group, but these differences were not statistically significant (p>0.05). This study demonstrated that the application of carbon dioxide laser irradiation significantly alters the surface of dentin but did not decrease the acid dissolution rate.

  13. Decontamination of deep dentin by means of erbium, chromium:yttrium-scandium-gallium-garnet laser irradiation.

    PubMed

    Franzen, René; Esteves-Oliveira, Marcella; Meister, Jörg; Wallerang, Anja; Vanweersch, Leon; Lampert, Friedrich; Gutknecht, Norbert

    2009-01-01

    The aim of this in vitro study was to evaluate the depth of effectiveness of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation on microorganism reduction. From human roots, dentin slices of 100 microm to 1,000 microm thickness were prepared. These specimens were sterilized and then inoculated with 1 microl of Enterococcus faecalis suspension. The backs of the specimens were then irradiated with Er,Cr:YSGG radiation at a pulse energy of 3.13 mJ, delivered at an incidence angle of 5 degrees to the dentin slice surface. A control group was left without irradiation. The remaining bacteria were collected in 1 ml sterilized NaCl solution, serially diluted and seeded in Columbia-Agar plates. Despite the low pulse energy of 3.13 mJ, the Er,Cr:YSGG laser irradiation resulted in significant bacterial reduction up to a dentin thickness of 500 microm (P < 0.05). Scanning electron microscopy (SEM) micrographs of the contaminated and irradiated surfaces showed the absence of a smear layer and opened dentinal tubules.

  14. Regional variation in root dentinal tubule infection by Streptococcus gordonii.

    PubMed

    Love, R M

    1996-06-01

    The purpose of this study was to investigate the pattern of bacterial invasion of dentinal tubules at different regions in human roots. Specimens were obtained from single-rooted teeth that had their root canals prepared in a standard manner. Roots were then sectioned longitudinally through the canals and the resulting specimens chemically treated to remove the smear layers. Specimens were immersed in a suspension of Streptococcus gordonii for 3 weeks and then prepared for histological analysis. Sections from the cervical, midroot, and apical areas were examined. The pattern of bacterial infection of the cervical and midroot areas was similar, characterized as a heavy infection with bacteria penetrating as deep as 200 microns. Invasion of the apical dentin was significantly different, with a mild infection and maximum penetration of 60 microns. PMID:8934987

  15. The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

    PubMed Central

    GERALDO-MARTINS, Vinícius Rangel; LEPRI, Cesar Penazzo; FARAONI-ROMANO, Juliana Jendiroba; PALMA-DIBB, Regina Guenka

    2014-01-01

    The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria. Objective To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz) irradiation associated with 2% neutral sodium fluoride (NaF) to prevent root dentin demineralization. Material and Methods One hundred human root dentin samples were divided into 10 groups (G) and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2) with water cooling (WC=5.4 mL/min); G4: laser (4.64 J/cm2) without WC; G5: laser (8.92 J/cm2) with WC; G6: laser (8.92 J/cm2) without WC; G7: laser (4.64 J/cm2) with WC and NaF; G8: laser (4.64 J/cm2) without WC and NaF; G9: laser (8.92 J/cm2) with WC and NaF; G10: laser (8.92 J/cm2) without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN) test was done at different depths (30, 60, 90 and 120 μm) from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher's test (α=5%). Results The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05). Conclusions The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm2 and 8.92 J/cm2 without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin. PMID:25466479

  16. Shear bond strength of two resin cements to human root dentin using three dentin bonding agents.

    PubMed

    Gogos, C; Stavrianos, C; Kolokouris, I; Economides, N; Papadoyannis, I

    2007-01-01

    This study compared the bond strength of two resin cements to human root dentin when used with three bonding agents. The materials used were Rely X ARC and Perma Cem, two one-bottle bonding agents (Single Bond, Bond-1) and one self-etching bonding agent (Clearfil SE Bond). The dentin was obtained from single rooted human teeth, and the specimens were treated with either 15% EDTA or 37% phosphoric acid to remove the smear layer, except in groups where the self-etching bonding agent was used. The resin cements were placed on dentin surfaces with the use of bonding agents. Shear bond strength (SBS) was tested using a single plane shear test assembly. The dentin specimens were divided into 10 groups. Eight groups were pre-treated with EDTA or phosphoric acid to remove the smear layer, followed by a bonding agent (Bond-1 or Single Bond) and resin cement (Rely X or Perma Cem). In the two remaining groups, the smear layer was left intact, and the two resins cements were used in combination with the self-etching bonding agent (Clearfil SE Bond). No statistically significant differences were observed among the eight groups treated with one-bottle bonding agents. The mean bond strengths of the two groups treated with the self-etching bonding agent did not differ significantly from each other but were both significantly greater than the bond strengths of all the other groups. The results of this study also showed that EDTA can be used as an alternative to phosphoric acid in bonding procedures for resin cements. However, the bond strengths of resin cements, in combination with a self-etching bonding agent, were significantly greater than those of the same cements when used with one-bottle bonding agents.

  17. In vivo model for microbial invasion of tooth root dentinal tubules

    PubMed Central

    BRITTAN, Jane L; SPRAGUE, Susan V; MACDONALD, Emma L; LOVE, Robert M; JENKINSON, Howard F; WEST, Nicola X

    2016-01-01

    ABSTRACT Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF). DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0) to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine. PMID:27119760

  18. In vivo model for microbial invasion of tooth root dentinal tubules.

    PubMed

    Brittan, Jane L; Sprague, Susan V; Macdonald, Emma L; Love, Robert M; Jenkinson, Howard F; West, Nicola X

    2016-04-01

    Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF). DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0) to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine. PMID:27119760

  19. A rapid non-destructive method for root dentin moisture measurements

    PubMed Central

    Komabayashi, Takashi; Zhu, Qiang; Jiang, Jin; Safavi, Kamran E.; Spångberg, Larz S.W.

    2009-01-01

    Dentin moisture content is important in adhesive bonding and structural strength research. However, there is no rapid method available to assess dentin moisture without sample destruction. This study examined the use of a digital grain moisture meter to measure root dentin moisture in vitro. Extracted mandibular single rooted teeth were sectioned at the CEJ. The moisture of the root dentin was measured at six measuring modes for different grains and repeated five times. Dentin weight changes before and after drying were measured to obtain control values. The control values were compared with machine readings. In conclusion, (1) Each non-destructive measurement took less than 30 seconds. (2) 24 hours storage at 37°C and 100 % humidity did not restore dentin moisture. (3) Five grain modes had a high validity, and could be used for dentin moisture measurements. PMID:19157921

  20. Dentine hypersensitivity. The effects in vitro of acids and dietary substances on root-planed and burred dentine.

    PubMed

    Addy, M; Absi, E G; Adams, D

    1987-05-01

    Evidence indicates that teeth exhibiting cervical dentine hypersensitivity have open dentinal tubules at the dentine surface. The identification of factors which render dentine exposed and tubules open is important both to the prevention and management of dentine hypersensitivity. In this study, recently extracted teeth were root planed or burred to expose the root dentine. Specimens were horizontally sectioned and then using the apical portion as control, the coronal portions placed in a variety of strong and weak acids and dietary fluids. Examination under the scanning electron microscope revealed a smear layer covering completely underlying tubules on the control root planed or burred portions. Test portions exposed to strong and weak acids showed loss of the smear layer and exposure of large numbers of tubules. Formic and tannic acids produced no changes. Some dietary fluids, in particular red and white wine, citrus fruit juices, apple juice and yogurt produced similar etching effects to the acids. The low pH carbonated drink, coca-cola, and a blackcurrent cordial produced no effects. The results of this study in vitro cannot necessarily be extrapolated to the clinical situation, but suggest that certain dietary factors could play a rôle in the aetiology of dentine hypersensitivity. Dietary advice to patients may prove important in the management of this often recurrent condition. PMID:3301914

  1. Effect of free electron laser (FEL) irradiation on tooth dentine

    NASA Astrophysics Data System (ADS)

    Ogino, Seiji; Awazu, Kunio; Tomimasu, Takio

    1996-12-01

    Free electron laser (FEL) gives high efficiency for the photo-induced effects when the laser is tuned to the absorption maximum of target materials. The effect on dentine was investigated using the FEL tuned to 9.4 micrometers , which is an absorption maximum of phosphoric acid in infrared region. As a result, irradiated dentine surface which was amorphous had changed to the recrystalized structure by the spectroscopic analysis of IR absorption and x-ray diffraction. Furthermore, the atomic ratio of P/Ca had reduced from 0.65 to 0.60. These results indicated that 9.4micrometers -FEL irradiation caused the selective ablation of phosphoric acid ion and the reconstruction of disordered atoms.

  2. Ablation of dentin by irradiation of violet diode laser

    NASA Astrophysics Data System (ADS)

    Hatayama, H.; Kato, J.; Akashi, G.; Hirai, Y.; Inoue, A.

    2006-02-01

    Several lasers have been used for clinical treatment in dentistry. Among them, diode lasers are attractive because of their compactness compared with other laser sources. Near-infrared diode lasers have been practically used for cutting soft tissues. Because they penetrate deep to soft tissues, they cause sufficiently thick coagulation layer. However, they aren't suitable for removal of carious dentin because absorption by components in dentin is low. Recently, a violet diode laser with a wavelength of 405nm has been developed. It will be effective for cavity preparation because dentin contains about 20% of collagen whose absorption coefficient at a violet wavelength is larger than that at a near-infrared wavelength. In this paper, we examined cutting performance of the violet diode laser for dentin. To our knowledge, there have been no previous reports on application of a violet laser to dentin ablation. Bovine teeth were irradiated by continuous wave violet diode laser with output powers in a range from 0.4W to 2.4W. The beam diameter on the sample was about 270μm and an irradiation time was one second. We obtained the crater ablated at more than an output power of 0.8W. The depth of crater ranged from 20μm at 0.8W to 90μm at 2.4W. Furthermore, the beam spot with an output power of 1.7W was scanned at a speed of 1mm/second corresponding to movement of a dentist's hand in clinical treatment. Grooves with the depth of more than 50μm were also obtained. From these findings, the violet diode laser has good potential for cavity preparation. Therefore, the violet diode laser may become an effective tool for cavity preparation.

  3. Essential role of Osterix for tooth root but not crown dentin formation

    PubMed Central

    Zhang, Hua; Jiang, Yong; Qin, Chunlin; Liu, Ying; Ho, Sunita P.; Feng, Jian Q.

    2015-01-01

    Tooth is made of crown and root. It is widely believed that dentin formation in crown and root uses the same regulatory mechanism. However, identification of NFIC’s unique function in determining root but not crown dentin formation challenges the old thought. In searching for the target molecules downstream of NFIC, we unexpectedly found a sharp reduction of OSX (osterix), the key transcription factor in skeleton formation, in the Nfic knockout (KO) tooth root. We then demonstrated a dose-dependent increase of Osx in the odontoblast cell line due to a transient transfection of Nfic expression plasmid. Studies of global and conditional Osx KO mice revealed no apparent changes in the crown dentin tubules and dentin matrix. However, the OSX conditional KO mice (crossed to the 2.3 kb Col 1-Cre) displayed an increase in cell proliferation but great decreases in expressions of root dentin matrix proteins (DMP1 and DSPP), leading to an inhibition in odontoblast differentiation, and short thin root dentin with few dentin tubules. Compared to the Nfic KO tooth, which contains essentially no dentin tubules and remains in a “root-less” status at adult stages, the Osx cKO root phenotype had partially improved at the late stage, indicating that other factors can compensate for OSX function. Thus, we conclude that OSX, one of the key downstream molecules of NFIC, plays a critical role in root, but not crown, formation. PMID:25349111

  4. Root dentine and endodontic instrumentation: cutting edge microscopic imaging.

    PubMed

    Atmeh, Amre R; Watson, Timothy F

    2016-06-01

    Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation-by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments. PMID:27274802

  5. Root dentine and endodontic instrumentation: cutting edge microscopic imaging.

    PubMed

    Atmeh, Amre R; Watson, Timothy F

    2016-06-01

    Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation-by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments.

  6. Tooth root dentin mineralization defects in a mouse model of hypophosphatasia

    PubMed Central

    Foster, B.L.; Nagatomo, K.J.; Tso, H.W.; Tran, A.B.; Nociti, F.H.; Narisawa, S.; Yadav, M.C.; McKee, M.D.; Millán, J.L.; Somerman, M.J.

    2012-01-01

    Tissue-nonspecific alkaline phosphatase (TNAP) is expressed in mineralizing tissues and functions to reduce pyrophosphate (PPi), a potent inhibitor of mineralization. Loss of TNAP function causes hypophosphatasia (HPP), a heritable disorder marked by increased PPi, resulting in rickets and osteomalacia. Tooth root cementum defects are well described in both HPP patients and in Alpl−/− mice, a model for infantile HPP. In Alpl−/− mice, dentin mineralization is specifically delayed in the root, however, reports from human HPP patients are variable and inconsistent regarding dentin defects. In the present study, we aimed to define the molecular basis for changes in dentinogenesis observed in Alpl−/− mice. TNAP was found to be highly expressed by mature odontoblasts, and Alpl−/− molar and incisor roots featured defective dentin mineralization, ranging from a mild delay to severely disturbed root dentinogenesis. Lack of mantle dentin mineralization was associated with disordered and dysmorphic odontoblasts having disrupted expression of marker genes osteocalcin and dentin sialophosphoprotein. The formation of, initiation of mineralization within, and rupture of matrix vesicles in Alpl−/− dentin matrix was not affected. Osteopontin (OPN), an inhibitor of mineralization that contributes to the skeletal pathology in Alpl−/− mice, was present in the generally unmineralized Alpl−/− mantle dentin at ruptured mineralizing matrix vesicles, as detected by immunohistochemistry and by immunogold labeling. However, ablating the OPN-encoding Spp1 gene in Alpl−/− mice was insufficient to rescue the dentin mineralization defect. Administration of bioengineered mineral-targeting human TNAP (ENB-0040) to Alpl−/− mice corrected defective dentin mineralization in the molar roots. These studies reveal that TNAP participates in root dentin formation and confirm that reduction of PPi during dentinogenesis is necessary for odontoblast differentiation, dentin

  7. mRNA expression and protein localization of dentin matrix protein 1 during dental root formation.

    PubMed

    Toyosawa, S; Okabayashi, K; Komori, T; Ijuhin, N

    2004-01-01

    Dentin matrix protein 1 (DMP1) is an acidic phosphoprotein. DMP1 was initially detected in dentin and later in other mineralized tissues including cementum and bone, but the DMP1 expression pattern in tooth is still controversial. To determine the precise localization of DMP1 messenger RNA (mRNA) and the protein in the tooth, we performed in situ hybridization and immunohistochemical analyses using rat molars and incisors during various stages of root formation. During root dentin formation of molars, DMP1 mRNA was detected in root odontoblasts in parallel with mineralization of the dentin. However, the level of DMP1 mRNA expression in root odontoblasts decreased near the coronal part and was absent in coronal odontoblasts. DMP1 protein was localized along dentinal tubules and their branches in mineralized root dentin, and the distribution of DMP1 shifted from the end of dentinal tubules to the base of the tubules as dentin formation progressed. During the formation of the acellular cementum, DMP1 mRNA was detected in cementoblasts lining the acellular cementum where its protein was localized. During the formation of the cellular cementum, DMP1 mRNA was detected in cementocytes embedded in the cellular cementum but not in cementoblasts, and its protein was localized in the pericellular cementum of cementocytes including their processes. During dentin formation of incisors, DMP1 mRNA was detected in odontoblasts on the cementum-related dentin, where its protein was localized along dentinal tubules near the mineralization front. The localization of DMP1 mRNA and protein in dentin and cementum was related to their mineralization, suggesting that one of the functions of DMP1 may be involved in the mineralization of dentin and cementum during root formation. PMID:14751569

  8. Microstructure and wettability of root canal dentine and root canal filling materials after different chemical irrigation

    NASA Astrophysics Data System (ADS)

    Antonijevic, Djordje; Milovanovic, Petar; Brajkovic, Denis; Ilic, Dragan; Hahn, Michael; Amling, Michael; Rakocevic, Zlatko; Djuric, Marija; Busse, Björn

    2015-11-01

    The objective of this study was to determine the effects of various irrigation solutions on root canal dentine and gutta-percha surface properties. In addition, the effects of disinfectant chemicals on the wettability and surface morphological properties of the filling materials were evaluated. Ethylenediaminetetraacetic acid (EDTA), citric acid, and ozone were employed as irrigation solutions for dentine and gutta-percha treatment. Thereafter, the samples' microstructure, degree of mineralization, and mechanical properties were assessed by means of quantitative backscattered electron imaging (qBEI) and reference point indentation (RPI). A contact angle analyzer was used to measure adhesion on the tested materials. Here, EDTA had the most significant affect on both the mechanical properties and the adhesive behavior of dentine. Citric acid did not affect dentine wettability, whereas the indentation properties and the mineralization were reduced. Similar effects were observed when ozone was used. The dentinal tubules were significantly widened in citric acid compared to the ozone group. EDTA causes considerable micromechanical surface alteration of dentine and gutta-percha, but represents the best option in clinical cases where a high adhesiveness of the filling materials is desired.

  9. Essential role of osterix for tooth root but not crown dentin formation.

    PubMed

    Zhang, Hua; Jiang, Yong; Qin, Chunlin; Liu, Ying; Ho, Sunita P; Feng, Jian Q

    2015-04-01

    Tooth is made of crown and root. It is widely believed that dentin formation in crown and root uses the same regulatory mechanism. However, identification of nuclear factor 1 C (NFIC)'s unique function in determining root but not crown dentin formation challenges the old thinking. In searching for the target molecules downstream of NFIC, we unexpectedly found a sharp reduction of osterix (OSX), the key transcription factor in skeleton formation, in the Nfic knockout (Nfic-KO) tooth root. We then demonstrated a dose-dependent increase of Osx in the odontoblast cell line due to a transient transfection of Nfic expression plasmid. Studies of global and conditional Osx-KO mice revealed no apparent changes in the crown dentin tubules and dentin matrix. However, the OSX conditional KO (cKO) mice (crossed to the 2.3-kb collagen type 1 [Col1]-Cre) displayed an increase in cell proliferation but great decreases in expressions of root dentin matrix proteins (dentin matrix protein 1 [DMP1] and dentin sialophosphoprotein [DSPP]), leading to an inhibition in odontoblast differentiation, and short, thin root dentin with few dentin tubules. Compared to the Nfic-KO tooth, which contains essentially no dentin tubules and remains in a "root-less" status at adult stages, the Osx-cKO root phenotype had partially improved at the late stage, indicating that other factors can compensate for OSX function. Thus, we conclude that OSX, one of the key downstream molecules of NFIC, plays a critical role in root, but not crown, formation.

  10. Dehydration-induced shrinkage of dentin as a potential cause of vertical root fractures.

    PubMed

    Winter, Werner; Karl, Matthias

    2012-10-01

    Vertical root fractures (VRF) of endodontically treated teeth constitute a severe clinical condition frequently requiring removal of the affected tooth. Numerous attempts have been made to find the cause for VRF without reaching definitive conclusions. As changes in moisture content have been reported to appear as a consequence of root canal therapy, it is the goal of this paper to evaluate associated volume changes as a possible cause for VRF. Considering disk shaped horizontal cross sections of endodontically treated teeth with a moisture content of dentin decreasing from the root surface towards the root canal, both relative circumferential and relative radial stresses resulting from volume changes of dentin were calculated. It could be shown that the presence of a root canal itself increases radial and circumferential stresses acting on root dentin by a factor of two. Reduction in moisture content of dentin at the wall of the root canal results in shrinkage of the tooth structure and tensile stress. On the outer surface of the root, compressive stresses occur. Thus, VRF would start at the canal wall and propagate to the root surface. The theory presented appears to be consistent with previous reports on stress development as a consequence of dehydration of dentin and finite element analysis on root fractures. It may be concluded that dehydration of dentin induces cracks at the walls of a root canal which subsequently grow as a result of cyclic loading or traumatic overload. PMID:22960027

  11. The effect of diode laser irradiation on dentin as a preventive measure against dental erosion: an in vitro study.

    PubMed

    de-Melo, Mary A S; Passos, Vanara F; Alves, Jose J; Barros, Eduardo B; Santiago, Sérgio L; Rodrigues, Lidiany K A

    2011-09-01

    Increasing rates of non-carious cervical lesions due to dental erosion, exposure of dentinal tubules, and hypersensitivity to environmental stimuli have led to the development of new prevention strategies. This study evaluated the effects of a low-intensity diode laser (λ = 808 nm) on the dentinal chemical composition and prevention of demineralization. In addition, the study monitored temperature changes during the course of irradiation. Forty dentin specimens were randomly allocated into four groups (n = 10): G1 - No treatment (control), G2 - irradiated with 15 J/cm(2), G3 - irradiated with 30 J/cm(2), and G4 - irradiated with 60 J/cm(2). Each specimen was partially covered with nail varnish, treated according to the group irradiation levels, and exposed to an erosive challenge (1.0 M hydrochloric acid) for 5 min. Afterwards, dentin loss was profilometrically analyzed and examined by scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDX). Intrapulpal temperatures were measured during the dentin irradiation. One-way ANOVA and Tukey tests (p < 0.05) were performed to assess differences. For all irradiated groups, intrapulpal temperature changes were less than 3°C. The G2 group showed statistically significant differences when compared to the other groups, representing the lowest temperature increase. A quantitative element analysis via EDX did not significantly differ (p < 0.05) for Ca, P, F, O, or C between the four groups when measured after irradiation/erosion. The mean wear rates (± SD, μm) were 35.66 ± 7.28; 40.70 ± 5.03; 38.17 ± 10.81 and 25.25 ± 6.87 for G1-G4, respectively. The G4 group statistically differed from all other groups representing the lowest wear rate. These results suggest that dentin irradiation, using a diode laser with levels set at 60 J/cm(2), may induce inhibitory effects on root dentin demineralization without causing any harmful thermal effects. However, the exact mechanism of the action of the laser

  12. Diode laser irradiation effects on the sealing ability of root canal sealers

    NASA Astrophysics Data System (ADS)

    Ribeiro, A. C.; Nogueira, G. E. C.; Mayer, M. P. A.; Antoniazzi, J. H.; Zezell, D. M.

    2010-06-01

    This study aimed to test the hypothesis that dentine alterations induced by 810 nm-diode laser may affect the interaction between root canal sealers and the dentin wall. Seventy-two single root human teeth were selected and root canals were enlarged with K-files. Dentine was treated with 0.5% NaOCl and 17% EDTA-T and irradiated (laser group) by diode laser (810 nm/ P = 2.5W/ I = 1989 W/cm2) or remained non-irradiated (control group). Six samples per group were analyzed by scanning electron microscopy (SEM). The remaining samples of each group were divided into three subgroups ( n = 10) and sealed with one of the tested sealers (N-Rickert/AHPlus™/Apexit®). Apical leakage was estimated by evaluating penetration of 0.5% methylene-blue dye. SEM analysis revealed that dentine at the apical third in irradiated samples was melted and fusioned whereas non-irradiated samples exhibited opened dentinal tubules. Despite the morphological changes induced by irradiation, laser did not affect the sealing ability of N-Rickert and AHPlusTM sealers. However, the length of apical leakage in roots filled with Apexit® was lower in irradiated root canals than in non-irradiated samples ( p < 0.05). Morphological changes of root canal walls promoted by diode laser irradiation may improve de sealing ability of Apexit®, a calcium hydroxide-based sealer, suggesting that improved sealing promoted by irradiation may represent an additional factor contributing to the endodontic clinical outcome.

  13. 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

  14. Comparative study of CO2 and Nd:YAG laser on dentin layer of human root canals of permanent teeth utilizing scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Brugnera, Aldo, Jr.; Lopes, Marcia C. S.; Matsumoto, Koukichi; Watanabe-Sei, Ii

    1998-04-01

    The present paper investigated the effects of two different laser beams on dentin and root canal walls. Five human intact teeth (incisors and canines), with endodontic treatment accomplished by Paiva and Antoniazzi technique, had their crowns separated from the roots using a diamond teeth. After polishing the dentin surfaces, they were irradiated with CO2 and NdYag laser and analyzed using SEM and light microscopy. The light microscopy revealed some cicunscribed carbonized areas with some cracks of varied depths in all samples but indicated that the CO2 laser, at power level of 5 watts, was more effective than NdYag laser at power level of 2 watts. The SEM showed formation of circular depressions with areas containing dentin fusion, melted dentin on small holes on the vitrified surfaces. From the data obtained, it was concluded that the methods analyzed are able to remove the remaining residues on the dentin layer and root canal walls. However, no complete fusion of the dentin layer occurred.

  15. Bactericidal effect of Er:YAG laser combined with sodium hypochlorite irrigation against Enterococcus faecalis deep inside dentinal tubules in experimentally infected root canals.

    PubMed

    Cheng, X; Chen, B; Qiu, J; He, W; Lv, H; Qu, T; Yu, Q; Tian, Y

    2016-02-01

    This study evaluated the bactericidal effect of Er:YAG laser radiation combined with sodium hypochlorite (NaOCl) irrigation in the treatment of Enterococcus faecalis deep inside dentinal tubules. The Er:YAG laser was activated, respectively, at 0.3, 0.5 and 1.0 W for either 20 or 30 s; 52.5 g l(-1) NaOCl and normal saline were used for the control groups. Root canals before and after treatments were examined using scanning electron microscopy (SEM). Bacterial reductions both on the root canal walls and at 100, 200, 300, 400 and 500 μm inside the dentinal tubules were analysed using a one-way analysis of variance. SEM results showed that the Er:YAG laser combined with NaOCl disinfected the dentinal tubules from 200 to over 500 μm depth as irradiation power and time increased. This combination killed significantly more bacteria than both the negative control group at each level tested and the positive control group at 300, 400 and 500 μm inside the dentinal tubules. It reached 100% in all experimental groups, both on the root canal walls and at 100 and 200 μm inside the dentinal tubules. However, at 300, 400 and 500 μm inside the dentinal tubules, only the groups treated with 0.5 and 1.0 W for 30s exhibited no bacterial growth. Of the two groups in which no bacteria were detected at all tested depths, Er:YAG laser irradiation at 0.5 W for 30 s combined with NaOCl irrigation was preferable because of the lower emission power and shorter irradiation time, and may serve as a new option for effective root canal disinfection. PMID:26645354

  16. 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.

  17. Wntless regulates dentin apposition and root elongation in the mandibular molar.

    PubMed

    Bae, C H; Kim, T H; Ko, S O; Lee, J C; Yang, X; Cho, E S

    2015-03-01

    Wnt signaling plays an essential role in the dental epithelium and mesenchyme during tooth morphogenesis. However, it remains unclear if Wnt ligands, produced from dental mesenchyme, are necessary for odontoblast differentiation and dentin formation. Here, we show that odontoblast-specific disruption of Wntless (Wls), a chaperon protein that regulates Wnt sorting and secretion, leads to severe defects in dentin formation and root elongation. Dentin thickness decreased remarkably and pulp chambers enlarged in the mandibular molars of OC-Cre;Wls(CO/CO) mice. Although the initial odontoblast differentiation was normal in the mutant crown, odontoblasts became cuboidal and dentin thickness was reduced. In immunohistochemistry, Wnt10a, β-catenin, type I collagen, and dentin sialoprotein were significantly down-regulated in the odontoblasts of mutant crown. In addition, roots were short and root canals were widened. Cell proliferation was reduced in the developing root apex of mutant molars. Furthermore, Wnt10a and Axin2 expression was remarkably decreased in the odontoblasts of mutant roots. Deletion of the Wls gene in odontoblasts appears to reduce canonical Wnt activity, leading to inhibition of odontoblast maturation and root elongation.

  18. Wntless Regulates Dentin Apposition and Root Elongation in the Mandibular Molar

    PubMed Central

    Bae, C.H.; Kim, T.H.; Ko, S.O.; Lee, J.C.; Yang, X.

    2015-01-01

    Wnt signaling plays an essential role in the dental epithelium and mesenchyme during tooth morphogenesis. However, it remains unclear if Wnt ligands, produced from dental mesenchyme, are necessary for odontoblast differentiation and dentin formation. Here, we show that odontoblast-specific disruption of Wntless (Wls), a chaperon protein that regulates Wnt sorting and secretion, leads to severe defects in dentin formation and root elongation. Dentin thickness decreased remarkably and pulp chambers enlarged in the mandibular molars of OC-Cre;WlsCO/CO mice. Although the initial odontoblast differentiation was normal in the mutant crown, odontoblasts became cuboidal and dentin thickness was reduced. In immunohistochemistry, Wnt10a, β-catenin, type I collagen, and dentin sialoprotein were significantly down-regulated in the odontoblasts of mutant crown. In addition, roots were short and root canals were widened. Cell proliferation was reduced in the developing root apex of mutant molars. Furthermore, Wnt10a and Axin2 expression was remarkably decreased in the odontoblasts of mutant roots. Deletion of the Wls gene in odontoblasts appears to reduce canonical Wnt activity, leading to inhibition of odontoblast maturation and root elongation. PMID:25595365

  19. Effect of a lactose-containing sweetener on root dentine demineralization in situ.

    PubMed

    Aires, C P; Tabchoury, C P M; Del Bel Cury, A A; Cury, J A

    2002-01-01

    Since lactose has been used as an excipient in powdered sweeteners, we evaluated its effect on dentine demineralization, in an in situ crossover study. Twelve adult volunteers wore palatal appliances containing 4 blocks of bovine root dentine, which were submitted 4 times a day to: distilled water (negative control), aqueous solution of powdered sweetener (Zero Cal); experimental group), 1.5% lactose solution (active group), 1.5% sucrose solution (positive control). After 15 days, microhardness was determined on dentine surface (SMH) and on the sectioned blocks (CSMH). All groups presented statistical differences in SMH before and after the treatments; water increased, while sweetener, lactose and sucrose decreased SMH. By CSMH, the only significant difference was observed after sucrose treatment. The data suggest that sweeteners containing lactose as a bulking agent may be cariogenic for root dentine.

  20. Investigations of radicular dentin permeability and ultrastructural changes after irradiation with Er,Cr:YSGG laser and dual wavelength (2780 and 940 nm) laser.

    PubMed

    Al-Karadaghi, Tamara Sardar; Franzen, Rene; Jawad, Hussein A; Gutknecht, Norbert

    2015-11-01

    The aim of this study was to assess the effectiveness of dual wavelength (2780 nm Er,Cr:YSGG, 940 nm diode) laser in elimination of smear layer comparing it with Er,Cr:YSGG laser in terms of radicular dentin permeability and ultrastructural changes of root canal walls. Fifty-one sound single-rooted extracted teeth were instrumented up to size F4 and divided into three groups: group Co, non-irradiated samples; group A, irradiated with Er,Cr:YSGG laser; group B, irradiated with the dual wavelength laser. Afterward, the roots were made externally impermeable, filled with 2% methylene blue dye, divided horizontally into three segments reflecting the cervical, middle, and apical thirds then examined under microscope. Using analytical software, the root section area and dye penetration area were measured, and then, the percentage of net dye penetration area was calculated. Additionally, scanning electron microscope investigations were accomplished. Analysis of variance (ANOVA) showed significant differences between all groups over the three root thirds. Dye permeation in dual wavelength laser group was significantly higher over the whole root length: cervical, middle, and apical compared to Er,Cr:YSGG laser group and non-irradiated samples (p < 0.001). Scanning electron micrographs of dual wavelength irradiated samples showed a distinctive removal of smear layer with preservation of the annular structure of dentinal tubules. Er,Cr:YSGG laser root canal irradiation produced uneven removal of smear layer, in efficient cleanliness especially in the apical third. There was no sign of melting and carbonization. Within the studied parameters, root canal irradiation with dual wavelength laser increased dentin permeability.

  1. Comparative study of dentine permeability after apicectomy and surface treatment with 9.6 microm TEA CO2 and Er:YAG laser irradiation.

    PubMed

    Gouw-Soares, S; Stabholz, A; Lage-Marques, J L; Zezell, D M; Groth, E B; Eduardo, C P

    2004-04-01

    Failure of apicectomies is generally attributed to dentine surface permeability as well as to the lack of an adequate marginal sealing of the retrofilling material, which allows the percolation of microorganisms and their products from the root canal system to the periodontal region, thus compromising periapical healing. The purpose of this study was to evaluate dentine and the marginal permeability after apicectomy and surface treatment with 9.6 micro m TEA CO(2) or Er:YAG 2.94 micro m laser irradiation. Sixty-five single rooted human endodontically treated teeth were divided into five experimental groups: group I (control), apicectomy with high speed bur; group II, similar procedure to that of group I, followed by dentinal surface treatment with 9.6 micro m CO(2) laser; group III, similar procedure to group I followed by dentinal surface treatment with Er:YAG laser 2.94 micro m; group IV, apicectomy and surface treatment with CO(2) 9.6 micro m laser; and group V, apicectomy and surface treatment with Er:YAG laser 2.94 micro m. The analysis of methylene blue dye infiltration through the dentinal surface and the retrofilling material demonstrated that the samples from the groups that were irradiated with the lasers showed significantly lower infiltration indexes than the ones from the control group. These results were compatible with the structural morphological changes evidenced through SEM analysis. Samples from groups II and IV (9.6 micro m CO(2)) showed clean smooth surfaces, fusion, and recrystallized dentine distributed homogeneously throughout the irradiated area sealing the dentinal tubules. Samples from groups III and V (Er:YAG 2.94 micro m) also presented clean surfaces, without smear layer, but roughly compatible to the ablationed dentine and without evidence of dentinal tubules. Through the conditions of this study, the Er:YAG 2.94 micro m and the 9.6 micro m CO(2) laser used for root canal resection and dentine surface treatment showed a reduction of

  2. Comparative study of dentine permeability after apicectomy and surface treatment with 9.6 microm TEA CO2 and Er:YAG laser irradiation.

    PubMed

    Gouw-Soares, S; Stabholz, A; Lage-Marques, J L; Zezell, D M; Groth, E B; Eduardo, C P

    2004-04-01

    Failure of apicectomies is generally attributed to dentine surface permeability as well as to the lack of an adequate marginal sealing of the retrofilling material, which allows the percolation of microorganisms and their products from the root canal system to the periodontal region, thus compromising periapical healing. The purpose of this study was to evaluate dentine and the marginal permeability after apicectomy and surface treatment with 9.6 micro m TEA CO(2) or Er:YAG 2.94 micro m laser irradiation. Sixty-five single rooted human endodontically treated teeth were divided into five experimental groups: group I (control), apicectomy with high speed bur; group II, similar procedure to that of group I, followed by dentinal surface treatment with 9.6 micro m CO(2) laser; group III, similar procedure to group I followed by dentinal surface treatment with Er:YAG laser 2.94 micro m; group IV, apicectomy and surface treatment with CO(2) 9.6 micro m laser; and group V, apicectomy and surface treatment with Er:YAG laser 2.94 micro m. The analysis of methylene blue dye infiltration through the dentinal surface and the retrofilling material demonstrated that the samples from the groups that were irradiated with the lasers showed significantly lower infiltration indexes than the ones from the control group. These results were compatible with the structural morphological changes evidenced through SEM analysis. Samples from groups II and IV (9.6 micro m CO(2)) showed clean smooth surfaces, fusion, and recrystallized dentine distributed homogeneously throughout the irradiated area sealing the dentinal tubules. Samples from groups III and V (Er:YAG 2.94 micro m) also presented clean surfaces, without smear layer, but roughly compatible to the ablationed dentine and without evidence of dentinal tubules. Through the conditions of this study, the Er:YAG 2.94 micro m and the 9.6 micro m CO(2) laser used for root canal resection and dentine surface treatment showed a reduction of

  3. Effect of root canal treatments on quartz fiber posts bonding to root dentin.

    PubMed

    Baldissara, Paolo; Zicari, Francesca; Valandro, Luiz Felipe; Scotti, Roberto

    2006-10-01

    The aim of this study was to evaluate the effect of irrigants and endodontic sealers on fiber post push-out strength in both fatigue cycling and no-cycling conditions. Fifty single-rooted human teeth received five endodontic treatments. The posts were cemented using a flowable composite and a three-steps adhesive. Five specimens from each group were subjected to 2 x 10(6) cycles of 37.5 N. There were 200 sections obtained for the push-out test. Fatigue cycled groups treated with an eugenol-containing sealer showed the lowest push-out strength (p < 0.001). No significant differences were found among no-cycled groups (p = 0.665). The post-cement interface was found to be weaker than the cement-dentin one. However, fatigue cycles increased the occurrence of cement-dentin failures (p = 0.001). The eugenol-containing sealer reduced the bonding of fiber posts when mechanically cycled, thus the use of a resin-based sealer is advisable.

  4. Effect of instrumentation with different irrigating solutions and with or without Er:YAG laser irradiation on radicular dentine permeability

    NASA Astrophysics Data System (ADS)

    Pecora, Jesus D.; Ribeiro, Rodrigo G.; Marchesan, Melissa A.; Brugnera, Aldo, Jr.

    2004-05-01

    This study evaluated radicular dentine permeability of root canal walls when using different irrigating solutions associated or not with Er:YAG laser. Fifty human maxillary incisors, obtained from laboratory stock, were randomly divided into ten groups of five teeth each. External surfaces of the teeth were impermeabilized with cyanoacrylate (Super Bonder). After chamber access, the root canals were instrumented with the step-back technique. Ten ml of irrigating solution was used in each root canal. Group I: irrigated with distilled and deionized water; Group II: irrigated as Group I and irradiated with laser; Group III: irrigated with 0.1% laurel diethyleneglycol ether sodium sulfate; Group IV: irrigated as Group III and irradiated with laser; Group V: irrigated with 1% sodium hypochlorite; Group VI: irrigated as Group V and irradiated with laser; Group VII: irrigated with 15% EDTA; Group VIII: irrigated as Group VII and irradiated with laser; Group IX: irrigated with 10% citric acid; Group X: irrigated as Group IX and irradiated with laser. Laser (KaVo Key Laser II) was applied with the following parameters: 15 Hz, 300 pulses, 42 J total energy, and 140mJ input and 51mJ ouput. The fiber optic tip was introduced until the apex and the laser was activated. The tip was withdrawn gently with helicoidally movement from the apex until the cervical portion. After preparation of the root canals, the root were immersed in 10% copper sulfate for 30 minute and then immersed in 1% rubeanic acid alcohol solution for the same period. The roots were sectioned transversally into 150μm slices, sanded, washed, dehydrated, cleared and mounted on glass slides for microscopic examination. The quantification of the penetration of copper ions was done by morphometric analysis. Results showed that distilled and deionized water + laser and 1% sodium hypochlorite presented the highest dentine permeability (p>0.05) and was statistically different from the other groups (p<0.05). The use of

  5. Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

    PubMed Central

    Vatkar, Niranjan Ashok; Hegde, Vivek; Sathe, Sucheta

    2016-01-01

    Aim: To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods. Materials and Methods: Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, and diode laser. The effect of disinfection methods was assessed by LIVE/DEAD BacLight stain under the confocal laser scanning microscopy to determine the “zone of dead bacteria” (ZDB). Mean values were calculated for ZDB and the difference between groups was established. Results: Penetration of E. faecalis was seen to a depth of >1000 μm. Viable bacteria were detected with NS irrigation. NaOCl and CHX showed partial ZDB. When the root canals were disinfected with Nd: YAG and diode lasers, no viable bacteria were found. Conclusion: E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules.

  6. Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

    PubMed Central

    Vatkar, Niranjan Ashok; Hegde, Vivek; Sathe, Sucheta

    2016-01-01

    Aim: To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods. Materials and Methods: Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, and diode laser. The effect of disinfection methods was assessed by LIVE/DEAD BacLight stain under the confocal laser scanning microscopy to determine the “zone of dead bacteria” (ZDB). Mean values were calculated for ZDB and the difference between groups was established. Results: Penetration of E. faecalis was seen to a depth of >1000 μm. Viable bacteria were detected with NS irrigation. NaOCl and CHX showed partial ZDB. When the root canals were disinfected with Nd: YAG and diode lasers, no viable bacteria were found. Conclusion: E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules. PMID:27656064

  7. [A Phd completed 4. Interactions between root canal irrigants, sealers and dentin].

    PubMed

    Neelakantan, P; Shemesh, H; Wesselink, P

    2016-09-01

    In the field of endodontology, antibacterial activity of irrigants has been investigated many times. The influence of these solutions on the bonding of root canal sealers, however, has hardly been studied. The objective of this doctoral research was to determine the interactions between root canal sealers and root dentin, and to determine the influence of irrigants on these interactions. The various studies revealed that irrigants have an influence on the bonding of sealers based on epoxy resin, calcium hydroxide, silicones and calcium silicate. In the case of a sealer based on epoxy resin (AH Plus), the irrigation protocol had an influence on the bond strength (adhesion) on dentin, by means of which the seal was also improved. The results of this research produced better insights into the mechanisms at play in the adhesive properties of root canal sealers. Eventually, this might result in improved treatment outcomes of root canal treatments. PMID:27643496

  8. Decalcifying capability of irrigating solutions on root canal dentin mineral content

    PubMed Central

    Poggio, Claudio; Dagna, Alberto; Vinci, Andrea; Beltrami, Riccardo; Cucca, Lucia; Giardino, Luciano

    2015-01-01

    Background: Chelating agents are believed to aid root canal irrigation and to be able to remove the inorganic smear layer. Aims: The purpose of the present study was to evaluate and to compare the decalcifying capability of different irrigating solutions (Tubuliclean, Largal Ultra, ethylenediaminetetraacetic acid 17%, Tetraclean, Tetraclean NA). Materials and Methods: Sixty maxillary central incisors were used. Root canals were instrumented and irrigated. From each root, four comparable slices of cervical dentin were obtained. At three successive 5-min interval immersion times, the concentration of calcium extracted from root canal dentin was assessed with an inductively coupled plasma-atomic emission spectrometer. Statistical Analysis Used: Data were analyzed by means of Kruskal Wallis and Mann–Whitney tests. Significance was predetermined at P < 0.05. Results and Conclusions: For all irrigating solutions, the maximum amount of Ca2+ extracted from root canal dentin samples was reached after 10 min contact time except for citric acid-based agents (Tetraclean and Tetraclean NA) which induced a higher and still increasing calcium release even after 10 min contact time. In order to obtain an efficient decalcifying action on dentin and to facilitate the biomechanical procedures, citric acid-based irrigants can be applied. PMID:26097355

  9. Comparison of Acid Resistance of Root Dentin after Treatment with a Mid-Infrared Free Electron Laser at between λ=9.0 and 9.7 µm

    NASA Astrophysics Data System (ADS)

    Heya, Manabu; Sano, Shu; Kumasaki, Hiroaki; Hashishin, Yuichi; Sunada, Kazuhisa; Yoshikawa, Kazushi; Inoue, Masayoshi; Horiike, Hiroshi

    2008-11-01

    The purpose of this study was to compare the acid resistance of root dentin treated with a free electron laser emitting at between λ=9.0 and 9.7 µm, corresponding to the absorption peaks due to the phosphate ions. In order to obtain the optimum irradiation time for effective surface modification in the acid resistance test, we measured the temporal behaviors of acoustic wave emission and temperature rise. Lased and unlased samples were immersed in 0.1 M lactic acid, and the amount of Ca dissolved in the solution was determined after immersion times of 1-22 h. The acid resistances for λ=9.0 and 9.7 µm increased only until ˜3 h. We conclude that the surface modification of root dentin leads to improved acid resistance, but that this only persists for a few hours. Subsurface modification but not surface modification would be effective in the treatment of root surface caries.

  10. Adaptation and penetration of resin-based root canal sealers in root canals irradiated with high-intensity lasers.

    PubMed

    Moura-Netto, Cacio; Mello-Moura, Anna Carolina Volpi; Palo, Renato Miotto; Prokopowitsch, Igor; Pameijer, Cornelis H; Marques, Marcia Martins

    2015-03-01

    This research analyzed the quality of resin-based sealer adaptation after intracanal laser irradiation. Extracted teeth (n = 168) were root canal treated and divided into four groups, according to dentin surface treatment: no laser; Nd:YAG laser (1.5 W, 100 mJ, 15 Hz); diode laser (2.5 W in CW), and Er:YAG laser (1 W, 100 mJ, 10 Hz). The teeth were divided into four subgroups according to the sealer used: AH Plus, EndoREZ, Epiphany, and EpiphanySE. For testing the sealing after root canal obturation, the penetration of silver nitrate solution was measured, whereas to evaluate the adaptation and penetration of the sealer into the dentin, environmental scanning electron microscopy (ESEM) was used. The ESEM images were analyzed using a four-grade criteria score by three evaluators. The inter-examiner agreement was confirmed by Kappa test and the scores statistically compared by the Kruskal-Wallis' test (p < 0.05). Both adaptation and sealer penetration in root canals were not affected by the laser irradiation. Nd:YAG and diode laser decreased the tracer penetration for AH Plus, whereas EndoREZ and EpiphanySE performances were affected by Nd:YAG irradiation (p < 0.05). It can be concluded that intracanal laser irradiation can be used as an adjunct in endodontic treatment; however, the use of hydrophilic resin sealers should be avoided when root canals were irradiated with Nd:YAG laser.

  11. Adaptation and penetration of resin-based root canal sealers in root canals irradiated with high-intensity lasers

    NASA Astrophysics Data System (ADS)

    Moura-Netto, Cacio; Mello-Moura, Anna Carolina Volpi; Palo, Renato Miotto; Prokopowitsch, Igor; Pameijer, Cornelis H.; Marques, Marcia Martins

    2015-03-01

    This research analyzed the quality of resin-based sealer adaptation after intracanal laser irradiation. Extracted teeth (n=168) were root canal treated and divided into four groups, according to dentin surface treatment: no laser; Nd:YAG laser (1.5 W, 100 mJ, 15 Hz) diode laser (2.5 W in CW), and Er:YAG laser (1 W, 100 mJ, 10 Hz). The teeth were divided into four subgroups according to the sealer used: AH Plus, EndoREZ, Epiphany, and EpiphanySE. For testing the sealing after root canal obturation, the penetration of silver nitrate solution was measured, whereas to evaluate the adaptation and penetration of the sealer into the dentin, environmental scanning electron microscopy (ESEM) was used. The ESEM images were analyzed using a four-grade criteria score by three evaluators. The inter-examiner agreement was confirmed by Kappa test and the scores statistically compared by the Kruskal-Wallis' test (p<0.05). Both adaptation and sealer penetration in root canals were not affected by the laser irradiation. Nd:YAG and diode laser decreased the tracer penetration for AH Plus, whereas EndoREZ and EpiphanySE performances were affected by Nd:YAG irradiation (p<0.05). It can be concluded that intracanal laser irradiation can be used as an adjunct in endodontic treatment; however, the use of hydrophilic resin sealers should be avoided when root canals were irradiated with Nd:YAG laser.

  12. 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

  13. Effect of Peracetic Acid as A Final Rinse on Push Out Bond Strength of Root Canal Sealers to Root Dentin

    PubMed Central

    Gaddala, Naresh; Veeramachineni, Chandrasekhar

    2015-01-01

    Background Smear layer which was formed during the instrumentation of root canals hinders the penetration of root canal sealers to root dentin and affect the bond strength of root canal sealers to root dentin. Final irrigant such as demineralizing agents are used to remove the inorganic portion of the smear layer. In the present study, peracetic acid used as a final rinse, to effect the bond strength of root canal sealers to root dentin. Aim The purpose of the present study was to evaluate the efficacy of peracetic acid as a final irrigant on bond strength of root canal sealers to root dentin. Materials and Methods Sixty six freshly extracted human single rooted mandibular premolars were used for this study. After decoronation the samples were instrumented with Protaper upto F3 and irrigated with 5.25% NaOcl. The teeth were then divided into three groups based on final irrigant used: Group-1(control group) Canals were irrigated with distilled water. Group-2: Canals were irrigated with peracetic acid. Group-3: Canals were irrigated with smear clear. Each group was further divided into three subgroups (n=30) based on the sealer used to obturate the canals. Subgroup-1: kerr, Subgroup-2: Apexit plus, Subgroup-3: AH PLUS. Each sealer was mixed and coated to master cone and placed in the canal. The bonding between sealer and dentin surface was evaluated using push out bond strength by universal testing machine. The mean bond strength values of each group were statistically evaluated using Two-way ANOVA followed by Tukey post-hoc test. Results Significant difference was found among the bond strength of the sealers. But, there is no statistically significant difference between the groups irrigated with peracetic acid and smear clear compared to control group. AH Plus showed highest bond strength irrespective of the final irrigant used. Conclusion Peracetic acid when employed as final irrigant improved the bond strength of root canal sealers compared to control group but

  14. Periapical Microsurgery: The effect of root dentinal defects on short and long term outcome

    PubMed Central

    Tawil, Peter Z.; Saraiya, Veeral M.; Galicia, Johnah C.; Duggan, Derek J.

    2015-01-01

    Introduction The purpose of this prospective clinical study is to evaluate the clinical outcome of endodontic microsurgery on roots exhibiting the presence or absence of dentinal defects at one year and three-year follow up period. Methods 155 teeth were treated with periapical microsurgery using a modern microsurgical protocol in a private practice setting. The root apices were resected and inspected for dentinal defects with a Surgical Operating Microscope and a 0.8mm head diameter LED microscope diagnostic probe light. After inspection, retrograde preparations were performed using ultrasonic tips and retrograde fillings were placed. Follow up visits occurred at one year and three years post-operatively. The primary outcome measure employed was the change in the radiographic apical bone density and the secondary outcome measure used was the absence of clinical symptoms. Results Out of the 155 treated teeth, a total of 134 teeth were assessed at the one-year follow-up and 127 teeth at the three-year evaluation. The “Intact” group had 94.8% healed at one year and 97.3% healed at three years. The “Dentinal Defect” group had 29.8% healed at one year and 31.5% healed at three years. The baseline root condition of either “Dentinal Defect” or “Intact” showed a statistical difference in the healing outcome at both one year and at three years. Conclusions This prospective periapical microsurgery study showed a significant superior clinical outcome for intact roots when compared to roots with dentinal defects at both 1 year and at 3 years post-operatively. PMID:25282374

  15. The initial attachment of cemental fibrils to the root dentin surface in acellular and cellular cementogenesis in rat molars.

    PubMed

    Yamamoto, T; Domon, T; Takahashi, S; Islam, M N; Suzuki, R

    2001-03-01

    To elucidate the initial attachment mechanism of cemental fibrils to the root dentin surface in acellular and cellular cementogenesis, developing rat molars were observed by light microscopy and scanning electron microscopy combined with NaOH maceration. The NaOH maceration was used to observe details of the positional association of cemental and dentinal fibrils during cementogenesis. An initial hematoxylin stained, cementum layer began to form on the root dentin surface with the first dentin mineralization in both acellular and cellular cementogenesis. The initial attachment of cemental fibrils to the dentin surface also began at this point. At the initial attachment the intermingling of cemental and dentinal fibrils occurred only in places. With advanced cementogenesis the initial cementum layer became the fibril-poor cemento-dentinal junction. This suggests that cemental fibrils attach on the initial cementum layer, and not directly on dentinal fibrils, so that the layer results in the fibril-poor cemento-dentinal junction. The present study suggests that an intervening adhesive is necessary for the cemento-dentinal attachment at any stage of cementogenesis in rat molars. PMID:11325058

  16. Ionizing irradiation affects the microtensile resin dentin bond strength under simulated clinical conditions

    PubMed Central

    Yadav, Suman; Yadav, Harish

    2013-01-01

    Objectives: This study evaluated the effect of ionizing radiations on resin–dentin interface in terms of marginal adaptation and micro-tensile bond strength under thermocycling and mechanical loading. Materials and Methods: Forty extracted human mandibular third molars were divided into four groups. GR I: No Irradiation and Class II MO cavities were prepared that were restored with composite restorations; GR II: Teeth were irradiated and restored; GR III: Teeth were restored and irradiated; GR IV: Teeth were restored during irradiation dosage fractions. All samples were thermal and mechanical loaded with 5000 cycles, 5 ± 2-55 ± 2°C, dwell time 30 s and 150,000 cycles at 60N. Resin–dentin slabs were trimmed into dumbbell-shaped slabs and microtensile bond strength was measured. The bond strength data was analyzed by one-way analysis of variance test. Results and Conclusions: Irradiation before tooth preparation deteriorated the microtensile bond strength. PMID:23716968

  17. Effect of gutta-percha solvents on fiberglass post bond strength to root canal dentin.

    PubMed

    Guedes, Orlando A; Chaves, Gustavo S; Alencar, Ana H G; Borges, Alvaro H; Estrela, Cyntia R A; Soares, Carlos J; Estrela, Carlos

    2014-06-01

    The purpose of this study was to investigate the influence of gutta-percha solvents on the bond strength of fiberglass post to root canal dentin. Forty bovine incisors were decoronated, prepared, filled, and randomly distributed into four groups (n = 10) according to the gutta-percha solvent used: control, xylene, eucalyptol and orange oil. After root canal treatment, the posts were cemented into the prepared root canals using a resin-based cement. A micro push-out test was executed, and the patterns of failure were assessed with microscopy. The data were analyzed using two-way ANOVA followed by Tukey's test. The control group exhibited greater bond strength compared to the eucalyptol group in the cervical and middle thirds of the root (P < 0.05); however, it did not differ significantly from the xylene and orange oil groups (P > 0.05). No difference was observed in the values of the xylene, orange oil, and eucalyptol groups (P > 0.05). The cervical third had higher values than the apical third for all tested solvents (P < 0.05). Adhesive failure between resin cement and dentin was the most frequent type of failure. The use of xylene and orange oil as gutta-percha solvents did not influence the bond strength of fiberglass posts to root canal dentin.

  18. Crystallographic Texture and Elemental Composition Mapped in Bovine Root Dentin at the 200 nm Level

    PubMed Central

    Deymier-Black, A. C.; Veis, A.; Cai, Z.; Stock, S. R.

    2015-01-01

    Summary The relationship between the mineralization of peritubular dentin (PTD) and intertubular dentin (ITD) is not well understood. Tubules are quite small, diameter ~2 μm, and this makes the near-tubule region of dentin difficult to study. Here, advanced characterization techniques are applied in a novel way to examine what organic or nanostructural signatures may indicate the end of ITD or the beginning of PTD mineralization. X-ray fluorescence intensity (Ca, P, and Zn) and X-ray diffraction patterns from carbonated apatite (cAp) were mapped around dentintubules at resolutions ten times smaller than the feature size (200 nm pixels), representing a 36% increase in resolution over earlier work. In the near tubule volumes of near-pulp, root dentin, Zn intensity was higher than in ITD remote from the tubules. This increase in Zn2+, as determined by X-ray absorption near edge structure analysis, may indicate the presence of metalloenzymes or transcription factors important to ITD or PTD mineralization. The profiles of the cAp 00.2 X-ray diffraction rings were fitted with a pseudo-Voigt function, and the spatial and azimuthal distribution of these rings’ integrated intensities indicated that the cAp platelets were arranged with their c-axes aligned tangential to the edge of the tubule lumen. This texture was continuous throughout the dentin indicating a lack of structural difference between in the Zn rich near-tubular region and the remote ITD. PMID:23630059

  19. Raman study of human dentin irradiated with Er:YAG laser

    NASA Astrophysics Data System (ADS)

    S. Soares, Luis E.; Martin, Airton A.; Brugnera, Aldo, Jr.; Zanin, Fatima A.; Arisawa, Emilia A.; T. Pacheco, Marcos T.

    2004-09-01

    Raman Spectroscopy was used to examine the distribution of the mineral and organic components in the human dentin before and after the chemical and thermal etching process. Polished dentin disks (n = 6/group) with 4mm thickness from twelve third molars were irradiated with Er:YAG laser. The dentin disks were prepared by polishing through a series of SiO2 papers with water and cleaned by ultrasonic system. Four pretreatment were performed. The disks were etched with 37% phosphoric acid (group I), Er:YAG laser 80mJ, 3Hz, 30s. (group II), Er:YAG laser 120mJ, 3Hz, 30s. (group III) and Er:YAG laser 180mJ, 3Hz, 30s. (group IV). The Raman spectra obtained from normal and treated dentin were analyzed. Attention was paid to the mineral PO4 (962 cm-1), CO3 (1073 cm-1) and to the organic component (1453cm-1). Raman spectroscopy showed that the mineral and organic dentin content were more affected in autoclaved teeth than in the specimens treated by Thymol. Peak area reduction in the specimens treated by Thymol in group I and II showed to be the most conservative procedures regarding to changes in organic and inorganic dentin components. Pulse energies of 120 and 180mJ showed to produce more reduction in the organic and inorganic content associated with more reduction in the peak areas at 960 and 1453cm-1.

  20. Er:YAG laser irradiation of human dentin: Raman study of collagen

    NASA Astrophysics Data System (ADS)

    Soares, Luis E. S.; Martin, Airton A.; Brugnera, Aldo, Jr.; Zanin, Fatima; Arisawa, Emilia A.; Pacheco, Marcos T. T.

    2004-05-01

    Raman Spectroscopy was used to examine the distribution of the organic components in the human dentin before and after the chemical and thermal etching process. Polished dentin disks (n = 6/group) with 4mm thickness from twelve third molars were irradiated with Er:YAG laser. The dentin disks were prepared by polishing through a series of SiO2 papers with water and cleaned by ultrasonic system. Four pretreatment were performed. The disks were etched with 37% phoshporic acid for 15 s (group 1), Er:YAG laser 80 mJ, 3Hz, 30s. (group II), Er:YAG laser 120 mJ, 3Hz, 30s. (group III) and Er:YAG laser 180mJ, 3Hz, 30s. (group IV). The Raman spectra obtained from normal and treated dentin were analyzed. Attention was paid to the organic component (1453cm-1). Raman spectroscopy showed that the organic dentin content were more affected in autoclaved teeth than in the specimens treated by Thymol. Peak area reduction in the specimens treated by Thymol in group I and II showed to be the most conservative procedures regarding to changes in organic dentin components. Pulse energies of 120 and 180 mJ showed to preduce more reduction in the organic content associated with more reduction in the peak areas at 1453 cm-1.

  1. Effects of the Er, Cr:YSGG laser irradiation on dentin bond strength

    NASA Astrophysics Data System (ADS)

    Piccioni, M. A. R. V.; Neves, T. P. C.; Kubo, C. S.; Saad, J. R. C.; Campos, E. A.

    2016-02-01

    The aim of this study is to evaluate the influence of Er,Cr:YSGG laser irradiation and bur on the bond strength of different single step self-etch adhesive systems in normal and artificially hypermineralized dentin. In total, 112 human molars were selected. The specimens were randomly divided into two different groups according to the type of dentin. The teeth from each group were randomly divided into two subgroups according to the adhesive system used: Clearfil S3 Bond and Optibond All in One. Each subgroup received different treatments: (1) conditioning conventional; (2) conditioning of the dentin surface with Er,Cr:YSGG  +  application of the adhesive system; (3) ‘surface roughening’ dentin with 3098 diamond bur  +  application of the adhesive system. The matrices were positioned, filled with composite resin and photoactivated for 40 s. After a storage period of 24 h in a humid environment, the specimens were submitted to microshear bond strength testing. Subsequently, the fracture pattern of each sample was determined. One specimen per group was prepared in order to evaluate the interface and/or appearance of resin tags. The data of the microshear bond strength (μSBS) were analyzed by two-way ANOVA and Tukey’s (p  <0.05). In the hypermineralized dentin, there was no significant statistical difference between all the treatments employed, enhancing the option of employing single step self-etch adhesives in dentin sclerotic.

  2. Effect of various laser irradiations on the mineral content of dentin

    PubMed Central

    Dilber, Erhan; Malkoc, Meral Arslan; Ozturk, A. Nilgun; Ozturk, Firat

    2013-01-01

    Objective: The aim of this study was to evaluate the mineral content of dentin irradiation with Erbium: yttrium-aliminum-garnet (Er:YAG), Neodmiyum:yttrium-aliminum garnet (Nd:YAG) and potassium titanium phosphate (KTP) laser used for in the treatment of dentin hypersensitivity. Methods: Six extracted wisdom, unerupted molar teeth were used in this study. The enamel of the teeth was removed with a conventional bur under water cooling to expose the dentin surface. The teeth were mounted in a slow-speed, diamond-saw, sectioning machine. Two dentin slabs were obtained from each tooth and each slab was sectioned so that 4 slabs were made from each teeth. Then dentin slabs were randomly divided into four groups. Group A: Control Group, Group B: Er:YAG laser, Group C: Nd:YAG laser, Group D: KTP laser. The levels of Ca, K, Mg, Na,P and Ca/P mineral ratio in each dentin slab were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Data were analysed by one way analysis of variance (ANOVA) and Tukey HSD tests. One sample from each group was prepared for scanning electron microscopy (SEM). Results: There were no significant differences between the groups for Ca, K, Mg, Na,P and Ca/P mineral ratio (P>.05). SEM photographs indicated that there were melted areas around the exposed dentin tubules in groups treated with Er:YAG and KTP lasers. Conclusion: This study demonstrated that laser etching with the Er:YAG, Nd:YAG, KTP laser systems did not affect the compositional structure of the dentin surfaces. PMID:23407579

  3. Identification of resected root-end dentinal cracks: a comparative study of transillumination and dyes.

    PubMed

    Wright, Henry M; Loushine, Robert J; Weller, R Norman; Kimbrough, W Frank; Waller, Jennifer; Pashley, David H

    2004-10-01

    The dilemma of diagnosing and possibly treating dentinal cracks continues to present a challenge in endodontics. The purpose of this in vitro study was to compare the effectiveness of transillumination and dyes in identifying root-end dentinal cracks. Fifty maxillary central incisors were decoronated, and the canals were instrumented to an ISO size 50 at the working length. The apical 3 mm of the roots was resected, and cracks were artificially created in the apical dentin. Four independent examiners evaluated the root ends at x8 magnification with a surgical operating microscope using transillumination (group 1), sodium fluorescein dye (group 2), caries detect dye (group 3), methylene blue dye (group 4), and methylene blue plus transillumination (group 5). The examiners' ability to identify root ends correctly with and without cracks was analyzed by comparing the data with the predetermined standard (cracked and noncracked) using logistic regression analysis. All techniques used were shown to be more effective than random chance at diagnosing cracks. The areas under the curve of the different techniques were as follows: transillumination, 0.81 (95% confidence interval [CI], 0.69-0.93); sodium fluorescein, 0.72 (95% CI, 0.58-0.86); caries detector, 0.76 (95% CI, 0.63-0.89); methylene blue, 0.70 (95% CI, 0.55-0.84); and methylene blue plus transillumination, 0.82 (95% CI, 0.70-0.94). Thus, the crack assessment techniques that gave the best discrimination between cracked and noncracked specimens, regardless of rater, was methylene blue plus transillumination. This study emphasizes the usefulness of transillumination along with magnification in detecting dentinal cracks.

  4. 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.

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

    PubMed Central

    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. PMID:26731743

  6. 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. PMID:26731743

  7. Characterization of caries progression on dentin after irradiation with Nd:YAG laser by FTIR spectroscopy and fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Ana, P. A.; Brito, A. M. M.; Zezell, D. M.; Lins, E. C. C. C.

    2015-06-01

    Considering the use of high intensity lasers for preventing dental caries, this blind in vitro study evaluated the compositional and fluorescence effects promoted by Nd:YAG laser (λ=1064 nm) when applied for prevention of progression of dentin caries, in association or not with topical application of acidulated phosphate fluoride (APF). Sixty bovine root dentin slabs were prepared and demineralized by 32h in order to create early caries lesions. After, the slabs were distributed into six experimental groups: G1- untreated and not submitted to a pH-cycling model; G2- untreated and submitted to a pH-cycling model; G3- acidulated phosphate fluoride application (APF); G4- Nd:YAG irradiation (84.9 J/cm2, 60 mJ/pulse); G5- treated with Nd:YAG+APF; G6- treated with APF+Nd:YAG. After treatments, the samples of groups G2 to G6 were submitted to a 4-day pH-cycling model in order to simulate the progression of early caries lesions. All samples were characterized by the micro-attenuated total reflection technique of Fourier transformed infrared spectroscopy (μATR-FTIR), using a diamond crystal, and by a fluorescence imaging system (FIS), in which it was used an illuminating system at λ= 405±30 nm. Demineralization promoted reduction in carbonate and phosphate contents, exposing the organic matter; as well, it was observed a significant reduction of fluorescence intensity. Nd:YAG laser promoted additional chemical changes, and increased the fluorescence intensity even with the development of caries lesions. It was concluded that the compositional changes promoted by Nd:YAG, when associated to APF, are responsible for the reduction of demineralization progression observed on root dentin.

  8. Bond strength and SEM observation of CO2 laser irradiated dentin, bonded with simplified-step adhesives.

    PubMed

    Koshiro, K; Inoue, S; Niimi, K; Koase, K; Sano, H

    2005-01-01

    This study investigated, mechanically and morphologically, whether the dentin surface irradiated by CO2 laser could be a possible adherent when bonded with simplified-step adhesives. Buccal enamel and cementum of extracted human premolars were removed to expose a flat dentin surface. The dentin surfaces were irradiated continuously with CO2 laser at 1.0 W. Before bonding with either a single-bottle adhesive (Single Bond) or a self-etching priming system (Mega Bond), the irradiated dentin surface was treated as follows: no treatment, NaHCO3 powder abrasion and wet-grinding with 600-grit SiC paper. The treated dentin surfaces were bonded to resin composite with either of the two adhesives. Non-irradiated dentin surfaces were also used as control. Resin bonded specimens were stored in water at 37 degrees C for 24 hours and subjected to microtensile bond test. Additionally, to observe the resin/irradiated dentin interface, resin-bonded specimens were similarly prepared, sectioned into slabs, embedded in epoxy resin, polished with diamond pastes, sputter coated Au-Pd and examined with scanning electron microscopy (SEM). After SEM observation, the specimens were further polished with diamond paste to remove the Au-Pd sputter-coat, immersed in HCL and NaOCl and finally observed by SEM again. In the presence of carbonized dentin, microtensile bond strength drastically decreased but recovered to the control value by removing the carbonized dentin layer visually with SiC paper for both adhesive systems. However, the laser-affected dentin that remained on the bonded interface was easily dissolved with NaOCl and HCl. PMID:15853101

  9. Marginal adaptation of newer root canal sealers to dentin: A SEM study

    PubMed Central

    Polineni, Swapnika; Bolla, Nagesh; Mandava, Pragna; Vemuri, Sayesh; Mallela, Madhusudana; Gandham, Vijaya Madhuri

    2016-01-01

    Aim: This in vitro study evaluated and compared the marginal adaptation of three newer root canal sealers to root dentin. Materials and Methods: Thirty freshly extracted human single-rooted teeth with completely formed apices were taken. Teeth were decoronated, and root canals were instrumented. The specimens were randomly divided into three groups (n = 10) based upon the sealer used. Group 1 - teeth were obturated with epoxy resin sealer (MM-Seal). Group 2 - teeth were obturated with mineral trioxide aggregate (MTA) based sealer (MTA Fillapex), Group 3 - teeth were obturated with bioceramic sealer (EndoSequence BC sealer). Later samples were vertically sectioned using hard tissue microtome and marginal adaptation of sealers to root dentin was evaluated under coronal and apical halves using scanning electron microscopy (SEM) and marginal gap values were recorded. Results: The data were statistically analyzed by two-way ANOVA and Tukey's multiple post hoc test. The highest marginal gap was seen in Group 2 (apical-16680.00 nm, coronal-10796 nm) and the lowest marginal gap was observed in Group 1 (apical-599.42 nm, coronal-522.72 nm). Coronal halves showed superior adaptation compared to apical halves in all the groups under SEM. Conclusion: Within the limitations of this study epoxy resin-based MM-Seal showed good marginal adaptation than other materials tested. PMID:27563187

  10. Effect of QMix, peracetic acid and ethylenediaminetetraacetic acid on calcium loss and microhardness of root dentine

    PubMed Central

    Taneja, Sonali; Kumari, Manju; Anand, Surbhi

    2014-01-01

    Objectives: The objective of this in vitro study was to assess the effect of different chelating agents on the calcium loss and its subsequent effect on the microhardness of the root dentin. Materials and Methods: Ten single rooted lower premolars were selected. The teeth were decoronated and thick transverse sections of 2 mm were obtained from the coronal third of the root. Each section was then divided into four quarters, each part constituting a sample specimen from the same tooth for each group. The treatment groups were: Group 1 (Control): 5% Sodium hypochlorite (NaOCl) for 5 min + distilled water for 5 min; Group 2: 5% NaOCl for 5 min + 17% ethylenediaminetetraacetic acid (EDTA) for 5 min; Group 3: 5% NaOCl for 5 min + 2.25% Peracetic acid (PAA) for 5 min and Group 4: 5% NaOCl for 5 min + QMix for 5 min respectively. The calcium loss of the samples was evaluated using the Atomic Absorption Spectrophotometer followed by determination of their microhardness using Vickers Hardness Tester. Data was analyzed using one-way ANOVA, Post hoc Tukey test and Pearson correlation. Results: The maximum calcium loss and minimum microhardness was observed in Group 3 followed by Group 2, Group 4 and Group 1. There was a statistically significant difference between all the groups except between Groups 2 and 4. Conclusions: Irrigation with NaOCl + 2.25% PAA caused the maximum calcium loss from root dentin and reduced microhardness. A negative correlation existed between the calcium loss and reduction in the microhardness of root dentin. PMID:24778513

  11. Morphological analysis of the retrofilled apical dentin surfaces irradiated with CO2 laser

    NASA Astrophysics Data System (ADS)

    Aun, Carlos E.; Lage-Marques, Jose L.; Gavini, Giulio; Clasen, Naya F.; Matsumoto, Koukichi

    1998-04-01

    Countless researches conducted in these last years have compared the sealing capacity of various materials for retrofillings. Besides, the association of laser irradiation to traditional procedures inquires to increase the success of this kind of treatment. The purpose of this study was to evaluate the morphological changes on dentin surface and the junction between retrofilling material and apical cavity, with different materials irradiated or not with CO2 laser, in scanning electron microscopy. The following materials were used: Group A yields Super EBA; group B yields Super EBA and CO2 laser irradiation (Luxar System); group C yields Glass Ionomer Cement; group D yields Glass Ionomer Cement and CO2 laser. In groups B and D the power set was 2 watts, 20 msec, with a CT3105 ceramic point, and the power density for the CO2 laser application was 397,93 w/cm2. The morphological analysis permitted to conclude that the dentin laser irradiation showed different and less intense superficial alteration when compared with retrofilling materials. In most cases, the alterations to the material surfaces showed cavities and craters. Group B presented more irregular and affected surfaces, creating blank spaces in the adjacent areas to the radicular dentinal surfaces after laser application, probably because of the carbonization.

  12. Effect of diode laser radiation in root canal wall dentine: a microbiological study

    NASA Astrophysics Data System (ADS)

    Gutknecht, Norbert; Conrads, Georg; Apel, Christian; Schubert, Claus; Lampert, Friedrich

    2000-03-01

    The aim of this study was to investigate the antibacterial effect of a diode laser in deep root canal dentine. The microbial colonization of root canal dentine can lead to failures in conventional endodontic treatment if only an inadequate bacterial reduction is achieved through canal treatment and chemical disinfection. 100 micrometer, 300 micrometer and 500 micrometer bovine dentine slices obtained by longitudinal sections were sterilized and inoculated on one side with an Enterococcus faecalis suspension. Laser radiation was performed on the opposite side with the diode laser, emits light at 810 nm and operates in the continuous wave mode (cw). Radiation was performed using a 400 micrometer tapered fiber tip at an angle of approx. 5 degrees to the surface over a period of 30 s. The output power at the distal end of the tip was 0.6 watt. The bacteria were then eluted through vibration and cultured on blood agar plates. The colony count reflected the antibacterial effect of laser radiation as a function of the layer thickness. A mean bacterial reduction of 74% was achieved even with a 500 micrometer thick slice. This investigation indicates that the diode laser can support the bacterial reduction in endodontic treatment.

  13. [The influence of the difference of caries detective methods on the bond strength for caries affected root canal dentin].

    PubMed

    Otake, Shiho

    2010-03-01

    Firm adhesion of composite resin and dentin is the basic premise for building up resin composite cores successfully. To assess the efficacy of several caries detective methods (stained with Caries Detector and probing with sharp probe) for caries affected root canal dentin, microtensile bond strengths of resin composite to caries-affected root canal dentin and failure mode distribution were analyzed in this study. Color and hardness were used for assessment of root caries as follows: Dye stain group (pale pink stained with Caries Detector), Probing group (probing with sharp probe) and Sound dentin group (Control). The bond strengths (mean +/- standard deviation) of the Probing group (64.6 +/- 11.9 MPa) and the Sound dentin group (68.7 +/- 11.1 MPa) were significantly higher than those of the Dye stain group (46.9 +/- 7.9 MPa, p<0.05). However, there is no significant difference in fracture mode between the Dye stain group and the Probing group (p<0.05). This could be attributed to that the thick smear layer caused a loss of hybrid layer strength. In conclusion, the caries removal technique of the root canal dentin affected the bond strength of the resin composite.

  14. Effect of Citric Acid and Ethylenediaminetetraacetic Acid on the Surface Morphology of Young and Old Root Dentin

    PubMed Central

    Scelza, Miriam Zaccaro; de Noronha, Fernando; da Silva, Licinio Esmeraldo; Maurício, Marcos; Gallito, Marco Antonio; Scelza, Pantaleo

    2016-01-01

    Introduction: The aim of this in vitro study was to evaluate the effect of 10% citric acid and 17% ethylenediaminetetraacetic acid (EDTA) irrigating solutions on the surface morphology of young and old root dentin by determining the number and diameter of dentinal tubules using scanning electron microscopy (SEM). Methods and Materials: Fifty healthy human teeth collected from young (≤30 years) and old (≥60 years) individuals (n=25) were first prepared with a Largo bur #2 to produce smear layer on the root canal surface. Subsequently, the crowns and the root middle and apical thirds were sectioned and removed, and the cervical thirds were sectioned vertically in the buccal-lingual direction into two equal halves. The obtained samples were then immersed in 2.5% sodium hypochlorite for 30 min and randomly separated into two treatment groups for each age group. In each age group, ten samples were selected as controls and did not receive any type of treatment. The rest of the specimens were then rinsed, dried and treated for 4 min with 10% citric acid or 17% EDTA. The samples were then assessed with SEM regarding the number and diameter of dentinal tubules. All data were assessed using Student’s t-test. The level of significance was set at 0.05. Results: Regardless of the type of treatment, no significant differences were observed in the number of open tubules between the young and old root dentin (P>0.05). Nonetheless, the diameter of the tubules in the old root dentin was larger when 17% EDTA was used (P<0.05). Both, young and old root dentin did not differ with the 10% citric acid treatment (P>0.05). Conclusion: The results showed that 17% EDTA treatment induced a significant demineralization in old root dentin. PMID:27471529

  15. Strain Distribution in Root Surface Dentin of Maxillary Central Incisors during Lateral Compaction

    PubMed Central

    Pilo, Raphael; Metzger, Zvi; Brosh, Tamar

    2016-01-01

    Aim To precisely quantify the circumferential strains created along the radicular dentin of maxillary incisors during a simulated clinical procedure of lateral compaction. Methods Six miniature strain gauges were bonded on the roots of fourteen recently extracted maxillary central incisors that were subjected to root canal instrumentation. The strain gauges were bonded at three levels (apical, middle, and coronal) and four aspects (buccal, lingual, mesial, and distal) of the roots. Each tooth was embedded in a PVC cylinder containing polyvinyl-siloxane impression material. Root filling was then performed by simulating the clinical procedure of lateral compaction using nickel-titanium finger spreaders. The force applied to the spreader and the strains developing in the surface root dentin were continuously recorded at a frequency of 10 Hz. Results The highest strains that developed during lateral compaction were in the mesial and distal aspects at the apical level of the root. The magnitudes of the maximal mesial/distal strains at the apical as well as the mid-root levels were approximately 2.5–3 times higher than those at the buccal/lingual aspects (p = 0.041). The strains decreased significantly (p<0.04) from the apical through the mid-root levels to the coronal level, yielding gradients of 2.5- and 6-fold, respectively. The mesial and distal strains were consistently tensile and did not differ significantly; however, the buccal strains were generally 35–65% higher than the lingual strains (p = 0.078). Lateral compaction resulted in the gradual build-up of residual strains, resulting in generation of a 'stair-step' curve. These strains declined gradually and almost completely disappeared after 1000 sec. Conclusions With proper mounting of several miniature strain gauges at various levels and aspects of the root, significant circumferential strains can be monitored under clinically relevant compaction forces. The residual strains at the end of lateral

  16. Chemical and morphological changes in human dentin after Er:YAGlaser irradiation: EDS and SEM analysis.

    PubMed

    Contreras-Arriaga, Belinda; Rodríguez-Vilchis, Laura Emma; Contreras-Bulnes, Rosalía; Olea-Mejìa, Oscar Fernando; Scougall-Vilchis, Rogelio José; Centeno-Pedraza, Claudia

    2015-11-01

    Sixty samples of human dentin were divided into six groups (n = 10) and were irradiated with Er:YAG laser at 100 mJ-19.9 J/cm(2), 150 mJ-29.8 J/cm(2), 100 mJ-35.3 J/cm(2), 150 mJ-53.0 J/cm(2), 200 mJ-70.7 J/cm(2), and 250 mJ-88.5 J/cm(2), respectively, at 7 Hz under a water spray. The atomic percentages of carbon, oxygen, magnesium, calcium, and phosphorus and the Ca-to-P molar ratio on the dentin were determined by energy dispersive X-ray spectroscopy. The morphological changes were observed using scanning electron microscopy. A paired t-test was used in statistical analysis before and after irradiation, and a one-way ANOVA was performed (P ≤ 0.05). The atomic percent of C tended to decrease in all of the groups after irradiation with statistically significant differences, O and Mg increased with significant differences in all of the groups, and the Ca-to-P molar ratio increased in groups IV, V, and VI, with statistically significant differences between groups II and VI. All the irradiated samples showed morphological changes. Major changes in the chemical composition of dentin were observed in trace elements. A significant increase in the Ca-to-P ratio was observed in the higher energy density groups. Morphological changes included loss of smear layer with exposed dentinal tubules. The changes produced by the different energy densities employed could have clinical implications, additional studies are required to clarify them. PMID:26397964

  17. Influence of endodontic sealer composition and time of fiber post cementation on sealer adhesiveness to bovine root dentin.

    PubMed

    Rosa, Ricardo Abreu da; Barreto, Mirela Sangoi; Moraes, Rafael do Amaral; Broch, Juliana; Bier, Carlos Alexandre Souza; Só, Marcus Vinícius Reis; Kaizer, Osvaldo Bazzan; Valandro, Luiz Felipe

    2013-01-01

    This study aimed to assess the influence of the type of endodontic sealer (salicylate resin-based sealer vs. two endodontic sealers) and the time of fiber post cementation after root filling on the post adhesion to bovine root dentin. Sixty bovine roots were assigned to six groups (n=10), considering an experimental design with two factors (factorial 3x2): endodontic sealer factor in three levels [epoxy resin-based sealer (AH Plus), eugenol-based sealer (Endofill), and salicylate resin-based sealer plus mineral trioxide aggregate - MTA (MTA Fillapex)] and time for post cementation factor in two levels (immediate post cementation or 15 days after root canal filling). After post cementation, 2-mm-thick slices were produced and submitted to push-out test. The failure modes were analyzed under a 40× stereomicroscope and scored as: adhesive at cement/dentin interface; adhesive at cement/post interface; cement cohesive; post cohesive; dentin cohesive; or mixed. Data were analyzed using two-way ANOVA and Tukey's post-hoc tests (α=0.05). When the fiber posts were cemented immediately after the root canal filling, the bond strengths were similar, independent of the endodontic sealer type. However, after 15 days, the epoxy resin-based sealer presented higher bond strength than the other sealers (p<0.05). Comparison between each sealer in different experimental times did not reveal any differences. The main failure type was adhesive at dentin/cement interface (89.4%). The time elapsed between the root canal filling and post cementation has no influence on post/root dentin adhesion. On the contrary, the type of endodontic sealer can influence the adhesion between fiber posts and root dentin.

  18. Thin and thick layers of resin-based sealer cement bonded to root dentine compared: Adhesive behaviour.

    PubMed

    Pane, Epita S; Palamara, Joseph E A; Messer, Harold H

    2015-12-01

    This study aims to evaluate tensile and shear bond strengths of one epoxy (AH) and two methacrylate resin-based sealers (EZ and RS) in thin and thick layers bonded to root dentine. An alignment device was prepared for accurate positioning of 20 root dentine cylinders in a predefined gap of 0.1 or 1 mm. Sealer was placed in the interface. Bond strength tests were conducted. Mode of failures and representative surfaces were evaluated. Data were analysed using anova and post-hoc tests, with P < 0.05. The thick layer of sealer produced higher bond strength, except for the shear bond strength of EZ. Significant differences between thin and thick layers were found only in tensile bond strengths of AH and RS. Mixed type of failure was constantly found with all sealers. Bond strengths of thick layers of resin-based sealers to root dentine tended to be higher than with thin layers.

  19. Root dentin strain and temperature rise during endodontic treatment and post rehabilitation.

    PubMed

    Amade, Euridsse Sulemane; Novais, Veridiana Resende; Roscoe, Marina Guimarães; Azevedo, Fabiane Maria Ferreira; Bicalho, Aline Aredes; Soares, Carlos José

    2013-01-01

    This study investigated the effects of endodontic treatment procedures and different post systems rehabilitation steps on the strain and temperature rise on apical and cervical root dentin regions. Twenty-one extracted human canine teeth had two strain gages attached to the distal root surface and two thermocouples attached to the mesial root surface (cervical and apical). The strain and temperature rise were recorded during the following procedures: root canal preparation, final rinse and drying, root canal filling and canal relief. Then the teeth were divided into three groups (n=7), according to the type of post system: CPC, cast post and core; FGP, fiberglass post; and PSP, prefabricated steel post. Data continued to be recorded during the post space preparation, post modeling (only for CPC), post trying and post cementation. Data were subjected to a two-way ANOVA followed by Tukey's test (α=0.05). The post-space preparation caused the highest temperature rise (4.0-14.9 °C) and the highest strain in the apical region during irrespective of post type. The resin cement light-activation resulted in significant temperature increases in the cervical region for all of the groups. The canal relief and the post-space preparation produced highest temperature rises. The CPC post modeling resulted in higher root strain level similarly the level of post preparation. The PSP resulted in highest strain during post trying and post cementation. PMID:24474355

  20. Root dentin strain and temperature rise during endodontic treatment and post rehabilitation.

    PubMed

    Amade, Euridsse Sulemane; Novais, Veridiana Resende; Roscoe, Marina Guimarães; Azevedo, Fabiane Maria Ferreira; Bicalho, Aline Aredes; Soares, Carlos José

    2013-01-01

    This study investigated the effects of endodontic treatment procedures and different post systems rehabilitation steps on the strain and temperature rise on apical and cervical root dentin regions. Twenty-one extracted human canine teeth had two strain gages attached to the distal root surface and two thermocouples attached to the mesial root surface (cervical and apical). The strain and temperature rise were recorded during the following procedures: root canal preparation, final rinse and drying, root canal filling and canal relief. Then the teeth were divided into three groups (n=7), according to the type of post system: CPC, cast post and core; FGP, fiberglass post; and PSP, prefabricated steel post. Data continued to be recorded during the post space preparation, post modeling (only for CPC), post trying and post cementation. Data were subjected to a two-way ANOVA followed by Tukey's test (α=0.05). The post-space preparation caused the highest temperature rise (4.0-14.9 °C) and the highest strain in the apical region during irrespective of post type. The resin cement light-activation resulted in significant temperature increases in the cervical region for all of the groups. The canal relief and the post-space preparation produced highest temperature rises. The CPC post modeling resulted in higher root strain level similarly the level of post preparation. The PSP resulted in highest strain during post trying and post cementation.

  1. Tensile Bond Strengths of Two Adhesives on Irradiated and Nonirradiated Human Dentin

    PubMed Central

    Bernard, Cécile; Abouelleil, Hazem; Gustin, Marie-Paule; Grosgogeat, Brigitte

    2015-01-01

    The aim of this study was to assess the effect of radiotherapy on bond efficiency of two different adhesive systems using tensile bond strength test. Twenty extracted teeth after radiotherapy and twenty nonirradiated extracted teeth were used. The irradiation was applied in vivo to a minimal dose of 50 Gy. The specimens of each group were randomly assigned to two subgroups to test two different adhesive systems. A three-step/etch-and-rinse adhesive system (Optibond FL) and a two-steps/self-etch adhesive system (Optibond XTR) were used. Composite buildups were performed with a nanohybrid composite (Herculite XTR). All specimens were submitted to thermocycling ageing (10000 cycles). The specimens were sectioned in 1 mm2 sticks. Microtensile bond strength tests were measured. Nonparametric statistical analyses were performed due to nonnormality of data. Optibond XTR on irradiated and nonirradiated teeth did not show any significant differences. However, Optibond FL bond strength was more effective on nonirradiated teeth than on irradiated teeth. Within the limitations of an in vitro study, it can be concluded that radiotherapy had a significant detrimental effect on bond strength to human dentin. However, it seems that adhesive choice could be adapted to the substrata. According to the present study, the two-steps/self-etch (Optibond XTR) adhesive system tested could be more effective on irradiated dentin compared to three-steps/etch-and-rinse adhesive system (Optibond FL). PMID:26783528

  2. Prognosis of intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin.

    PubMed

    Hayashi, Mikako; Kinomoto, Yoshifumi; Takeshige, Fumio; Ebisu, Shigeyuki

    2004-03-01

    There is no particular treatment established to preserve vertically fractured teeth. We evaluated the long-term prognosis of the intentional replantation of 26 vertically fractured roots after reconstruction with 4-META/MMA-TBB dentin-bonded resin. Replanted teeth were evaluated according to clinical criteria and radiographic examinations for periods ranging from 4 to 76 months. Eighteen cases were functional and retained, with six fully successful; the others needed further observation. Eight cases failed to respond to treatment because of refracture, recurrence of gingival inflammation, or both. Longevity was calculated as 88.5% at 12 months after replantation, 69.2% at 36 months, and 59.3% at 60 months. All failures occurred in premolar and molar teeth. Longitudinal fractures extending more than 2/3 from the cervical portion toward the apex showed significantly shorter longevity compared with fractures within the 2/3 area (log-rank test, p = 0.02). Intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin may be considered for incisors as an alternative to extraction, although the long-term success is not optimal.

  3. The effects of different nickel-titanium instruments on dentinal microcrack formations during root canal preparation

    PubMed Central

    Ustun, Yakup; Aslan, Tugrul; Sagsen, Burak; Kesim, Bertan

    2015-01-01

    Objective: The aim of the present study was to investigate the incidence of dentinal microcracks caused by different preparation techniques. Materials and Methods: 120 extracted human mandibular incisor teeth were divided into five experimental groups and one control group (n = 20): Group 1: Hand preparation with balanced force technique up to #25 K-file. Group 2: Preparation with only ProTaper F2 instrument in a reciprocating movement. Group 3: Preparation with Reciproc R25 instrument in a reciprocating movement. Group 4: Preparation with ProTaper instruments up to F2 instrument. Group 5: Preparation with ProTaper Next instruments up to X2 instrument. No procedure was applied to control group. The roots were sectioned horizontally at 3, 6 and 9 mm from the apex and examined. Absence or presence of dentinal microcracks was noted. Results: The Chi-square test was performed to compare the appearance of cracked roots between all groups. There were no significant differences among the groups (P > 0.05). Conclusions: In conclusion, except the hand file and control group, all experimental groups showed microcrack formations. PMID:25713483

  4. Evaluation of Chlorine Dioxide Irrigation Solution on the Microhardness and Surface Roughness of Root Canal Dentin.

    PubMed

    Ballal, Nidambur Vasudev; Khandewal, Deepika; Karthikeyan, Saravana; Somayaji, Krishnaraj; Foschi, Federico

    2015-12-01

    The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1: 13.8% chlorine dioxide, Group 2: 17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5 ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth. PMID:26767238

  5. Evaluation of Chlorine Dioxide Irrigation Solution on the Microhardness and Surface Roughness of Root Canal Dentin.

    PubMed

    Ballal, Nidambur Vasudev; Khandewal, Deepika; Karthikeyan, Saravana; Somayaji, Krishnaraj; Foschi, Federico

    2015-09-01

    The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1:13.8% chlorine dioxide, Group 2:17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth. PMID:26591249

  6. Dentinal defects before and after rotary root canal instrumentation with three different obturation techniques and two obturating materials

    PubMed Central

    Kumaran, Ponnuswamy; Sivapriya, Elangovan; Indhramohan, Jamuna; Gopikrishna, Velayutham; Savadamoorthi, K Subramani; Pradeepkumar, Angambakkam Rajasekharan

    2013-01-01

    Aim: To evaluate the role of rotary root canal instrumentation followed by obturation with three different techniques and two different materials on the incidence of dentinal defects. Materials and Methods: One hundred and sixty mandibular premolars were divided into eight groups (n = 20). Group I was left untreated and served as control. The other seven groups were prepared with profile rotary instruments till #40.06 taper. After preparation, group II was left unfilled, groups III, IV, and V were obturated with Gutta-percha and AH Plus sealer using passive technique, lateral compaction and warm vertical compaction, respectively. Groups VI, VII, and VIII were obturated with Resilon and Realseal sealer using passive technique, lateral compaction, and warm vertical compaction, respectively. Roots were then sectioned at 3, 6, and 9 mm from the apex and inspected under a stereomicroscope (50×) for dentinal defects. Chi-square test was performed to compare the incidence of dentinal defects between the groups (P < 0.05). Results: The unprepared control group had no dentinal defects. The instrumentation group (group II) and the obturation group (groups III-VIII) showed significantly more defects than the uninstrumented control group (group I) (P < 0.001). There was no significant difference between the root canal obturating techniques (group III-VIII) when compared with the instrumentation group (group II). On inter group comparison among the obturation groups the number of defects after lateral compaction with Gutta-percha (group IV) was significantly larger than passive Gutta-percha obturation (group III) (P < 0.05). Conclusions: The results suggest that root canal instrumentation significantly influenced the incidence of dentinal defects or fracture. Dentinal defects were more significantly attributed to the role of root canal instrumentation rather than the type of obturation technique or material. Lateral compaction with Gutta-percha significantly produces more

  7. Chronological comparison of root dentin moisture in extracted human teeth stored in formalin, sodium azide, and distilled water

    PubMed Central

    Komabayashi, Takashi; Ahn, Chul; Zhang, Song; Zhu, Qiang

    2009-01-01

    This study quantified in vitro the root dentin moisture when 10% formalin (Group A), 3% sodium azide (Group B), and distilled water (Group C) were used as teeth storage media. The root dentin moisture of 66 extracted human mandibular single-rooted teeth was measured at baseline (day 0) and at 1, 3, 7, and 14 days using a digital grain moisture meter. The baseline dentin moisture value was used as a covariate in the generalized estimating equation (GEE) analysis. The mean dentin moisture values (%) ± standard deviation on days 0, 1, 3, 7, and 14 were 10.6±0.64, 14.3±0.71, 14.6±0.84, 14.4±0.64, and 14.7±0.75 (Group A); 11.4±0.94, 14.6±0.95, 14.6±0.76, 14.6±0.93, and 14.8±0.81 (Group B); and 10.2±0.95, 12.8±0.90, 13.3±0.95, 13.0±0.91, and 13.2±0.89 (Group C), respectively. The dentin moisture increased in all three groups; however, there was no overall significant difference in moisture between the formalin and sodium azide groups. PMID:19540443

  8. 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

  9. Regional bond strengths to root canal dentin of fiber posts luted with three cementation systems.

    PubMed

    Gomes, Giovana Mongruel; Gomes, Osnara Maria Mongruel; Reis, Alessandra; Gomes, João Carlos; Loguercio, Alessandro Dourado; Calixto, Abraham Lincoln

    2011-01-01

    This study evaluated the influence of the cementation system on the regional push-out bond strength and failure pattern of fiber posts to radicular dentin. The roots of 48 extracted human incisors were prepared and divided into 3 groups (n = 16), according to the cementation system: AdperScotchbond Multi-Purpose + resin cement RelyX ARC (SBMP+ARC); Adper SingleBond 2 + RelyX ARC (SB+ARC) and; RelyX U100 self-adhesive resin cement (U100). The posts were cemented as per manufacturer's instructions for each cementation system. After 1 week, the roots were sectioned transversely into 6 discs. Two discs were obtained from the cervical, middle and apical thirds and the push-out test was carried out. The failure pattern was examined on all debonded specimens. The data were analyzed by two-way repeated measures ANOVA and Tukey's test. When U100 was used, no statistically significant difference (p>0.05) was observed among the different root regions. Statistically higher push-out bond strength values were detected in the cervical third for SBMP+ARC and SB+ARC (p<0.05). The U100 showed significantly more mixed failures than SBMP+ARC in the apical third (p<0.05). In conclusion, the self-adhesive cement RelyX U100 was the only cement not sensitive to the root canal region.

  10. Antimicrobial activity and substantivity of Uncaria tomentosa in infected root canal dentin.

    PubMed

    Herrera, Daniel Rodrigo; Durand-Ramirez, Jorge Enrique; Falcão, Amanda; Silva, Emmanuel João Leal Nogueira da; Santos, Elizabete Brasil Dos; Gomes, Brenda Paula Figueiredo de Almeida

    2016-01-01

    The aim of this study was to analyze the antimicrobial activity and substantivity of Uncaria tomentosa Willd DC (cat's claw, CC) in root dentin contaminated with Enterococcus faecalis. Forty-eight human premolars were contaminated with E. faecalis (ATCC 29212) and randomly divided into four groups according to the irrigant used during chemomechanical preparation (CMP): CC group: 2% CC gel; CHX group: 2% chlorhexidine digluconate gel (CHX); NaOCl group: 5.25% sodium hypochlorite (NaOCl); and SS group: sterile saline (SS). Microbiological samples were collected before (S1) and after (S2) CMP and after 7 days (S3). Colony-forming units (CFU/mL) at the different sampling times and comparisons among the groups were statistically analyzed by Wilcoxon and Kruskal-Wallis tests (p < 0.05). Significant bacterial reduction was achieved in all groups after CMP (p < 0.05). Results show no significant difference between S3 and S2 (p > 0.05) in the CC and CHX groups. Bacterial load was higher in S3 than in S2 samples (p < 0.05) in the NaOCl and SS groups. Our results suggest antibacterial effect of 2% CC gel against E. faecalis in infected dentin, in addition to antibacterial substantivity of 2% CC and 2% CHX up to 7 days.

  11. Antimicrobial activity and substantivity of Uncaria tomentosa in infected root canal dentin.

    PubMed

    Herrera, Daniel Rodrigo; Durand-Ramirez, Jorge Enrique; Falcão, Amanda; Silva, Emmanuel João Leal Nogueira da; Santos, Elizabete Brasil Dos; Gomes, Brenda Paula Figueiredo de Almeida

    2016-01-01

    The aim of this study was to analyze the antimicrobial activity and substantivity of Uncaria tomentosa Willd DC (cat's claw, CC) in root dentin contaminated with Enterococcus faecalis. Forty-eight human premolars were contaminated with E. faecalis (ATCC 29212) and randomly divided into four groups according to the irrigant used during chemomechanical preparation (CMP): CC group: 2% CC gel; CHX group: 2% chlorhexidine digluconate gel (CHX); NaOCl group: 5.25% sodium hypochlorite (NaOCl); and SS group: sterile saline (SS). Microbiological samples were collected before (S1) and after (S2) CMP and after 7 days (S3). Colony-forming units (CFU/mL) at the different sampling times and comparisons among the groups were statistically analyzed by Wilcoxon and Kruskal-Wallis tests (p < 0.05). Significant bacterial reduction was achieved in all groups after CMP (p < 0.05). Results show no significant difference between S3 and S2 (p > 0.05) in the CC and CHX groups. Bacterial load was higher in S3 than in S2 samples (p < 0.05) in the NaOCl and SS groups. Our results suggest antibacterial effect of 2% CC gel against E. faecalis in infected dentin, in addition to antibacterial substantivity of 2% CC and 2% CHX up to 7 days. PMID:27119588

  12. Structure, chemical composition and mechanical properties of human and rat cementum and its interface with root dentin

    PubMed Central

    Ho, Sunita P.; Yu, Bo; Yun, Wenbing; Marshall, Grayson W.; Ryder, Mark I.; Marshall, Sally J.

    2009-01-01

    This work seeks to establish comparisons of the physical properties of rat and human cementum, root dentin and their interface, including the cementum–dentin junction (CDJ), as a basis for future studies of the entire periodontal complex using rats as animal models. In this study the structure, site-specific chemical composition and mechanical properties of cementum and its interface with root dentin taken from 9- to 12-month-old rats were compared to the physiologically equivalent 40- to 55-year-old human age group using qualitative and quantitative characterization techniques, including histology, atomic force microscopy (AFM), micro-X-ray computed tomography, Raman microspectroscopy and AFM-based nanoindentation. Based on results from this study, cementum taken from the apical third of the respective species can be represented as a woven fabric with radially and circumferentially oriented collagen fibers. In both species the attachment of cementum to root dentin is defined by a stiffness-graded interface (CDJ/cementum–dentin interface). However, it was concluded that cementum and the cementum–dentin interface from a 9- to 12-month-old rat could be more mineralized, resulting in noticeably decreased collagen fiber hydration and significantly higher modulus values under wet conditions for cementum and CDJ (Erat-cementum = 12.7 ± 2.62 GPa; Erat-CDJ = 11.6 ± 3.20 GPa) compared to a 40- to 55-year-old human (Ehuman-cementum = 3.73 ± 1.81 GPa; Ehuman-CDJ = 1.5 ± 0.71 GPa). The resulting data illustrated that the extensions of observations made from animal models to humans should be justified with substantial and equivalent comparison of data across age ranges (life spans) of mammalian species. PMID:18829402

  13. Er:YAG and Nd:YAG laser irradiation effect on dental root cut: a SEM analysis

    NASA Astrophysics Data System (ADS)

    Mello, Guilherme P. S.; Paradella, Thais C.; Munin, Egberto; Mello, Jose B.; Pacheco, Marcos T. T.; Neto, Sizenando P.

    2000-11-01

    The root end cut, also called apicoectomy, consists on the surgical removal of the root's end, as one of the last alternatives for teeth preservation. This procedure may be done with conventional diamond burs, as well as Er:YAG laser only, or in association with Nd:YAG laser. In this paper, the quality of the root end cut for the different mentioned procedures, was compared for a better analysis of these techniques, regarding surface finishing. The Er:YAG laser dosimetry applied during the experiment was of 400 mJ/10 Hz, using a laser beam with a 0.8 mm diameter. The Nd:YAG laser was irradiated at 1.5 W/10 Hz, being the samples submitted to a scanning electron microscope. On the Er:YAG laser irradiated samples, there was absence of smear layer, as well as the presence of some open dentinal tubules, presenting the surface a smooth texture. On the roots cut with the Er:YAG laser, in association with the Nd:YAG laser, below the ablative regime, there was the presence of a melted dentin surface, with an appearance which suggests a non-crystalline structure, closing the tubules. Regarding the conventional apicoectomy, the samples presented a plain surface, with the dentinal tubules being closed by the smear layer.

  14. Evaluation of dentinal defect formation after root canal preparation with two reciprocating systems and hand instruments: an in vitro study

    PubMed Central

    Helvacioglu-Yigit, Dilek; Aydemir, Seda; Yilmaz, Ayca

    2015-01-01

    The purpose of this study was to evaluate the presence of dentinal defects after root canal preparation with hand instruments and two different reciprocating instruments. Sixty freshly extracted mandibular incisor teeth were selected for this in vitro study. On the basis of root length, mesiodistal and buccolingual dimensions, the teeth were allocated into three identical experimental groups (n = 15) and one control group (n = 15). The teeth in the control group were left unprepared. The other groups were: stainless steel hand instruments, WaveOne® Primary instruments and RECIPROC® R25 instruments. The reciprocating instruments were used with a reciprocating gentle in-and-out motion in a torque-limited electric motor at the appropriate preset mode. Horizontal sections were made 3, 6 and 9 mm from the apex. Samples were stained with methylene blue and viewed through a stereomicroscope. The presence of dentinal defects (fractures, incomplete cracks and craze lines) and their locations were investigated by two endodontists. These data were analysed statistically by Fisher's exact and chi-square tests. No defects were observed in the unprepared group. All instruments caused dentinal defects, with no significant differences between the instrument systems. All experimental groups demonstrated significantly more defects at the 3-mm level in comparison with the unprepared group (p = 0.032). At the other levels, there was no significant difference between the experimental groups and the control group. The use of hand or reciprocating instruments could induce the formation of dentinal defects during root canal preparation. PMID:26019654

  15. Influence of fluoride-releasing restorative material on root dentine secondary caries in situ.

    PubMed

    Hara, A T; Turssi, C P; Ando, M; González-Cabezas, C; Zero, D T; Rodrigues, A L; Serra, M C; Cury, J A

    2006-01-01

    The usefulness of fluoride-releasing restorations in secondary caries prevention may be questioned because of the presence of other common sources of fluoride and because of ageing of the restorations. This study tested the hypothesis that glass-ionomer cement restorations, either aged or unaged, do not prevent secondary root caries, when fluoride dentifrice is frequently used. Sixteen volunteers wore palatal appliances in two phases of 14 days, according to a 2 x 2 crossover design. In each phase the appliance was loaded with bovine root dentine slabs restored with either glass-ionomer or resin composite, either aged or unaged. Specimens were exposed to cariogenic challenge 4 times/day and to fluoridated dentifrice 3 times/day. The fluoride content in the biofilm (FB) formed on slabs and the mineral loss (DeltaZ) around the restorations were analysed. No differences were found between restorative materials regarding the FB and the DeltaZ, for either aged (p = 0.792 and p = 0.645, respectively) or unaged (p = 1.00 and p = 0.278, respectively) groups. Under the cariogenic and fluoride dentifrice exposure conditions of this study, the glass-ionomer restoration, either aged or unaged, did not provide additional protection against secondary root caries.

  16. Bond strength and fracture analysis between resin cements and root canal dentin.

    PubMed

    Lopes, Guilherme Carpena; Ballarin, Andressa; Baratieri, Luiz N

    2012-04-01

    The aim of this research is to evaluate bond strength between translucent fibre posts (White Post DC, FGM or FRC Postec Plus, Ivoclar/Vivadent) and intraradicular dentin at three different levels (cervical, middle and apical) using a dual-cure (AllCem, FGM) or self-curing (Multilink, Ivoclar/Vivadent) resin cement. Also, the fracture type after push-out test was analysed under SEM. Thirty-two extracted single-root teeth were selected. After undergoing endodontic therapy, they were randomly divided into four groups according to their post type and resin cement. Root canals were etched using 37% phosphoric acid, and Excite DSC adhesive (Ivoclar/Vivadent) was applied in all groups. The root was sectioned to obtain nine 1-mm-thick slices (three per third: coronal, middle, apical). All slices were subjected to push-out tests. Data were analysed using two-way anova. The mean bond strengths vary from 6.6 (4.6) MPa [apical] to 11.9 (5.9) MPa [cervical]. There were no significant differences between groups. Pearson χ(2)-test revealed significant differences in fracture types for all groups (P < 0.0001). The apical third had the lowest bond strengths and it was also shown to be the most critical region for luting fibre posts. PMID:22432821

  17. Bond strength and fracture analysis between resin cements and root canal dentin.

    PubMed

    Lopes, Guilherme Carpena; Ballarin, Andressa; Baratieri, Luiz N

    2012-04-01

    The aim of this research is to evaluate bond strength between translucent fibre posts (White Post DC, FGM or FRC Postec Plus, Ivoclar/Vivadent) and intraradicular dentin at three different levels (cervical, middle and apical) using a dual-cure (AllCem, FGM) or self-curing (Multilink, Ivoclar/Vivadent) resin cement. Also, the fracture type after push-out test was analysed under SEM. Thirty-two extracted single-root teeth were selected. After undergoing endodontic therapy, they were randomly divided into four groups according to their post type and resin cement. Root canals were etched using 37% phosphoric acid, and Excite DSC adhesive (Ivoclar/Vivadent) was applied in all groups. The root was sectioned to obtain nine 1-mm-thick slices (three per third: coronal, middle, apical). All slices were subjected to push-out tests. Data were analysed using two-way anova. The mean bond strengths vary from 6.6 (4.6) MPa [apical] to 11.9 (5.9) MPa [cervical]. There were no significant differences between groups. Pearson χ(2)-test revealed significant differences in fracture types for all groups (P < 0.0001). The apical third had the lowest bond strengths and it was also shown to be the most critical region for luting fibre posts.

  18. Bond strength of composite to dentin: effect of acid etching and laser irradiation through an uncured self-etch adhesive system

    NASA Astrophysics Data System (ADS)

    Castro, F. L. A.; Carvalho, J. G.; Andrade, M. F.; Saad, J. R. C.; Hebling, J.; Lizarelli, R. F. Z.

    2014-08-01

    This study evaluated the effect on micro-tensile bond strength (µ-TBS) of laser irradiation of etched/unetched dentin through an uncured self-etching adhesive. Dentinal surfaces were treated with Clearfil SE Bond Adhesive (CSE) either according to the manufacturer’s instructions (CSE) or without applying the primer (CSE/NP). The dentin was irradiated through the uncured adhesive, using an Nd:YAG laser at 0.75 or 1 W power settings. The adhesive was cured, composite crowns were built up, and the teeth were sectioned into beams (0.49 mm2) to be stressed under tension. Data were analyzed using one-way ANOVA and Tukey statistics (α = 5%). Dentin of the fractured specimens and the interfaces of untested beams were observed under scanning electron microscopy (SEM). The results showed that non-etched irradiated surfaces presented higher µ-TBS than etched and irradiated surfaces (p < 0.05). Laser irradiation alone did not lead to differences in µ-TBS (p > 0.05). SEM showed solidification globules on the surfaces of the specimens. The interfaces were similar on irradiated and non-irradiated surfaces. Laser irradiation of dentin through the uncured adhesive did not lead to higher µ-TBS when compared to the suggested manufacturer’s technique. However, this treatment brought benefits when performed on unetched dentin, since bond strengths were higher when compared to etched dentin.

  19. The effect of a desensitizer and CO2 laser irradiation on bond performance between eroded dentin and resin composite

    PubMed Central

    Ding, Meng; Shin, Sang-Wan; Kim, Min-Soo

    2014-01-01

    PURPOSE This study was aimed to evaluate effect of the desensitizing pretreatments on the micro-tensile bond strengths (µTBS) to eroded dentin and sound dentin. MATERIALS AND METHODS Forty-two extracted molars were prepared to form a flat dentin surface, and then they were divided into two groups. Group I was stored in distilled water while group II was subjected to a pH cycling. Each group was then subdivided into three subgroups according to desensitizing pretreatment used: a) pretreatment with desensitizer (Gluma); b) pretreatment with CO2 Laser (Ultra Dream Pluse); c) without any pretreatment. All prepared surfaces were bonded with Single Bond 2 and built up with resin composite (Filtek Z250). The micro-tensile bond test was performed. Fracture modes were evaluated by stereomicroscopy. Pretreated surfaces and bonded interfaces were characterized by scanning electron microscope (SEM). The data obtained was analyzed by two-way ANOVA (α=0.05). RESULTS For both sound and eroded dentin, samples treated with desensitizer showed the greatest µTBS, followed by samples without any treatment. And samples treated with CO2 laser showed the lowest µTBS. SEM study indicated that teeth with eroded dentin appeared prone to debonding, as demonstrated by existence of large gaps between adhesive layers and dentin. CONCLUSION Pretreatment with Gluma increased the µTBS of Single Bond 2 for eroded and sound teeth. CO2 laser irradiation weakened bond performance for sound teeth but had no effect on eroded teeth. PMID:25006379

  20. Effect of root canal rinsing protocol on dentin bond strength of two resin cements using three different method of test

    PubMed Central

    Khoroushi, Maryam; Sheikhi, Mohammadreza; Soleimani, Bahram

    2016-01-01

    Background Different studies have used different tests to evaluate bond strength of resin cements to root dentin. In this in vitrostudy, three different tests were used to evaluate the bond strength of two resin cements to root dentin using two root dentin irrigation protocols. Material and Methods Ninety-six intact single-rooted teeth were selected for this study. Forty-eight teeth, with a root length of 15mm, were randomly divided into two groups and irrigated with normal saline or 2.5% sodium hypochlorite solutions during root canal preparation, respectively. For each 12 specimens from each group, fiber post #1 was bonded using an etch-and-rinse (Duo-Link) and a self-adhesive (BisCem) resin cement, respectively. After incubation, two specimens were prepared for the push-out test from the middle thirds of the roots. In another 24 teeth, after two 1.5-mm sections were prepared from the middle thirds of the prepared roots, sections of the post were bonded in two subgroups with each of the cements mentioned above and the samples were prepared for the pull-out test. For shear test, the crowns of 48 teeth were cut away, the dentin surfaces were prepared, the two irrigation solutions were used, and the resin cements were bonded. Data collected from the three tests were evaluated by ANOVA, post-hoc Tukey and Weibull tests (α=0.05). Results There were significant differences in the mean bond strength values between the three bond strength tests (P<0.001). Rinsing protocol and cement type resulted in similar variations in the mean bond strength in all tests (P>0.05). Conclusions Under the limitations of the present study, the method of the test used had an effect on the recorded bond strength between the resin cement and root dentin. Cement type and irrigation protocol resulted in similar variations with all the tests. Push-out and shear tests exhibited more coherent results. Key words:Bond strength, endodontically treated tooth, fiber post, resin cement, sodium

  1. Age-related ransparent root dentin: mineral concentration,crystallite size and mechanical properties

    SciTech Connect

    Kinney, John H.; Nalla, Ravi K.; Pople, John A.; Breunig, Tom M.; Ritchie, Robert O.

    2004-12-29

    Many fractures occur in teeth that have been altered, forexample restored or endodontically repaired. It is therefore essential toevaluate the structure and mechanical properties of these altereddentins. One such altered form of dentin is transparent (sometimes calledsclerotic) dentin, which forms gradually with aging. The present studyfocuses on differences in the structure and mechanical properties ofnormal versus transparent dentin. The mineral concentration, as measuredby X-ray computed microtomography, was signifcantly higher in transparentdentin, the elevated concentration being consistent with the closure ofthe tubule lumens. Crystallite size, as measured by small angle X-rayscattering, was slightly smaller in transparent dentin, although theimportance of this ending requires further study. The elastic propertieswere unchanged by transparency; however, transparent dentin, unlikenormal dentin, exhibited almost no yielding before failure. In addition,the fracture toughness was lowered by roughly 20 percent while thefatigue lifetime was deleteriously affected at high stress levels. Theseresults are discussed in terms of the altered microstructure oftransparent dentin.

  2. Effects of Er:YAG laser irradiation and manipulation treatments on dentin components, part 1: Fourier transform-Raman study.

    PubMed

    Soares, Luís Eduardo Silva; do Espírito Santo, Ana Maria; Junior, Aldo Brugnera; Zanin, Fátima Anto Nia Aparecida; da Silva Carvalho, Carolina; de Oliveira, Rodrigo; Martin, Airton Abrahão

    2009-01-01

    The effects of laser etching, decontamination, and storage treatments on dentin components were studied using Fourier transform (FT)-Raman spectroscopy. Thirty bovine incisors were prepared to expose the dentin surface and then divided in two main groups based upon the decontamination process and storage procedure: autoclaved (group A, n=15) or stored in thymol aqueous solution (group B, n=15). The surfaces of the dentin slices were schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control subgroup) or irradiated with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ, and total energy of 12 J). Samples were analyzed by FT-Raman spectroscopy; we collected three spectra for each area (before and after treatment). The integrated areas of five Raman peaks were calculated to yield average spectra. The areas of the peaks associated with phosphate content (P<0.001), type I collagen, and organic C-H bonds (P<0.05) were reduced significantly in group A (control). Analyses of samples irradiated with reduced laser energies did not show significant changes in the dentin components. These results suggest that thymol storage treatment is advised for in vitro study; furthermore, 12 J of Er:YAG laser energy does not affect dentin components.

  3. Effects of Er:YAG laser irradiation and manipulation treatments on dentin components, part 1: Fourier transform-Raman study

    NASA Astrophysics Data System (ADS)

    Soares, Luís Eduardo Silva; Do Espírito Santo, Ana Maria; Junior, Aldo Brugnera; Zanin, Fátima Antônia Aparecida; da Silva Carvalho, Carolina; de Oliveira, Rodrigo; Martin, Airton Abraha~O.

    2009-03-01

    The effects of laser etching, decontamination, and storage treatments on dentin components were studied using Fourier transform (FT)-Raman spectroscopy. Thirty bovine incisors were prepared to expose the dentin surface and then divided in two main groups based upon the decontamination process and storage procedure: autoclaved (group A, n=15) or stored in thymol aqueous solution (group B, n=15). The surfaces of the dentin slices were schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control subgroup) or irradiated with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ, and total energy of 12 J). Samples were analyzed by FT-Raman spectroscopy; we collected three spectra for each area (before and after treatment). The integrated areas of five Raman peaks were calculated to yield average spectra. The areas of the peaks associated with phosphate content (P<0.001), type I collagen, and organic C-H bonds (P<0.05) were reduced significantly in group A (control). Analyses of samples irradiated with reduced laser energies did not show significant changes in the dentin components. These results suggest that thymol storage treatment is advised for in vitro study; furthermore, 12 J of Er:YAG laser energy does not affect dentin components.

  4. Dentin bond strength of an adhesive system irradiated with an Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Ruschel, V. C.; Malta, D. A. M. P.; Monteiro, S., Jr.

    2016-11-01

    The objective of this study was to evaluate the microtensile bond strength of an adhesive system applied to dentin, followed by Nd:YAG laser irradiation. Twenty-two recently extracted third molars were divided into four groups (n  =  5). In the G1 and G2 groups, the adhesive system was applied conventionally, and in groups G3 and G4, the adhesive system was irradiated with an Nd:YAG laser (100 J cm‑2). The specimens were stored in distilled water at 37 °C, those in groups G1 and G3 for 24 h, and those in groups G2 and G4 for 3 months. Two teeth from groups G1 and G3 were used for observation of the hybrid layer, using a confocal microscope (n  =  1). The teeth were submitted to a microtensile bond strength test. Analysis of the type of fracture was performed using a stereoscope (40×). The results for microtensile bond strength (MPa) and standard deviation (±SD) were: G1—31.68 (5.14); G2—37.88 (±5.04) G3—35.32 (±8.79) G4—31.53 (±9.01). There were no significant differences among the groups (p  >  0.05). Adhesive failure was predominant in all the groups. The Nd:YAG laser irradiation of the adhesives did not influence dentin bond strength during the periods of 24 h or 3 months of storage in distilled water.

  5. Dentin hypersensitivity clinical study comparing LILT and LEDT keeping the same irradiation parameters

    NASA Astrophysics Data System (ADS)

    Lizarelli, R. F. Z.; Miguel, F. A. C.; Freitas-Pontes, K. M.; Villa, G. E. P.; Nunez, S. C.; Bagnato, V. S.

    2010-11-01

    Dentin hypersensitivity is a common condition associated with high dental pain. A new LED-based (light emitting diode) light source has been used as an experimental tool in some studies. Purpose: The main objective was to compare these two light sources emitting in the same spectral band (red - from 625 to 660 nm) to promote pain relief. Material and methods: A total of 6 sessions were accomplished, being three irradiation sessions and three follow-up sessions. This single-blind study compared a control group (Placebo) and two other groups with different equipments: low laser intensity treatment (LILT) and a light emitting diode system treatment (LEDT). Results: The results showed that there is no statistical difference between LILT and LEDT groups, however, both were better than control group (p <= 0.01) in terms of treatment efficiency; there is no difference between the second and the third sessions for both treatment, it means that the third session was not necessary; finally, the improvement at the end of the entire research (follow up care of 30 days) was very expressive in comparison to pre-treatment situation for all teeth (p <= 0.01). Conclusion: LILT and LEDT were equally effective to treat dentine hypersensitivity, a 3rd treatment session was not necessary/two sessions are enough.

  6. [Morphologic evaluation of the bonding between adhesive/composite resin and dentin irradiated with Er:YAG and Nd:YAG lasers: comparative study using scanning microscopy].

    PubMed

    Oda, M; Oliveira, D C; Liberti, E A

    2001-01-01

    Since bonding systems were introduced in the restorative procedures carried out with esthetic materials, the treatment of dentin surfaces has been widely studied in order to establish the ideal technique. The application of 37% phosphoric acid on dentin is still the best known method. However, alternative methods for treating the dentin surface have been discussed in the literature, including the utilization of some kinds of laser irradiation. The purpose of this research was to morphologically evaluate the bond between adhesive materials and the dentin treated with Er:YAG and Nd:YAG lasers, in a comparative study by means of scanning electron microscopy (SEM). Irradiation either substituted acid etching, or was associated to it. Recently extracted bovine incisors were utilized. They received class V cavity preparations and were restored with a bonding system and a light-cured composite resin. Meanwhile, some of the teeth underwent irradiation with Er:YAG laser or Nd:YAG laser before the application of the bonding agent and the composite resin. The samples were selected, prepared for SEM and submitted to morphological analysis. Data were registered in photomicrographs. Based on the microscopic observations, we concluded that only in the dentin surfaces submitted to irradiation with Er:YAG laser and to acid conditioning there was penetration of resin into the dentine. With the Nd:YAG laser treatment, there was only visual superposition of resin over the dentin surface, which suggests that there was only occlusion of the tubules, with characteristics of fusion in the superficial dentine.

  7. Thermal stress in dentin and enamel under CO2 laser irradiation

    NASA Astrophysics Data System (ADS)

    Meyer, Dirk H.; Foth, Hans-Jochen

    1996-01-01

    Ablation of dentin and tartar was studied under carbon dioxide-laser irradiation in cw and pulse mode with pulse length down to 150 microseconds. The specimens had been cut by a diamant blade to slices of thicknesses between 0.8 and 2.8 mm. The laser induced temperature rise was measured by an infrared camera monitoring the backside of the samples. The specimens shape and structure at the laser spot was analyzed by electron microscopy. Of special interest was the testing of the SwiftLaseTM to reducing the heat. The experimental results show the necessity of a water cooling in all application modes. The origin of the cracks which had been observed in many of the samples, is currently under investigation.

  8. Management of Root Perforations Using MTA with or without Er:YAG Laser Irradiation: An In Vitro Study

    PubMed Central

    Tielemans, M.; Saloukas, I.; Heysselaer, D.; Compere, Ph.; Nyssen-Behets, C.; Nammour, S.

    2012-01-01

    The aim of this in vitro study is to compare the microleakage of a root perforation sealed with MTA (mineral trioxide aggregate) (group M) to that sealed with MTA following Er:YAG laser irradiation (group ML). Forty-two recently extracted human monoroot teeth were used. Two cavities were prepared on each root surface. Randomly, on each root, the exposed dentine of one cavity was irradiated prior to MTA filling using an Er:YAG laser with the following settings: 200 mJ/pulses under an air water spray, 10 Hz, pulse duration of 50 μsec, and 0.7 mm beam diameter. All cavities were then sealed with MTA. submitted to thermocycling and immersed in 2% methylene blue dye solution for 12 h. The penetration of methylene blue in the microleakage of cavity was observed and recorded. The mean value dye penetration in cavities sealed with MTA following Er:YAG laser irradiation (23.91 ± 14.63%) was lower than that of unlased cavities sealed only with MTA (25.17 ± 17.53%). No significant difference was noted. The use of an Er:YAG laser beam for dentinal conditioning prior to MTA filling of perforated roots did not decrease significantly the microleakage of MTA sealing when compared to the conventional use of MTA filling. PMID:22888350

  9. Bond strength of an adhesive system irradiated with Nd:YAG laser in dentin treated with Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Malta, D. A. M. P.; Costa, M. M.; Pelino, J. E. P.; de Andrade, M. F.; Lizarelli, R. F. Z.

    2008-02-01

    The purpose of this in vitro study was to verify through micro tensile bond test the bond strength of an adhesive system irradiated with Nd:YAG laser in dentine previously treated with Er:YAG laser. Twenty caries free extracted human third molars were used. The teeth were divided in four experimental groups (n = 5): (G1) control group; (G2) irradiation of the adhesive system with the Nd:YAG laser; (G3) dentin treatment with Er:YAG laser; (G4) dentin treatment with Er:YAG laser followed by the irradiation of the adhesive system with Nd:YAG laser. The Er:YAG laser fluency parameter for the dentin treatment was of 60 J/cm2. The adhesive system was irradiated with the Nd:YAG laser with fluency of 100 J/cm2. Dental restorations were performed with Adper Single Bond 2/Z250. One tooth from each group was prepared for the evaluation of the adhesive interface under SEM and bond failure tests were also performed and evaluated. The statistical analysis showed statistical significant difference between the groups G1 and G3, G1 and G4, G2 and G3, and G2 and G4; and similarity between the groups G1 and G2, and G3 and G4. The adhesive failures were predominant in all the experimental groups. The SEM analysis showed an adhesive interface with features confirming the results of the mechanical tests. The Nd:YAG laser on the adhesive system did not influence the bond strength in dentin treated or not with the Er:YAG laser.

  10. Age-related transparent root dentin: mineral concentration, crystallite size, and mechanical properties.

    PubMed

    Kinney, J H; Nalla, R K; Pople, J A; Breunig, T M; Ritchie, R O

    2005-06-01

    Many fractures occur in teeth that have been altered, for example restored or endodontically repaired. It is therefore essential to evaluate the structure and mechanical properties of these altered dentins. One such altered form of dentin is transparent (sometimes called sclerotic) dentin, which forms gradually with aging. The present study focuses on differences in the structure and mechanical properties of normal versus transparent dentin. The mineral concentration, as measured by X-ray computed microtomography, was significantly higher in transparent dentin, the elevated concentration being consistent with the closure of the tubule lumens. Crystallite size, as measured by small angle X-ray scattering, was slightly smaller in transparent dentin, although the importance of this finding requires further study. The elastic properties were unchanged by transparency; however, transparent dentin, unlike normal dentin, exhibited almost no yielding before failure. In addition, the fracture toughness was lowered by roughly 20% while the fatigue lifetime was deleteriously affected at high stress levels. These results are discussed in terms of the altered microstructure of transparent dentin.

  11. A new weak chelator in endodontics: effects of different irrigation regimens with etidronate on root dentin microhardness.

    PubMed

    Tartari, Talita; de Almeida Rodrigues Silva E Souza, Patrícia; Vila Nova de Almeida, Bruno; Carrera Silva Júnior, José Otávio; Facíola Pessoa, Oscar; Silva E Souza Junior, Mario Honorato

    2013-01-01

    This study investigated the effect of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated in different irrigation regimens on root dentin microhardness. Forty-five root halves of single-rooted teeth were sectioned into thirds that were embedded in acrylic resin, polished, randomly assigned into 3 groups, and treated as follows: G1: saline solution; G2: 5% NaOCl + 18% HEBP, mixed in equal parts; and G3: 2.5% NaOCl. After measurements, the G3 samples were distributed into subgroups G4, G5, and G6, which were submitted to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measurements, these groups received a final flush with 2.5% NaOCl, producing G7, G8, and G9. Microhardness was measured with Knoop indenter under a 25 g load for 15 seconds, before and after treatments. The data were statistically analyzed using paired Student's t-test (α<0.05) to compare values before and after treatments and analysis of variance (ANOVA) (α<0.05) to detect any differences among thirds. Except G1, all tested irrigation regimens significantly decreased the microhardness. There were no differences between root thirds before treatments, and all root thirds exhibited equal responses to same treatment. Except saline, all tested irrigation regimens reduced the root dentin microhardness. PMID:23983692

  12. A New Weak Chelator in Endodontics: Effects of Different Irrigation Regimens with Etidronate on Root Dentin Microhardness

    PubMed Central

    Tartari, Talita; de Almeida Rodrigues Silva e Souza, Patrícia; Vila Nova de Almeida, Bruno; Carrera Silva Júnior, José Otávio; Facíola Pessoa, Oscar; Silva e Souza Junior, Mario Honorato

    2013-01-01

    This study investigated the effect of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated in different irrigation regimens on root dentin microhardness. Forty-five root halves of single-rooted teeth were sectioned into thirds that were embedded in acrylic resin, polished, randomly assigned into 3 groups, and treated as follows: G1: saline solution; G2: 5% NaOCl + 18% HEBP, mixed in equal parts; and G3: 2.5% NaOCl. After measurements, the G3 samples were distributed into subgroups G4, G5, and G6, which were submitted to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measurements, these groups received a final flush with 2.5% NaOCl, producing G7, G8, and G9. Microhardness was measured with Knoop indenter under a 25 g load for 15 seconds, before and after treatments. The data were statistically analyzed using paired Student's t-test (α<0.05) to compare values before and after treatments and analysis of variance (ANOVA) (α<0.05) to detect any differences among thirds. Except G1, all tested irrigation regimens significantly decreased the microhardness. There were no differences between root thirds before treatments, and all root thirds exhibited equal responses to same treatment. Except saline, all tested irrigation regimens reduced the root dentin microhardness. PMID:23983692

  13. Forensic dental age estimation by measuring root dentin translucency area using a new digital technique.

    PubMed

    Acharya, Ashith B

    2014-05-01

    Dentin translucency measurement is an easy yet relatively accurate approach to postmortem age estimation. Translucency area represents a two-dimensional change and may reflect age variations better than length. Manually measuring area is challenging and this paper proposes a new digital method using commercially available computer hardware and software. Area and length were measured on 100 tooth sections (age range, 19-82 years) of 250 μm thickness. Regression analysis revealed lower standard error of estimate and higher correlation with age for length than for area (R = 0.62 vs. 0.60). However, test of regression formulae on a control sample (n = 33, 21-85 years) showed smaller mean absolute difference (8.3 vs. 8.8 years) and greater frequency of smaller errors (73% vs. 67% age estimates ≤ ± 10 years) for area than for length. These suggest that digital area measurements of root translucency may be used as an alternative to length in forensic age estimation.

  14. Application of a proanthocyanidin agent to improve the bond strength of root dentin treated with sodium hypochlorite

    PubMed Central

    Manimaran, V Sujatha; Srinivasulu, Sakhamuri; Rajesh Ebenezar, AV; Mahalaxmi, S; Srinivasan, N

    2011-01-01

    Aim: The objective of this study was to analyze the application of PA agent that improves the bond strength of root dentin treated with NaOCl. Materials and Methods: Group 1: root canals were irrigated using 0.9% isotonic saline as an irrigant (negative control); Group 2: root canals were irrigated using 5.25% NaOCl (positive control); Group 3: root canals were irrigated with 5.25% NaOCl followed by 10% sodium ascorbate for 10 minutes; Group 4: root canals were irrigated with 5.25% NaOCl followed by 5% PA for 10 minutes. All the canals were then coated with self-etch dentin bonding agent, filled with resin cement, stored for one day in water, and then cross sectioned into three slabs of 2-mm thickness that were prepared and tested for microtensile bond strength. Results: The results demonstrated that 5.25% NaOCl caused significant reduction (P<0.05) in the bond strength, but this can be reversed by 5% PA significantly more than the 10% sodium ascorbate. PMID:22025839

  15. Effect of irrigation technique for removal of triple antibiotic paste on bond strength of MTA to root dentin.

    PubMed

    Dumani, Aysin; Yilmaz, Sehnaz; Yoldas, Oguz; Bek, Zeliha Gonca

    2016-01-01

    This study evaluated the bond strength of mineral trioxide aggregate (MTA) to root canal dentin after the performance of various irrigation procedures to remove triple antibiotic paste (TAP). A total of 56 single-rooted human mandibular premolars were instrumented using a rotary system to size 40 and divided randomly into a control group (no intracanal dressing) and three experimental groups (TAP application for 28 days). TAP was then removed by rinsing with 10 mL 2.5% NaOCl using three irrigation systems (Vibringe sonic irrigation, CanalBrush, and syringe irrigation). The coronal and middle parts of root canals were then obturated with MTA. After storage for 1 week, each specimen was embedded in an acrylic block and sectioned horizontally (2-mm-thick slices) at two levels (coronal and middle). Bond strength of MTA to root canal dentin was assessed in 28 samples per group via push-out test using a universal testing machine. Data from the four groups were compared using one-way analysis of variance. Tukey's test was used for multiple comparisons. Push-out bond strength values were significantly higher in the control and Vibringe groups than in the CanalBrush and syringe irrigation groups (p < 0.001). TAP removal from root canals with the Vibringe irrigation system may increase the push-out bond strength of MTA compared with the use of the CanalBrush or syringe irrigation.

  16. The influence of sodium hypochlorite and root canal sealers on post retention in different dentin regions.

    PubMed

    Muniz, Leonardo; Mathias, Paula

    2005-01-01

    This study evaluated the influence of 5.25% NaOCl irrigant and root canal sealers on post retention in different dentin regions. Seventy-two human incisors were decoronated at the cemento-enamel junction and randomly divided into six groups (n=12) according to irrigant and sealer technique: G1-Distilled water (DW) without sealer; G2-DW + AH Plus (Dentsply/Maillefer); G3-DW + Endofill (Dentsply/Maillefer); G4-5.251%NaOCl without sealer; G5-5.25% NaOCl + AH Plus; G6-5.25% NaOCl + Endofill. Specimens were stored in a humid environment for 30 days at 37 degrees C and were prepared with FRC Postec's drills for post insertion. The posts were cemented with Excite DSC/Variolink II (Ivoclar/Vivadent). The specimens were sectioned through their long axis into three dental slices approximately 2.5 mm each, representing the cervical (C), middle (M) and apical (A) thirds of the root preparation. After calculating the adhered area of the specimens, they were submitted to the push-out test in a universal testing machine. The data were submitted to an analysis of variance (ANOVA) at a 5% significance level and to the Tukey test (p<0.05). The mean values (MPa) obtained for cervical, middle and apical areas of the root preparation, respectively, were: G1=8.6; 12.5 and 14.3, G2=13.5; 15.4 and 16.9; G3=6.9; 10.0 and 12.1; G4=13.0; 14.9 and 15.4; G5=11.3; 13.5 and 18.0; and G6=11.0; 11.8 and 11.5. Based on the results, the eugenol-based sealer (Endofill) resulted in significantly lower mean retention strength values compared with the resin-based sealer (AH Plus). The apical region showed the greatest retention. The lowest resistance to dislodgment was found in the cervical region, mainly in the groups that used distilled water for irrigating the root canal.

  17. Comparative assessment of time-related bioactive glass and calcium hydroxide effects on mechanical properties of human root dentin.

    PubMed

    Marending, Monika; Stark, Wendelin J; Brunner, Tobias J; Fischer, Jens; Zehnder, Matthias

    2009-02-01

    Suspensions of micro- or nanoparticulate SiO(2)-Na(2)O-CaO-P(2)O(5) bioactive glasses could potentially be used as dressings in traumatized front teeth with open apices as an alternative to Ca(OH)(2). These materials have a disinfecting capacity similar to Ca(OH)(2), but bear the advantage of bioactivity. However, because bioactive glasses initially act as alkaline biocides just as Ca(OH)(2) does, they may also negatively affect mechanical dentin properties over time. This was assessed in the current study using standardized human root dentin bars. Specimens were immersed in 1:20 (wt vol(-1)) suspensions of nanometric bioactive glass 45S5 or calcium hydroxide for 1, 10, or 30 days. Control specimens were immersed in pure saline for 30 days (n = 20 per group). Subsequently, modulus of elasticity (E) and flexural strength (FS) of the specimens were determined. Results were compared between groups using one-way anova and Scheffé's post-hoc test. Ca(OH)(2) caused a significant (P < 0.001) 35% drop in mean flexural strength values compared to the control treatment after 10 days. No further change was observed between 10 days and 30 days. Bioactive glass caused a 20% drop in mean flexural strength as compared to the control after 10 days. However, this difference did not reach statistical significance (P > 0.05). No effects of either material on dentin modulus of elasticity values were observed. It was concluded that the calcium hydroxide suspension affected the dentin more than the bioactive glass counterpart; however, the effect was self-limiting and probably restricted to superficial dentin layers, as suggested by the mere decrease in flexural strength but not in modulus of elasticity values.

  18. 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

  19. Evaluation of carbon dioxide laser irradiation associated with calcium hydroxide in the treatment of dentinal hypersensitivity. A preliminary study.

    PubMed

    Romano, Ana Cristina Cury Camargo; Aranha, Ana Cecilia Corrêa; da Silveira, Bruno Lopes; Baldochi, Sônia Lícia; Eduardo, Carlos de Paula

    2011-01-01

    Attempts have been made to treat dentinal hypersensitivity by sealing exposed dentinal tubules, and the carbon dioxide (CO(2)) laser has been shown to have a sealing effect on dentinal surfaces. The purpose of this study was to analyze the morphological ultra-structure and temperature change after CO(2) laser irradiation of dentin. Fourteen human third molars were selected and cleaned. An area was delimited, and the samples were randomly divided into seven groups: Group 1 (G1): control; G2, calcium hydroxide paste (CA) + CO(2) laser (L) (0.5 W/63,69 W/cm(2)); G3, CA + L (1 W/125,38 W/cm(2)); G4, CA + L (1.5 W/191,08 W/cm(2)); G5, L (0.5 W); G6, L (1 W); G7, L (1.5 W). All irradiation was performed in unfocused mode. The electron micrographs were analyzed by three observers. For temperature analysis, a thermocouple was used. Data were subjected to statistical analysis. The Kruskal-Wallis non-parametric test showed statistical differences between the groups (P < 0.05). For the two by two comparisons, all groups treated with calcium hydroxide paste presented significantly higher mean scores. In the groups treated by CO(2) laser only, fusion, re-crystallization, cracks and carbonization were observed. A change of 1 ± 5°C was noted in the temperature. Under the limitation of an in vitro study, and with the protocols used, we concluded that CO(2) laser is safe to use for the establishment of partial fusion and re-solidification of the dentinal surface. PMID:20127133

  20. Gray value differences to dentin of root posts radiographed with digital intraoral systems and conventional X-ray films.

    PubMed

    Wicht, S; Pfeiffer, P; Rother, U; Nergiz, I; Schmage, P

    2011-01-01

    This study compared the gray value differences to dentin of titanium and FRC root posts in anterior and posterior teeth radiographed with digital intraoral systems and conventional x-ray film. Radiographic images (n=5) of titanium or fiber-reinforced composite (FRC) root posts placed in extracted teeth were taken with six digital intraoral radiographic devices and conventional x-ray film (control group). Gray value differences were evaluated between the root posts and root dentin. Statistical analyses of the results were performed with three-way and one-way ANOVA with Bonferroni-Dunn's multiple comparisons post-hoc analyses (α=0.05). Significantly higher gray value differences of titanium and FRC posts were found in anterior teeth but not in molars for XIOS, Sidexis and Visualix digital intraoral systems, but not for RVG, DenOptix and VistaScan (FRC posts). Except for DenOptix with incisors and molars and VistaScan with molars, conventional x-ray films showed significantly lower gray value differences of titanium posts in incisors and molars compared to the corresponding digital radiographs.

  1. Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

    PubMed Central

    PEREIRA, Jefferson Ricardo; da ROSA, Ricardo Abreu; SÓ, Marcus Vinícius Reis; AFONSO, Daniele; KUGA, Milton Carlos; HONÓRIO, Heitor Marques; do VALLE, Accácio Lins; VIDOTTI, Hugo Alberto

    2014-01-01

    Objective The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resin-modified glass ionomer cements (RMGICs). Material and Methods Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. Results Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs. Conclusions Except for Ionoseal, all cements provided satisfactory bond strength values. PMID:25004052

  2. Effect of Metalloproteinase Inhibitors on the Microtensile Bond Strength of Composite Resin to Er:YAG Laser-Irradiated Dentin.

    PubMed

    Correa, Beatriz Carlos; Galo, Rodrigo; Scatena, Camila; Borsatto, Maria Cristina; Spazzin, Aloísio Oro; Corona, Silmara Aparecida Milori; Galafassi, Daniel

    2016-01-01

    This study evaluated the effect of matrix metalloproteinase (MMP) inhibitors - 2% (CHX) and sodium fluoride (NaF) (5000 ppm) - on microtensile bond strength (μTBS) of composite resin to Er:YAG laser-irradiated dentin after chemical degradation of the bond interface. The occlusal surface of forty sound human molars was removed exposing the dentin surface (n=10), which was polished, irradiated with Er:YAG laser, acid etched and dried. Twenty specimens were rewetted with 2% CHX (control group) and 20 were rewetted with NaF (5000 ppm). The adhesive system was applied and a 4-mm-high plateau of light-cured composite resin was built up. Resin-dentin sticks were obtained with a rectangular cross-sectional area (0.8-1 mm2) and were either stored in water at 37 ?#61616;C for 24 h or submitted to chemical degradation. For chemical degradation, they were immersed in 10% NaOCl aqueous solution for 5 h and rinsed in water for 1 h. The sticks were submitted to microtensile test in a mechanical testing machine at 0.5 mm/min until failure. Fracture pattern was analyzed using SEM. μTBS values were calculated in MPa and submitted to analysis of variance ANOVA (α=0.05). The variance analysis showed that the 'MMP inhibitor' and 'degradation' factors (p=0.214 and p=0.093, respectively) and interaction between the factors were not statistically significant (p=0.143). Mixed failure predominated in all groups. In conclusion, the 2% CHX and NaF 5000 ppm presented similar μTBS of composite resin to laser-irradiated dentin before and after chemical degradation. PMID:27652708

  3. The effect of three different antioxidants on the dentinal tubular penetration of Resilon and Real Seal SE on sodium hypochlorite-treated root canal dentin: An in vitro study

    PubMed Central

    Christopher, Sarah Renjelina; Mathai, Vijay; Nair, Rajesh Sasidharan; Angelo, Jeyabalaji Mano Christaine

    2016-01-01

    Objective: The effect of 10% ascorbic acid, 10% tannic acid, and 10% gallic acid on the dentinal tubular penetration of Resilon and Real Seal SE on sodium hypochlorite-treated root canal dentin was evaluated. Materials and Methods: Fifty human premolars were decoronated to attain 14-mm root length and divided into five groups of 10 teeth each. Biomechanical preparation was done with rotary instruments. Group I specimens were irrigated with saline and 17% ethylenediaminetetraacetic acid (EDTA). Specimens from groups II, III, IV, and V were irrigated with 5.25% sodium hypochlorite and 17% EDTA. Specimens from groups III, IV, and V underwent additional irrigation with antioxidants–10% ascorbic acid, 10% tannic acid, and 10% gallic acid, respectively. Following obturation with Resilon and Real Seal SE, scanning electron microscope (SEM) analysis was done to note the maximum dentinal tubular penetration at the cervical, middle, and apical thirds of each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA), Post hoc and Dunnett's test. Results: Maximum dentinal tubular penetration of Resilon and Real Seal SE was obtained following irrigation with 10% gallic acid. Conclusion: 10% gallic acid was superior among the antioxidant irrigants that enabled the increased dentinal tubular penetration of Resilon and Real Seal SE. PMID:27099424

  4. Push-out bond strength and dentinal tubule penetration of different root canal sealers used with coated core materials

    PubMed Central

    Purali, Nuhan; Coşgun, Erdal; Calt, Semra

    2016-01-01

    Objectives The aim of this study was to compare the push-out bond strength and dentinal tubule penetration of root canal sealers used with coated core materials and conventional gutta-percha. Materials and Methods A total of 72 single-rooted human mandibular incisors were instrumented with NiTi rotary files with irrigation of 2.5% NaOCl. The smear layer was removed with 17% ethylenediaminetetraacetic acid (EDTA). Specimens were assigned into four groups according to the obturation system: Group 1, EndoRez (Ultradent Product Inc.); Group 2, Activ GP (Brasseler); Group 3, SmartSeal (DFRP Ltd. Villa Farm); Group 4, AH 26 (Dentsply de Trey)/gutta-percha (GP). For push-out bond strength measurement, two horizontal slices were obtained from each specimen (n = 20). To compare dentinal tubule penetration, remaining 32 roots assigned to 4 groups as above were obturated with 0.1% Rhodamine B labeled sealers. One horizontal slice was obtained from the middle third of each specimen (n = 8) and scanned under confocal laser scanning electron microscope. Tubule penetration area, depth, and percentage were measured. Kruskall-Wallis test was used for statistical analysis. Results EndoRez showed significantly lower push-out bond strength than the others (p < 0.05). No significant difference was found amongst the groups in terms of percentage of sealer penetration. SmartSeal showed the least penetration than the others (p < 0.05). Conclusions The bond strength and sealer penetration of resin-and glass ionomer-based sealers used with coated core was not superior to resin-based sealer used with conventional GP. Dentinal tubule penetration has limited effect on bond strength. The use of conventional GP with sealer seems to be sufficient in terms of push-out bond strength. PMID:27200279

  5. Thermal, ablative, and physicochemical effects of XeCl laser on dentin

    NASA Astrophysics Data System (ADS)

    Lee, Jon P.; Cheung, Eric M.; Wilder-Smith, Petra B. B.; Desai, T. J.; Liaw, Lih-Huei L.; Berns, Michael W.; Neev, Joseph

    1995-05-01

    Previous studies have reported altered dentinal structure and properties after laser irradiation. It was the aim of this investigation to determine the thermal and ablative effects of XeCl irradiation in dentin and then to investigate microstructural and physicochemical changes in the residual dentin structure. Extracted human molar tooth roots were bisected and coated with acid-resistant varnish, leaving a window. After irradiation of one half at 1 Hz, 15 ns pulse durations, fluences of 0.5 - 2 J/cm2, both halves were subjected to acidified gelatin gel at pH 4.5. The carious lesions were bisected and used to perform SEM and microhardness measurements.

  6. Short-term evaluation of intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin.

    PubMed

    Hayashi, Mikako; Kinomoto, Yoshifumi; Miura, Masabumi; Sato, Ikuko; Takeshige, Fumio; Ebisu, Shigeyuki

    2002-02-01

    The purpose of this study was to evaluate intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin. Twenty vertically fractured teeth were extracted intentionally and reconstructed with 4-META/MMA-TBB dentin-bonded resin. After reconstruction, the teeth were replanted into the original sockets. The replanted teeth were evaluated by clinical criteria and radiographic examination. The observation periods ranged between 4 and 45 months. Longevity was calculated by the Kaplan-Meier method, and factors that had significant influence on the longevity were analyzed with the Log rank test at a 95% level of confidence. From this short-term observation, 14 of 20 cases were functioned in the oral environment. Of these 14 cases, 6 could be considered truly successful and 8 cases needed further observation. The other six cases were total failures and were extracted. The longevity was calculated as 83.3% at 12 months and 36.3% at 24 months. Teeth with thin roots or with longitudinal fractures extending over 2/3 of the root from the cervical portion toward the apex showed significantly lower longevity. It was concluded that this method had the potential to preserve vertically fractured teeth.

  7. Dentinal crack formation during root canal preparations by the twisted file adaptive, Reciproc and WaveOne instruments

    PubMed Central

    Gergi, Richard M.; Osta, Nada E.; Naaman, Alfred S.

    2015-01-01

    Objective: This study aimed to compare the frequency of dentinal microcracks after root canal shaping with 2 reciprocating (Reciproc and WaveOne) and 1 combined continuous reciprocating motion twisted files adaptive (TFA) rotary system. Materials and Methods: Ninety molars were chosen and divided into three groups of 30 each. Root canal preparation was achieved by using Reciproc R25, Primary WaveOne and TFA systems. All the roots were horizontally sectioned at 15, 9, and 3 mm from the apex. The slices were then viewed each under a microscope at × 25 magnification to determine the presence of cracks. The absence/presence of cracks was recorded, and the data were analyzed with a Chi-square test. The significance level was set at P < 0.05. Results: Instrumentation with Reciproc produced significantly more complete cracks than WaveOne and TFA (P = 0.032). The TFA system produced significantly less cracks then the Reciproc and WaveOne systems apically (P = 0.004). Conclusions: Within the limits of this study, the TFA system caused less cracks then the full reciprocating system (Reciproc and WaveOne). Single-file reciprocating files produced significantly more incomplete dentinal cracks than full-sequence adaptive rotary motion. PMID:26929688

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

    PubMed

    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/cm(2)), and Er,Cr:YSGG (2.78 μm, 7.8 J/cm(2)) 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.

  9. Effect of Nd:YAG laser irradiation and fluoride application in the progression of dentin erosion in vitro.

    PubMed

    João-Souza, Samira Helena; Scaramucci, Tais; Hara, Anderson T; Aranha, Ana Cecilia Corrêa

    2015-12-01

    Nd:YAG laser and its association with fluoride have been proposed as an option for the prevention of dental erosion. This study evaluated the progression of existing dentin erosive lesions after treatment with different Nd:YAG laser (1064 nm) protocols, associated or not with fluoride. Erosive lesions were created with 1 % citric acid for 10 min in human dentin specimens. They were randomly assigned into eight groups (n = 15): no treatment (control), 1-min application of 2 % sodium fluoride gel (NaF), Nd:YAG1 (Nd:YAG laser irradiation 0.5 W; 50 mJ; ~41.66 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG2 (0.7 W; 70 mJ; ~62.50 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG3 (1 W; 100 mJ; ~54,16 J/cm(2); 10 Hz; 40 s; 1 mm unfocused), NaF + Nd:YAG1, NaF + Nd:YAG2, and NaF + Nd:YAG3. After treatment, the specimens were submitted to a 5-day erosion-remineralization cycling model, 6×/day. Dentin surface loss (SL) was evaluated with optical profilometry after the formation of the initial lesion; after treatment; and after days 1, 3, and 5. Data were statistically analyzed (alpha = 0.05). Significant differences were observed among the groups in all testing times (p < 0.001), except after initial lesion formation. Loss of dentin surface was observed after irradiation with all Nd:YAG laser protocols (p < 0.05). The association fluoride and laser did not differ significantly from laser alone. NaF showed the lowest values of SL and Nd:YAG2 and NaF + Nd:YAG2, the highest. Within the limitations of an in vitro study, it was concluded that laser irradiation, according to the parameters used, was not an appropriated approach to prevent dentin erosion progression, even when it was associated with fluoride.

  10. Effect of Nd:YAG laser irradiation and fluoride application in the progression of dentin erosion in vitro.

    PubMed

    João-Souza, Samira Helena; Scaramucci, Tais; Hara, Anderson T; Aranha, Ana Cecilia Corrêa

    2015-12-01

    Nd:YAG laser and its association with fluoride have been proposed as an option for the prevention of dental erosion. This study evaluated the progression of existing dentin erosive lesions after treatment with different Nd:YAG laser (1064 nm) protocols, associated or not with fluoride. Erosive lesions were created with 1 % citric acid for 10 min in human dentin specimens. They were randomly assigned into eight groups (n = 15): no treatment (control), 1-min application of 2 % sodium fluoride gel (NaF), Nd:YAG1 (Nd:YAG laser irradiation 0.5 W; 50 mJ; ~41.66 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG2 (0.7 W; 70 mJ; ~62.50 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG3 (1 W; 100 mJ; ~54,16 J/cm(2); 10 Hz; 40 s; 1 mm unfocused), NaF + Nd:YAG1, NaF + Nd:YAG2, and NaF + Nd:YAG3. After treatment, the specimens were submitted to a 5-day erosion-remineralization cycling model, 6×/day. Dentin surface loss (SL) was evaluated with optical profilometry after the formation of the initial lesion; after treatment; and after days 1, 3, and 5. Data were statistically analyzed (alpha = 0.05). Significant differences were observed among the groups in all testing times (p < 0.001), except after initial lesion formation. Loss of dentin surface was observed after irradiation with all Nd:YAG laser protocols (p < 0.05). The association fluoride and laser did not differ significantly from laser alone. NaF showed the lowest values of SL and Nd:YAG2 and NaF + Nd:YAG2, the highest. Within the limitations of an in vitro study, it was concluded that laser irradiation, according to the parameters used, was not an appropriated approach to prevent dentin erosion progression, even when it was associated with fluoride. PMID:26370205

  11. [Dentinal hypersensitivity].

    PubMed

    Steinkeller-Dekel, M; Smidt, A; Pilo, R

    2010-01-01

    Dentinal hypersensitivity is defined as short and transient painful response of exposed dentin, usually cervical, to different stimuli, such as thermal, mechanical osmotic or chemical. The etiology of dentinal hypersensitivity is open tubules (because of enamel loss or gingival recession), allowing painful stimulus to reach the pulp. The hydrodynamic theory explains the mechanism through which pain is aroused. When treating dentinal hypersensitivity, dentists always have to rule out other pathologies, such as carries, leakage, postoperative sensitivity, cracked tooth etc., and only then assess pain intensity and treat the tooth. Treatment always starts with prevention of both stimulus and exposure of dentin, and reducing predisposing factors. The treatment options include OTC products, such as fluoride and/or potassium enriched mouth washes and dentifrices, or in-office treatments, such as high content fluoride varnishes and gels, potassium oxalate chelating agents, Glutaraldehyde containing tissue fixating agents, bonding materials, low viscosity glass ionomers and even non-conservative treatments such as root canal therapy or mucogingival surgical interventions.

  12. [Dentinal hypersensitivity].

    PubMed

    Steinkeller-Dekel, M; Smidt, A; Pilo, R

    2010-01-01

    Dentinal hypersensitivity is defined as short and transient painful response of exposed dentin, usually cervical, to different stimuli, such as thermal, mechanical osmotic or chemical. The etiology of dentinal hypersensitivity is open tubules (because of enamel loss or gingival recession), allowing painful stimulus to reach the pulp. The hydrodynamic theory explains the mechanism through which pain is aroused. When treating dentinal hypersensitivity, dentists always have to rule out other pathologies, such as carries, leakage, postoperative sensitivity, cracked tooth etc., and only then assess pain intensity and treat the tooth. Treatment always starts with prevention of both stimulus and exposure of dentin, and reducing predisposing factors. The treatment options include OTC products, such as fluoride and/or potassium enriched mouth washes and dentifrices, or in-office treatments, such as high content fluoride varnishes and gels, potassium oxalate chelating agents, Glutaraldehyde containing tissue fixating agents, bonding materials, low viscosity glass ionomers and even non-conservative treatments such as root canal therapy or mucogingival surgical interventions. PMID:20597258

  13. Effect of Er,Cr:YSGG Laser Irradiation with Radial Firing Tips on Candida albicans in Experimentally Infected Root Canals

    PubMed Central

    2014-01-01

    Aim. To compare the disinfection effect of Er,Cr:YSGG laser using radial firing tips with NaOCI in root canals infected with C. albicans and to evaluate the irradiation effect on the dentinal surfaces. Material and Methods. In total seventy-six mandibular premolar teeth were used. In order to standardize the incubation and sterilization procedure, eight teeth were used. Sixty-eight of the root canals were incubated with C. albicans suspension for 72 hours. The specimens were divided into 5 experimental groups. Two groups were constituted as Group 1 was irradiated with 1.5 W laser (n = 8) and group 2, which was irradiated with 2 W laser (n = 8). Two more groups were formed as Group 3 (2 W laser (n = 25) and Group 4 NaOCI (5%) (n = 25). Group 5 (n = 2) did not receive any treatment. Mann-Whitney U and Kruskal-Wallis H tests were used to compare the different laser output powers. Wilcoxon Signed Ranks Test was used in order to compare the Candida cfu/ml levels according to treatment protocols (P < 0.05). Results. Both 1.5 W and 2 W laser resulted in a major reduction of C. albicans without a significant difference. The comparison of the dentin surfaces irradiated with Er,Cr:YSGG laser at two power settings resulted in similar morphological changes. However, NaOCI was found to be more effective in reduction of C. albicans than 2 W laser application. Conclusion. According to the results of the present study, the Er,Cr:YSGG laser with radial firing tips presented less antifungal effects on C. albicans in root canals of infected teeth than NaOCl solution. PMID:24955367

  14. Comparison of bond strength of different endodontic sealers to root dentin: An in vitro push-out test

    PubMed Central

    Madhuri, G. Vijaya; Varri, Sujana; Bolla, Nagesh; Mandava, Pragna; Akkala, Lakshmi Swathi; Shaik, Jaheer

    2016-01-01

    Aim: To compare the bond strength of four different endodontic sealers to root dentin through push-out test design. Materials and Methods: Forty single-rooted teeth with completely formed apices were selected. Teeth were decoronated, and working length was determined. Instrumentation and irrigation were performed. The teeth were divided into four groups based upon the sealer used. Group 1: Bioceramic sealer (Endosequence), Group 2: Mineral trioxide aggregate (MTA) based sealer (MTA Fill apex), Group 3: Epoxy resin based sealer (MM-Seal), and Group 4: Dual cure resin-based sealer (Hybrid Root Seal). Manipulation and application of the sealer was done as per the manufacturer instructions. All the teeth were obturated using 6% gutta-percha. After obturation, each tooth was prepared for push-out test with root slices of 2 mm thickness using universal testing machine. Results: The highest bond strength was found in Group 1 (Endosequence) (P < 0.05) compared to other groups. The lowest bond strength was found in Group 2 (MTA Fill apex). Statistical analysis is done by two-way ANOVA and Newman-Keuls multiple post hoc. Conclusion: The push-out bond strength of Bioceramic sealer was highest followed by resin-based sealer and lowest bond strength was observed in MTA-based sealer.

  15. Comparison of bond strength of different endodontic sealers to root dentin: An in vitro push-out test

    PubMed Central

    Madhuri, G. Vijaya; Varri, Sujana; Bolla, Nagesh; Mandava, Pragna; Akkala, Lakshmi Swathi; Shaik, Jaheer

    2016-01-01

    Aim: To compare the bond strength of four different endodontic sealers to root dentin through push-out test design. Materials and Methods: Forty single-rooted teeth with completely formed apices were selected. Teeth were decoronated, and working length was determined. Instrumentation and irrigation were performed. The teeth were divided into four groups based upon the sealer used. Group 1: Bioceramic sealer (Endosequence), Group 2: Mineral trioxide aggregate (MTA) based sealer (MTA Fill apex), Group 3: Epoxy resin based sealer (MM-Seal), and Group 4: Dual cure resin-based sealer (Hybrid Root Seal). Manipulation and application of the sealer was done as per the manufacturer instructions. All the teeth were obturated using 6% gutta-percha. After obturation, each tooth was prepared for push-out test with root slices of 2 mm thickness using universal testing machine. Results: The highest bond strength was found in Group 1 (Endosequence) (P < 0.05) compared to other groups. The lowest bond strength was found in Group 2 (MTA Fill apex). Statistical analysis is done by two-way ANOVA and Newman-Keuls multiple post hoc. Conclusion: The push-out bond strength of Bioceramic sealer was highest followed by resin-based sealer and lowest bond strength was observed in MTA-based sealer. PMID:27656067

  16. Effect of Resin Cement Pre-heating on the Push-out Bond Strength of Fiber Post to Root Canal Dentin

    PubMed Central

    Alizadeh Oskoee, Parnian; Nooroloyouni, Ahmad; Pornaghi Azar, Fatemeh; Sajjadi Oskoee, Jafar; Pirzadeh Ashraf, Ahmad

    2015-01-01

    Background and aims. Various factors influence the interfacial bond between the fiber posts and root canal dentin. The aim of the present study was to evaluate the effect of pre-warming of resin cement on the push-out bond strength of fiber posts to various segments of root canal dentin. Materials and methods. In this in vitro study, 40 single-rooted human premolars were decoronated and underwent root canal treatment along with post space preparation. The samples were randomly divided into two groups: In group 1, Panavia F 2.0 cement was used at room temperature; in group 2, the same cement was warmed to 55‒60°C before mixing. After fiber posts were placed and cemented in the root canals, 3 dentin/post sections (coronal, middle and apical) with a thickness of 3 mm were prepared. A universal testing machine was used to measure push-out bond strength in MPa. Data was analyzed using two-factor ANOVA and a post hoc Tukey test at α=0.05. Results. The mean value of push-out bond strength was high at room temperature, and the differences in the means of push-out bond strength values between the resin cement temperatures and between different root segments in each temperature were significant (P<0.05). Conclusion. Pre-warming of Panavia F 2.0 resin cement up to 55-60°C reduced push-out bond strength to root canal dentin. In addition, in each temperature group bond strengths decreased from coronal to apical segments. PMID:26889360

  17. Adhesion to root canal dentine using one and two-step adhesives with dual-cure composite core materials.

    PubMed

    Foxton, R M; Nakajima, M; Tagami, J; Miura, H

    2005-02-01

    The regional tensile bond strengths of two dual-cure composite resin core materials to root canal dentine using either a one or two-step self-etching adhesive were evaluated. Extracted premolar teeth were decoronated and their root canals prepared to a depth of 8 mm and a width of 1.4 mm. In one group, a one-step self-etching adhesive (Unifil Self-etching Bond) was applied to the walls of the post-space and light-cured for 10 s. After which, the post-spaces were filled with the a dual-cure composite resin (Unifil Core) and then half the specimens were light-cured for 60 s and the other half placed in darkness for 30 min. In the second group, a self-etching primer (ED Primer II) was applied for 30 s, followed by an adhesive resin (Clearfil Photo Bond), which was light-cured for 10 s. The post-spaces were filled with a dual-cure composite resin (DC Core) and then half the specimens were light-cured for 60 s and the other half placed in darkness for 30 min. Chemical-cure composite resin was placed on the outer surfaces of all the roots, which were then stored in water for 24 h. They were serially sliced perpendicular to the bonded interface into 8, 0.6 mm-thick slabs, and then transversely sectioned into beams, approximately 8 x 0.6 x 0.6 mm, for the microtensile bond strength test (muTBS). Data were divided into two (coronal/apical half of post-space) and analysed using three-way anova and Scheffe's test (P < 0.05). Failure modes were observed under an scanning electron microscope (SEM) and statistically analysed. Specimens for observation of the bonded interfaces were prepared in a similar manner as for bond strength testing, cut in half and embedded in epoxy resin. They were then polished to a high gloss, gold sputter coated, and after argon ion etching, observed under an SEM. For both dual-cure composite resins and curing strategies, there were no significant differences in muTBS between the coronal and apical regions (P > 0.05). In addition, both dual

  18. Effect of titanium dioxide and 3.5% hydrogen peroxide with 405-nm diode laser irradiation on bonding of resin to pulp chamber dentin

    NASA Astrophysics Data System (ADS)

    Haruyama, A.; Kato, J.; Kameyama, A.; Hirai, Y.; Oda, Y.

    2010-04-01

    This study was conducted to determine the effect of a 3.5% hydrogen peroxide solution containing titanium dioxide on bonding of resin to pulp chamber dentin. Extracted bovine anterior teeth were allocated to three groups of ten teeth each. The coronal labial pulp chamber dentin was exposed and bleached with 3.5% hydrogen peroxide with titanium dioxide with 405-nm diode laser irradiation for 15 min (Group 1); 30% hydrogen peroxide with halogen lamp irradiation for 15 min (Group 2); and distilled water for 15 min (Group 3). After bleaching, the pulp chamber dentin was prepared for composite resin bonding and the interface between the resin and dentin was observed by scanning electron microscopy. The microtensile bond strength (μTBS) and failure patterns were determined. The μTBS values (mean ± SD) were: 17.28 ± 5.79 MPa ( n = 36), 0 MPa, and 26.50 ± 9.83 MPa ( n = 36) in Groups 1, 2, and 3, respectively. The μTBS in Group 3 was significantly higher than that in Group 1 ( P < 0.05). Hybrid layers and resin tags were clearly observed at the interface in Groups 1 and 3, but not in Group 2. Adhesive failure was mainly observed in Group 1, whereas dentin failure was the main failure pattern in Group 3.

  19. 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

  20. Analysis of peripheral thermal damage after laser irradiation of dentin using polarized light microscopy and synchrotron radiation infrared spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Dela Rosa, Alfredo; Sarma, Anupama V.; Le, Charles Q.; Jones, Robert S.; Fried, Daniel

    2004-05-01

    It is necessary to minimize peripheral thermal damage during laser irradiation, since thermal damage to collagen and mineral compromises the bond strength to restorative materials in dentin and inhibits healing and osteointegration in bone. The overall objective of this study was to test the hypothesis that lasers resonant to the specific absorption of water, collagen, and hydroxyapatite with pulse durations less than the thermal relaxation times at each respective laser wavelength will efficiently remove dentin with minimal peripheral thermal damage. Precise incisions were produced in 3 x 3 mm2 blocks of human dentin using CO2 (9.6 μm), Er:YSGG (2.79 μm), and Nd:YAG (355 nm) lasers with and without a computer controlled water spray. Polarization-sensitive optical coherence tomography was used to obtain optical cross-sections of each incision to determine the rate and efficiency of ablation. The peripheral thermal damage zone around each incision was analyzed using polarized light microscopy (PLM) and Synchrotron-Radiation Fourier Transform Infrared Spectro-microscopy (SR-FTIR). Thermally induced chemical changes to both mineral and the collagen matrix was observed with SR-FTIR with a 10-μm spatial resolution and those changes were correlated with optical changes observed with PLM. Minimal (<10-μm) thermal damage was observed for pulse durations less than the thermal relaxation time (Tr ) of the deposited laser energy, with and without applied water at 9.6 um and only with applied water at 2.79 μm. For pulse durations greater than Tr, significantly greater peripheral thermal damage was observed for both IR laser wavelengths with and without the water spray. There was minimal thermal damage for 355-nm laser pulses, however extensive mechanical damage (cracks) was observed. High resolution SR-FTIR is well suited for characterization of the chemical changes that occur due to thermal damage peripheral to laser incisions in proteinaceous hard tissues. Sub

  1. Influence of powder composition and morphology on penetration of Gray and White ProRoot mineral trioxide aggregate and calcium hydroxide into dentin tubules.

    PubMed

    Komabayashi, Takashi; Long, Leann; Ahn, Chul; Spears, Robert; Zhu, Qiang; C Eberhart, Robert

    2014-12-01

    This study examined the influence of powder composition and morphology on the penetration of Gray and White ProRoot mineral trioxide aggregate (GMTA, WMTA) and calcium hydroxide (CH) into open dentin tubules. GMTA, WMTA, and CH particle dimensions were analyzed by flow particle image analysis (FPIA). Penetration of open dentin tubules into dentin discs was studied by scanning electron microscopy. Five samples of each material were randomly selected and prepared for this study. The GMTA averages for length (μm), width (μm), perimeter (μm), and aspect ratio were 1.94 ± 1.65, 1.43 ± 1.19, 5.61 ± 4.27, and 0.76 ± 0.14, respectively. Corresponding averages for WMTA were 2.04 ± 1.87, 1.49 ± 1.33, 5.88 ± 4.81, and 0.76 ± 0.14, and for CH were 2.26 ± 1.99, 1.62 ± 1.46, 6.70 ± 5.60, and 0.74 ± 0.15, respectively. The rank order of the averages for particle length, width and perimeter from the largest to the smallest material was CH > WMTA > GMTA. The rank order of the averaged aspect ratios was GMTA > WMTA > CH. SEM showed that all three materials, when deposited and agitated on dentin discs, penetrated the open dentin tubules. Tubule occlusion occurred as particle surface concentrations increased. Significant differences in particle length, width, perimeter, and aspect ratio were observed for GMTA, WMTA, and CH (P < 0.0001 in all cases). All particle types penetrated into open tubules when agitated on dentin discs; all tubules were eventually occluded as particle concentrations grew. (J Oral Sci 56, 287-293, 2014).

  2. Effects of Er:YAG laser irradiation and manipulation treatments on dentin components, part 2: energy-dispersive X-ray fluorescence spectrometry study.

    PubMed

    Soares, Luís Eduardo Silva; do Espírito Santo, Ana Maria; Brugnera, Aldo; Zanin, Fátima Anto Nia Aparecida; Martin, Airton Abrahão

    2009-01-01

    The effects of laser etching, decontamination, and storage treatments on dentin components were studied by energy-dispersive X-ray fluorescence spectrometry (EDXRF). Thirty bovine incisors were prepared to expose the dentin surface and then divided into two main groups based upon the decontamination process and storage procedure: autoclaved (group A, n=15) or stored in aqueous thymol solution (group B, n=15). The surfaces of the dentin slices were schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control subgroup) or irradiated with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ). Samples were analyzed by micro-EDXRF, yielding three spectra for each area (before and after treatment). Surface mappings covering an area of 80x60 points with steps of 20 mum were also performed on selected specimens. The amount of Ca and P in group A specimens decreased significantly (P<0.05) after the acid etching and the CaP ratio increased (P<0.001). Er:YAG laser-etching using lower laser energies did not produce significant changes in dentin components. The mapping data support the hypothesis that acid etching on dentin produced a more chemically homogeneous surface and thus a more favorable surface for the diffusion of adhesive monomers.

  3. Effects of Er:YAG laser irradiation and manipulation treatments on dentin components, part 2: energy-dispersive X-ray fluorescence spectrometry study

    NASA Astrophysics Data System (ADS)

    Silva Soares, Luís Eduardo; Do Espírito Santo, Ana Maria; Brugnera, Aldo; Zanin, Fátima Antônia Aparecida; Martin, Airton Abraha~O.

    2009-03-01

    The effects of laser etching, decontamination, and storage treatments on dentin components were studied by energy-dispersive X-ray fluorescence spectrometry (EDXRF). Thirty bovine incisors were prepared to expose the dentin surface and then divided into two main groups based upon the decontamination process and storage procedure: autoclaved (group A, n=15) or stored in aqueous thymol solution (group B, n=15). The surfaces of the dentin slices were schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control subgroup) or irradiated with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ). Samples were analyzed by micro-EDXRF, yielding three spectra for each area (before and after treatment). Surface mappings covering an area of 80×60 points with steps of 20 μm were also performed on selected specimens. The amount of Ca and P in group A specimens decreased significantly (P<0.05) after the acid etching and the Ca/P ratio increased (P<0.001). Er:YAG laser-etching using lower laser energies did not produce significant changes in dentin components. The mapping data support the hypothesis that acid etching on dentin produced a more chemically homogeneous surface and thus a more favorable surface for the diffusion of adhesive monomers.

  4. Combination of aligned PLGA/Gelatin electrospun sheets, native dental pulp extracellular matrix and treated dentin matrix as substrates for tooth root regeneration.

    PubMed

    Chen, Gang; Chen, Jinlong; Yang, Bo; Li, Lei; Luo, Xiangyou; Zhang, Xuexin; Feng, Lian; Jiang, Zongting; Yu, Mei; Guo, Weihua; Tian, Weidong

    2015-06-01

    In tissue engineering, scaffold materials provide effective structural support to promote the repair of damaged tissues or organs through simulating the extracellular matrix (ECM) microenvironments for stem cells. This study hypothesized that simulating the ECM microenvironments of periodontium and dental pulp/dentin complexes would contribute to the regeneration of tooth root. Here, aligned PLGA/Gelatin electrospun sheet (APES), treated dentin matrix (TDM) and native dental pulp extracellular matrix (DPEM) were fabricated and combined into APES/TDM and DPEM/TDM for periodontium and dental pulp regeneration, respectively. This study firstly examined the physicochemical properties and biocompatibilities of both APES and DPEM in vitro, and further investigated the degradation of APES and revascularization of DPEM in vivo. Then, the potency of APES/TDM and DPEM/TDM in odontogenic induction was evaluated via co-culture with dental stem cells. Finally, we verified the periodontium and dental pulp/dentin complex regeneration in the jaw of miniature swine. Results showed that APES possessed aligned fiber orientation which guided cell proliferation while DPEM preserved the intrinsic fiber structure and ECM proteins. Importantly, both APES/TDM and DPEM/TDM facilitated the odontogenic differentiation of dental stem cells in vitro. Seeded with stem cells, the sandwich composites (APES/TDM/DPEM) generated tooth root-like tissues after being transplanted in porcine jaws for 12 w. In dental pulp/dentin complex-like tissues, columnar odontoblasts-like layer arranged along the interface between newly-formed predentin matrix and dental pulp-like tissues in which blood vessels could be found; in periodontium complex-like tissues, cellular cementum and periodontal ligament (PDL)-like tissues were generated on the TDM surface. Thus, above results suggest that APES and DPEM exhibiting appropriate physicochemical properties and well biocompatibilities, in accompany with TDM, could

  5. Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation

    NASA Astrophysics Data System (ADS)

    da Fonseca Alvarez, Andrea; Moura-Netto, Cacio; Daliberto Frugoli, Alexandre; Fernando, Casemiro; Correa Aranha, Ana Cecilia; Davidowicz, Harry

    2012-01-01

    Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 °C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls.

  6. Evaluation of reparative dentin formation of ProRoot MTA, Biodentine and BioAggregate using micro-CT and immunohistochemistry

    PubMed Central

    Kim, Jia; Song, Young-Sang; Min, Kyung-San; Kim, Sun-Hun; Koh, Jeong-Tae

    2016-01-01

    Objectives The purpose of this study was to assess the ability of two new calcium silicate-based pulp-capping materials (Biodentine and BioAggregate) to induce healing in a rat pulp injury model and to compare them with mineral trioxide aggregate (MTA). Materials and Methods Eighteen rats were anesthetized, cavities were prepared and the pulp was capped with either of ProRoot MTA, Biodentine, or BioAggregate. The specimens were scanned using a high-resolution micro-computed tomography (micro-CT) system and were prepared and evaluated histologically and immunohistochemically using dentin sialoprotein (DSP). Results On micro-CT analysis, the ProRoot MTA and Biodentine groups showed significantly thicker hard tissue formation (p < 0.05). On H&E staining, ProRoot MTA showed complete dentin bridge formation with normal pulpal histology. In the Biodentine and BioAggregate groups, a thick, homogeneous hard tissue barrier was observed. The ProRoot MTA specimens showed strong immunopositive reaction for DSP. Conclusions Our results suggest that calcium silicate-based pulp-capping materials induce favorable effects on reparative processes during vital pulp therapy and that both Biodentine and BioAggregate could be considered as alternatives to ProRoot MTA. PMID:26877988

  7. Pull-out bond strength of a self-adhesive resin cement to NaOCl-treated root dentin: effect of antioxidizing agents

    PubMed Central

    Kachuei, Marzieh

    2014-01-01

    Objectives This study evaluated the effect of three antioxidizing agents on pull-out bond strengths of dentin treated with sodium hypochlorite. Materials and Methods Root canals of 75 single-rooted human teeth were prepared. Fifteen teeth were irrigated with normal saline for a negative control group, and the remaining 60 teeth (groups 2 - 5) with 2.5% NaOCl. The teeth in group 2 served as a positive control. Prior to post cementation, the root canals in groups 3 - 5 were irrigated with three antioxidizing agents including 10% rosmarinic acid (RA, Baridge essence), 10% hesperidin (HPN, Sigma), and 10% sodium ascorbate hydrogel (SA, AppliChem). Seventy-five spreaders (#55, taper .02, Produits Dentaires S.A) were coated with silica and silanized with the Rocatec system and ceramic bond. All the prepared spreaders were cemented with a self-adhesive resin cement (Bifix SE, Voco Gmbh) in the prepared canals. After storage in distilled water (24 h/37℃), the spreaders were pulled out in a universal testing machine at a crosshead speed of 1.0 mm/min. Pull-out strength values were analyzed by one-way ANOVA and Tukey's HSD test (α = 0.05). Results There were significant differences between study groups (p = 0.016). The highest pull-out strength was related to the SA group. The lowest strength was obtained in the positive control group. Conclusions Irrigation with NaOCl during canal preparation decreased bond strength of resin cement to root dentin. Amongst the antioxidants tested, SA had superior results in reversing the diminishing effect of NaOCl irrigation on the bond strength to root dentin. PMID:24790921

  8. [Photoelastic stress analysis of root dentin with different composite resin post and core systems and crowns].

    PubMed

    Takei, Hidenori

    2010-03-01

    Much research has been reported about post and core systems with composite resin, but the influence of the different types of prefabricated posts on the distribution of stress in the root has not yet been elucidated. It is necessary to clarify the influence of the relationship between core and crown materials to obtain combined restorations. The aim of this study is to analyze the influence of the combination of various post and core systems and different kinds of crown material on the stress distribution in the root. Six 2-dimensional photoelastic premolar models were designed. Three types of post and core systems (composite resin post and core, composite resin core with the fiber post, and composite resin core with a prefabricated stainless steel post) and two kinds of crown materials (metal and hybrid-type hard composite resin) were fabricated and cemented to each model. In these models, we applied a load of 200 N at an angle of 45 degrees to the tooth axis and analyzed the fringe order using a transmission polariscope. As a result, it has been clarified that the combination of the post and core and the crown plays an important role in preventing stress concentration within root Stress concentration can be prevented using a crown fabricated with a high-elastic modulus for the post and core with a high-elastic modulus, and a crown fabricated with a low-elastic modulus for the post and core with a low-elastic modulus.

  9. Does the moment of fiber post cutting influence on the retention to root dentin?

    PubMed

    Borges, Marcela G; Faria-e-Silva, André L; Santos-Filho, Paulo C F; Silva, Fernanda P; Martins, Luís R M; Menezes, Murilo de Sousa

    2015-01-01

    Despite several advantages associated with pre-fabricated glass-fiber posts, the coronal portion of these posts must be cut to allow their use in various clinical situations. However, cutting the cemented post can generate stress on the bonding interface and affect the bond strength. The aim of this study was to investigate the effect the of fiber post cutting on the bond strength of root canals. Sixty bovine incisor roots were included in resin cylinders with simulated periodontal ligaments. Glass-fiber posts were luted using regular resin cement RelyX ARC (3M ESPE) or self-adhesive cement RelyX Unicem (3M ESPE). The posts were cut prior to cementation, immediately after luting or after building up the core (n=10). After storage for 24 h, the samples were cut and subject to push-out testing using a mechanical testing machine (EMIC DL 2000). Data were analyzed using two-way ANOVA (resin cement x moment of post cutting) and Tukey's post hoc test (α=0.05). The moment of fiber post cutting did not affect the bond strength when Unicem was used. However, the bond strength was reduced when ARC was used and when the post was cut immediately. In conclusion, the moment of fiber post cutting may affect the retention of root canal posts when a regular resin cement is used.

  10. An in Vitro Evaluation of Antimicrobial Efficacy of 2% Chlorhexidine Gel, Propolis and Calcium Hydroxide Against Enterococcus faecalis in Human Root Dentin

    PubMed Central

    T S, Ashwini; Patil, Chetan R

    2014-01-01

    Aim: To evaluate in vitro the antimicrobial efficacy of 2% Chlorhexidine gel, Propolis and Calcium hydroxide against Enterococcus faecalis in human root dentin. Methodology: One hundred and twenty human extracted anterior teeth were decoronated below CEJ and the apical part of root was removed to obtain 6mm of middle of the root. GG no 3 was used to standardize the internal diameter of root canal. Dentin blocks were infected with E faecalis for 21 d. They were assigned into four groups (n = 30).Group 1, Saline (negative control); Group 2, Propolis; Group 3, 2% CHX; Group 4, Calcium hydroxide, At the end of 1, 3, and 5 days an assessment of microbial cells was carried out at a depth of 400 μm and colony counts were calculated.The data were analysed statistically with one-way analysis of variance followed by Scheffe multiple comparison test (p < 0.05). Results: The number of colony-forming units was significantly lower in all experimental groups compared to the control group – Saline. 2% Chlorhexidinegluconate produced better antimicrobial efficacy (100%) on day 1, 3 and 5. Propolis (66.37%) had greater antimicrobial activity than Calcium hydroxide (50.89%) on day 1 but there was no significant difference in their antimicrobial activities on day 3 and day 5. Conclusion: 2% Chlorhexidine gel showed the maximum antimicrobial activity against E faecalis and Calcium hydroxide the least. Propolis can be used as an effective alternative intracanal medicament. PMID:25584319

  11. Root anomalies and dentin dysplasia in autosomal recessive hyperphosphatemic familial tumoral calcinosis (HFTC)

    PubMed Central

    Vieira, Alexandre R.; Lee, Moses; Vairo, Filippo; Leite, Julio Cesar Loguercio; Munerato, Maria Cristina; Visioli, Fernanda; D’Ávila, Stéphanie Rodrigues; Wang, Shih-Kai; Choi, Murim; Simmer, James P.; Hu, Jan C-C.

    2015-01-01

    Hyperphosphatemic familial tumoral calcinosis (HFTC, OMIM #211900) is an autosomal recessive metabolic disorder characterized by hyperphosphatemia, tooth root defects, and the progressive deposition of calcium phosphate crystals in periarticular spaces, soft tissues, and sometimes bone.1 In this HFTC case report, we document the dental phenotype associated with a homozygous missense mutation (g.29077 C>T; c.484 C>T; p.Arg162*) in GALNT3 (OMIM 6017563), a gene encoding UDP-GalNAc transferase 3 that catalyzes the first step of O-linked oligosaccharide biosynthesis in the Golgi. The medical and dental pathology is believed to be caused primarily by high serum phosphate levels (hyperphosphatemia), which, in turn, is caused by failure of GALNT3 to glycosylate the phosphate regulator protein FGF23, impairing its ability inhibit reabsorption of filtered phosphate in the kidneys. PMID:26337219

  12. Effect of gamma irradiation on microbiological, chemical and sensory characteristics of licorice root product

    NASA Astrophysics Data System (ADS)

    Al-Bachir, M.; Al-Adawi, M. A.; Al-Kaid, A.

    2004-03-01

    Licorice root products were irradiated at doses of 0, 5, 10, 15 and 20 kGy in a 60Co package irradiator. Irradiated and unirradiated samples were stored at room temperatures. Microbial population on product, chemical changes and sensory properties of produced solution of licorice root products were evaluated after 0 and 12 months of storage. The results indicated that gamma irradiation reduced the counts of microorganisms on licorice root products. D10 of total count and klebsiella spp. were about 1.4 and 0.7 kGy, respectively. The mineral ions (Na, Ca and K) concentration in solution produced from irradiated products were lower than non-irradiated ones. Glycyrrhezinic acid and maltose concentration in solution produced from irradiated products were higher than non-irradiated ones. Sensory evaluation indicated that no significant differences ( P<0.05) were found between solution produced from irradiated and unirradiated products in color, flavor, texture, or taste.

  13. Infected Dentine Revisited.

    PubMed

    Kidd, Edwina; Fejerskov, Ole; Nyvad, Bente

    2015-11-01

    Dentine becomes infected as a result of caries lesion formation on root surfaces and when lesions progress following cavitation of enamel lesions. However, this infection is unimportant because the driving force for lesion formation and progression is the overlying biofilm. This explains why root surface caries can be controlled by mechanical plaque control and fluoride, and restorations are not needed to arrest these lesions. Similarly, the infected dentine in cavitated coronal lesions does not have to be removed to arrest the lesion. If the lesion is either accessible or opened for cleaning by the patient or parent, the lesion can be arrested. Sealing of infected dentine within the tooth, either by a Hall crown in the primary dentition or by partial caries removal prior to placing a well-sealed filling, will also arrest the lesion. When restoring deep lesions in symptomless, vital teeth, vigorous excavation of infected dentine is likely to expose the pulp and make root canal treatment necessary. Thus complete excavation'is not needed and should be avoided. CPD/CLINICAL RELEVANCE: Root surface caries can be arrested by cleaning and fluoride application. Restorations are not essential. Vigorous excavation of softened dentine in deep cavities of symptomless, vital teeth is contra-indicated. It is not needed and increases the risk of pulp exposure. PMID:26749788

  14. Surface change of root canal dentin after the use of irrigation activation protocols: electron microscopy and an energy-dispersive X-ray microanalysis.

    PubMed

    Capar, Ismail Davut; Aydinbelge, Hale Ari

    2013-09-01

    This study evaluated the mineral contents of root-canal dentin after treatment with different irrigation activation protocols. One hundred and eight maxillary lateral incisor teeth were randomly divided into eight experimental groups and one control group. Root canals were prepared using ProTaper rotary files, with the exception of the Self-Adjusting File (SAF) group. Canals were irrigated with 2 mL of 5% sodium hypochlorite (NaOCl) at each instrument change, and received a final flush with 10 mL of 17% ethylenediaminetetraacetic acid (EDTA) and 10 mL of 5% NaOCl for 1 min. The control group was irrigated with distilled water. Group I (GI): Needle syringe irrigation; Group II (GII): NaviTip FX; Group III (GIII): CanalBrush; Group IV (GIV): Manual dynamic activation with gutta-percha; Group V (GV): Passive ultrasonic irrigation; Group VI (GVI): EndoActivator; Group VII (GVII): EndoVac; Group VIII (GVIII): SAF. The level of elemental composition was analyzed by a scanning electron microscopy and an energy-dispersive spectrometer (EDS) system. The results were then statistically analyzed by one-way ANOVA and Tukey tests. Ca/P ratio was changed after treatment with SAF and EndoActivator. The Ca, P, Mg, and S level changes were not statistically significant (P > 0.05). Final irrigation activation protocols did not alter the mineral level of root dentin surface.

  15. Effect of Resin Cement Porosity on Retention of Glass-Fiber Posts to Root Dentin: An Experimental and Finite Element Analysis.

    PubMed

    Da Silva, Natércia Rezende; Aguiar, Grazielle Crystine Rodrigues; Rodrigues, Monise de Paula; Bicalho, Aline Aredes; Soares, Priscilla Barbosa Ferreira; Veríssimo, Crisnicaw; Soares, Carlos José

    2015-01-01

    The aim of this study was to evaluate the effect of porosity of self-adhesive resin on the stress distribution, post retention and failure mode of fiber post cemented to human root dentin. Ten human central upper incisors with circular root canal were selected. They were sectioned with 15 mm and were endodontically filled. The roots were scanned using micro-CT after post space preparation for root filling remaining evaluation. Fiber posts were cemented using self-adhesive resin cement (Rely X U200, 3M-ESPE). Two 1-mm-thick slices from the cervical, medium and apical thirds were scanned for resin cement bubbles volume measurements and submitted to a push-out test (PBS). Three operators using stereomicroscopy and confocal laser microscopy classified the failure mode. Stress distributions during the push-out test were analyzed using 3D finite element analysis. PBS values (MPa) were submitted to one-way ANOVA and Tukey's post hoc tests and the failure modes using the Kappa coefficient to assess inter-operator agreement. Chi-square test was used to determine significant differences between the methods ( = 0.05). Push-out bond strength was significantly affected by the bubbles presence in all root depth (p<0.05). The stress concentration was higher when the bubbles were present. Adhesive dentin/resin cement interface failure was the most frequent type of failure. Confocal microscopy was better than stereomicroscopy for failure analysis. Bubbles generated during resin cement insertion into the root canal negatively affect the stress distribution and the bond strength. The use of confocal microscopy is recommended for failure analysis. PMID:26963208

  16. In vitro effects of Er,Cr:YSGG laser on dentine hypersensitivity. Dentine permeability and scanning electron microscopy analysis.

    PubMed

    Aranha, Ana Cecilia Corrêa; Eduardo, Carlos de Paula

    2012-07-01

    The aim of the present study was to determine clinical parameters for the use of Er,Cr:YSGG laser in the treatment of dentine hypersensitivity. Two antagonist areas were determined as control and experimental areas for irradiation in 90 premolar roots. Each surface was conditioned with 24% EDTA (sub-group 1) and 35% phosphoric acid (sub-group 2) and irradiated with the following settings: 1) Er:YAG, 60 mJ, 2 Hz, defocused; groups 2 to 9: irradiation with Er,Cr:YSGG laser, 20 Hz, Z6 tip, 0% of air and water: 2) Er,Cr:YSGG 0.25 W; 3) 0.5 W; 4) 0.75 W; 5) 1.0 W; 6) 1.25 W, 7) 1.50 W, 8) 2 W; 9) 2 W. After irradiation, samples were immersed in methylene blue solution and included in epoxy resin to obtain longitudinal cuts. The images were digitalized and analyzed by computer software. Although the samples irradiated with Er:YAG laser showed less microleakage, sub-group 1 showed differences between the groups, differing statistically from groups 3, 6, and 9. The results of sub-group 2 showed that the mean values of Er:YAG samples showed a negative trend, however, no differences were detected between the groups. For scanning electron microscopy analysis, dentine squares were obtained and prepared to evaluate the superficial morphology. Partial closure of dentinal tubules was observed after irradiation with Er:YAG and Er,Cr:YSGG laser in the 0.25 and 0.50 W protocols. As the energy densities rose, open dentinal tubules, carbonization and cracks were observed. It can be concluded that none of the parameters were capable of eliminating microleakage, however, clinical studies with Er:YAG and Er,Cr:YSGG lasers should be conducted with the lowest protocols in order to determine the most satisfactory setting for dentine hypersensitivity. PMID:21948399

  17. Dentin ablation-rate measurements in endodontics witj HF and CO2 laser radiation

    NASA Astrophysics Data System (ADS)

    Makropoulou, Mersini I.; Serafetinides, Alexander A.; Khabbaz, Marouan; Sykaras, Sotirios; Tsikrikas, G. N.

    1996-01-01

    Recent studies focused on the ability of the laser light to enlarge the root canal during the endodontic therapy. The aim of this research is the experimental and theoretical study of the ablation rate of two infrared laser wavelengths on dentin. Thirty freshly extracted human teeth were longitudinally sectioned at thicknesses ranged from 0.5 to 2 mm, and irradiated on the root canal dentin. The measured ablation rates in dentinal wall of the root canal showed that the HF laser at 2.9 micrometer can more effectively penetrate into the tissue, whereas the carbon dioxide laser at 10.6 micrometer leads to high thermal damage of the ablation crater surroundings.

  18. Push-out bond strength of quartz fibre posts to root canal dentin using total-etch and self-adhesive resin cements

    PubMed Central

    Mohammadi, Narmin; Navimipour, Elmira J.; Shakerifar, Maryam

    2012-01-01

    Objectives: Several adhesive systems are available for cementation of fibre posts into the root canal. The aim of the present study was to investigate the push-out bond strengths of quartz fibre posts to root dentin with the use of different total-etch and self-adhesive resin cements. Study Design: Ninety single-rooted human premolars were endodontically treated and standardized post-spaces were prepared. Fibre posts were cemented with different luting agents: total-etch (Nexus NX3, Duo-Link, and RelyX ARC) and self-adhesive resin cements (Maxcem Elite, BisCem, and RelyX Unicem). Three post/dentin sections (coronal, middle and apical) were obtained from each specimen, and push-out bond strength test was performed in each section at a cross-head speed of 0.5 mm/min. Data was analyzed with two-factor and one-way analysis of variance and a post-hoc Tukey test at a significance level of p < 0.05. Results: Cement type, canal region, and their interaction significantly influenced bond strength. Significantly higher bond strength values were observed in the apical region of self-adhesive cements. Only Duo-Link and RelyX ARC cements resulted in homogeneous bond strengths. Conclusions: Cementation of quartz fibre posts using self-adhesive cements provided higher push-out bond strengths especially in the apical region, while total-etch cements resulted in more uniform bond strengths in different regions of the root canal. Key words: Push-out bond strength; quartz fibre post; total-etch resin cement; self-adhesive resin cement. PMID:22143695

  19. Thermal and microstructural effects of nanosecond pulsed Nd:YAG laser irradiation on tooth root surface

    NASA Astrophysics Data System (ADS)

    Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.; Grill, G.; Liaw, Lih-Huei L.; Berns, Michael W.

    1995-05-01

    Plaque, calculus and altered cementum removal by scaling and root planing is a fundamental procedure in periodontal treatment. However, the residual smear layer contains cytotoxic and inflammatory mediators which adversely affect healing. Chemical smear layer removal is also problematic. In previous investigations effective smear layer removal was achieved using long pulsed irradiation at 1.06 (mu) . However, laser irradiation was not adequate as an alternative to scaling and root planing procedures and concurrent temperature rises exceeded thermal thresholds for pulpal and periodontal safety. It was the aim of this study to determine whether nanosecond pulsed irradiation at 1.06 (mu) could be used as an alternative or an adjunct to scaling and root planing. Sixty freshly extracted teeth were divided as follows: 5 control, 5 root planed only, 25 irradiated only, 25 root planed and irradiated. Irradiation was performed at fluences of 0.5 - 2.7 J/cm2, total energy densities of 12 - 300 J/cm2, frequencies of 2 - 10 Hz using the Medlite (Continuum) laser. Irradiation-induced thermal events were recorded using a thermocouple within the root canal and a thermal camera to monitor surface temperatures. SEM demonstrated effective smear layer removal with minimal microstructural effects. Surface temperatures increased minimally (< 3 C) at all parameters, intrapulpal temperature rises remained below 4 C at 2 and 5 Hz, F < 0.5 J/cm2. Without prior scaling and root planing, laser effects did not provide an adequately clean root surface.

  20. Effect of chlorhexidine on bond strength between glass-fiber post and root canal dentine after six month of water storage.

    PubMed

    Toman, M; Toksavul, S; Tamaç, E; Sarikanat, M; Karagözoğlu, I

    2014-03-01

    Aim of this study was to assess the influence of chlorhexidine digluconate (CHX) application on bond strength of glass fibre reinforced composite (FRC) posts to root dentine using adhesive luting systems. Forty extracted human mandibular premolars were endodontically treated and root canals were prepared. Teeth were divided into 2 groups according to luting system as SuperBond C&B (etch-and-rinse/chemical cure) and FuturaBond DC (self-etch/ dual cure). Each group was further divided in 2 subgroups (n=10) according to whether CHX was applied or not. Group Futura/CHX: FuturaBond DC + CHX; group Futura: FuturaBond DC; group Super/CHX: Super Bond C&B + CHX; group Super: SuperBond C&B + CHX. Mean and standard deviation (in parenthesis) values of bond strength in MPa were: group Futura/CHX: 8.86 (1.96), group Futura: 7.65 (1.01), group Super/CHX: 17.47(2.93), group Super: 12.41 (3.83). Bond strength values were affected by the type of luting agent and CHX irrigation (p=0.001, two-way ANOVA). There were statistically significant differences among the groups according to one-way ANOVA (p<0.001). Significant differences were observed in bond strength between groups Super/CHX and Super (p=0.023), between groups Futura/CHX and Super/CHX (p<0.001). Application of CHX before luting procedure with etch-and-rinse/chemical cure luting agent of glass FRC post improved long-term bond strength between glass FRC and root dentine.

  1. Multi-step adhesive cementation versus one-step adhesive cementation: push-out bond strength between fiber post and root dentin before and after mechanical cycling.

    PubMed

    Amaral, Marina; Rippe, Marilia Pivetta; Bergoli, Cesar Dalmolin; Monaco, Carlo; Valandro, Luiz Felipe

    2011-01-01

    This study evaluated the effects of mechanical cycling on resin push-out bond strength to root dentin, using two strategies for fiber post cementation. Forty bovine roots were embedded in acrylic resin after root canal preparation using a custom drill of the fiber post system. The fiber posts were cemented into root canals using two different strategies (N = 20): a conventional adhesive approach using a three-step etch-and-rinse adhesive system combined with a conventional resin cement (ScotchBond Multi Purpose Plus + RelyX ARC ), or a simplified adhesive approach using a self-adhesive resin cement (RelyX U100). The core was built up with composite resin and half of the specimens from each cementation strategy were submitted to mechanical cycling (45 degree angle; 37 degrees C; 88 N; 4 Hz; 700,000 cycles). Each specimen was cross-sectioned and the disk specimens were pushed-out. The means from every group (n = 10) were statistically analyzed using a two-way ANOVA and a Tukey test (P = 0.05). The cementation strategy affected the push-out results (P < 0.001), while mechanical cycling did not (P = 0.3716). The simplified approach (a self-adhesive resin cement) had better bond performance despite the conditioning. The self-adhesive resin cement appears to be a good option for post cementation. Further trials are needed to confirm these results.

  2. 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.

  3. Stress distribution on dentin-cement-post interface varying root canal and glass fiber post diameters. A three-dimensional finite element analysis based on micro-CT data

    PubMed Central

    LAZARI, Priscilla Cardoso; de OLIVEIRA, Rodrigo Caldeira Nunes; ANCHIETA, Rodolfo Bruniera; de ALMEIDA, Erika Oliveira; FREITAS JUNIOR, Amilcar Chagas; KINA, Sidney; ROCHA, Eduardo Passos

    2013-01-01

    Objective The aim of the present study was to analyze the influence of root canal and glass fiber post diameters on the biomechanical behavior of the dentin/cement/post interface of a root-filled tooth using 3D finite element analysis. Material and Methods Six models were built using micro-CT imaging data and SolidWorks 2007 software, varying the root canal (C) and the glass fiber post (P) diameters: C1P1-C=1 mm and P=1 mm; C2P1-C=2 mm and P=1 mm; C2P2-C=2 mm and P=2 mm; C3P1-C=3 mm and P=1 mm; C3P2-C=3 mm and P=2 mm; and C3P3-C=3 mm and P=3 mm. The numerical analysis was conducted with ANSYS Workbench 10.0. An oblique force (180 N at 45º) was applied to the palatal surface of the central incisor. The periodontal ligament surface was constrained on the three axes (x=y=z=0). Maximum principal stress (σmax) values were evaluated for the root dentin, cement layer, and glass fiber post. Results: The most evident stress was observed in the glass fiber post at C3P1 (323 MPa), and the maximum stress in the cement layer occurred at C1P1 (43.2 MPa). The stress on the root dentin was almost constant in all models with a peak in tension at C2P1 (64.5 MPa). Conclusion The greatest discrepancy between root canal and post diameters is favorable for stress concentration at the post surface. The dentin remaining after the various root canal preparations did not increase the stress levels on the root. PMID:24473716

  4. 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.

  5. 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.

  6. [The radiation-increased synthesis of phytochelatins in roots of gamma-irradiated barley seedlings].

    PubMed

    Danilin, I A; Dikarev, V G; Geras'kin, S A

    2004-01-01

    It was shown that gamma-irradiation and cadmium nitrate increased synthesis of phytochelatins in roots of barley seedlings. The stimulation of synthesis of phytochelatins in gamma-irradiated plants was shown for the first time. The results obtained indicate more important role of phytochelatins in intercellular metabolism than heavy-metal-binding.

  7. Evaluating the Effect of CPP-ACP as a Final Irrigant in Improving the Micro-Hardness of Erosive Root Dentin and its Influence on the Bond Strength of Self Etch Resin Sealer – An In-vitro Study

    PubMed Central

    Bollineni, Swetha; Janga, Ravi Kumar; Saraswati, Disha; Babu, Mandava Ramesh

    2016-01-01

    Introduction Smear layer removal from the root canal wall involves the use of 17% EDTA and 5.25% sodium hypochlorite, which thereby improves the adhesion of obturating materials to root dentin. But these chemical irrigants have shown to decrease micro hardness, increase roughness, cause erosion and reduce the root dentin fracture toughness. To combat these adverse effects, studies can be focussed on the remineralisation of the erosive root dentin and this novel idea has been utilized in the present study. Aim To evaluate the micro hardness of erosive root dentin when Casein Phosphopeptide–Amorphous Calcium Phosphate (CPP-ACP) was used as a final irrigant and its influence on resin sealer bonding tested by push-out bond strength method. Materials and Methods Sixty extracted maxillary incisors were divided into three groups based on the final irrigation protocol. Group 1-normal saline, Group 2-17% EDTA (Ethylene Diamine Tetraacetic Acid) + 5.25% NaOCl (Sodium Hypochlorite), Group 3 - 17% EDTA + 5.25% NaOCl + CPP-ACP; each group was divided into two subgroups. Half the specimens of each group were evaluated for Vicker’s micro hardness test after the treatment. In continuation with the above methodology the remaining specimens were tested for push-out bond strength after obturation of the specimens with self etch adhesive resin sealer and conventional 6% gutta percha cones. Results Micro hardness was statistically analysed using Kruskal Wallis test and push-out bond strength was evaluated using Mann Whitney test and paired t-test. CPP-ACP treated group showed increased micro hardness (p<0.05). There was no statistically significant difference between the push-out bond strength values between group EDTA + NaOCl group and EDTA + NaOCl + CPP-ACP group. Conclusion Within the limitations of this study it can be concluded that, CPP-ACP improved the micro hardness of erosive root dentin and is not affecting its bond strength. Therefore, CPP-ACP may be used before bonding

  8. Dentinal Microcracks After Root Canal Preparation” A Comparative Evaluation with Hand, Rotary and Reciprocating Instrumentation

    PubMed Central

    Chandrasekhar, Veeramachaneni; Anita, S.; Tummala, Muralidhar; Raj, T.B. Phanindhar; Badami, Vijetha; Kumar, Pradeep; Soujanya, E.

    2014-01-01

    Introduction: The purpose of this study was to compare the incidence of dentinal micro cracks after instrumentation with various types of NiTi files in rotary and reciprocating motion. Materials and Methods: One hundred human extracted mandibular central incisors were taken and divided into 10 groups (n=10 teeth per group). Group 1- No preparation, Group 2 – Hand instrumentation, Groups 3,4 - ProTaper files in rotary and reciprocating motion, Groups 5,6 - ProTaper Next files in rotary and reciprocating motion, Groups 7,8 – Oneshape files in rotary and reciprocating motion, Groups 9,10 – Reciproc files in rotary and reciprocating motion. Specimens were sectioned horizontally at 3,6 and 9 mm from the apex and dentinal micro cracks were observed under a stereomicroscope. Results: There was a statistically significant difference between the groups (p<0.05). There were no significant differences in crack formation between the groups (Protaper Next - Rot, Protaper Next - Rec, Reciproc – Rec); (ProTaper - Rot, ProTaper - Rec, Oneshape – Rot), (Oneshape – Rot, Reciproc – Rot), (One shape Reciproc, Reciproc – Rec); (p >.05). Conclusion: Least cracks were seen in canals instrumented with Pro Taper Next files both in rotary and reciprocating motion. Full sequence rotary systems showed less cracks than single file systems and full sequence rotary systems showed less cracks in reciprocating motion than in rotary motion. PMID:25654036

  9. 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.

  10. Dentine hypersensitivity.

    PubMed

    West, Nicola; Seong, Joon; Davies, Maria

    2014-01-01

    Dentine hypersensitivity is a common oral pain condition affecting many individuals. The aetiology is multifactorial; however, over recent years the importance of erosion has become more evident. For dentine hypersensitivity to occur, the lesion must first be localised on the tooth surface and then initiated to exposed dentine tubules which are patent to the pulp. The short, sharp pain symptom is thought to be derived from the hydrodynamic pain theory and, although transient, is arresting, affecting quality of life. This episodic pain condition is likely to become a more frequent dental complaint in the future due to the increase in longevity of the dentition and the rise in tooth wear, particularly amongst young adults. Many efficacious treatment regimens are now available, in particular a number of over-the-counter home use products. The basic principles of treatment are altering fluid flow in the dentinal tubules with tubule occlusion or modifying or chemically blocking the pulpal nerve. PMID:24993261

  11. CO2 laser irradiation on vertical root fracture

    NASA Astrophysics Data System (ADS)

    da Silva, Luciana X.; Aun, Carlos E.; de Campos Ferraz, Jussara

    1997-05-01

    Vertical root fracture has been requested tooth extraction or root hemisection. There is no conservative treatment. The purpose of this paper was to analyze the CO2 laser effects on root fracture, associated with other materials. Forty two extracted human canines divided into 6 groups have their root vertically fractured. In groups A and B the CO2 laser was used with power of 5 W and 7 W respectively and the fracture line was covered with glass ionomer cement. In groups C and D the laser was used with 5 and 7 W and fracture line was covered with a dual composite. Groups E and F were controls, treated with glass ionomer cement and FLC dual composite. The teeth were placed in 5 percent methylene blue dye for 48 hs. The dye penetration was lowest in groups with glass ionomer cement and laser (A and B), at about (1.06mm). The difference between groups was statistically significant at 1 percent. All experimental groups showed dye penetration. The laser seemed to favor the sealing of the fracture line.

  12. Comparative evaluation of fracture resistance of root dentin to resin sealers and a MTA sealer: An in vitro study

    PubMed Central

    Mandava, Jyothi; Chang, Pin Chen; Roopesh, B; Faruddin, Md Ghazan; Anupreeta, A; Uma, Ch

    2014-01-01

    Background: Endodontic obturating materials should form monoblocks, reinforcing the treated teeth against fracture. Aim: To evaluate and compare the effect of two resin sealers and a MTA sealer on the fracture resistance of endodontically treated teeth. Materials and Methods: Fifty single-rooted mandibular premolars, decoronated at cemento-enamel junction, were divided into 5 groups (n = 10 each). Group 1 and group 2 served as negative and positive controls. Cleaning and shaping of root canals was done using ProTaper rotary files and 3% sodium hypochlorite irrigation. Obturation was done using AH plus (Dentsply, Germany) (group 3), MetaSEAL (Parkell, USA) (group 4), MTA Fillapex (Angeles, Brazil) (group 5) sealers and gutta-percha. Teeth were subjected to vertical loading using a universal testing machine and the point at which fracture of the roots occurred was recorded. The data was subjected to statistical analysis using one way analysis of variance (ANOVA) followed by pair-wise comparison using Tukey's Post-hoc test. Results: AH Plus showed better fracture resistance among the sealer groups. Statistically, no significant difference was found between MetaSEAL and Fillapex groups. Conclusion: MTA Fillapex as a root canal sealer was not able to reinforce the tooth against fracture. PMID:24554862

  13. Holmium:YAG laser: effects on dentin demineralization

    NASA Astrophysics Data System (ADS)

    Holt, Raleigh A.; Nordquist, Robert E.

    1995-05-01

    The Holmium:YAG laser at 2.12 microns wavelength was used to compare the changes in resistance to demineralization of the dentinal root surfaces of human extracted teeth in vitro. Three protocols were used: Group #1, and application of nonfilled resin/NaF (4%) solution followed by exposure with the Holmium:YAG laser beam; Group #2, an application of an aqueous solution of NaF (4%) only; and Group #3, irradiation with the laser beam only. The teeth were exposed on the root surfaces with untreated control and experimental sites on opposite sides of the teeth. A 3 mm spot size covered an area of 3 X 5 mm with 0.450 (+/- .05) joules at a fluence of 2.66 - 3.3 J/cm2. All teeth were decalcified in a 10% Formic acid solution for a timed period. Samples were prepared for staining by sectioning the teeth at the dentoenamel junction and 3 mm apically to produce a cross-section of each tooth root surface. Each sample was placed in toluidine blue dye to observe the depth of dye penetration into the dentin of treated and control sites. Toluidine blue dye showed a consistent greater depth of dye penetration into the dentinal areas of the untreated control sites versus the resin/NaF-lased group. The topical fluoride only group did not appear different than the untreated control sites of the teeth. The lased only group showed areas of dye penetration similar to the untreated control sides with other areas of little or no dye penetration. The finding that HO:YAG laser energy/chemical agent produced increased resistance to demineralization of dentinal surfaces in vitro suggested potential clinical applications of this combined modality.

  14. Role of surface tension and roughness on the wettability of Er:YAG laser irradiated dentin: In vitro study

    PubMed Central

    Brulat, Nathalie; Rocca, Jean-Paul; Darque-Ceretti, Evelyne

    2013-01-01

    Introduction: The aim of this “in vitro” study was to evaluate the role of surface tension and surface roughness in the wettability, considered essential for a good adhesion, comparing Er:YAG laser - to bur-prepared dentin. Materials and Methods: Dentin surfaces of third human molars were Er:YAG laser- and bur-prepared to evaluate the effects of surface tension and roughness on wettability and interferometric analysis was used to compare the roughness of the two groups surfaces, after gold-coating them. Results: In bur-prepared samples the time taken for the water drop to spread out was approximately the same with or without metallization while, in the Er:YAG laser-prepared surfaces the spreading-out time was less than 10 seconds but longer after metallization i.e. nearly two minutes. Large differences in wettability measurements were observed because the water drop was almost immediately absorbed on the Er:YAG laser-prepared surface. The wettability test demonstrated that the porous and hydrophilic properties of Er:YAG laser-prepared surfaces are higher than bur-prepared surfaces. Conclusion: Surface tension, surface morphology and porosity had different effects on the spreading time of a water drop on both Er:YAG laser- and bur-prepared surfaces. And, while surface tension does not seem to influence the results, roughness appears to be the main parameter involved in water drop spreading, this being an indication, by the clinical point of view, to the choice of Er:YAG laser parameters in conservative dentistry. PMID:24204092

  15. 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.

  16. Role of Dentin Compositional Changes and Structural Loss on Fracture Predilection in Endodontically Treated Teeth

    NASA Astrophysics Data System (ADS)

    Ossareh, Arezou

    The aim of this study was to examine the role of chemical compositional changes and iatrogenic dentin structural loss on the mechanical response of teeth to force and resistance to fracture. The experiments were divided into three phases. In phase 1, experimental studies were performed to evaluate the effect of chemicals used during treatment on ultrastructure, composition and resistance to fracture of dentin. In phase 2, experimental studies were used to evaluate the influence of dentin removal and remaining dentin volume on the resistance to fracture and microcrack formation in root dentin. In phase 3 finite element analysis was carried out to examine the influence of dentin loss on the stress distribution in root dentin. The combination of experimental and numerical analysis highlighted the role of remaining dentin volume and moment of inertia on root dentin biomechanics.

  17. Optical Spectroscopy Study of Transparent Non-Carious Human Dentin and Dentin-Enamel Junction

    SciTech Connect

    Marshall, G.W.; Marshall, S.J.; Gallagher, R.R.; Demos, S.

    1999-12-14

    Improving our knowledge of the morphology, composition and properties of the dentin, enamel, and the dentin-enamel junction (DEJ) is vital for the development of improved restorative materials and clinical placement techniques. Most studies of dental tissues have used light microscopy for characterization. In our investigation, the spectroscopic properties of normal and non-carious transparent human root dentin, and the dentin-enamel junction were investigated using emission imaging microscopy, and micro-spectroscopy. Experimental results reveal new information on the structural and biochemical characteristics of these dental tissues.

  18. Functional remineralization of carious dentin

    NASA Astrophysics Data System (ADS)

    Pugach, Megan Kardon

    A primary goal of dental tissue engineering is the biological reconstruction of tooth substrate destroyed by caries or other diseases affecting tooth mineralization. Traditionally, dentists treat caries by using invasive techniques to remove the diseased dental tissue and restore the lesion, ideally preventing further progression of decay. Success in strategies associated with remineralization of enamel and root caries have contributed to the less invasive prospect of remineralization of dentinal carious lesions. The central hypothesis of this dissertation is that carious dentin lesions can be remineralized if the lesions contain residual mineral. Caries Detector (CD) stained zones (pink, light pink, transparent and normal) of arrested carious dentin lesions were characterized according to microstructure by atomic force microscopy (AFM) imaging, mineral content by digital transverse microradiography, and nanomechanical properties by AFM-based nanoindentation. CD-stained and unstained zones had significantly different microstructure, mineral content and nanomechanical properties. Furthermore, the most demineralized carious zone contained residual mineral. To obtain reproducible, standardized dentin caries lesions, we characterized the lesions from an artificial carious dentin lesion model using a 0.05M acetate demineralization buffer. The artificial caries-like lesions produced by the buffer had similar mineral content and nanomechanical properties in the stained and unstained zones as natural dentin lesions. Both natural and artificial lesions had significant correlations between mineral content and nanomechanical properties. Mineral crystallite size and shape was examined by small angle x-ray scattering. Both natural and artificial carious dentin had different mineral sizes than normal dentin. Collagen in natural and artificial carious dentin lesions was examined by trichrome stain, AFM high-resolution imaging, and UV resonance Raman spectroscopy, to determine if

  19. Influence of instrumentation techniques and irrigating solutions on bond strength of glass fiber posts to root dentin.

    PubMed

    Marques, Eduardo Fernandes; Bueno, Carlos Eduardo da Silveira; Veloso, Heloisa Helena Pinho; Almeida, Gustavo; Pinheiro, Sergio Luiz

    2014-01-01

    This study sought to evaluate how instrumentation techniques and irrigating solutions affected the bond strength of glass fiber posts. For this study, 80 human maxillary central incisors were selected. Endodontic access was obtained, root canal length was measured, and the coronal third was prepared using Gates-Glidden drills. The specimens were embedded in acrylic resin and randomly assigned to 8 groups (n = 10): manual instrumentation only (Group 1), rotary instrumentation only (Group 2), irrigation with 2.5% sodium hypochlorite (NaOCl) (Group 3), irrigation with 2% chlorhexidine (CHX) (Group 4), manual instrumentation and irrigation with 2.5% NaOCl (Group 5), manual instrumentation and irrigation with 2% CHX (Group 6), rotary instrumentation and irrigation with 2.5% NaOCl (Group 7), and rotary instrumentation and irrigation with 2% CHX (Group 8). Specimens in Groups 5-8 also received a 1 minute final rinse with ethylenediaminetetraacetic acid. Canals were filled and the specimens stored for 30 days in distilled water. The restoration material was removed down to the apical 4 mm of the root canal. The glass fiber posts were luted with resin cement and stored for 24 hours at 37°C. Specimens were subjected to a tensile strength test at a constant speed of 1.0 mm/minute and a load of 2,000 kgf. The results were analyzed by analysis of variance and Tukey's test. Irrigation with 2.5% NaOCl reduced the bond strength of fiber posts significantly (P < 0.01), while CHX showed no effect (P > 0.05). It was concluded that irrigation with 2.5% NaOCl has a negative effect on micromechanical retention of glass fiber posts, whether manual or rotary instrumentation is used.

  20. Effect of light-curing units on push-out fiber post bond strength in root canal dentin

    NASA Astrophysics Data System (ADS)

    Calixto, L. R.; Bandéca, M. C.; Silva, F. B.; Rastelli, A. N. S.; Porto-Neto, S. T.; Andrade, M. F.

    2009-08-01

    The purpose of this study was to evaluate the effectiveness of different light-curing units on the bond strength (push-out) of glass fiber posts in the different thirds of the root (cervical, middle and apical) with different adhesive luting resin systems (dual-cure total-etch; dual-cured and self-etch bonding system; and dual-cure self-adhesive cements), Disks of the samples ( n = 144) were used, with approximately 1 mm of thickness of 48 bovine roots restored with glass fiber posts, that were luted with resin cements photo-activated by halogen LCU (QTH, Optilux 501) and blue LED (Ultraled), with power densities of 600 and 550 mW/cm2, respectively. A universal testing machine (MTS 810 Material Test System) was used with a 1 mm diameter steel rod at cross-head speed of 0.5 mm/min until post extrusion, with load cell of 50 kg, for evaluation of the push-out strength in the different thirds of each sample. The push-out strength values in kgf were converted to MPa and analyzed through Analysis of Variance and Tukey’s test, at significance level of 5%. The results showed that there were no statistical differences between the QTH and LED LCUs. The self-adhesive resin cement had lower values of retention. The total-etch and self-adhesive system resin cements seem to be a possible alternative for glass fiber posts cementation into the radicular canal and the LED LCU can be applied as an alternative to halogen light on photo-activation of dual-cured resin cements.

  1. Transmission electron microscopic characterization of hypersensitive human radicular dentin

    SciTech Connect

    Yoshiyama, M.; Noiri, Y.; Ozaki, K.; Uchida, A.; Ishikawa, Y.; Ishida, H. )

    1990-06-01

    Transmission electron microscopy (TEM) and x-ray microanalysis (XMA) were used for the study of the ultrastructure of the lumens of dentinal tubules in superficial layers of dentin specimens obtained by use of a new biopsy technique from both hypersensitive and naturally desensitized areas of exposed root surfaces, in vivo. The TEM images showed clearly that the lumens of most of the tubules were occluded with mineral crystals in naturally desensitized areas, but such lumens were empty and surrounded with peritubular and intertubular dentin in hypersensitive areas. Moreover, electron-dense structures that lined peritubular dentin were observed in the empty lumens of dentinal tubules.

  2. Invasion of dentinal tubules by oral bacteria.

    PubMed

    Love, R M; Jenkinson, H F

    2002-01-01

    Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics. PMID:12097359

  3. Comparing irradiation parameters on disinfecting enterrecoccus faecalis in root canal disinfection

    NASA Astrophysics Data System (ADS)

    Sarp, Ayşe. S.; Gülsoy, Murat

    2016-02-01

    Although conventional method carries all the debris, studies on persisting infections in root canals show bacteria and their toxins spread from the root canal and contaminate the apical region. Thus developes apical periodontitis or symptoms, and loss of tooth. Even if the treatment has adequate success, anatomy of root canal system can be very complexwith accessory canals. The disinfecting effect of laser radiation has only recently been used in dentistry. Laser irradiation has a bactericidal effect. Each wavelength has its own advantages and limitations according to their different absorption characteristics, depending on their 'absorption coefficient'. The sterilizing efficiency of two types of wavelengths, a new fiber laser 1940- nm Thulium fiber Laser and an 2940 nm Er:YAG Laser were compared in this study. Irradiation with a power of 0.50 W with 1940- nm Thulium fiber Laser disinfected 95,15% of bacteria, however irradiation with same laser power with Er:YAG Laser caused a reduction of 96,48 %. But there was no significant difference in the disinfection effect of two different laser groups ( p < 0.05, Mann- U-Whitney Test). In addition to this, Er :YAG Laser caused three times more reduction from its own positive control group where 1940- nm Thulium fiber Laser caused 2,5 times effective disinfection.

  4. Scanning ablation of root caries with acoustic feedback control

    NASA Astrophysics Data System (ADS)

    Fan, Kenneth; Fried, Daniel

    2007-02-01

    It has been previously demonstrated that short λ=355-nm laser pulses can be used for the selective removal of caries lesions and composite restorative materials from occlusal surfaces with minimal damage to the peripheral sound tooth structure. One advantage of laser-systems is they can be integrated with acoustic and optical feedback systems for the automated discrimination of dental caries and restorative materials. The objective of this study was to test the hypothesis that root caries could be selectively removed from tooth surfaces using a computer controlled laserscanning system coupled with an acoustic feedback system. Dental root caries surfaces on extracted teeth were scanned with λ=355-nm laser pulses at irradiation intensities ranging from 0.6 to 0.8 J/cm2. Acoustic feedback signals were acquired and used to control the laser output and scanning stages were used to position the laser over carious dentin until all the caries were removed to a fixed depth. Polarization optical coherence tomography (PSOCT) was used to acquire images of the root caries lesions before and after removal by the laser in order to assess if ablation was selective. The amplitude of the acoustic waves generated during the ablation of carious dentin was higher than for sound dentin allowing the acoustic feedback system to discriminate between sound and carious dentin. PS-OCT showed that caries were removed to a depth of up to 1.5-mm with minimal peripheral damage to peripheral sound dentin. The acoustic feedback was successfully used to distinguish between root caries and sound dentin, enabling the selective removal of caries from dentin surfaces using a λ=355-nm, Nd:YAG Q-switched laser system.

  5. A scanning electron microscopic study on the distribution of peritubular dentine in cheek teeth of Cervidae and Suidae (Mammalia, Artiodactyla).

    PubMed

    Kierdorf, H; Kierdorf, U

    1992-09-01

    Distribution of peritubular dentine was studied in cheek teeth of fallow deer (Dama dama), roe deer (Capreolus capreolus) and wild boar (Sus scrofa). In the two cervid species, especially intense peritubular dentine formation was found in the outer regions of mid and cuspal coronal dentine. In these areas a marked asymmetry occurred, peritubular dentine being predominantly secreted onto the side of the dentinal tubule walls nearest to the dentinoenamel junction. Intensity and asymmetry of peritubular dentine formation decreased cervically. In root dentine, the walls of the dentinal tubules were covered with only a thin peritubular dentine layer of even thickness. Here, in contrast to peripheral coronal dentine, the volume of intertubular dentine far exceeded that of peritubular dentine. In porcine coronal dentine, PTD asymmetry, being of lesser extent than in cervids, was observed only in peripheral areas of cuspal and flank regions of the cheek teeth. Because peritubular is more highly mineralized than intertubular dentine, the relative volume of dentine made up from the two components has an important influence on dentinal wear resistance. The significance of variations in volume and distribution of peritubular dentine between different dentinal regions for achieving and maintaining a functional occlusal surface is shown for cervid cheek teeth. Our results suggest that dentinal structure (in addition to enamel structure) should be taken more into consideration when discussing occlusal surface morphology in herbi- and omnivores from a functional point of view.

  6. In-vitro evaluation of adhesion to human dentine of different canal sealers after Er:YAG laser application

    NASA Astrophysics Data System (ADS)

    Sousa-Neto, Manoel D.; Marchesan, Melissa A.; Pecora, Jesus D.; Brugnera, Aldo, Jr.; Silva-Sousa, Yara T.; Saquy, Paulo C.

    2000-03-01

    Adhesion of endodontic sealers to root canal walls is a property material must have to promote a hermetic seal of the root canal. The present study evaluates the effect of Er:YAG laser applied to human dentine in vitro on adhesion of Grossman, Endomethasone, N-Rickert and Sealer 26 root canal sealers. The crowns of 40 human molars were cut on the occlusal side until a flat dentine surface was obtained. The teeth were divided into 2 groups: group 1, saline solution; group 2, irradiation with Er:YAG laser (KaVo Key Laser 2; 11 mm focal distance, perpendicular to the dentine surface, 4 Hz frequency, 200 mJ energy, 62 J total energy and 313 pulses, one minute application time and 2.25 W power). Five repetitions were done for each sealer and each group. An Instron universal testing machine was used for the adhesion test.The results showed a statistically significant difference at 1% for the sealers and the dentine surface treatments. Sealer 26 showed the best adhesion both with laser application and saline. Application of Er:YAG laser did not alter the adhesion of Grossman, N-Rickert or Endomethasone sealers compared to saline; however, laser application increased the adhesion of Sealer 26.

  7. Comparison of tensile bond strengths of four one-bottle self-etching adhesive systems with Er:YAG laser-irradiated dentin.

    PubMed

    Jiang, Qianzhou; Chen, Minle; Ding, Jiangfeng

    2013-12-01

    This study aimed to investigate the interaction of current one-bottle self-etching adhesives and Er:YAG laser with dentin using a tensile bond strength (TBS) test and scanning electron microscopy (SEM) in vitro. Two hundred and thirteen dentin discs were randomly distributed to the Control Group using bur cutting and to the Laser Group using an Er:YAG laser (200 mJ, VSP, 20 Hz). The following adhesives were investigated: one two-step total-etch adhesive [Prime & Bond NT (Dentsply)] and four one-step self-etch adhesives [G-Bond plus (GC), XENO V (Dentsply), iBond Self Etch (Heraeus) and Adper Easy One (3 M ESPE)]. Samples were restored with composite resin, and after 24-hour storage in distilled water, subjected to the TBS test. For morphological analysis, 12 dentin specimens were prepared for SEM. No significant differences were found between the control group and laser group (p = 0.899); dentin subjected to Prime & Bond NT, XENOV and Adper Easy One produced higher TBS. In conclusion, this study indicates that Er:YAG laser-prepared dentin can perform as well as bur on TBS, and some of the one-step one-bottle adhesives are comparable to the total-etch adhesives in TBS on dentin.

  8. Induction of micronuclei in germinating onion seed root tip cells irradiated with high energy heavy ions.

    PubMed

    Takatsuji, Toshihiro; Takayanagi, Hiroki; Morishita, Kana; Nojima, Kumie; Furusawa, Yoshiya; Nakazawa, Yuka; Matsuse, Michiko; Akamatsu, Sakura; Hirano, Natsuko; Hirashima, Natsuko; Hotokezaka, Saori; Ijichi, Toyomi; Kakimoto, Chika; Kanemaru, Tomomi; Koshitake, Mayumi; Moriuchi, Akiko; Yamamoto, Kensuke; Yoshikawa, Isao

    2010-01-01

    Effects of high LET charged particles on a perfect in-vivo system are an essential theme for the study of the biological effects of radiation. Germinating onion seeds are independent complete organisms and the radiation induced micronuclei in the root chip cells can be examined quantitatively and theoretically. We irradiated with three types of high energy accelerated heavy ions germinating onion seeds using a synchrotron and observed micronuclei in the root tip cells. Micronuclei induction showed characteristic dose responses of an upward convex bell shape and a steep rise near zero doses for all types of the ions. The bell curve dose responses, however, could be explained by a simple mathematical model. A parameter in the model which indicates micronuclei induction frequency and another parameter which indicates induction frequency of lethal damages (or damages delaying cell divisions) per heavy ion track were both proportional to square of the LET. Because we suspected by-stander effect concerning the dose responses rising steeply near zero doses and tapering off for higher doses, we tested acute irradiation to remove time of information transmittance between cells using a single spill (about 0.3 s) of the synchrotron beam. No difference was detected between normal multiple spill irradiations and single spill.

  9. Antimicrobial effect of Er:YAG laser irradiation in infected root canals: an in vitro study

    NASA Astrophysics Data System (ADS)

    Sampaio Moura, Marcelo; Zanin, Fatima A. A.; Brugnera, Aldo, Jr.; Rodrigues de Araujo Estrela, Cyntia; Estrela, Carlos; Djalma Pecora, Jesus

    2003-06-01

    This study evaluated in vitro the antimicrobial action of Er:YAG laser in infected root canals. A total of 36 human anterior teeth were prepared, sterilized and inoculated with suspensions of S. aureus, E. faecalis, P aeruginosa, B. subtilis and C. albicans. After the contamination period (28 days), the teeth were irrigated with sterile distilled water or 1% sodium hypochlorite and, then, irradiated with an Er:YAG laser (wavelength 2094 nm) with two different evaluation parameters: 52 mJ and 110 mJ laser output at the fiber tip. After the irradiation, the teeth were irrigated with sterile distilled water and the solutions were collected with sterile paper points and incubated in Letheen Broth for 48 hours. After this period 0,1 ml of this solution was transferred to 10 ml of Brain Heart Infusion and incubated for 48 hours. After 72 hours a new collect ion was done and incubated again. Based on the data, it was concluded that the distilled water or 1% sodium hypochlorite irradiated or not with an Er:YAG laser with two different parameters: 10 Hz, 110 mJ input and 52 mJ output, and 10 Hz, 250 mJ input and 110 mJ output had no antimicrobial activity in the root canals contaminated with the following microorganisms: Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Candida albicans.

  10. A histochemical study of the regeneration process after injury by pulsed Nd:YAG laser irradiation of root canals.

    PubMed

    Murakami, Yoshiko; Unno, Arine; Kimura, Yuichi; Okano, Tomohiro; Hossain, Mozammal; Nakamura, Yukio; Matsumoto, Koukichi

    2002-01-01

    Histological changes of rat dental pulp cells were followed after injury. The regeneration process after 3, 6 and 10 days was monitored. Mandibular incisors were irradiated with a pulsed Nd:YAG laser at 2 W and 20 pulses per sec (pps) for 5 sec and the pulp was examined histologically and immunohistochemically for TGF-beta1. Eruption of the developing tooth was disturbed for a short period only. Rapid formation of osteodentin was observed. After 3 days, a zone of fibrodentin matrix as well as newly formed vessels were found. Afterwards, regenerative dentin formation was observed accompanied by the formation of a layer of odontoblast-like cells in the damaged area. Immunohistochemical staining of TGF-beta1 showed that positivity was present in small tissue areas beneath the mantle dentin, the zone of fibrodentin matrix and odontoblast-like cells. These results indicate that pulsed Nd:YAG laser irradiation of rat incisor pulp induces formation of osteodentin, and TGF-beta1 plays a role during regeneration. PMID:12086333

  11. Evaluation of absorbed dose in irradiated sugar-containing plant material (peony roots) by an ESR method

    NASA Astrophysics Data System (ADS)

    Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

    2015-12-01

    The relationship between electron spin resonance (ESR) signal intensity of irradiated plant materials and sugar content was investigated by spectral analysis using peony roots. A weak background signal near g=2.005 was observed in the roots. After a 10 kGy irradiation, the ESR line broadened and the intensity increased, and the spectral characteristics were similar to a typical spectrum of irradiated food containing crystalline sugars. The free radical concentration was nearly stable 30 days after irradiation. The spectrum of peony root 30 days after irradiation was simulated using the summation of the intensities of six assumed components: radical signals derived from (a) sucrose, (b) glucose, (c) fructose, (d) cellulose, (e) the background signal near g=2.005 and (f) unidentified component. The simulated spectra using the six components were in agreement with the observed sample spectra. The intensity of sucrose radical signal in irradiated samples increased proportionally up to 20 kGy. In addition, the intensity of sucrose radical signals was strongly correlated with the sucrose contents of the samples. The results showed that the radiation sensitivity of sucrose in peony roots was influenced little by other plant constituents. There was also a good correlation between the total area of the spectra and the sucrose content, because the sucrose content was higher than that of other sugars in the samples. In peony roots, estimation of the absorbed dose from the ESR signal intensity may be possible by a calibration method based on the sucrose content.

  12. A novel type of developmental dentin defect.

    PubMed

    Lukinmaa, P L; Waltimo, J; Hölttä, P; Risteli, L; Risteli, J; Alaluusua, S

    1996-01-01

    We describe a developmental dentin disorder distinct from dentin defects characterized thus far. The proband was a 9-year-old boy who was the only family member known to be affected in five generations. The dental defect was not associated with any general disease or developmental disorder. The teeth appeared normal with the exception of the pink hue seen in some primary teeth. Radiographs showed pathological resorption of primary teeth and abnormally shaped pulp chambers and denticles in permanent teeth. Root canals were wide in developing teeth, but appeared thin in erupted teeth. Histological examination of two primary molars revealed canal-like defects in dentin. In the crown, the canals appeared as clusters, which alternated with columns of normal tubular dentin, and in the virtually atubular root dentin they were haphazardly distributed. Scanning electron microscopic examination confirmed the distribution pattern of the canals. In transmission electron microscopy, the defects were found to contain symmetrically banded, segmental collagenous structures. The canal contents immunostained with antibodies to the N-terminal propeptide of type I procollagen, suggesting retention of the propeptide extension in type I collagen. Whereas type III collagen reactivity was barely detectable in the canal region, staining for type V collagen and the non-fibril-forming type VI collagen was strong. The findings imply that the pathogenesis of the defect could be related to a local failure of odontoblasts to produce normal dentin matrix.

  13. Effects of root planing procedures with hand instrument or erbium, chromium:yttrium-scandium-gallium-garnet laser irradiation on the root surfaces: a comparative scanning electron microscopy study.

    PubMed

    Hakki, Sema S; Berk, Gizem; Dundar, Niyazi; Saglam, Mehmet; Berk, Nukhet

    2010-05-01

    The purpose of this study was to investigate the efficiency of hand instrumentation and laser irradiation on calculus removal from the root surfaces, in vitro. Thirty-two human teeth, extracted for periodontal reasons, were used in this study. Root surfaces of single-rooted teeth were treated by different methods including (1) conventional hand instruments; (2) hand instruments and tetracycline-hydrochloride (Tet-HCl); (3) erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation, setting I (short pulse); (4) Er,Cr:YSGG laser irradiation, setting II (long pulse). Three premolar teeth, extracted for orthodontic reasons, served as control. The morphology of the root surfaces was evaluated by light and scanning electron microscopy. Energy dispersive X-ray (EDX) analysis was performed to compare the mineral content of root surfaces treated with hand instrumentation and lasing procedures. The results of this study demonstrated that all treatments were efficient in calculus removal from the root surfaces. Thermal changes, including melting and carbonization, were not observed in either lasing procedure. The surface was rougher in the laser groups than in the groups treated with hand instruments. Moreover, roughness was greater in the long-pulse laser setting than in the short-pulse setting. While increased calcium (Ca) and decreased phosphate (P) (weight concentration percent) were observed in all treatments when compared with the control, laser procedures resulted in a more similar mineral content than in the groups treated with hand instruments. Based on these findings, laser procedures, when used in appropriate settings, are capable of performing scaling and root planing in the treatment of periodontitis. It may be concluded that short pulse laser may be more suitable for the micro-morphology of the root surface. However, additional in vitro and clinical studies are necessary to clarify the success of laser in periodontal therapy. PMID:19219484

  14. 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

  15. 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.

  16. Photodynamically crosslinked and chitosan-incorporated dentin collagen.

    PubMed

    Shrestha, A; Friedman, S; Kishen, A

    2011-11-01

    A lingering concern with restored root-filled teeth is the loss of structural integrity of the dentin and dentin-sealer interface over time. We hypothesized that crosslinking of dentin collagen with simultaneous incorporation of a biopolymer into collagen matrix would improve its structural stability. This study aimed to investigate the effects of combining chemical/photodynamic crosslinking of dentin collagen with the incorporation of carboxymethyl-chitosan (CMCS) on the resistance to enzymatic degradation and mechanical properties of dentin collagen. Ninety-six demineralized dentin collagen specimens (human, n = 72; and bovine, n = 24) were prepared and crosslinked chemically/ photodynamically, with/without CMCS. Glutaraldehyde and carbodiimides were used for chemical crosslinking, while rose Bengal activated with a non-coherent light (540 nm) at 20 J/cm(2) was applied for photodynamic crosslinking. The crosslinked human dentin collagen was subjected to chemical characterization, 7 days enzymatic degradation, and transmission electron microscopy (TEM), while the bovine dentin collagen was used for tensile-testing. Crosslinked collagen showed significantly higher resistance to enzymatic degradation (p < 0.01), stable ultrastructure, and increased tensile strength (p < 0.05). Crosslinking CMCS with collagen matrix as observed in the TEM further improved the mechanical properties of dentin collagen (p < 0.01). This study highlighted the possibility of improving the resistance and toughness of dentin collagen by chemically/photodynamically crosslinking collagen matrix with CMCS.

  17. Innervation of different parts of the predentin and dentin in young human premolars.

    PubMed

    Lilja, J

    1979-01-01

    The innervation of the predentin and inner part of the mineralized dentin was studied at the ultrastructural level in ten premolars. Each tooth was divided into fifteen different parts, each containing odontoblasts, predentin and dentin. It was found that the innervation in the coronal dentin was more compact than in the root dentin. Within the coronal dentin itself, the most densely innervated area was the dentin covering the pulp horns. No nerves were identified more than 100 microns from the pulp-dentinal border. No nervous structures were found in the mineralized dentin of the root. Nervous structures which seemed to have no connection with the odontoblastic processes were frequently observed in the predentin of the root. Signs of degeneration of the nervous structures of the predentin of the root was also a common finding. The observation that the intradentinal nerves were confined to the predentin and the most pulpal part of the dentin supports the theory that surface stimulation on dentin has an indirect effect on the nerves activated by movements in the liquid of the dentinal tubules.

  18. Dentin matrix protein 1 and phosphate homeostasis are critical for postnatal pulp, dentin and enamel formation.

    PubMed

    Rangiani, Afsaneh; Cao, Zheng-Guo; Liu, Ying; Voisey Rodgers, Anika; Jiang, Yong; Qin, Chun-Lin; Feng, Jian-Quan

    2012-12-01

    Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate (Pi) or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmp1-null (Dmp1(-/-)), Klotho-deficient (kl/kl), Dmp1/Klotho-double-deficient (Dmp1(-/-)/kl/kl) and wild-type (WT) mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography (μCT), scanning electron microscopy (SEM), histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmp1(-/-) (a low Pi level) or kl/kl (a high Pi level) mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice (a high Pi level) displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment (a high Pi level).

  19. 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

  20. Morphological Changes of Human Dentin after Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) and Carbon Dioxide (CO2) Laser Irradiation and Acid-etch Technique: An Scanning Electron Microscopic (SEM) Evaluation

    PubMed Central

    Shahabi, Sima; Chiniforush, Nasim; Juybanpoor, Nasrin

    2013-01-01

    Introduction: The aim of this study was to investigate the morphological changes of human dentin after Erbium-Doped Yttrium Aluminum Garnet (Er:YAG), Carbon Dioxide(CO2) laser-irradiation and acid-etching by means of scanning electron microscopic (SEM) Methods: 9 extracted human third molars were used in this study. The teeth were divided in three groups: first group, CO2 laser with power of 1.5 w and frequency of 80 Hz; second group, Er:YAG laser with output power of 1.5 W frequency of 10 Hz, very short pulse with water and air spray was applied; and third group, samples were prepared by acid-etching 37% for 15 sec and rinsed with air-water spray for 20 sec. Then, the samples were prepared for SEM examination. Results: Melting and cracks can be observed in CO2 laser but in Er:YAG laser cleanedablated surfaces and exposed dentinal tubules, without smear layer was seen. Conclusion: It can be concluded that Er:YAG laser can be an alternative technique for surface treatment and can be considered as safe as the conventional methods. But CO2 laser has some thermal side effects which make this device unsuitable for this purpose. PMID:25606306

  1. Soluble carbohydrate allocation to roots, photosynthetic rate of leaves, and nitrate assimilation as affected by nitrogen stress and irradiance

    NASA Technical Reports Server (NTRS)

    Henry, L. T.; Raper, C. D. Jr

    1991-01-01

    Upon resupply of exogenous nitrogen to nitrogen-stressed plants, uptake rate of nitrogen is enhanced relative to nonstressed plants. Absorption of nitrogen presumably is dependent on availability of carbohydrates in the roots. A buildup in soluble carbohydrates thus should occur in roots of nitrogen-stressed plants, and upon resupply of exogenous nitrogen the increased uptake rate should be accompanied by a rapid decline in carbohydrates to prestress levels. To evaluate this relationship, three sets of tobacco plants growing in a complete hydroponic solution containing 1.0 mM NO3- were either continued in the complete solution for 21 d, transferred to a minus-nitrogen solution for 21 d, or transferred to a minus-nitrogen solution for 8-9 d and then returned to the 1.0 mM NO3- solution. These nitrogen treatments were imposed upon plants growing at photosynthetic photon flux densities of 700 and 350 micromoles m-2 s-1. Soluble carbohydrate levels in roots increased during onset of nitrogen stress to levels that were fourfold greater than in roots of non-stressed plants. Following resupply of external nitrogen, a rapid resumption of nitrogen uptake was accompanied by a decline in soluble carbohydrates in roots to levels characteristic of nonstressed plants. This pattern of soluble carbohydrate levels in roots during onset of and recovery from nitrogen stress occurred at both irradiance levels. The response of net photosynthetic rate to nitrogen stress could be expressed as a nonlinear function of concentration of reduced nitrogen in leaves. The net photosynthetic rate at a given concentration of reduced nitrogen, however, averaged 10% less at the lower than at the higher irradiance. The decline in net photosynthetic rate per unit of reduced nitrogen in leaves at the lower irradiance was accompanied by an increase in the nitrate fraction of total nitrogen in leaves from 20% at the higher irradiance to 38% at the lower irradiance.

  2. Soluble carbohydrate allocation to roots, photosynthetic rate of leaves, and nitrate assimilation as affected by nitrogen stress and irradiance.

    PubMed

    Henry, L T; Raper, C D

    1991-03-01

    Upon resupply of exogenous nitrogen to nitrogen-stressed plants, uptake rate of nitrogen is enhanced relative to nonstressed plants. Absorption of nitrogen presumably is dependent on availability of carbohydrates in the roots. A buildup in soluble carbohydrates thus should occur in roots of nitrogen-stressed plants, and upon resupply of exogenous nitrogen the increased uptake rate should be accompanied by a rapid decline in carbohydrates to prestress levels. To evaluate this relationship, three sets of tobacco plants growing in a complete hydroponic solution containing 1.0 mM NO3- were either continued in the complete solution for 21 d, transferred to a minus-nitrogen solution for 21 d, or transferred to a minus-nitrogen solution for 8-9 d and then returned to the 1.0 mM NO3- solution. These nitrogen treatments were imposed upon plants growing at photosynthetic photon flux densities of 700 and 350 micromoles m-2 s-1. Soluble carbohydrate levels in roots increased during onset of nitrogen stress to levels that were fourfold greater than in roots of non-stressed plants. Following resupply of external nitrogen, a rapid resumption of nitrogen uptake was accompanied by a decline in soluble carbohydrates in roots to levels characteristic of nonstressed plants. This pattern of soluble carbohydrate levels in roots during onset of and recovery from nitrogen stress occurred at both irradiance levels. The response of net photosynthetic rate to nitrogen stress could be expressed as a nonlinear function of concentration of reduced nitrogen in leaves. The net photosynthetic rate at a given concentration of reduced nitrogen, however, averaged 10% less at the lower than at the higher irradiance. The decline in net photosynthetic rate per unit of reduced nitrogen in leaves at the lower irradiance was accompanied by an increase in the nitrate fraction of total nitrogen in leaves from 20% at the higher irradiance to 38% at the lower irradiance.

  3. [SEM investigations on the human sclerosed dentinal tubules].

    PubMed

    Yagi, T; Suga, S

    1990-08-01

    Sclerotic changes of dentinal tubules appeared in the dentin beneath the carious, attrition and abrasion lesions and in the transparent root dentin were investigated using the scanning electron microscopy. 1) Shape of crystal-like substances appeared in the dentinal tubules could not be closely related to kinds of dentin destruction. 2) In the dentinal tubules beneath the carious lesions, cuboidal or rhomboid-shaped, short rod-like, long rod-like, plate-like and droplet-like crystals were mainly observed. Combination of cuboidal or rhomboid-shaped and short rod-like crystals or that of long rod-like and plate-like crystals were most frequently observed. 3) In the dentinal tubules beneath attrition and abrasion lesions, cuboidal or rhomboid-shaped, short rod-like and droplet-like crystals were mainly observed, however, the size of cuboidal or rhomboid-shaped crystal was usually smaller than that observed beneath carious lesion and they deposited compactly within the tubules. 4) In the sclerosed dentinal tubules in the transparent root dentin, compact deposition of rhomboid-shaped and irregular sand-like crystals were usually observed. Size of rhomboid-shaped crystal is smaller than that observed beneath carious lesion. The deposit of sand-like crystal in the tubules was easily discriminated from the matrix of peritubular dentin. 5) In any case, the kinds of crystals and pattern of deposition were not necessarily same between the neighboring tubules. However, in a tubule, they were almost same in shape and mode of deposition throughout the entire length of tubule from the outer side to the pulpal side. These facts seem to indicate that mineral deposition within the tubule due to sclerosis is performed under individual condition. 6) Finding showing biological control of mineral deposition within the dentinal tubules by the odontoblasts could not be observed.

  4. Comparison of Push-out Bond Strength of Gutta-percha to Root Canal Dentin in Single-cone and Cold Lateral Compaction Techniques with AH Plus Sealer in Mandibular Premolars.

    PubMed

    Mokhtari, Hadi; Rahimi, Saeed; Forough Reyhani, Mohammad; Galledar, Saeedeh; Mokhtari Zonouzi, Hamid Reza

    2015-01-01

    Background and aims. The single-cone technique has gained some popularity in some European countries. The aim of the present study was to compare the push-out bond strength of gutta-percha to root canal dentin with the single-cone and cold lateral compaction canal obturation techniques. Materials and methods . The root canals of 58 human mandibular premolars were prepared using modified crown-down technique with ProTaper rotary files up to #F3as a master apical file (MAF) and divided randomly into groups A and B based on canal obturation technique. In group A (n = 29) the root canals were obturated with single-cone technique with #F3(30/.09) ProTaper gutta-percha, which was matched with MAF in relation to diameter, taper and manufacturer; in group B (n = 29) the canals were obturated with gutta-percha using cold lateral compaction technique. In both groups AH plus sealer were used. After two weeks of incubation, three 2-mm slices were prepared at a distance of 2 mm from the coronal surface and push-out test was carried out. Data were analyzed with descriptive statistics using independent samples t-test. Results. There were statistically significant differences between two groups. The mean push-out bond strength was higher in group B (lateral compaction technique) compared to group A (single-cone technique; P < 0.05). Conclusion . Use of single-cone technique for obturation of root canals resulted in a lower bond strength compared to cold lateral compaction technique.

  5. Comparison of Push-out Bond Strength of Gutta-percha to Root Canal Dentin in Single-cone and Cold Lateral Compaction Techniques with AH Plus Sealer in Mandibular Premolars

    PubMed Central

    Mokhtari, Hadi; Rahimi, Saeed; Forough Reyhani, Mohammad; Galledar, Saeedeh; Mokhtari Zonouzi, Hamid Reza

    2015-01-01

    Background and aims. The single-cone technique has gained some popularity in some European countries. The aim of the present study was to compare the push-out bond strength of gutta-percha to root canal dentin with the single-cone and cold lateral compaction canal obturation techniques. Materials and methods. The root canals of 58 human mandibular premolars were prepared using modified crown-down technique with ProTaper rotary files up to #F3as a master apical file (MAF) and divided randomly into groups A and B based on canal obturation technique. In group A (n = 29) the root canals were obturated with single-cone technique with #F3(30/.09) ProTaper gutta-percha, which was matched with MAF in relation to diameter, taper and manufacturer; in group B (n = 29) the canals were obturated with gutta-percha using cold lateral compaction technique. In both groups AH plus sealer were used. After two weeks of incubation, three 2-mm slices were prepared at a distance of 2 mm from the coronal surface and push-out test was carried out. Data were analyzed with descriptive statistics using independent samples t-test. Results. There were statistically significant differences between two groups. The mean push-out bond strength was higher in group B (lateral compaction technique) compared to group A (single-cone technique; P < 0.05). Conclusion. Use of single-cone technique for obturation of root canals resulted in a lower bond strength compared to cold lateral compaction technique. PMID:26889358

  6. Intrapulpal temperature changes during root surface irradiation with dual-wavelength laser (2780 and 940 nm): in vitro study

    NASA Astrophysics Data System (ADS)

    Franzen, Rene; Rashidisangsary, Borna; Ozturan, Seda; Vanweersch, Leon; Gutknecht, Norbert

    2015-01-01

    The present study evaluated the intrapulpal thermal changes that occurred during the treatment of the root surfaces with a laser system emitting Er,Cr:YSGG 2780- and 940-nm diode laser irradiation in an alternating sequence. Thirty single-rooted human teeth were collected. The teeth were divided into three groups (n=10 each) and irradiated with Er,Cr:YSGG alone or combined with a 940-nm diode laser. To investigate the intrapulpal temperature changes, specimens were embedded in a resin block with a set of thermocouples introduced at different positions within the root canals. The first group was irradiated with only Er,Cr:YSGG (25 mJ, 50 Hz, 50 μs pulse duration, water and air spray); the second group was irradiated with Er,Cr:YSGG (same setting) and a 940-nm diode (2 W, chopped mode with 20% duty cycle); the third group was irradiated with Er,Cr:YSGG (same setting) and a diode (2 W, chopped mode with 50% duty cycle). During all irradiations, thermal changes were recorded in real time with thermocouples. While group 3 showed thermal rises on average of 1.68±0.98°C in the pulp chamber, groups 1 and 2 showed average temperature rises of <0.5°C. The combined laser emission of 2780 and 940 nm is a promising way for root surface debridement without inducing intrapulpal thermal damage when using an appropriate water/air spray. All measured temperatures were considerably below the critical value of 5.6°C.

  7. Biomimetic remineralization of dentin

    PubMed Central

    Niu, Li-na; Zhang, Wei; Pashley, David H.; Breschi, Lorenzo; Mao, Jing; Chen, Ji-hua; Tay, Franklin R.

    2013-01-01

    Objectives Remineralization of demineralized dentin is important for improving dentin bonding stability and controlling primary and secondary caries. Nevertheless, conventional dentin remineralization strategy is not suitable for remineralizing completely-demineralized dentin within hybrid layers created by etch-and-rinse and moderately aggressive self-etch adhesive systems, or the superficial part of a caries-affected dentin lesion left behind after minimally invasive caries removal. Biomimetic remineralization represents a different approach to this problem by attempting to backfill the demineralized dentin collagen with liquid-like amorphous calcium phosphate nanoprecursor particles that are stabilized by biomimetic analogs of noncollagenous proteins. Methods This paper reviewed the changing concepts in calcium phosphate mineralization of fibrillar collagen, including the recently discovered, non-classical particle-based crystallization concept, formation of polymer-induced liquid- precursors (PILP), experimental collagen models for mineralization, and the need for using phosphate-containing biomimetic analogs for biomimetic mineralization of collagen. Published work on the remineralization of resin-dentin bonds and artificial caries-like lesions by various research groups was then reviewed. Finally, the problems and progress associated with the translation of a scientifically-sound concept into a clinically-applicable approach are discussed. Results and Significance The particle-based biomimetic remineralization strategy based on the PILP process demonstrates great potential in remineralizing faulty hybrid layers or caries-like dentin. Based on this concept, research in the development of more clinically feasible dentin remineralization strategy, such as incorporating poly(anionic) acid-stabilized amorphous calcium phosphate nanoprecursor-containing mesoporous silica nanofillers in dentin adhesives, may provide a promising strategy for increasing of the

  8. Disorders of human dentin.

    PubMed

    Hart, P Suzanne; Hart, Thomas C

    2007-01-01

    Dentin, the most abundant tissue in teeth, is produced by odontoblasts, which differentiate from mesenchymal cells of the dental papilla. Dentinogenesis is a highly controlled process that results in the conversion of unmineralized predentin to mineralized dentin. By weight, 70% of the dentin matrix is mineralized, while the organic phase accounts for 20% and water constitutes the remaining 10%. Type I collagen is the primary component (>85%) of the organic portion of dentin. The non-collagenous part of the organic matrix is composed of various proteins, with dentin phosphoprotein predominating, accounting for about 50% of the non-collagenous part. Dentin defects are broadly classified into two major types: dentinogenesis imperfectas (DIs, types I-III) and dentin dysplasias (DDs, types I and II). To date, mutations in DSPP have been found to underlie the dentin disorders DI types II and III and DD type II. With the elucidation of the underlying genetic mechanisms has come the realization that the clinical characteristics associated with DSPP mutations appear to represent a continuum of phenotypes. Thus, these disorders should likely be called DSPP-associated dentin defects, with DD type II representing the mild end of the phenotypic spectrum and DI type III representing the severe end.

  9. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation. PMID:27652705

  10. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

  11. Comprehensive analyses of how tubule occlusion and advanced glycation end-products diminish strength of aged dentin

    PubMed Central

    Shinno, Yuko; Ishimoto, Takuya; Saito, Mitsuru; Uemura, Reo; Arino, Masumi; Marumo, Keishi; Nakano, Takayoshi; Hayashi, Mikako

    2016-01-01

    In clinical dentistry, since fracture is a major cause of tooth loss, better understanding of mechanical properties of teeth structures is important. Dentin, the major hard tissue of teeth, has similar composition to bone. In this study, we investigated the mechanical properties of human dentin not only in terms of mineral density but also using structural and quality parameters as recently accepted in evaluating bone strength. Aged crown and root dentin (age ≥ 40) exhibited significantly lower flexural strength and toughness than young dentin (age < 40). Aged dentin, in which the dentinal tubules were occluded with calcified material, recorded the highest mineral density; but showed significantly lower flexural strength than young dentin. Dentin with strong alignment of the c-axis in hydroxyapatite exhibited high fracture strength, possibly because the aligned apatite along the collagen fibrils may reinforce the intertubular dentin. Aged dentin, showing a high advanced glycation end-products (AGEs) level in its collagen, recorded low flexural strength. We first comprehensively identified significant factors, which affected the inferior mechanical properties of aged dentin. The low mechanical strength of aged dentin is caused by the high mineral density resulting from occlusion of dentinal tubules and accumulation of AGEs in dentin collagen. PMID:26797297

  12. On the repair of the dentine barrier.

    PubMed

    Fransson, Helena

    2012-01-01

    The overall aim of this thesis was to study some aspects of the repair of the dentine barrier, especially in conjunction with dental pulp capping. Understanding the events leading to the healing of the dentine and pulp, and hence successfully preserving the vitality and functions of the tooth, would lead to a scientific basis for a less invasive treatment of pulp exposures than performing root canal treatments. The surfaces of the body have physiological barrier functions aimed at protecting the body from external noxious agents. In the tooth, the odontoblasts, which line the outermost part of the pulp and are responsible for the formation of dentine, play a central role in the barrier function and thus in the defence mechanisms of the tooth. The micro-organisms in the caries lesion can reach the pulp via the dentinal tubules. However, the barrier function helps to prevent microbial invasion and thereby avoid deleterious inflammation and subsequent necrosis of the pulp. Dentine repair is an important part of the barrier function. There are however doubts as to whether the repair also leads to restitution of the function and the ability to withstand bacterial influx over the longer term. Pulp capping is a treatment method used when the pulp has been exposed in order to stimulate healing of the pulp and dentine. The evidence for repair of the dentine after pulp capping in humans has been studied by means of a systematic review. The focus of the literature search was studies performed in humans where hard tissue formation had been studied with the aid of a microscope. We concluded, based on the limited evidence available, that calcium hydroxide based materials but not bonding agents promote formation of a hard tissue bridge. Scientific evidence was lacking as to whether MTA was better than calcium hydroxide based materials in this regard. A gel (Emdogain Gel) containing amelogenin, known to be involved in dentinogenesis, was evaluated with regard to formation of hard

  13. Irradiation effects on color and functional properties of persimmon ( Diospyros kaki L. folium) leaf extract and licorice ( Glycyrrhiza Uralensis Fischer) root extract during storage

    NASA Astrophysics Data System (ADS)

    Jo, Cheorun; Son, Jun Ho; Shin, Myung Gon; Byun, Myung Woo

    2003-06-01

    Irradiation effects on color and functional properties of persimmon ( Diospyros kaki L. folium) leaf extract and licorice ( Glycyrrhiza Uralensis Fischer) root extract were studied. Persimmon leaf and licorice root extracts were irradiated using 60Co gamma irradiator at 0 and 20 kGy absorbed dose and stored at 4°C or -20°C for 2 weeks. Tyrosinase inhibition effect (TIE) of both extracts was not different by 20 kGy-irradiation but reduced during storage. Electron donating ability (EDA) of the persimmon leaf extract was generally consistent, but that of licorice root extract was reduced by irradiation except for 1 week of storage. Both TIE and EDA of persimmon leaf extract were higher than that of licorice root. Hunter color L*-, a*-, and b*-values were changed, resulting in a desirable brighter color by irradiation. During storage, the bright yellow color of irradiated sample changed to brown gradually, and especially the changes in the refrigeration condition (4°C) was faster than frozen (-20°C). Results indicate that irradiation can be a useful method to produce value-added natural ingredients with functions such as persimmon leaf or licorice root for food or cosmetic industry in addition to elimination of microbial load.

  14. Effects of Er:YAG and Nd:YAG laser irradiation on the permeability of instrumented root canal walls

    NASA Astrophysics Data System (ADS)

    Brugnera, Aldo, Jr.; Zanin, Fatima A. A.; Barbin, Eduardo L.; Emboava Spano, Julio C.; Santana da Silva, Reginaldo; Pecora, Jesus D.

    2002-06-01

    The aim of this study was to evaluate the effect of Er:YAG and Nd:YAG laser on radicular dentine permeability when using distilled and deionized water and 1% sodium hypochlorite as irrigating solutions. Thirty human maxillary canines obtained from laboratory stock and conserved in 0.1% thymol until use were divided randomly into six groups of five teeth each. The root canals were instrumented with K files and the step-back technique. The surgical diameter was achieved 4 files above the original anatomical diameter. Group I, the teeth were irrigated with distilled and deionized water; Group II, the teeth were irrigated with 1% sodium hypochlorite, Group II the teeth were irrigated with distilled and deionized water and then Er:YAG laser was applied with 140mJ, 15Hz, 300 pulses and 42J; group 4 the teeth were irrigated with 1% sodium hypochlorite and Er:YAG laser was applied in the same parameters as Group III, Group V, the teeth received irrigation with distilled and deionized water and Nd:YAG laser application with 150mJ, 15Hz, 2,25W and Group VI the teeth were irrigated with 1% sodium hypochlorite and Nd:YAG laser was applied with the same parameters as Group V. During laser application the teeth were always filled with irrigating solution. The fiber optic tip was introduced until the apex and the laser was activated. The tip was withdrawn gently with helicoidally movement from the apex until the pulp chamber. After preparation the teeth were immersed in 10% copper sulfate for 30 minutes, in vacuum for the first 5 minutes. The teeth were then placed in a 1% rubianic acid alcohol solution for the same periodsin solution and in vacuum as above. Upon completion of this reaction the teeth were sectioned transversally, in 150micrometers slices, and sanded, washed, dehydrated, cleared and mounted on glass slides for microscopic examination. The quantification of the penetration of copper ions was done by morphmetric analysis with a 400-point grid. The data was submitted

  15. Histological and SEM analysis of root cementum following irradiation with Er:YAG and CO2 lasers.

    PubMed

    Almehdi, Aslam; Aoki, Akira; Ichinose, Shizuko; Taniguchi, Yoichi; Sasaki, Katia M; Ejiri, Kenichiro; Sawabe, Masanori; Chui, Chanthoeun; Katagiri, Sayaka; Izumi, Yuichi

    2013-01-01

    Recently, the Er:YAG and CO(2) lasers have been applied in periodontal therapy. However, the characteristics of laser-irradiated root cementum have not been fully analyzed. The aim of this study was to precisely analyze the alterations of root cementum treated with the Er:YAG and the CO(2) lasers, using non-decalcified thin histological sections. Eleven cementum plates were prepared from extracted human teeth. Pulsed Er:YAG laser contact irradiation was performed in a line at 40 mJ/pulse (14.2 J/cm(2)/pulse) and 25 Hz (1.0 W) under water spray. Continuous CO(2) laser irradiation was performed in non-contact mode at 1.0 W, and ultrasonic instrumentation was performed as a control. The treated samples were subjected to stereomicroscopy, scanning electron microscopy (SEM), light microscopy and SEM energy dispersive X-ray spectroscopy (SEM-EDS). The Er:YAG laser-treated cementum showed minimal alteration with a whitish, slightly ablated surface, whereas CO(2) laser treatment resulted in distinct carbonization. SEM analysis revealed characteristic micro-irregularities of the Er:YAG-lased surface and the melted, resolidified appearance surrounded by major and microcracks of the CO(2)-lased surface. Histological analysis revealed minimal thermal alteration and structural degradation of the Er:YAG laser-irradiated cementum with an affected layer of approximately 20-μm thickness, which partially consisted of two distinct affected layers. The CO(2)-lased cementum revealed multiple affected layers showing different structures/staining with approximately 140 μm thickness. Er:YAG laser irradiation used with water cooling resulted in minimal cementum ablation and thermal changes with a characteristic microstructure of the superficial layer. In contrast, CO(2) laser irradiation produced severely affected distinct multiple layers accompanied by melting and carbonization.

  16. Histological and SEM analysis of root cementum following irradiation with Er:YAG and CO2 lasers.

    PubMed

    Almehdi, Aslam; Aoki, Akira; Ichinose, Shizuko; Taniguchi, Yoichi; Sasaki, Katia M; Ejiri, Kenichiro; Sawabe, Masanori; Chui, Chanthoeun; Katagiri, Sayaka; Izumi, Yuichi

    2013-01-01

    Recently, the Er:YAG and CO(2) lasers have been applied in periodontal therapy. However, the characteristics of laser-irradiated root cementum have not been fully analyzed. The aim of this study was to precisely analyze the alterations of root cementum treated with the Er:YAG and the CO(2) lasers, using non-decalcified thin histological sections. Eleven cementum plates were prepared from extracted human teeth. Pulsed Er:YAG laser contact irradiation was performed in a line at 40 mJ/pulse (14.2 J/cm(2)/pulse) and 25 Hz (1.0 W) under water spray. Continuous CO(2) laser irradiation was performed in non-contact mode at 1.0 W, and ultrasonic instrumentation was performed as a control. The treated samples were subjected to stereomicroscopy, scanning electron microscopy (SEM), light microscopy and SEM energy dispersive X-ray spectroscopy (SEM-EDS). The Er:YAG laser-treated cementum showed minimal alteration with a whitish, slightly ablated surface, whereas CO(2) laser treatment resulted in distinct carbonization. SEM analysis revealed characteristic micro-irregularities of the Er:YAG-lased surface and the melted, resolidified appearance surrounded by major and microcracks of the CO(2)-lased surface. Histological analysis revealed minimal thermal alteration and structural degradation of the Er:YAG laser-irradiated cementum with an affected layer of approximately 20-μm thickness, which partially consisted of two distinct affected layers. The CO(2)-lased cementum revealed multiple affected layers showing different structures/staining with approximately 140 μm thickness. Er:YAG laser irradiation used with water cooling resulted in minimal cementum ablation and thermal changes with a characteristic microstructure of the superficial layer. In contrast, CO(2) laser irradiation produced severely affected distinct multiple layers accompanied by melting and carbonization. PMID:22580557

  17. Dentin sialophosphoprotein in biomineralization.

    PubMed

    Prasad, Monica; Butler, William T; Qin, Chunlin

    2010-10-01

    Two of the proteins found in significant quantity in the extracellular matrix (ECM) of dentin are dentin phosphoprotein (DPP) and dentin sialoprotein (DSP). DPP, the most abundant of the noncollagenous proteins (NCPs) in dentin is an unusually polyanionic protein, containing a large number of aspartic acids (Asp) and phosphoserines (Pse) in the repeating sequences of (Asp-Pse)(n). and (Asp-Pse-Pse)(n). The many negatively charged regions of DPP are thought to promote mineralization by binding calcium and presenting it to collagen fibers at the mineralization front during the formation of dentin. This purported role of DPP is supported by a sizeable pool of in vitro mineralization data showing that DPP is an important initiator and modulator for the formation and growth of hydroxyapatite (HA) crystals. Quite differently, DSP is a glycoprotein, with little or no phosphate. DPP and DSP are the cleavage products of dentin sialophosphoprotein (DSPP). Human and mouse genetic studies have demonstrated that mutations in, or knockout of, the Dspp gene result in mineralization defects in dentin and/or bone. The discoveries in the past 40 years with regard to DPP, DSP, and DSPP have greatly enhanced our understanding of biomineralization and set a new stage for future studies. In this review, we summarize the important and new developments made in the past four decades regarding the structure and regulation of the Dspp gene, the biochemical characteristics of DSPP, DPP, and DSP as well as the cell/tissue localizations and functions of these molecules.

  18. Treatment of dentin hypersensitivity.

    PubMed

    Trushkowsky, Richard D; Oquendo, Anabella

    2011-07-01

    Dentinal hypersensitivity is exemplified by brief, sharp, well-localized pain in response to thermal, evaporative, tactile, osmotic, or chemical stimuli that cannot be ascribed to any other form of dental defect or pathology. Pulpal pain is usually more prolonged, dull, aching, and poorly localized and lasts longer than the applied stimulus. Up to 30% of adults have dentinal hypersensitivity at some time. Current techniques for treatment may be only transient in nature and results are not always predictable. Two methods of treatment of dentin hypersensitivity are tubular occlusion and blockage of nerve activity. A differential diagnosis needs to be accomplished before any treatment. PMID:21726693

  19. 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

  20. Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems.

    PubMed

    Cabanillas, Cristina; Monterde, Manuel; Pallarés, Antonio; Aranda, Susana; Montes, Raquel

    2015-01-01

    Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests. Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, a p value of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p < 0.05). Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences. PMID:26664361

  1. Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems

    PubMed Central

    Cabanillas, Cristina; Monterde, Manuel; Pallarés, Antonio; Aranda, Susana; Montes, Raquel

    2015-01-01

    Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests. Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, a p value of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p < 0.05). Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences. PMID:26664361

  2. Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems.

    PubMed

    Cabanillas, Cristina; Monterde, Manuel; Pallarés, Antonio; Aranda, Susana; Montes, Raquel

    2015-01-01

    Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests. Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, a p value of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p < 0.05). Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences.

  3. Effect of delayed light curing of a resin composite on marginal integrity in cylindrical dentine cavities.

    PubMed

    Manabe, A; Debari, K; Itoh, K; Hisamitsu, H; Wakumoto, S

    1993-12-01

    The effect of delayed light curing of resin composite on marginal adaptation has been examined by measuring the wall-to-wall polymerization contraction gap when using a commercial resin composite together with experimental dentine bonding systems to restore cylindrical preparations in dentine. Morphological changes in dentine during dentine bonding procedures were observed using a scanning electron microscope. In a previous report, the contraction gap width for a resin composite increased when irradiation of the resin system was delayed, despite the use of a dentine bonding system considered to be 'contraction' gap free. Such deterioration in marginal adaptation was minimized by use of an experimental dentine primer, 40% erythritol methacrylate aqueous solution (EM), followed by the use of a commercial dual- or autocured dentine bonding agent. Under scanning electron microscopy, the dentine surface microstructure became unclear after EM priming, and a polymer film was detected after polymerization of the dual-cured dentine bonding agent. The hydrogelled primer and the formation of a polymer network on the dentine surface may prevent the flow of fluid from the pulp through the dentine tubules, and maintain marginal integrity if there is delay in light curing of light-activated resin composite systems.

  4. Combating photooxidative stress in green hairy roots of Daucus carota cultivated under light irradiation.

    PubMed

    Mukherjee, Chiranjit; Sircar, Debabrata; Chatterjee, Moniya; Das, Sampa; Mitra, Adinpunya

    2014-01-15

    The light-dependent generation of active oxygen species, which can disrupt normal metabolic process of plant, is termed as photo-oxidative stress. Plants are equipped with enzymatic and non-enzymatic antioxidative defence system to reduce the effect of such stress. Hairy root culture of Daucus carota when cultivated under continuous illumination (250 μmol m(-2)s(-1)) turned green. To know the reason behind that and photo-oxidative stress response in green hairy roots, activities of several antioxidant enzymes were measured. When compared with normal hairy roots, green hairy roots showed an enhanced superoxide dismutase (SOD) activity. Treatment with a SOD inhibitor diethyldithiocarbamate led to suppression of SOD activity in a concentration-dependent manner in green hairy roots. Interestingly, SOD-suppressed root showed three-fold enhanced caffeic acid glucoside accumulation in the soluble fraction as compared to untreated ones. While ascorbate peroxidase activity showed marginal increase in green hairy roots, a decrease in the activities of guaiacol peroxidase and catalase were observed. SDS-PAGE of crude protein profile from green hairy roots showed a distinct band, which was absent in normal hairy roots. MALDI-TOF-MS/MS analysis of the extracted protein confirmed it as the large subunit of RuBisCO. RT-PCR based expression analysis of betaine aldehyde dehydrogenase showed enhanced transcript levels in green hairy roots as compared to normal hairy roots, whereas reverse trends were observed with the transcripts accumulation for phenylalanine ammonia-lyase and chalcone synthase. These findings corroborate with the in vitro BADH activities in hairy roots, and thus indicate an important role of this stress enzyme in combating photo-oxidative stress in green hairy roots upon continuous light exposure.

  5. Residual Dentin Thickness of Bifurcated Maxillary Premolars Following Two Post Space Preparation Methods

    PubMed Central

    Ghoddusi, Jamileh; Bagherpour, Ali; Mahmudabadi, Fatemeh; Forghani, Maryam; Sarmad, Majid

    2013-01-01

    Introduction The aim of this in vitro study was to compare the effect of Gates-Glidden and Peeso reamer drills on residual dentin thickness during post space preparation in order to discover which method has minimum root structure damage. Materials and Methods Thirty extracted human maxillary premolars with bifurcations at root middle were horizontally cut 15 mm coronal to the apical end after root canal treatment. The samples were scannedby Cone Beam Computed Tomography (CBCT) before and after preparing the post space. Residual dentin thicknesses were measured at 4-, 6-, and 8-mm levels from the apex. Data were analyzed using repeated measured ANOVA. Results Endodontic therapy and post space preparations removed more dentin within the bifurcation of both roots compared to outer dentin. The difference in residual dentin thickness was highly significant regarding stage (before and after post space preparation) in all levels and stage × device in coronal and middle levels (P<.05). This in vitro study emphasizes the minimal dentin width in the buccal root of maxillary premolars, especially near the bifurcation. Conclusion Lack of adequate residual dentin thickness after post space preparation implies that the use of posts in maxillary first premolars should be limited. When mandatory, it is recommended that post space be prepared with Gates-Glidden drill in the palatal root of maxillary first premolars and use of Peeso reamer be avoided. PMID:23922568

  6. Frameshift mutations in dentin phosphoprotein and dependence of dentin disease phenotype on mutation location.

    PubMed

    Nieminen, Pekka; Papagiannoulis-Lascarides, Lisa; Waltimo-Siren, Janna; Ollila, Päivi; Karjalainen, Sara; Arte, Sirpa; Veerkamp, Jaap; Tallon Walton, Victoria; Chimenos Küstner, Eduard; Siltanen, Tarja; Holappa, Heidi; Lukinmaa, Pirjo-Liisa; Alaluusua, Satu

    2011-04-01

    We describe results from a mutational analysis of the region of the dentin sialophosphoprotein (DSPP) gene encoding dentin phosphoprotein (DPP) in 12 families with dominantly inherited dentin diseases. In eight families (five mutations in the N-terminal third of DPP), the clinical and radiologic features were uniform and compatible with dentin dysplasia type II (DD-II) with major clinical signs in the deciduous dentition. In the other families (four mutations in the more C-terminal part), the permanent teeth also were affected, and the diseases could be classified as variants of dentinogenesis imperfecta. Attrition was not prominent, but periapical infections were common. Discoloring with varying intensity was evident, and pulps and root canals were obliterated in the permanent dentition. All mutations caused a frameshift that replaced the Ser-Ser-Asx repeat by a code for a hydrophobic downstream sequence of approximately original length. We conclude that frameshift mutations in DSPP explain a significant part of dentin diseases. Furthermore, we propose that the location of the mutation is reflected in the phenotypic features as a gradient from DD-II to more severe disease that does not conform to the classic definitions of DI-II. PMID:20949630

  7. Frameshift mutations in dentin phosphoprotein and dependence of dentin disease phenotype on mutation location.

    PubMed

    Nieminen, Pekka; Papagiannoulis-Lascarides, Lisa; Waltimo-Siren, Janna; Ollila, Päivi; Karjalainen, Sara; Arte, Sirpa; Veerkamp, Jaap; Tallon Walton, Victoria; Chimenos Küstner, Eduard; Siltanen, Tarja; Holappa, Heidi; Lukinmaa, Pirjo-Liisa; Alaluusua, Satu

    2011-04-01

    We describe results from a mutational analysis of the region of the dentin sialophosphoprotein (DSPP) gene encoding dentin phosphoprotein (DPP) in 12 families with dominantly inherited dentin diseases. In eight families (five mutations in the N-terminal third of DPP), the clinical and radiologic features were uniform and compatible with dentin dysplasia type II (DD-II) with major clinical signs in the deciduous dentition. In the other families (four mutations in the more C-terminal part), the permanent teeth also were affected, and the diseases could be classified as variants of dentinogenesis imperfecta. Attrition was not prominent, but periapical infections were common. Discoloring with varying intensity was evident, and pulps and root canals were obliterated in the permanent dentition. All mutations caused a frameshift that replaced the Ser-Ser-Asx repeat by a code for a hydrophobic downstream sequence of approximately original length. We conclude that frameshift mutations in DSPP explain a significant part of dentin diseases. Furthermore, we propose that the location of the mutation is reflected in the phenotypic features as a gradient from DD-II to more severe disease that does not conform to the classic definitions of DI-II.

  8. Effects of CO2 laser irradiation on tooth-root cementum.

    PubMed

    Lee, C Q; Lemire, D H; Cobb, C M

    1997-01-01

    With the aging of the American population and the endemic problem of gingival recession, patients will inevitably suffer from greater exposure of root surfaces and therefore will be more likely to develop root caries. The treatment of root caries is often frustrating. Traditional biomaterials used for the restoration of enamel caries have been less than satisfactory when margins of a cavity are adjacent to cementum. Although topical fluoride gels, toothpastes, and rinses have been used to prevent or to inhibit the development of root caries, there is a problem of access to the proximal surfaces. Consequently, the development of better methods to facilitate the prevention of root caries has become an important issue in dentistry.

  9. Penetration of smeared or nonsmeared dentine by Streptococcus gordonii.

    PubMed

    Love, R M; Chandler, N P; Jenkinson, H F

    1996-01-01

    The purpose of this study was to investigate the penetration of smeared and nonsmeared dentine by Streptococcus gordonii. Prepared human roots, grouped as either nonsmeared or smeared, were immersed in a suspension of S. gordonii cells for 3 weeks. The roots were then prepared for scanning electron microscopy and histological analysis. Dentine discs prepared from coronal dentine were grouped similarly. Using a fluid filtration apparatus, the hydraulic conductance (Lp) of each disc was determined before and after incubation with bacterial suspension. Scanning electron microscopy evaluation of the roots following infection with bacteria showed no change in the smear layer (P < 0.0001). Histological sections revealed that bacterial penetration of all the nonsmeared samples had occurred, while nine out of 10 smeared samples showed no bacterial penetration (P < 0.0001). The Lp of the nonsmeared discs was significantly reduced by 42% (P < 0.0001) after bacterial penetration. However, the smeared samples revealed a 1% reduction in Lp which was not significant (P > 0.05). The results suggest that dentinal smear layers are an effective barrier to dentinal tubule invasion by S. gordonii. PMID:9206406

  10. Dentin Caries Zones

    PubMed Central

    Pugach, M.K.; Strother, J.; Darling, C.L.; Fried, D.; Gansky, S.A.; Marshall, S.J.; Marshall, G.W.

    2009-01-01

    Caries Detector staining reveals 4 zones in dentin containing caries lesions, but characteristics of each zone are not well-defined. We therefore investigated the physical and microstructural properties of carious dentin in the 4 different zones to determine important differences revealed by Caries Detector staining. Six arrested dentin caries lesions and 2 normal controls were Caries-Detector-stained, each zone (pink, light pink, transparent, apparently normal) being analyzed by atomic force microscopy (AFM) imaging for microstructure, by AFM nano-indentation for mechanical properties, and by transverse digital microradiography (TMR) for mineral content. Microstructure changes, and nanomechanical properties and mineral content significantly decreased across zones. Hydrated elastic modulus and mineral content from normal dentin to pink Caries-Detector-stained dentin ranged from 19.5 [10.6-25.3] GPa to 1.6 [0.0-5.0] GPa and from 42.9 [39.8-44.6] vol% to 12.4 [9.1-14.2] vol%, respectively. Even the most demineralized pink zone contained considerable residual mineral. PMID:19131321

  11. CO2 laser and fluoride on the inhibition of root caries—an in vitro microbial model

    NASA Astrophysics Data System (ADS)

    Steiner-Oliveira, C.; Rodrigues, L. K. A.; Parisotto, T. M.; Sousa E Silva, C. M.; Hara, A. T.; Nobre-Dos-Santos, M.

    2010-09-01

    An increase in the dental caries prevalence on root surfaces has been observed mainly in elderly. This research assessed, in vitro, the effectiveness of a pulsed CO2 (λ = 10.6 μm) laser associated or not with fluoride, in reducing human root dentine demineralization in conditions that mimic an oral high cariogenic challenge. After sterilization, root dentine specimens were randomly assigned into 6 groups ( n = 30), in triplicate. The groups were Control (C), Streptococcus mutans (SM), Fluoride (F), Laser (L), Fluoride + laser (FL), and Laser + fluoride (LF). Except for the control group, all the specimens were inoculated with SM and immersed 3 times a day in a 40% sucrose bath. After a 7-day cariogenic challenge, the mineral loss and lesion depth were evaluated by transverse microradiography and fluoride in the biofilm was determined using an ion-selective electrode. Results were statistically analyzed by analysis of variance, at 5% of significance level. For groups C, SM, F, L, FL and LF, the means (standard-deviation) of mineral loss were 816.3 (552.5)a, 3291.5 (1476.2)c, 2508.5 (1240.5)bc, 2916.2 (1323.7)c, 1839.7 (815.2)b and 1955.0 (1001.4)b, respectively; while lesion depths were 39.6 (22.8)a, 103.1 (38.9)c, 90.3 (44.6)bc, 91.7 (27.0)bc, 73.3 (26.6)b, 75.1 (35.2)b, respectively (different superscript letters indicate significant differences among groups). In conclusion, irradiation of root dentine with a pulsed CO2 laser at fluency of 12.0 J/cm2 was able to inhibit root surface demineralization only when associated with fluoride. No synergy effect on the inhibition of root dentine mineral loss was provided by the combination of fluoride application and laser irradiation.

  12. Dentin sialoprotein and dentin phosphoprotein have distinct roles in dentin mineralization.

    PubMed

    Suzuki, Shigeki; Sreenath, Taduru; Haruyama, Naoto; Honeycutt, Cherlita; Terse, Anita; Cho, Andrew; Kohler, Thomas; Müller, Ralph; Goldberg, Michel; Kulkarni, Ashok B

    2009-05-01

    Dentin sialophosphoprotein (DSPP), a major non-collagenous matrix protein of odontoblasts, is proteolytically cleaved into dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Our previous studies revealed that DSPP null mice display a phenotype similar to human autosomal dominant dentinogenesis imperfecta, in which teeth have widened predentin and irregular dentin mineralization resulting in sporadic unmineralized areas in dentin and frequent pulp exposure. Earlier in vitro studies suggested that DPP, but not DSP, plays a significant role in initiation and maturation of dentin mineralization. However, the precise in vivo roles of DSP and DPP are far from clear. Here we report the generation of DPPcKO mice, in which only DSP is expressed in a DSPP null background, resulting in a conditional DPP knockout. DPPcKO teeth show a partial rescue of the DSPP null phenotype with the restored predentin width, an absence of irregular unmineralized areas in dentin, and less frequent pulp exposure. Micro-computed tomography (micro-CT) analysis of DPPcKO molars further confirmed this partial rescue with a significant recovery in the dentin volume, but not in the dentin mineral density. These results indicate distinct roles of DSP and DPP in dentin mineralization, with DSP regulating initiation of dentin mineralization, and DPP being involved in the maturation of mineralized dentin.

  13. Resin–Dentin Bonding Interface After Photochemical Surface Treatment

    PubMed Central

    Sano, Kazunobu; Ichinose, Shizuko; Araki, Kouji

    2015-01-01

    Abstract Objective The aim of this study is to elucidate the structure of the resin–dentin interface formed by photochemical dentin treatment using an argon fluoride (ArF) excimer laser. Background data The ArF excimer laser processes material by photochemical reaction without generating heat, while also providing surface conditioning that enhances material adhesion. In the case of bonding between resin and dentin, we demonstrated in a previous study that laser etching using an ArF excimer laser produced bonding strength comparable to that of the traditional bonding process; however, conditions of the bonding interface have not been fully investigated. Methods A dentin surface was irradiated in air with an ArF excimer laser followed by bonding treatment. Cross sections were observed under light microscope, transmission electron microscope (TEM), and scanning electron microscope, then analyzed using an energy dispersive X-ray spectroscope (EDS): EDS line profiles of the elements C, O, Si, Cl, P, and Ca at the resin–dentin interface were obtained. Results The density of C in resin decreased as it approached the interface, reaching its lowest level within the dentin at a depth of 2 μm from the resin–dentin interface on EDS. There was no hybrid layer observed at the interface on TEM. Therefore, it was suggested that the resin monomer infiltrated into the microspaces produced on the dentin surface by laser abrasion. Conclusions The monomer infiltration without hybrid layer is thought to be the adhesion mechanism after laser etching. Therefore, the photochemical processes at the bonding interface achieved using the ArF excimer laser has great potential to be developed into a new bonding system in dentistry. PMID:25555032

  14. Morphometric analysis of root canal cleaning after rotary instrumentation with or without laser irradiation

    NASA Astrophysics Data System (ADS)

    Marchesan, Melissa A.; Geurisoli, Danilo M. Z.; Brugnera, Aldo, Jr.; Barbin, Eduardo L.; Pecora, Jesus D.

    2002-06-01

    The present study examined root canal cleaning, using the optic microscope, after rotary instrumentation with ProFile.04 with or without laser application with different output energies. Cleaning and shaping can be accomplished manually, with ultra-sonic and sub-sonic devices, with rotary instruments and recently, increasing development in laser radiation has shown promising results for disinfection and smear layer removal. In this study, 30 palatal maxillary molar roots were examined using an optic microscope after rotary instrumentation with ProFile .04 with or without Er:YAG laser application (KaVo KeyLaser II, Germany) with different output energies (2940 nm, 15 Hz, 300 pulses, 500 milli-sec duration, 42 J, 140 mJ showed on the display- input, 61 mJ at fiberoptic tip-output and 140 mJ showed on the display-input and 51 mJ at fiberoptic tip-output). Statistical analysis showed no statistical differences between the tested treatments (ANOVA, p>0.05). ANOVA also showed a statistically significant difference (p<0.01) between the root canal thirds, indicating that the middle third had less debris than the apical third. We conclude that: 1) none of the tested treatments led to totally cleaned root canals; 2) all treatments removed debris similarly, 3) the middle third had less debris than the apical third; 4) variation in output energy did not increase cleaning.

  15. Investigation of Er:YAG laser root canal irradiation using en face OCT

    NASA Astrophysics Data System (ADS)

    Todea, Carmen; Balabuc, Cosmin; Filip, Laura; Calniceanu, Mircea; Bradu, Adrian; Hughes, Michael; Podoleanu, Adrian G.

    2009-07-01

    This pilot study was designed to investigate the quality of endodontic treatment performed with/without Er:YAG laser using en-face Optical Coherence Tomography (OCT) prototype which evinced the presence of voids and microleakage within the root canal.

  16. Possible role of dentin matrix in region-specific deposition of cellular and acellular extrinsic fibre cementum.

    PubMed

    Takano, Yoshiro; Sakai, Hideo; Watanabe, Eiko; Ideguchi-Ohma, Noriko; Jayawardena, Chantha K; Arai, Kazumi; Asawa, Yukiyo; Nakano, Yukiko; Shuda, Yoko; Sakamoto, Yujiro; Terashima, Tatsuo

    2003-01-01

    The mechanism whereby a region-specific deposition of the two types of cementum (cellular cementum and acellular extrinsic fibre cementum) is regulated on the growing root surface was tested using bisphosphonate-affected teeth of young rats and guinea pigs. The animals were injected subcutaneously with 8 or 10 mg P x kg body weight(-1) x day(-1) of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 1 or 2 weeks. In rat molars, HEBP prevented mineralization of newly formed root dentin matrix and totally inhibited de novo deposition of acellular extrinsic fibre cementum. Instead, thick cellular cementum was induced on the non-mineralized root dentin surface, irrespective of the position of the root. In both animals, cellular cementum was also induced on the non-mineralized surface of root analogue dentin in HEBP-affected incisors, where only acellular extrinsic fibre cementum is deposited under normal conditions. In normal rat molars, dentin sialoprotein (DSP) was concentrated along the dentin-cellular cementum border, but not that of dentin and acellular extrinsic fibre cementum. In HEBP-affected rat incisors, DSP was shown to penetrate through the non-mineralized dentin into the surrounding tissues, but not through the mineralized portions. These data suggest that, at the site of cellular cementum formation, putative inducing factors for cellular cementum might diffuse into the periodontal space through the newly deposited mantle dentin matrix before it is mineralized. At earlier stages of root formation, mantle dentin might mineralize more promptly not to allow such diffusion. The timing of mineralization of mantle dentin matrix might be the key determinant of the types of the cementum deposited on the growing root surface. PMID:14756246

  17. Orthodontic force accelerates dentine mineralization during tooth development in juvenile rats.

    PubMed

    Kong, Xiangwei; Cao, Meng; Ye, Ruidong; Ding, Yin

    2010-08-01

    Malocclusion, the improper positioning of the teeth and jaws, is among the most important global oral health burdens. People with malocclusion may require orthodontic treatment to correct the problem. Orthodontic treatment is a way of straightening or moving teeth, to improve the appearance of the teeth and how they work. It is generally best carried out in children aged 9 to 12 years, whose teeth are mainly young permanent teeth with incomplete root formation. However, the relationship between orthodontic force and tooth development has not been fully understood. In this study, we sought to investigate the effects of orthodontic force on dentine formation and mineralization during the development of young permanent teeth. Standardized orthodontic tooth movement was performed with the orthodontic appliance in five-week-old rats. To obtain longitudinal assessment of dentine formation, tetracycline was administered on the operation day and 1, 3, 7, 14 or 21 days afterward. We found that the distance between two tetracycline stripes, which indicates the amount of dentine formation during orthodontic treatment, increased with time. Importantly, no significant difference was detected in dentine formation between treated and control rats. In contrast, immunohistochemical analysis showed that the expression of dentin sialoprotein, a marker of odontoblast differentiation and mineral apposition, was significantly elevated in crown and root dentine after orthodontic treatment. In conclusion, orthodontic treatment does not affect the dentine formation of young permanent teeth, but it promotes the activation of odontoblasts and accelerates the dentine mineralization. These results suggest the safety of early orthodontic treatment.

  18. 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

  19. Efficacy of different treatments of root canal walls on the pull-out bond strength of the fiber posts.

    PubMed

    Arslan, Hakan; Yılmaz, Cenk Burak; Karatas, Ertugrul; Barutcigil, Cagatay; Topcuoglu, Hüseyin Sinan; Yeter, Kübra Yesildal

    2015-02-01

    The aim of this study was to evaluate the efficacy of different irrigation protocols, including laser, on the retention of the fiber-reinforced composite posts to root canal dentinal walls using pull-out tests. Root canals of 60 single-rooted human teeth were filled and post spaces were prepared. Finally, specimens were divided randomly into five groups, each consisting of 12 specimens as follows: 5% NaOCl (control group), 17% EDTA, ultrasonic with 17% EDTA, single 1.5-W Er:YAG laser application, and the combined use of Er:YAG laser and 17% EDTA. After the root canal procedures, fiber posts were cemented to the root canal. Pull-out tests were performed using a universal testing machine at a crosshead speed of 2 mm/min. The data were analyzed using a one-way ANOVA and Bonferroni post hoc test (p = 0.05). Irradiation by the Er:YAG laser with/without EDTA positively affected the pull-out bond strength (p < 0.001). The pull-out strength was significantly higher in the ultrasonic group than that of the single irrigation with NaOCl or EDTA (p < 0.001). Er:YAG laser irradiation with/without EDTA enhanced the bond strength of fiber posts to root canal dentin walls. Additionally, ultrasonic-EDTA combination increased the bond strength.

  20. Dentin Hypersensitivity and Oxalates

    PubMed Central

    Cunha-Cruz, J.; Stout, J.R.; Heaton, L.J.; Wataha, J.C.

    2011-01-01

    Treatment of dentin hypersensitivity with oxalates is common, but oxalate efficacy remains unclear. Our objective was to systematically review clinical trials reporting an oxalate treatment compared with no treatment or placebo with a dentin hypersensitivity outcome. Risk-of-bias assessment and data extraction were performed independently by two reviewers. Standardized mean differences (SMD) were estimated by random-effects meta-analysis. Of 677 unique citations, 12 studies with high risk-of-bias were included. The summary SMD for 3% monohydrogen-monopotassium oxalate (n = 8 studies) was -0.71 [95% Confidence Interval: -1.48, 0.06]. Other treatments, including 30% dipotassium oxalate (n = 1), 30% dipotassium oxalate plus 3% monohydrogen monopotassium oxalate (n = 3), 6% monohydrogen monopotassium oxalate (n = 1), 6.8% ferric oxalate (n = 1), and oxalate-containing resin (n = 1), also were not statistically significantly different from placebo treatments. With the possible exception of 3% monohydrogen monopotassium oxalate, available evidence currently does not support the recommendation of dentin hypersensitivity treatment with oxalates. PMID:21191127

  1. Immunohistochemical localization of dentin matrix protein 1 in human dentin.

    PubMed

    Orsini, G; Ruggeri, A; Mazzoni, A; Nato, F; Falconi, M; Putignano, A; Di Lenarda, R; Nanci, A; Breschi, L

    2008-01-01

    Dentin matrix protein 1 (DMP1) is a non-collagenous matrix protein with a recognized role in the formation of mineralized tissues such as dentin. The aim of this study was to analyze the distribution of DMP1 in human dentin by means of immunofluorescence and high-resolution immunogold labeling. Fully developed, sound human dentin specimens were submitted to fluorescence labeling and post-embedding immunolabeling techniques with a rabbit polyclonal antihuman DMP1 antibody followed by corresponding fluorochrome-conjugated or gold-conjugated secondary antibodies. Both immunofluorescence and immunogold labeling showed an intense labeling associated with the peritubular dentin. In addition, at the ultrastructural level, there was also a moderate and diffuse immunoreaction over intertubular dentin, and a weak labeling within predentin which increased in density towards the mineralization front. This study suggests that in adult human teeth, like in rodents, DMP1 is prevalently concentrated at the level of peritubular dentin and this feature is preserved also in fully developed-teeth. These data are consistent with what has been observed in rodents and suggest that DMP1 plays a role in maintenance of the dentin tubular space.

  2. Bovine dentin ablation using an MIR-FEL at the wavelength of 6.05 μm

    NASA Astrophysics Data System (ADS)

    Heya, Manabu; Yoshikawa, Kazushi; Kato, Junji

    2008-02-01

    Background and Objective: 6.05-μm-laser is strongly absorbed by means of both the OH bending of water and the amide-I of proteins. In order to prove the usefulness of dentin ablation by laser irradiation with λ = 6.05 μm, we investigated an ablative behavior of bovine dentin without a water spray. Study Design/Materials and Methods: The dehydrated bovine dentin was irradiated without a water spray by the mid-infrared Free Electron Laser at λ = 6.05 μm and λ = 9.7 μm, while varying the laser parameters, such as the incident fluence and the number of pulse. We observed the configurational changes in the irradiated dentin surface using a scanning electron microscope and estimated the removed volume using a laser confocal microscope. Also, we measured the temperature rise using a radiation thermometer and the emission spectrum using a fiber optics spectrometer during laser irradiation. Results: We found the followings: (1) the dentin was ablated by the evaporation of proteins at the maximum temperature rise of ~400 degC; (2) the irradiated dentin surface had dentinal tubules and was not melted; (3) the extent of the ablative behavior was proportional to the laser parameters used; (4) the tensile bonding strength between the irradiated dentin surface and the composite resin was significantly higher than that for Er:YAG laser irradiation. Conclusion: We can conclude that 6.05-μm-laser can thermo-mechanically excise dentin by the evaporation of proteins even without a water spray. We showed the applicability of a 6.05-μm-laser to a non-invasive laser treatment.

  3. Simultaneous effects of leaf irradiance and soil moisture on growth and root system architecture of novel wheat genotypes: implications for phenotyping

    PubMed Central

    Nagel, Kerstin A.; Bonnett, David; Furbank, Robert; Walter, Achim; Schurr, Ulrich; Watt, Michelle

    2015-01-01

    Plants in the field are exposed to varying light and moisture. Agronomic improvement requires knowledge of whole-plant phenotypes expressed in response to simultaneous variation in these essential resources. Most phenotypes, however, have been described from experiments where resources are varied singularly. To test the importance of varying shoot and root resources for phenotyping studies, sister pre-breeding lines of wheat were phenotyped in response to independent or simultaneous exposure to two light levels and soil moisture profiles. The distribution and architecture of the root systems depended strongly on the moisture of the deeper soil layer. For one genotype, roots, specifically lateral roots, were stimulated to grow into moist soil when the upper zone was well-watered and were inhibited by drier deep zones. In contrast, the other genotype showed much less plasticity and responsiveness to upper moist soil, but maintained deeper penetration of roots into the dry layer. The sum of shoot and root responses was greater when treated simultaneously to low light and low soil water, compared to each treatment alone, suggesting the value of whole plant phenotyping in response to multiple conditions for agronomic improvement. The results suggest that canopy management for increased irradiation of leaves would encourage root growth into deeper drier soil, and that genetic variation within closely related breeding lines may exist to favour surface root growth in response to irrigation or in-season rainfall. PMID:26089535

  4. Simultaneous effects of leaf irradiance and soil moisture on growth and root system architecture of novel wheat genotypes: implications for phenotyping.

    PubMed

    Nagel, Kerstin A; Bonnett, David; Furbank, Robert; Walter, Achim; Schurr, Ulrich; Watt, Michelle

    2015-09-01

    Plants in the field are exposed to varying light and moisture. Agronomic improvement requires knowledge of whole-plant phenotypes expressed in response to simultaneous variation in these essential resources. Most phenotypes, however, have been described from experiments where resources are varied singularly. To test the importance of varying shoot and root resources for phenotyping studies, sister pre-breeding lines of wheat were phenotyped in response to independent or simultaneous exposure to two light levels and soil moisture profiles. The distribution and architecture of the root systems depended strongly on the moisture of the deeper soil layer. For one genotype, roots, specifically lateral roots, were stimulated to grow into moist soil when the upper zone was well-watered and were inhibited by drier deep zones. In contrast, the other genotype showed much less plasticity and responsiveness to upper moist soil, but maintained deeper penetration of roots into the dry layer. The sum of shoot and root responses was greater when treated simultaneously to low light and low soil water, compared to each treatment alone, suggesting the value of whole plant phenotyping in response to multiple conditions for agronomic improvement. The results suggest that canopy management for increased irradiation of leaves would encourage root growth into deeper drier soil, and that genetic variation within closely related breeding lines may exist to favour surface root growth in response to irrigation or in-season rainfall.

  5. Machining human dentin by abrasive water jet drilling.

    PubMed

    Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike

    2014-01-01

    The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 μm; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin.

  6. Machining human dentin by abrasive water jet drilling.

    PubMed

    Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike

    2014-01-01

    The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 μm; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin. PMID:24642975

  7. Effect of dentin on the antimicrobial efficacy of 3% sodium hypochlorite, 2% chlorhexidine, 17% ethylenediaminetetraacetic acid, and 18% etidronic acid on Candida albicans: An in vitro study

    PubMed Central

    Karale, Rupali; Odedra, Kamal Maldebhai; Srirekha, A.; Champa, C.; Shetty, Ashwija; Pushpalatha, S; Sharma, Rini

    2016-01-01

    Aim: The aim of this study was to evaluate the effect of dentin on the antimicrobial efficacy of 3% sodium hypochlorite, 2% chlorhexidine, 17% EDTA and 18% etidronic acid against C. albicans. Methodology: Dentin powder was prepared from mandibular first premolar using electrical grinder and sterilized. 3% NaOCl, 2%CHX, 17% EDTA and 18% etidronic acid were tested against C. albicans in the presence and absence of dentin, in eppendorf tubes. Group 1 (presence of dentin):- 100ul dentin powder + 100ul C. albicans suspension + 100ul irrigating solution. Group 2 (absence of dentin):- 100ul C. albicans suspension+ 100ul irrigating solution. Control group:- 100ul C. albicans suspension.+ 100ul sterile saline Suspension was thoroughly mixed, submitted for serial dilution upto10-5 after 1 min and colony forming units were counted. Results: In group 2 (without dentin powder), 3% NaOCl and 2% CHX showed the lowest bacterial count compared to group 1 (with dentin powder). Dentin had a significant inhibitory effect on 3% NaOCl (P < 0.001) and 2% CHX (P<0.001). 17% EDTA showed lowest bacterial count in group 1 (with dentin powder) compared to group 2 (without dentin powder). 18% Etidronic acid showed similar bacterial counts in the both the groups. No reduction was observed in the control group. Conclusion: NaOCl & EDTA showed measurable antimicrobial effect even in the presence of dentin which can be promising in the reduction of C. albicans in root canal therapy.

  8. Effect of dentin on the antimicrobial efficacy of 3% sodium hypochlorite, 2% chlorhexidine, 17% ethylenediaminetetraacetic acid, and 18% etidronic acid on Candida albicans: An in vitro study

    PubMed Central

    Karale, Rupali; Odedra, Kamal Maldebhai; Srirekha, A.; Champa, C.; Shetty, Ashwija; Pushpalatha, S; Sharma, Rini

    2016-01-01

    Aim: The aim of this study was to evaluate the effect of dentin on the antimicrobial efficacy of 3% sodium hypochlorite, 2% chlorhexidine, 17% EDTA and 18% etidronic acid against C. albicans. Methodology: Dentin powder was prepared from mandibular first premolar using electrical grinder and sterilized. 3% NaOCl, 2%CHX, 17% EDTA and 18% etidronic acid were tested against C. albicans in the presence and absence of dentin, in eppendorf tubes. Group 1 (presence of dentin):- 100ul dentin powder + 100ul C. albicans suspension + 100ul irrigating solution. Group 2 (absence of dentin):- 100ul C. albicans suspension+ 100ul irrigating solution. Control group:- 100ul C. albicans suspension.+ 100ul sterile saline Suspension was thoroughly mixed, submitted for serial dilution upto10-5 after 1 min and colony forming units were counted. Results: In group 2 (without dentin powder), 3% NaOCl and 2% CHX showed the lowest bacterial count compared to group 1 (with dentin powder). Dentin had a significant inhibitory effect on 3% NaOCl (P < 0.001) and 2% CHX (P<0.001). 17% EDTA showed lowest bacterial count in group 1 (with dentin powder) compared to group 2 (without dentin powder). 18% Etidronic acid showed similar bacterial counts in the both the groups. No reduction was observed in the control group. Conclusion: NaOCl & EDTA showed measurable antimicrobial effect even in the presence of dentin which can be promising in the reduction of C. albicans in root canal therapy. PMID:27656066

  9. The effect of endodontic regeneration medicaments on mechanical properties of radicular dentin

    NASA Astrophysics Data System (ADS)

    Yassen, Ghaeth H.

    Endodontic regeneration treatment of necrotic immature teeth has gained popularity in recent years. The approach suggests a biological alternative to induce a continuous root development. In this project, three in vitro experiments were conducted to investigate the effect of three medicaments used in endodontic regeneration on mechanical properties and chemical structure of radicular dentin. In the first experiment, we investigated longitudinally the effect of medicaments on the indentation properties of the root canal surface of immature teeth using a novel BioDent reference point indenter. A significant difference in the majority of indentation parameters between all groups was found after one-week and one-month application of medicaments (p double antibiotic paste (DAP) > control > calcium hydroxide [Ca(OH)2]. The four-week exposure of dentin to TAP and DAP caused 43% and 31% increase in total indentation distance outcome, respectively. In the second experiment, we investigated longitudinally the effect of medicaments on the chemical structure of immature radicular dentin by measuring the phosphate/amide I ratios of dentin using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy. Phosphate/amide I ratios were significantly different between the four groups after one week, two weeks and four week application of medicaments (p untreated dentin > DAP-treated dentin > TAP-treated dentin. In the third experiment, we investigated longitudinally the effect of medicaments on root fracture resistance and microhardness of radicular dentin. For the microhardness, the two-way interaction between group and time was significant (p<0.001). TAP and DAP caused a significant and continuous decrease in dentin microhardness after one and three month application, respectively. The three-month intracanal application of Ca(OH)2 significantly increased the microhardness of root dentin. The time factor had a significant effect on fracture resistance (p<0.001). All

  10. Enlargement of the apical gap after laser root resection

    NASA Astrophysics Data System (ADS)

    Mello, Guilherme P. S.; Paradella, Thais C.; Munin, Egberto; Mello, Jose B.; Pacheco, Marcos T. T.

    2000-11-01

    An apical filling material should establish, as perfect as possible, the hermetic sealing of an apical cavity. However, a gap is formed between the filling material (gutta-percha) and the root canal wall. The egress of irritants into the root canal system to the periapical tissues is considered the principal cause of fails in apicoectomy and retro-filling, being assumed that irritants penetrate mainly through the gap located between the gutta-percha and the dentin. In this paper, we report the observation of an enlargement of the apical gap, after laser apicoectomy, comparing to conventional apicoectomy. The samples were divided into groups, and the conventional apicoectomy group, together with the Er:YAG laser group (400 mJ/10 Hz) produced both similar results, being the gap unaltered. On the other hand, the samples that were irradiated with the Er:YAG laser, followed by Nd:YAG laser irradiation (1.5 W/10 Hz) presented a larger gap, conclusions that were drawn from Scanning Electronic Microscope analysis. The enlargement of the gap was due to the fusion of the dentin on the border, close to the gutta-percha. This pronounced behavior might have been caused by the surface discontinuity, imposing a non-homogeneous condition, in relation to heat propagation, existing many clinical applications of these observations.

  11. Requirement of Smad4-mediated signaling in odontoblast differentiation and dentin matrix formation

    PubMed Central

    Yun, Chi-Young; Choi, Hwajung; You, Young-Jae; Yang, Jin-Young

    2016-01-01

    Dentin is the major part of tooth and formed by odontoblasts. Under the influence of the inner enamel epithelium, odontoblasts differentiate from ectomesenchymal cells of the dental papilla and secrete pre-dentin which then undergo mineralization into dentin. Transforming growth factor-beta (TGF-β)/bone morphogenetic protein (BMP) signaling is essential for dentinogenesis; however, the precise molecular mechanisms remain unclear. To understand the role of TGF-β/BMP signaling in odontoblast differentiation and dentin formation, we generated mice with conditional ablation of Smad4, a key intracellular mediator of TGF-β/BMP signaling, using Osr2 or OC-Cre mice. Here we found the molars of Osr2CreSmad4 mutant mice exhibited impaired odontoblast differentiation, and normal dentin was replaced by ectopic bone-like structure. In Osr2CreSmad4 mutant mice, cell polarity of odontoblast was lost, and the thickness of crown dentin was decreased in later stage compared to wild type. Moreover, the root dentin was also impaired and showed ectopic bone-like structure similar to Osr2CreSmad4 mutant mice. Taken together, our results suggest that Smad4-dependent TGF-β/BMP signaling plays a critical role in odontoblast differentiation and dentin formation during tooth development. PMID:27722013

  12. Dental Pulp and Dentin Tissue Engineering and Regeneration – Advancement and Challenge

    PubMed Central

    Huang, George T.-J.

    2012-01-01

    Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cememtum can regenerate with limited capacity. Enamel and dentin are commonly under the attack by caries. Extensive forms of caries destroy enamel and dentin and can lead to dental pulp infection. Entire pulp amputation followed by the pulp space disinfection and filled with an artificial rubber-like material is employed to treat the infection --commonly known as root canal or endodontic therapy. Regeneration of dentin relies on having vital pulps; however, regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. With the advent of modern tissue engineering concept and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the recent endeavor on pulp and dentin tissue engineering and regeneration. The prospective outcome of the current advancement and challenge in this line of research will be discussed. PMID:21196351

  13. Effects of ultramorphological changes on adhesion to lased dentin-Scanning electron microscopy and transmission electron microscopy analysis.

    PubMed

    Moretto, Simone G; Azambuja, Nilton; Arana-Chavez, Victor E; Reis, Andre F; Giannini, Marcelo; Eduardo, Carlos de P; De Freitas, Patricia M

    2011-08-01

    Dentin irradiation with erbium lasers has been reported to alter the composite resin bond to this treated surface. There is still a lack of studies reporting the effect of erbium lasers on dentin organic content and elucidating how laser treatment could interfere in the quality of the resin-dentin interface. This study aimed to evaluate the effect of erbium laser irradiation on dentin morphology and microtensile bond strength (μTBS) of an adhesive to dentin. Seventy-two dentin disks were divided into nine groups (n = 8): G1-Control (600-grit SiC paper); Er:YAG groups: G2- 250 mJ/4 Hz; G3- 200 mJ/4 Hz; G4- 180 mJ/10 Hz; G5- 160 mJ/10 Hz; Er,Cr:YSGG groups: G6- 2 W/20 Hz; G7- 2.5 W/20 Hz; G8- 3 W/20 Hz; G9- 4 W/20 Hz. Specimens were processed for cross-sectional analysis by scanning electron microscopy (SEM) (n = 3), transmission electron microscopy (TEM) (n = 2), and adhesive interface (n = 3). Forty-five dentin samples (n = 5) were restored and submitted to μTBS testing. ANOVA (α = 5%) revealed that G1 presented the highest μTBS values and irradiated groups did not differ from each other. TEM micrographs showed a superficial layer of denatured collagen fibrils. For SEM micrographs, it was possible to verify the laser effects extending to dentin subsurface presenting a rough aspect. Cross-sectional dentin micrographs of this hybridized surface revealed a pattern of modified tags with ringlike structures around it. This in vitro study showed that erbium laser irradiation interacts with the dental hard tissue resulting in a specific morphological pattern of dentin and collagen fibrils that negatively affected the bond strength to composite resin.

  14. Treatment of Dentinal Hypersensitivity by means of Nd:YAP Laser: A Preliminary In Vitro Study

    PubMed Central

    Namour, Amaury; Nammour, Samir; Peremans, André; Heysselaer, Daniel; De Moor, Roeland J. G.

    2014-01-01

    Objective. The aim of this study is to evaluate the effectiveness of Nd:YAP laser to seal dentinal tubules at different parameters. Material and Methods. 24 caries-free human wisdom impacted molars were used. The crowns were sectioned transversally in order to totally expose the dentin. The smear layer was removed by a 1 min application of EDTA. Each surface was divided into four quadrants, but only three quadrants were irradiated at a different output power setting (irradiation speed: 1 mm/sec; optical fiber diameter: 320 µm; tangential incidence of beam and in noncontact mode). Samples were smeared with a graphite paste prior to laser irradiation. All specimens were sent for SEM analysis. Pulp temperature increases in additional twenty teeth were measured by a thermocouple. Results. Morphological changes in dentin surfaces depend on the value of used energy density. Higher energy densities (2 W–4 W; 200–400 mJ; pulse duration: 100 m sec.; and 10 Hz) induce higher dentin modifications. Our results confirmed that Nd:YAP laser irradiations can lead to total or partial occlusion of dentin tubules without provoking fissures or cracks. Measurements of pulp temperature increases showed that Nd:YAP laser beam can be considered as harmless for pulp vitality for following irradiation conditions: 2 W (200 mJ) to 4 W (400 mJ) with an irradiation speed of 1 mm/sec; fiber diameter: 320 micrometers; 10 Hz; pulse duration: 100 m sec; noncontact mode and in tangential incidence to exposed dentin. The perpendicular incidence of the laser beam on exposed dentin may injure pulp vitality even at low output power of 3 W. Conclusions. Nd:YAP laser beam was able to seal the dentin tubules without damaging dentinal surfaces and without harming pulp vitality. Nd:YAP laser is effective and may be safely used for future in vivo treatments of dentinal hypersensitivity under certain conditions. PMID:25383368

  15. 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.

  16. Anacardic acid from brazilian cashew nut trees reduces dentine erosion.

    PubMed

    Silveira, Cintia; Oliveira, Flávia; Dos Santos, Maria Lucilia; de Freitas, Thiago; Imparato, José Carlos; Magalhães, Ana Carolina

    2014-01-01

    The aim of this study was to analyze the effect of solutions containing saturated anacardic acid (AA) on dentine erosion in vitro. AA was chemically isolated from natural cashew nutshell liquid obtained by continuous extraction in a Soxhlet extractor and was fully saturated by catalytic hydrogenation. Matrix metalloproteinase 2 (MMP-2) activity, when exposed to buffers containing 100 µmol/l AA, was analyzed using zymography. Bovine root samples were subjected to erosive demineralization (Sprite Zero™, 4 × 90 s/day) and remineralization with artificial saliva between the erosive cycles for 5 days. The samples were treated as follows, after the first and the last acid exposure (1 min; n = 12/group): (1) 100 µmol/l epigallocatechin-3-gallate (EGCG) (positive control); (2) 0.05% NaF; (3) 100 µmol/l saturated AA; (4) saturated AA and EGCG; (5) saturated AA, EGCG and NaF; (6) untreated (negative control). Dentine erosion was measured using a contact profilometer. Two dentine samples from each group were analyzed using scanning electron microscopy. Saturated AA reduced the activity of MMP-2. ANOVA and Tukey's test revealed that all treatments significantly reduced dentine loss compared to the negative control (6.03 ± 0.98 µm). Solutions containing saturated AA (1.97 ± 1.02 µm) showed the greatest reduction in dentine erosion compared to the NaF (3.93 ± 1.54 µm) and EGCG (3.79 ± 0.83 µm) solutions. Therefore, it may be concluded that AA significantly reduces dentine erosion in vitro, possibly by acting as an MMP-2 inhibitor. PMID:24993776

  17. Anacardic acid from brazilian cashew nut trees reduces dentine erosion.

    PubMed

    Silveira, Cintia; Oliveira, Flávia; Dos Santos, Maria Lucilia; de Freitas, Thiago; Imparato, José Carlos; Magalhães, Ana Carolina

    2014-01-01

    The aim of this study was to analyze the effect of solutions containing saturated anacardic acid (AA) on dentine erosion in vitro. AA was chemically isolated from natural cashew nutshell liquid obtained by continuous extraction in a Soxhlet extractor and was fully saturated by catalytic hydrogenation. Matrix metalloproteinase 2 (MMP-2) activity, when exposed to buffers containing 100 µmol/l AA, was analyzed using zymography. Bovine root samples were subjected to erosive demineralization (Sprite Zero™, 4 × 90 s/day) and remineralization with artificial saliva between the erosive cycles for 5 days. The samples were treated as follows, after the first and the last acid exposure (1 min; n = 12/group): (1) 100 µmol/l epigallocatechin-3-gallate (EGCG) (positive control); (2) 0.05% NaF; (3) 100 µmol/l saturated AA; (4) saturated AA and EGCG; (5) saturated AA, EGCG and NaF; (6) untreated (negative control). Dentine erosion was measured using a contact profilometer. Two dentine samples from each group were analyzed using scanning electron microscopy. Saturated AA reduced the activity of MMP-2. ANOVA and Tukey's test revealed that all treatments significantly reduced dentine loss compared to the negative control (6.03 ± 0.98 µm). Solutions containing saturated AA (1.97 ± 1.02 µm) showed the greatest reduction in dentine erosion compared to the NaF (3.93 ± 1.54 µm) and EGCG (3.79 ± 0.83 µm) solutions. Therefore, it may be concluded that AA significantly reduces dentine erosion in vitro, possibly by acting as an MMP-2 inhibitor.

  18. Polymer nanocarriers for dentin adhesion.

    PubMed

    Osorio, R; Osorio, E; Medina-Castillo, A L; Toledano, M

    2014-12-01

    To obtain more durable adhesion to dentin, and to protect collagen fibrils of the dentin matrix from degradation, calcium- and phosphate-releasing particles have been incorporated into the dental adhesive procedure. The aim of the present study was to incorporate zinc-loaded polymeric nanocarriers into a dental adhesive system to facilitate inhibition of matrix metalloproteinases (MMPs)-mediated collagen degradation and to provide calcium ions for mineral deposition within the resin-dentin bonded interface. PolymP- N : Active nanoparticles (nanoMyP) were zinc-loaded through 30-minute ZnCl2 immersion and tested for bioactivity by means of 7 days' immersion in simulated body fluid solution (the Kokubo test). Zinc-loading and calcium phosphate depositions were examined by scanning and transmission electron microscopy, elemental analysis, and x-ray diffraction. Nanoparticles in ethanol solution infiltrated into phosphoric-acid-etched human dentin and Single Bond (3M/ESPE) were applied to determine whether the nanoparticles interfered with bonding. Debonded sticks were analyzed by scanning electron microscopy. A metalloproteinase collagen degradation assay was also performed in resin-infiltrated dentin with and without nanoparticles, measuring C-terminal telopeptide of type I collagen (ICTP) concentration in supernatants, after 4 wk of immersion in artificial saliva. Numerical data were analyzed by analysis of variance (ANOVA) and Student-Newman-Keuls multiple comparisons tests (p < .05). Nanoparticles were effectively zinc-loaded and were shown to have a chelating effect, retaining calcium regardless of zinc incorporation. Nanoparticles failed to infiltrate demineralized intertubular dentin and remained on top of the hybrid layer, without altering bond strength. Calcium and phosphorus were found covering nanoparticles at the hybrid layer, after 24 h. Nanoparticle application in etched dentin also reduced MMP-mediated collagen degradation. Tested nanoparticles may be

  19. Pulsed HF laser ablation of dentin

    NASA Astrophysics Data System (ADS)

    Papagiakoumou, Eirini I.; Papadopoulos, Dimitris N.; Makropoulou, Mersini I.; Khabbaz, Maruan G.; Serafetinides, Alexander A.

    2005-03-01

    The interaction of a TEA (Transversally Excited Atmospheric pressure) corona preionized oscillator double amplifier HF (hydrogen fluoride) laser beam with dentin tissue is reported. Pulses of 39 ns in the wavelength range of 2.65-3.35 μm and output energies in the range of 10-45 mJ, in a predominantly TEM00 beam were used to interact with dentin tissue. Ablation experiments were conducted with the laser beam directly focused on the tissue. Several samples of freshly extracted human teeth were used, cut longitudinally in facets of about 1mm thick and stored in phosphate buffered saline after being cleaned from the soft tissue remains. The experimental data (ablation thresholds, ablation rates) are discussed with respect to the ablation mechanism(s). Adequate tissue removal was observed and the ablation behavior was, in the greates part of the available fluences, almost linear. From the microscopic examination of teh samples, in a scanning electron microscope (SEM), the irradiated surfaces displayed oval craters (reflecting the laser beam shape) with absence of any melting or carbonization zone. It is suggested that the specific laser removes hard tissue by a combined photothermal and plasma mediated ablation mechanism, leaving a surface free from thermal damage and with a well-shaped crater.

  20. Evaluation of the Diode laser (810nm,980nm) on dentin tubule diameter following internal bleaching

    PubMed Central

    Kiomarsi, Nazanin; Salim, Soheil; Sarraf, Pegah; Javad-Kharazifard, Mohammad

    2016-01-01

    Background The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on the dentinal tubule diameter after laser bleaching. Material and Methods The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810 nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey test (p<0.05). Results A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant difference between groups 1 and 2 and between groups 3 and 4 after bleaching. Conclusions The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on dentin was dependent on chemical action of bleaching material. Key words:Laser, diode, dentin, tubule, diameter. PMID:27398172

  1. CO2 laser improves 45S5 bioglass interaction with dentin.

    PubMed

    Bakry, A S; Takahashi, H; Otsuki, M; Sadr, A; Yamashita, K; Tagami, J

    2011-02-01

    Bioglass 45S5 is a bioactive glass that can create a layer of calcium-phosphate crystals on mineralized hard tissues. In this study, 45S5 bioglass was mixed with phosphoric acid and irradiated with CO(2) laser and examined as a possible aid in the treatment of dentin hypersensitivity. The dentinal surface modified by the aforementioned technique was chemically and micro-morphologically examined with a field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive x-ray spectroscope (EDS), and the crystalline structures of the examined dentinal surfaces were examined by x-ray diffraction (XRD). Moreover, the mechanical properties of the newly formed layer were examined by nanoindentation. The results showed that 45S5 bioglass could occlude the dentinal tubule orifices with calcium-phosphate crystals. The application of CO(2) laser potentially improved the mechanical organization of these crystals. PMID:21084716

  2. Ginsenoside Production and Morphological Characterization of Wild Ginseng (Panax ginseng Meyer) Mutant Lines Induced by γ-irradiation (60Co) of Adventitious Roots

    PubMed Central

    Zhang, Jun-Ying; Bae, Tae-Woong; Boo, Kyung-Hwan; Sun, Hyeon-Jin; Song, In-Ja; Pham, Chi-Hoa; Ganesan, Markkandan; Yang, Dae-Hwa; Kang, Hong-Gyu; Ko, Suk-Min; Riu, Key-Zung; Lim, Pyung-Ok; Lee, Hyo-Yeon

    2011-01-01

    With the purpose of improving ginsenoside content in adventitious root cultures of Korean wild ginseng (Panax ginseng Meyer), the roots were treated with different dosages of γ-ray (5, 10, 25, 50, 75, 100, and 200 Gy). The growth of adventitious roots was inhibited at over 100 Gy. The irradiated adventitious roots showed significant variation in the morphological parameters and crude saponin content at 50 to100 Gy. Therefore, four mutant cell lines out of the propagation of 35 cell lines treated with 50 Gy and 100 Gy were selected on the basis of phenotypic morphology and crude saponin contents relative to the wild type control. The contents of 7 major ginsenosides (Rg1, Re, Rb1, Rb2, Rc, Rf, and Rd) were determined for cell lines 1 and 3 from 100 Gy and lines 2 and 4 from 50 Gy treatments. Cell line 2 showed more secondary roots, longer length and superior growth rate than the root controls in flasks and bioreactors. Cell line 1 showed larger average diameter and the growth rate in the bioreactor was comparable with that of the control but greater in the flask cultured roots. Cell lines 1 and 2, especially the former, showed much more ginsenoside contents than the control in flasks and bioreactors. Therefore, we chose cell line 1 for further study of ginsenoside contents. The crude saponin content of line 1 in flask and bioreactor cultures increased by 1.4 and 1.8-fold, respectively, compared to the control. Total contents of 7 ginsenoside types (Rg1, Re, Rb1, Rb2, Rc, Rf, and Rd) increased by 1.8 and 2.3-fold, respectively compared to the control. Crude saponin and ginsenoside contents in the bioreactor culture increased by about 1.4-fold compared to that the flask culture. PMID:23717071

  3. Sodium hypochlorite alterations of dentin and dentin collagen

    NASA Astrophysics Data System (ADS)

    Marshall, G. W.; Yücel, N.; Balooch, M.; Kinney, J. H.; Habelitz, S.; Marshall, S. J.

    2001-10-01

    NaOCl aq is used as a cleansing and non-specific deproteinizing agent in endodontic treatment, as a component of new chemomechanical caries treatment, and is under study for its alterations of dentin bonding characteristics. We sought to determine the microstructural and nanomechanical changes with such treatments and to test if NaOCl aq removed dentin collagen without microstructural or nanomechanical alteration of underlying mineralized dentin. Polished human dentin disks were prepared with a double reference technique that allowed changes to be determined following 10% citric acid etching for 15 s and subsequent treatment of the etched and unetched portions of the sample with 6.5% NaOCl aq, using atomic force microscopy (AFM) (Nanoscope III, Digital Instruments, Santa Barbara, CA). Images and measurements were made at intervals up to 1800 s. A Triboscope (Hysitron, Minneapolis, MN) on the AFM was used to measure nanohardness and the reduced elastic modulus. The double reference method allowed measurements immediately following etching and at intervals during deproteinization. Etching caused deep peritubular dentin removal and a small depth change of hydrated intertubular dentin as mineral was removed and left a remnant collagen matrix. NaOCl aq removed collagen over time, during which individual fibrils could be resolved; the underlying mineralized dentin was left with a unique porous surface containing numerous channels that are not normally observed in etched or fractured dentin. This could provide an attractive bonding substrate because of the increased surface area and high mineral content, if toughness is not reduced too much. Nanomechanical measurements showed that the reduced elastic modulus and hardness were 75% of original values after removal of the exposed collagen. Current dentin bonding systems rely on hybrid layer formation in which hydrophilic primers/polymers penetrate the opened collagen matrix exposed by etching. However some research suggests

  4. Hyperlipidemia induced by high-fat diet enhances dentin formation and delays dentin mineralization in mouse incisor.

    PubMed

    Ye, Xin; Zhang, Jin; Yang, Pishan

    2016-10-01

    Dyslipidemia has become a serious health problem in children and adolescents worldwide for its high prevalence. Since hard tissues of permanent teeth form mainly during this period and lipids are actively involved in tooth development, the effects of hyperlipidemia on dental tissue formation and mineralization need to be illustrated. In this study, hyperlipidemia model was established in mice fed with high-fat diet (HFD). Micro-CT and histomorphological analyses were performed on the mandibular bones to assess the morphological changes of the mandibular incisor and first molar. After 4 weeks of HFD feeding, mice had significantly elevated serum lipid levels compared with mice fed with control diet. After 8 weeks, the mandibular incisor presented significantly increased dentin thickness and decreased diameter of pulp cavity in HFD-fed mice compared with control diet-fed mice, while its gross morphology and enamel thickness were not altered. In the mandibular first molar, dentin thickness of root did not show difference between the two groups. Histological section showed that mandibular incisor of HFD-fed mice manifested a wider predentin region and a lower mineral apposition rate compared with that of the control mice. In conclusion, hyperlipidemia induced by HFD feeding enhances dentin formation and delays dentin mineralization in the developing mouse incisor. PMID:27558143

  5. Hyperlipidemia induced by high-fat diet enhances dentin formation and delays dentin mineralization in mouse incisor.

    PubMed

    Ye, Xin; Zhang, Jin; Yang, Pishan

    2016-10-01

    Dyslipidemia has become a serious health problem in children and adolescents worldwide for its high prevalence. Since hard tissues of permanent teeth form mainly during this period and lipids are actively involved in tooth development, the effects of hyperlipidemia on dental tissue formation and mineralization need to be illustrated. In this study, hyperlipidemia model was established in mice fed with high-fat diet (HFD). Micro-CT and histomorphological analyses were performed on the mandibular bones to assess the morphological changes of the mandibular incisor and first molar. After 4 weeks of HFD feeding, mice had significantly elevated serum lipid levels compared with mice fed with control diet. After 8 weeks, the mandibular incisor presented significantly increased dentin thickness and decreased diameter of pulp cavity in HFD-fed mice compared with control diet-fed mice, while its gross morphology and enamel thickness were not altered. In the mandibular first molar, dentin thickness of root did not show difference between the two groups. Histological section showed that mandibular incisor of HFD-fed mice manifested a wider predentin region and a lower mineral apposition rate compared with that of the control mice. In conclusion, hyperlipidemia induced by HFD feeding enhances dentin formation and delays dentin mineralization in the developing mouse incisor.

  6. Short-pulse Er:YAG laser increases bond strength of composite resin to sound and eroded dentin

    NASA Astrophysics Data System (ADS)

    Cersosimo, Maria Cecília Pereira; Matos, Adriana Bona; Couto, Roberta Souza D.'Almeida; Marques, Márcia Martins; de Freitas, Patricia Moreira

    2016-04-01

    This study evaluated the influence of the irradiation with a short-pulse Er:YAG laser on the adhesion of composite resin to sound and eroded dentin (SD and ED). Forty-six samples of occlusal dentine, obtained from human molars, had half of their surface protected, while the other half was submitted to erosive cycles. Afterward, 23 samples were irradiated with Er:YAG laser, resulting in four experimental groups: SD, sound irradiated dentine (SID-Er:YAG, 50 μs, 2 Hz, 80 mJ, and 12.6 J/cm2), ED, and eroded irradiated dentin (EID-erosion + Er:YAG laser). A self-etching adhesive system was used, and then cylinders of composite resin were prepared. A microshear bond strength test was performed after 24 h storage (n=20). The morphology of SD and ED, with or without Er:YAG laser irradiation, was evaluated under scanning electron microscopy (n=3). Bond strength values (MPa) were subjected to analysis of variance followed by Tukey's test. Statistically significant differences were found among the experimental groups: SD (9.76±3.39 B), SID (12.77±5.09 A), ED (5.12±1.72 D), and EID (7.62±3.39 C). Even though erosion reduces the adhesion to dentin, the surface irradiation with a short-pulse Er:YAG laser increases adhesion to both ED and SD.

  7. Short-pulse Er:YAG laser increases bond strength of composite resin to sound and eroded dentin

    NASA Astrophysics Data System (ADS)

    Cersosimo, Maria Cecília Pereira; Matos, Adriana Bona; Couto, Roberta Souza D.'Almeida; Marques, Márcia Martins; de Freitas, Patricia Moreira

    2016-04-01

    This study evaluated the influence of the irradiation with a short-pulse Er:YAG laser on the adhesion of composite resin to sound and eroded dentin (SD and ED). Forty-six samples of occlusal dentine, obtained from human molars, had half of their surface protected, while the other half was submitted to erosive cycles. Afterward, 23 samples were irradiated with Er:YAG laser, resulting in four experimental groups: SD, sound irradiated dentine (SID-Er:YAG, 50 μs, 2 Hz, 80 mJ, and 12.6 J/cm2), ED, and eroded irradiated dentin (EID-erosion + Er:YAG laser). A self-etching adhesive system was used, and then cylinders of composite resin were prepared. A microshear bond strength test was performed after 24 h storage (n=20). The morphology of SD and ED, with or without Er:YAG laser irradiation, was evaluated under scanning electron microscopy (n=3). Bond strength values (MPa) were subjected to analysis of variance followed by Tukey's test. Statistically significant differences were found among the experimental groups: SD (9.76±3.39 B), SID (12.77±5.09 A), ED (5.12±1.72 D), and EID (7.62±3.39 C). Even though erosion reduces the adhesion to dentin, the surface irradiation with a short-pulse Er:YAG laser increases adhesion to both ED and SD.

  8. Adhesive Approach Using Internal Coping for Vertical Root Fractured Teeth with Flared Root Canals.

    PubMed

    Takeuchi, Shuhei; Sekita, Toshiaki; Kobayashi, Ken'ichi

    2015-01-01

    Vertical root fractures are often observed in teeth with endodontic treatment and post space preparation. Frequently, because such teeth have flared root canals with thin dentin walls, conventional treatments are disadvantageous in terms of adhesiveness, sealability and risk of refracture. Here we devised an intentional replantation method that uses internal resin coping, with a reinforcing effect on thin root canal dentin. In two patients treated with this method, satisfactory conditions have been maintained. This report suggests that an intentional replantation method in which an internal resin coping is employed may be a useful therapy for fractured teeth with flared root canals.

  9. Adhesive Approach Using Internal Coping for Vertical Root Fractured Teeth with Flared Root Canals.

    PubMed

    Takeuchi, Shuhei; Sekita, Toshiaki; Kobayashi, Ken'ichi

    2015-01-01

    Vertical root fractures are often observed in teeth with endodontic treatment and post space preparation. Frequently, because such teeth have flared root canals with thin dentin walls, conventional treatments are disadvantageous in terms of adhesiveness, sealability and risk of refracture. Here we devised an intentional replantation method that uses internal resin coping, with a reinforcing effect on thin root canal dentin. In two patients treated with this method, satisfactory conditions have been maintained. This report suggests that an intentional replantation method in which an internal resin coping is employed may be a useful therapy for fractured teeth with flared root canals. PMID:26373031

  10. Ultrastructural organization of dentin in mice lacking dentin sialo-phosphoprotein.

    PubMed

    Fang, Ping-An; Verdelis, Kostas; Yang, Xu; Lukashova, Lyudmila; Boskey, Adele L; Beniash, Elia

    2014-08-01

    Dentin Sialophosphoprotein (DSPP) is the major non-collagenous protein of dentin and plays a significant role in dentin mineralization. Recently, animal models lacking DSPP have been developed and the DSPP KO phenotype has been characterized at the histological level. Little is known, however, about the DSPP KO dentin at nano- and meso-scale. Dentin is a hierarchical material spanning from nano- to macroscale, hence information on the effects of DSPP deficiency at the submicron scale is essential for understanding of its role in dentin biomineralization. To bridge this gap, we have conducted ultrastructural studies of dentin from DSPP KO animals. Transmission electron microscopy (TEM) studies of DSPP KO dentin revealed that although the overall ultrastructural organization was similar to the WT, the mineral particles were less organized. Scanning electron microscopy in the back-scattered mode (BS-SEM) of the DSPP KO dentin revealed that circumpulpal dentin comprises large areas of non-mineralized matrix, with numerous spherulitic mineralized inclusions, while the mantle dentin appeared largely unaffected. Analysis of the mineral distribution in the circumpulpal dentin of the DSPP KO mice suggests a reduction in the number of mineral nucleation sites and an increase in the nucleation barrier in DSPP KO dentin. These preliminary results indicate that in addition to the reduction of mineralized and total dentin volume in DSPP KO animals significant changes in the ultrastructural organization exist. These changes are likely related to the role of DSPP in the regulation of mineral formation and organization in dentin.

  11. 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.

  12. Stereomicroscopic evaluation of dentinal defects induced by new rotary system: “ProTaper NEXT”

    PubMed Central

    Shori, Deepa Deepak; Shenoi, Pratima Ramakrishna; Baig, Arshia R; Kubde, Rajesh; Makade, Chetana; Pandey, Swapnil

    2015-01-01

    Introduction: The objective of this study was to evaluate dentinal defects formed by new rotary system — Protaper next™ (PTN). Materials and Methods: Sixty single-rooted premolars were selected. All specimens were decoronated and divided into four groups, each group having 15 specimens. Group I specimens were prepared by Hand K-files (Mani), Group II with ProTaper Universal (PT; Dentsply Maillefer), Group III with Hero Shaper (HS; Micro-Mega, Besancon, France), and Group IV with PTN (Dentsply Maillefer). Roots of each specimen were sectioned at 3, 6, and 9mm from the apex and were then viewed under a stereomicroscope to evaluate presence or absence of dentinal defects. Results: In roots prepared with hand files (HFs) showed lowest percentage of dentinal defects (6.7%); whereas in roots prepared with PT, HS, and PTN it was 40, 66.7, and 26.7%, respectively. There was significant difference between the HS group and the PTN group (P < 0.05). Conclusion: All rotary files induced defects in root dentin, whereas the hand instruments induced minimal defects. PMID:26069406

  13. Selective excavation of human carious dentin using the nanosecond pulsed laser in 5.8-μm wavelength range

    NASA Astrophysics Data System (ADS)

    Kita, Tetsuya; Ishii, Katsunori; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    Less-invasive treatment of caries has been needed in laser dentistry. Based on the absorption property of dentin substrates, 6 μm wavelength range shows specific absorptions and promising characteristics for the excavation. In our previous study, 5.8 μm wavelength range was found to be effective for selective excavation of carious dentin and restoration treatment using composite resin from the irradiation experiment with bovine sound and demineralized dentin. In this study, the availability of 5.8 μm wavelength range for selective excavation of human carious dentin was investigated for clinical application. A mid-infrared tunable nanosecond pulsed laser by difference-frequency generation was used for revealing the ablation property of human carious dentin. Irradiation experiments indicated that the wavelength of 5.85 μm and the average power density of 30 W/cm2 realized the selective excavation of human carious dentin, but ablation property was different with respect to each sample because of the different caries progression. In conclusion, 5.8 μm wavelength range was found to be effective for selective excavation of human carious dentin.

  14. Oxidative potential of ultraviolet-A irradiated or nonirradiated suspensions of titanium dioxide or silicon dioxide nanoparticles on Allium cepa roots.

    PubMed

    Koce, Jasna Dolenc; Drobne, Damjana; Klančnik, Katja; Makovec, Darko; Novak, Sara; Hočevar, Matej

    2014-04-01

    The effect of ultraviolet-A irradiated or nonirradiated suspensions of agglomerates of titanium dioxide (TiO(2)) or silicon dioxide (SiO(2)) nanoparticles on roots of the onion (Allium cepa) has been studied. The reactive potential of TiO(2) nanoparticles, which have photocatalytic potential, and the nonphotocatalytic SiO(2) nanoparticles with the same size of agglomerates was compared. The authors measured the activity of antioxidant enzymes glutathione reductase, ascorbate peroxidase, guaiacol peroxidase, and catalase as well as lipid peroxidation to assess the oxidative stress in exposed A. cepa roots. A wide range of concentrations of nanoparticles was tested (0.1-1000 µg/mL). The sizes of agglomerates ranged in both cases from 300 nm to 600 nm, and the exposure time was 24 h. Adsorption of SiO(2) nanoparticles on the root surface was minimal but became significant when roots were exposed to TiO(2) agglomerates. No significant biological effects were observed even at high exposure concentrations of SiO(2) and TiO(2) nanoparticles individually. Plants appear to be protected against nanoparticles by the cell wall, which shields the cell membrane from direct contact with the nanoparticles. The authors discuss the need to supplement conventional phytotoxicity and stress end points with measures of plant physiological state when evaluating the safety of nanoparticles.

  15. Oxidative potential of ultraviolet-A irradiated or nonirradiated suspensions of titanium dioxide or silicon dioxide nanoparticles on Allium cepa roots.

    PubMed

    Koce, Jasna Dolenc; Drobne, Damjana; Klančnik, Katja; Makovec, Darko; Novak, Sara; Hočevar, Matej

    2014-04-01

    The effect of ultraviolet-A irradiated or nonirradiated suspensions of agglomerates of titanium dioxide (TiO(2)) or silicon dioxide (SiO(2)) nanoparticles on roots of the onion (Allium cepa) has been studied. The reactive potential of TiO(2) nanoparticles, which have photocatalytic potential, and the nonphotocatalytic SiO(2) nanoparticles with the same size of agglomerates was compared. The authors measured the activity of antioxidant enzymes glutathione reductase, ascorbate peroxidase, guaiacol peroxidase, and catalase as well as lipid peroxidation to assess the oxidative stress in exposed A. cepa roots. A wide range of concentrations of nanoparticles was tested (0.1-1000 µg/mL). The sizes of agglomerates ranged in both cases from 300 nm to 600 nm, and the exposure time was 24 h. Adsorption of SiO(2) nanoparticles on the root surface was minimal but became significant when roots were exposed to TiO(2) agglomerates. No significant biological effects were observed even at high exposure concentrations of SiO(2) and TiO(2) nanoparticles individually. Plants appear to be protected against nanoparticles by the cell wall, which shields the cell membrane from direct contact with the nanoparticles. The authors discuss the need to supplement conventional phytotoxicity and stress end points with measures of plant physiological state when evaluating the safety of nanoparticles. PMID:24812678

  16. Dentin hypersensitivity and its management.

    PubMed

    Chu, C H; Lam, Anty; Lo, Edward C M

    2011-01-01

    Dentin hypersensitivity is a common patient complaint that is more prevalent than the profession realizes. It is important for dentists to diagnose dentin hypersensitivity by exclusion and provide appropriate treatment recommendations for patients. Various treatment methods have been proposed but no universally accepted desensitizing agent or treatment has been identified. When a patient has symptoms that can be attributed to dentin hypersensitivity, a thorough clinical examination should be carried out to rule out other likely causes prior to diagnosis and treatment. Depending on the identified cause, a combination of individualized instructions on proper oral health behaviors, use of at-home products, and professional treatment may be required to manage the problem. PMID:21903521

  17. Effect of acidic solutions on the microhardness of dentin and set OrthoMTA and their cytotoxicity on murine macrophage

    PubMed Central

    Shon, Won-Jun; Lee, Woocheol

    2016-01-01

    Objectives To evaluate the effects of three acids on the microhardness of set mineral trioxide aggregate (MTA) and root dentin, and cytotoxicity on murine macrophage. Materials and Methods OrthoMTA (BioMTA) was mixed and packed into the human root dentin blocks of 1.5 mm diameter and 5 mm height. Four groups, each of ten roots, were exposed to 10% citric acid (CA), 5% glycolic acid (GA), 17% ethylenediaminetetraacetic acid (EDTA), and saline for five minutes after setting of the OrthoMTA. Vickers surface microhardness of set MTA and dentin was measured before and after exposure to solutions, and compared between groups using one-way ANOVA with Tukey test. The microhardness value of each group was analyzed using student t test. Acid-treated OrthoMTA and dentin was examined by scanning electron microscope (SEM). Cell viability of tested solutions was assessed using WST-8 assay and murine macrophage. Results Three test solutions reduced microhardness of dentin. 17% EDTA demonstrated severe dentinal erosion, significantly reduced the dentinal microhardness compared to 10% CA (p = 0.034) or 5% GA (p = 0.006). 10% CA or 5% GA significantly reduced the surface microhardness of set MTA compared to 17% EDTA and saline (p < 0.001). Acid-treated OrthoMTA demonstrated microporous structure with destruction of globular crystal. EDTA exhibited significantly more cellular toxicity than the other acidic solutions at diluted concentrations (0.2, 0.5, 1.0%). Conclusions Tested acidic solutions reduced microhardness of root dentin. Five minute's application of 10% CA and 5% GA significantly reduced the microhardness of set OrthoMTA with lower cellular cytotoxicity compared to 17% EDTA. PMID:26877986

  18. Main concepts of dentin adhesion (review).

    PubMed

    Mamaladze, M; Sanodze, L; Vadachkoria, D

    2009-03-01

    This review examines fundamental concepts in bonding to dentin. Emphasis is placed on the structure and permeability characteristics of dentin and how they may influence its interaction with adhesive resin. Several new techniques to examine the interfaces between resin and dentin are reviewed along with some of their limitations. The advantages and disadvantages of acid etchants/conditioners versus self-etching conditioners/primers are discussed. The problems of matching the surface tension of resin bonding systems to the surface energy of the substrate are reviewed in terms of wetting the various components of dentin. The problems associated with matching the permeability of intertubular dentin to the diffusibility of bonding reagents are explored. Speculation is advanced on how to ensure polymerization and wetting of dentinal collagen. Theoretical problems associated with dentin bonding and with bond testing are reviewed in order to encourage future research in this rapidly developing area. PMID:19359716

  19. Malformations of the tooth root in humans.

    PubMed

    Luder, Hans U

    2015-01-01

    The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation

  20. Malformations of the tooth root in humans

    PubMed Central

    Luder, Hans U.

    2015-01-01

    The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation

  1. Low-level laser therapy of dentin hypersensitivity: a short-term clinical trial.

    PubMed

    Orhan, Kaan; Aksoy, Umut; Can-Karabulut, Deniz C; Kalender, Atakan

    2011-09-01

    The aim of this study was to evaluate low-level laser therapy in cervical dentin hypersensitivity. A randomized controlled clinical trial was conducted with a total of 64 teeth. Dentin desensitizer and diode laser were applied on the cervical dentin surfaces. Distilled water and placebo laser was used as the placebo groups. The irradiance used was 4 J/cm(2) per treatment site. The baseline measurement of hypersensitivity was made by using visual analog scale (VAS). Twenty-four hours and 7 days after the application of desensitizer, diode laser and placebo groups, a new VAS analysis was conducted for the patients' sensitivity level. The mean pain scores of placebo groups were significantly higher than the desensitizer's and diode laser's mean scores (ANOVA, p < 0.05). The VAS analysis revealed a significant decrease in dentin hypersensitivity in 7 days with the use of the desensitizer and low-level laser therapy and no statistically significant difference was observed between these two treatments (p > 0.05). Although low-level laser and glutaraldehyde containing desensitizer present distinct modes of action, experimental agents caused a significant reduction of dentin hypersensitivity without showing secondary effects, not irritating the pulp or causing pain, not discoloring or staining the teeth, and not irritating the soft tissues at least for a period of 1 week with no drawbacks regarding handling and/or ease of application. Low-level laser therapy and desensitizer application had displayed similar effectiveness in reducing moderate dentin hypersensitivity.

  2. Dentin ablation by Ho: YAG laser: correlation of energy versus volume using stereophotogrammetry.

    PubMed

    Stevens, B H; Trowbridge, H O; Harrison, G; Silverton, S F

    1994-05-01

    The future use of lasers in endodontics is dependent upon predictable and consistent ablation of dentin. In this pilot study we used an Ho:YAG laser fiberoptic delivery system to apply laser energy to prepared tooth sections in vitro. Longitudinally sectioned single-rooted human teeth were subjected to single-energy pulses varying from 25 to 1750 mJ at a focal length of 1 mm. At different energy levels we observed changes in the dentin surface ranging from minute surface pitting to the formation of large craters. Scanning electron microscopy and stereophotogrammetry were used to determine the relationship between the amount of energy applied to dentin and the extent of dentin ablation. Dentin crater formation was quantified by determining surface area, depth, and volume of craters produced. Increases in laser energy were compared with increases in surface area, depth, and volume of craters produced within the range of 150 to 1200 mJ. The Ho:YAG laser fiberoptic delivery system used in this study provides an effective means of ablating dentin. Three-dimensional stereophotogrammetry may prove to be a useful method for further studies on the effects of laser energy on mineralized tissues.

  3. The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

    NASA Astrophysics Data System (ADS)

    Rodrigues, S. R.; Moraes, M.; Hanashiro, F. S.; Youssef, M. N.; Brugnera Junior, A.; Nobre-dos-Santos, M.; de Souza-Zaroni, W. C.

    2016-02-01

    Although the cariostatic effects of CO2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n  =  10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO2 laser with an energy density of 6.0 J cm-2  +  non-fluoride dentifrice; and L  +  FD, CO2 laser  +  fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey-Kramer test (p  ⩽  0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC-C group. It was concluded that CO2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used.

  4. Shear Bond Strength of an Etch-and-rinse Adhesive to Er:YAG Laser- and/or Phosphoric Acid-treated Dentin

    PubMed Central

    Davari, Abdolrahim; Sadeghi, Mostafa; Bakhshi, Hamid

    2013-01-01

    Background and aims. Er:YAG laser irradiation has been claimed to improve the adhesive properties of dentin; therefore, it has been proposed as an alternative to acid etching. The aim of this in vitro study was to investigate the shear bond strength of an etch-and-rinse adhesive system to dentin surfaces following Er:YAG laser and/or phosphoric acid etching. Materials and methods. The roots of 75 sound maxillary premolars were sectioned below the CEJ and the crowns were embedded in auto-polymerizing acrylic resin with the buccal surfaces facing up. The buccal surfaces were ground using a diamond bur and polished until the dentin was exposed; the samples were randomly divided into five groups (n=15) according to the surface treatment: (1) acid etching; (2) laser etching; (3) laser etching followed by acid etching; (4) acid etching followed by laser etching and (5) no acid etching and no laser etching (control group). Composite resin rods (Point 4, Kerr Co) were bonded to treated dentin surfaces with an etch-and-rise adhesive system (Optibond FL, Kerr Co) and light-cured.After storage for two weeks at 37°C and 100% humidity and then thermocycling, bond strength was measured with a Zwick Universal Testing Machine at a crosshead speed of 1 mm/min. Data was analyzed using parametric and non-parametric tests (P<0.05). Results. Mean shear bond strength for acid etching (20.1±1.8 MPa) and acid+laser (15.6±3.5 MPa) groups were significantly higher than those for laser+acid (15.6±3.5 MPa), laser etching (14.1±3.4 MPa) and control (8.1±2.1 MPa) groups. However, there were no significant differences between acid etching and acid+laser groups, and between laser+acid and laser groups. Conclusion. When the cavity is prepared by bur, it is not necessary to etch the dentin surface by Er:YAG laser following acid etching and acid etching after laser etching. PMID:23875083

  5. Influence of laser irradiation on fiber post retention.

    PubMed

    Nagase, Denis Y; de Freitas, Patricia M; Morimoto, Susana; Oda, Margareth; Vieira, Glauco F

    2011-05-01

    The purpose of this in vitro study was to compare the bond strength between fiber post and laser-treated root canals. Forty single-rooted bovine teeth were endodontically treated and randomly divided into four groups of equal size according to the root canal treatment: group 1 conventional treatment (without laser irradiation); group 2 Nd:YAG laser (1.5 W, 10 Hz, 100 mJ); group 3 Er,Cr:YSGG laser (0.75 W, 20 Hz); and group 4 Nd:YAG + Er,Cr:YSGG lasers. The fiber posts were cemented with an adhesive system + resin cement, in accordance with the manufacturer's instructions. A mini acrylic pipe was fixed on the coronal section of the post using a light-polymerized resin. Specimens were mounted on an acrylic pipe with a self-polymerized resin. Retention forces were determined using a universal testing machine (0.5 mm/min). Data were analyzed using one-way ANOVA and Tukey tests (p <0.05). The post retention force in group 2 was found to be lower than that in the other experimental groups. Fractures were observed at the interface between the dentin and the resin in all groups. High-intensity lasers can be used in conventional endodontic treatment; however, root canal surface irradiation using the Nd:YAG laser was shown to negatively affect the post retention force.

  6. Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

    PubMed

    Arslan, Hakan; Yeter, Kübra Y; Karatas, Ertugrul; Yilmaz, Cenk B; Ayranci, Leyla B; Ozsu, Damla

    2015-02-01

    The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA.

  7. Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

    PubMed

    Arslan, Hakan; Yeter, Kübra Y; Karatas, Ertugrul; Yilmaz, Cenk B; Ayranci, Leyla B; Ozsu, Damla

    2015-02-01

    The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA. PMID:23793370

  8. Cementum and dentin in hypophosphatasia.

    PubMed

    van den Bos, T; Handoko, G; Niehof, A; Ryan, L M; Coburn, S P; Whyte, M P; Beertsen, W

    2005-11-01

    Hypophosphatasia (HPP) often leads to premature loss of deciduous teeth, due to disturbed cementum formation. We addressed the question to what extent cementum and dentin are similarly affected. To this end, we compared teeth from children with HPP with those from matched controls and analyzed them microscopically and chemically. It was observed that both acellular and cellular cementum formation was affected. For dentin, however, no differences in mineral content were recorded. To explain the dissimilar effects on cementum and dentin in HPP, we assessed pyrophosphate (an inhibitor of mineralization) and the expression/activity of enzymes related to pyrophosphate metabolism in both the periodontal ligament and the pulp of normal teeth. Expression of nucleotide pyrophosphatase phosphodiesterase 1 (NPP1) in pulp proved to be significantly lower than in the periodontal ligament. Also, the activity of NPP1 was less in pulp, as was the concentration of pyrophosphate. Our findings suggest that mineralization of dentin is less likely to be under the influence of the inhibitory action of pyrophosphate than mineralization of cementum. PMID:16246934

  9. The effect of radiation therapy on the mechanical and morphological properties of the enamel and dentin of deciduous teeth—an in vitro study

    PubMed Central

    2014-01-01

    Purpose To evaluate the effects of radiation therapy on deciduous teeth. Materials and methods The enamel and dentin microhardness (n = 12) was evaluated at 3 depths, both before (control) and after each 10 Gy of irradiation and up to a dose of 60 Gy. The morphology was evaluated via scanning electron microscopy (SEM) (n = 8). The data were analyzed using a two-way analysis of variance (ANOVA) and Tukey’s test (α = 5%). Results The enamel microhardness, as a whole, increased (p < 0.05) after a dose of 60 Gy (211.4 KH), mostly in the superficial enamel. There was a significant difference between the values of nonirradiated dentin microhardness (28.9 KH) compared with dentin that was irradiated with doses of 10 Gy (23.8 KH), 20 Gy (25.6 KH), 30 Gy (24.8 KH), and 40 Gy (25.7 KH) (p < 0.05). There was no difference between nonirradiated dentin and dentin irradiated with 60 Gy (p > 0.05). The highest mean value of microhardness (29.9 KH) (p < 0.05) was found in the middle dentin. The groups that were irradiated with doses of 30 and 60 Gy exhibited greater surface changes in their enamel and dentin compared with the nonirradiated groups for all regions, exhibiting an amorphous surface upon increase of the irradiation doses. Conclusions The enamel microhardness increased at a dose of 60 Gy, whereas the value of the dentin microhardness did not change. A progressive disruption of enamel and dentin morphology was found with the increased radiation dose. PMID:24450404

  10. Transmission of Curing Light through Moist, Air-Dried, and EDTA Treated Dentine and Enamel

    PubMed Central

    Uusitalo, E.; Varrela, J.; Lassila, L.; Vallittu, P. K.

    2016-01-01

    Objective. This study measured light transmission through enamel and dentin and the effect of exposed dentinal tubules to light propagation. Methods. Light attenuation through enamel and dentin layers of various thicknesses (1 mm, 2 mm, 3 mm, and 4 mm) was measured using specimens that were (1) moist and (2) air-dried (n = 5). Measurements were repeated after the specimens were treated with EDTA. Specimens were transilluminated with a light curing unit (maximum power output 1869 mW/cm2), and the mean irradiance power of transmitting light was measured. The transmission of light through teeth was studied using 10 extracted intact human incisors and premolars. Results. Transmitted light irradiance through 1 mm thick moist discs was 500 mW/cm2 for enamel and 398 mW/cm2 for dentin (p < 0.05). The increase of the specimen thickness decreased light transmission in all groups (p < 0.005), and moist specimens attenuated light less than air-dried specimens in all thicknesses (p < 0.05). EDTA treatment increased light transmission from 398 mW/cm2 to 439 mW/cm2 (1 mm dentin specimen thickness) (p < 0.05). Light transmission through intact premolar was 6.2 mW/cm2 (average thickness 8.2 mm) and through incisor was 37.6 mW/cm2 (average thickness 5.6 mm). Conclusion. Light transmission through enamel is greater than that through dentin, probably reflecting differences in refractive indices and extinction coefficients. Light transmission through enamel, dentin, and extracted teeth seemed to follow Beer-Lambert's law. PMID:27446954

  11. Effect of cleaning methods on bond strength of self-etching adhesive to dentin

    PubMed Central

    Bronzato, Juliana Delatorre; Cecchin, Doglas; Miyagaki, Daniela Cristina; de Almeida, José Flávio Affonso; Ferraz, Caio Cezar Randi

    2016-01-01

    Aim: The aim of this study was to investigate the influence of cleaning methods to remove zinc oxide-eugenol-based root canal sealer (Endomethasone) on the bond strength of the self-etching adhesive to dentin. Materials and Methods: Twenty crowns of bovine incisors were cut to expose the pulp chamber. A zinc oxide- and eugenol-based sealer was placed for 10 min in contact with the pulp chamber dentin. Specimens were divided into four groups according to the cleaning method of dentin used: G1, no root canal sealer (control); G2, 0.9% sodium chlorite (NaCl); G3, ethanol; and G4, followed by diamond drill. After cleaning, the teeth were restored with composite resin and Clearfil SE Bond. All specimens were sectioned to produce rectangular sticks and dentin/resin interface was submitted to microtensile bond testing. The mean bond strengths were analyzed using ANOVA/Tukey (α = 0.05). Results: G3 and G4 showed bond strengths similar to the G1 (P > 0.05). A significant decrease in the bond strength in the G2 was observed (P < 0.05). G1, G3, and G4, the predominant failure mode was the mixed type. The prevalence of adhesive failure mode was verified in the G2. Conclusion: The cleaning methods affected the bond strength of the self-etching adhesive to dentin differently. PMID:26957789

  12. Photoactivated rose bengal functionalized chitosan nanoparticles produce antibacterial/biofilm activity and stabilize dentin-collagen

    PubMed Central

    Shrestha, Annie; Hamblin, Michael R.; Kishen, Anil

    2014-01-01

    Treatment of infected teeth presents two major challenges: persistence of the bacterial-biofilm within root canals after treatment and compromised structural integrity of the dentin hard-tissue. In this study bioactive polymeric chitosan nanoparticles functionalized with rose-bengal, CSRBnp was developed to produce antibiofilm effects as well as stabilize structural-integrity by photocrosslinking dentin-collagen. CSRBnp was less toxic to fibroblasts and had significant antibacterial activity even in the presence of bovine serum albumin. CSRBnp exerted antibacterial mechanism by adhering to bacterial cell surface, permeabilizing the membrane and lysing the cells subsequent to photodynamic treatment. Photoactivated CSRBnp resulted in reduced viability of Enterococcus faecalis biofilms and disruption of biofilm structure. Incorporation of CSRBnp and photocrosslinking significantly improved resistance to degradation and mechanical strength of dentin-collagen (p<0.05). The functionalized chitosan nanoparticles provided a single-step treatment of infected root dentin by combining the properties of chitosan and that of photosensitizer to eliminate bacterial-biofilms and stabilize dentin-matrix. PMID:24200522

  13. The use of dentin matrix scaffold and dental follicle cells for dentin regeneration.

    PubMed

    Guo, Weihua; He, Yong; Zhang, Xiaojun; Lu, Wei; Wang, Chunmei; Yu, Hua; Liu, Yuan; Li, Yuan; Zhou, Yalei; Zhou, Jing; Zhang, Manjing; Deng, Zhihong; Jin, Yan

    2009-12-01

    Scaffold and inductive microenvironment are the two most important factors for dentin regeneration. They have been addressed with hydroxyapatite, tricalcium phosphate, polyglycolic acid, calcined bovine bone, and collagen, among other things. However, as of yet, no scaffold and inductive microenvironment combination has been shown to contribute to the regeneration of complete and prefabricated-shaped dentin tissues that include dentin, predentin and odontoblasts. To test the supporting and inductive effects of treated dentin matrix (TDM) on complete and prefabricated-shaped dentin regeneration, dental follicle cells (DFCs) were seeded onto TDM and further incubated for 1 and 2 weeks in vitro and for 2 and 4 weeks in vivo. The results show that in vitro, in addition to dentin sialoprotein (DSP) and dentin matrix protein 1 (DMP1) (regarded as identifying markers of odontoblasts), DFCs induced by TDM expressed osteocalcin, bone sialoprotein, type I collagen, osteopontin, osteonectin and alkaline phosphatase (all expressed by odontoblasts), and that complete and prefabricated-shaped dentin was successfully regenerated. Most importantly, it was found that in vivo TDM supports and induces regeneration of complete and prefabricated-shaped dentin, and regenerated dentin expresses DSP and DMP1, which are identifying dentin markers. Taken together, these results suggest that, for dentin regeneration, TDM is a suitable scaffold and inductive microenvironment and DFCs are a suitable cell type. The combination of TDM and DFCs may constitute a promising approach for future clinical dentin regeneration.

  14. Holmium:YAG laser: effects of various treatments on root surface topography and acid resistance

    NASA Astrophysics Data System (ADS)

    Holt, Raleigh A.; Nordquist, Robert E.

    1996-04-01

    The effects of Holmium:YAG laser energy with and without a topical fluoride mixture (resin to NaF) was compared with two types of topical fluorides on surface topography and resistance to acid destruction of root surfaces. Scanning electron microscopy (SEM) was used to evaluate the effects of the selected treatments on surface topography before acid exposure. Toluidine blue dye was used to test the permeability of root surfaces after acid exposures. SEM examinations of the dentinal root surfaces showed consistently smooth surfaces with tubule closures when using topical resin to fluoride and HO:YAG laser treatment; in contrast, HO:YAG laser energy treatment alone exhibited increased roughness of root surfaces. Topical fluoride applications alone presented surfaces similar to untreated control sites. Toluidine blue dye penetration into root surfaces of the fluoride/laser-treated root surfaces showed significantly less dye penetration after acid exposures than controls and other treatment protocols. The results of this study indicate that the resin-fluoride application and holmium:YAG irradiation effectively produced increased smoothness and increased resistance to destruction of root surfaces in human extracted teeth under these in vitro conditions.

  15. Microshear bond strength according to dentin cleansing methods before recementation

    PubMed Central

    Taşar, Simge; Ulusoy, Mutahhar Muhammed

    2014-01-01

    PURPOSE The aim of this study was to determine the efficiency of Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser in different output powers for removing permanent resin cement residues and therefore its influence on microshear bond strength compared to other cleaning methods. MATERIALS AND METHODS 90 extracted human molars were sectioned in 1 mm thickness. Resin cement was applied to surface of sliced teeth. After the removal of initial cement, 6 test groups were prepared by various dentin surface treatment methods as follows: no treatment (Group 1), ethylene diamine tetra acetic acid application (Group 2), Endosolv R application (Group 3), 1.25 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 4), 2 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 5) and 3.5 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 6). The topography and morphology of the treated dentin surfaces were investigated by scanning electron microscopy (n=2 for each group). Following the repetitive cementation, microshear bond strength between dentin and cement (n=26 in per group) were measured with universal testing machine and the data were analyzed by Kruskal Wallis H Test with Bonferroni correction (P<.05). Fracture patterns were investigated by light microscope. RESULTS Mean microshear bond strength ± SD (MPa) for each group was 34.9 ± 17.7, 32.1 ± 15.8, 37.8 ± 19.3, 31.3 ± 12.7, 44.4 ± 13.6, 40.2 ± 13.2 respectively. Group 5 showed significantly difference from Group 1, Group 2 and Group 4. Also, Group 6 was found statistically different from Group 4. CONCLUSION 2 W and 3.5 W Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser application were found efficient in removing resin residues. PMID:24843391

  16. Contraction stress in dentin adhesives bonded to dentin.

    PubMed

    Hashimoto, M; de Gee, A J; Kaga, M; Feilzer, A J

    2006-08-01

    Adhesives cured under constrained conditions develop contraction stresses. We hypothesized that, with dentin as a bonding substrate, the stress would reach a maximum, followed by a continuous decline. Stress development was determined with a tensilometer for two total-etch systems and two systems with self-etching primers. The adhesives were placed in a thin layer between a glass plate and a flat dentin surface pretreated with phosphoric acid or self-etching primer. After an initial maximum shortly after light-curing, the stress decreased dramatically for the total-etch systems (70%) and, to a lesser extent, for the adhesives with self-etching primers (30%). The greater stress decrease for the total-etch systems was ascribed to water and/or solvents released into the adhesives from the fully opened dentinal tubules by the pulling/sucking action of the contraction stress. This happened less with the adhesives with self-etching primers, where the tubules remained mainly closed.

  17. 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.

  18. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia.

    PubMed

    Barron, Martin J; McDonnell, Sinead T; Mackie, Iain; Dixon, Michael J

    2008-11-20

    The hereditary dentine disorders, dentinogenesis imperfecta (DGI) and dentine dysplasia (DD), comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear. Currently, three sub-types of DGI and two sub-types of DD are recognised but this categorisation may change when other causative mutations are found. DGI type I is inherited with osteogenesis imperfecta and recent genetic studies have shown that mutations in the genes encoding collagen type 1, COL1A1 and COL1A2, underlie this condition. All other forms of DGI and DD, except DD-1, appear to result from mutations in the gene encoding dentine sialophosphoprotein (DSPP), suggesting that these conditions are allelic. Diagnosis is based on family history, pedigree construction and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Differential diagnoses include hypocalcified forms of amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann's disease, cyclic neutropenia, Chediak-Hegashi syndrome, histiocytosis X, Papillon-Lefevre syndrome), permanent teeth discolouration due to tetracyclines, Vitamin D-dependent and vitamin D-resistant rickets. Treatment involves removal of sources of infection or pain, improvement of aesthetics and protection of the posterior teeth from wear. Beginning in infancy, treatment usually continues into adulthood with a number of options including

  19. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia

    PubMed Central

    Barron, Martin J; McDonnell, Sinead T; MacKie, Iain; Dixon, Michael J

    2008-01-01

    The hereditary dentine disorders, dentinogenesis imperfecta (DGI) and dentine dysplasia (DD), comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear. Currently, three sub-types of DGI and two sub-types of DD are recognised but this categorisation may change when other causative mutations are found. DGI type I is inherited with osteogenesis imperfecta and recent genetic studies have shown that mutations in the genes encoding collagen type 1, COL1A1 and COL1A2, underlie this condition. All other forms of DGI and DD, except DD-1, appear to result from mutations in the gene encoding dentine sialophosphoprotein (DSPP), suggesting that these conditions are allelic. Diagnosis is based on family history, pedigree construction and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Differential diagnoses include hypocalcified forms of amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann's disease, cyclic neutropenia, Chediak-Hegashi syndrome, histiocytosis X, Papillon-Lefevre syndrome), permanent teeth discolouration due to tetracyclines, Vitamin D-dependent and vitamin D-resistant rickets. Treatment involves removal of sources of infection or pain, improvement of aesthetics and protection of the posterior teeth from wear. Beginning in infancy, treatment usually continues into adulthood with a number of options including

  20. Ex vivo fracture resistance of endodontically treated maxillary central incisors restored with fiber-reinforced composite posts and experimental dentin posts

    PubMed Central

    Kathuria, Ambica; Kavitha, M; Khetarpal, Suchit

    2011-01-01

    Aim: To compare the fracture resistance of teeth restored with fiber-reinforced composite (FRC) posts and experimental dentin posts milled from human root dentin. Materials and Methods: Thirty maxillary central incisors were divided into three groups of ten each. Twenty teeth were restored with FRC posts and solid dentin posts and numbered as Groups 2 and 3 respectively while Group 1 acted as the control, without any post. The teeth were loaded at 135° angle to their long axes after core build-up and the failure loads were recorded. Results: One-way Analysis of Variance (ANOVA) and Bonferroni multiple comparisons revealed a significant difference among test groups with the control group showing the highest fracture resistance, followed by the dentin post group and lastly the FRC post group. Conclusions: Teeth restored with dentin posts exhibited better fracture resistance than those restored with FRC posts. PMID:22144812

  1. Degradation in the dentin-composite interface subjected to multi-species biofilm challenges.

    PubMed

    Li, Y; Carrera, C; Chen, R; Li, J; Lenton, P; Rudney, J D; Jones, R S; Aparicio, C; Fok, A

    2014-01-01

    Oral biofilms can degrade the components in dental resin-based composite restorations, thus compromising marginal integrity and leading to secondary caries. This study investigates the mechanical integrity of the dentin-composite interface challenged with multi-species oral biofilms. While most studies used single-species biofilms, the present study used a more realistic, diverse biofilm model produced directly from plaques collected from donors with a history of early childhood caries. Dentin-composite disks were made using bovine incisor roots filled with Z100(TM) or Filtek(TM) LS (3M ESPE). The disks were incubated for 72 h in paired CDC biofilm reactors, using a previously published protocol. One reactor was pulsed with sucrose, and the other was not. A sterile saliva-only control group was run with sucrose pulsing. The disks were fractured under diametral compression to evaluate their interfacial bond strength. The surface deformation of the disks was mapped using digital image correlation to ascertain the fracture origin. Fracture surfaces were examined using scanning electron microscopy/energy-dispersive X-ray spectroscopy to assess demineralization and interfacial degradation. Dentin demineralization was greater under sucrose-pulsed biofilms, as the pH dropped <5.5 during pulsing, with LS and Z100 specimens suffering similar degrees of surface mineral loss. Biofilm growth with sucrose pulsing also caused preferential degradation of the composite-dentin interface, depending on the composite/adhesive system used. Specifically, Z100 specimens showed greater bond strength reduction and more frequent cohesive failure in the adhesive layer. This was attributed to the inferior dentin coverage by Z100 adhesive, which possibly led to a higher level of chemical and enzymatic degradation. The results suggested that factors other than dentin demineralization were also responsible for interfacial degradation. A clinically relevant in vitro biofilm model was therefore

  2. Evaluation of the dentinal wall adaptation ability of MTA Fillapex using stereo electron microscope

    PubMed Central

    Demiriz, Levent; Koçak, Mustafa Murat; Koçak, Sibel; Sağlam, Baran Can; Türker, Sevinç Aktemur

    2016-01-01

    Background: An ideal root canal obturation requires a complete dentinal wall adaptation of sealer and Gutta-percha combinations without any gap formations. Aims: The aim of the study was to evaluate the dentinal wall adaptation ability of MTA Fillapex root canal sealer using stereo electron microscope (SEM). Methods: Twenty-four, single-rooted, human maxillary incisor teeth were used. All canals were prepared with a rotary nickel–titanium (Ni–Ti) instrument to a size F3 file. Teeth divided into two equal groups and one of the experimental groups was filled with AH Plus, and the other group was filled with MTA Fillapex using Gutta-percha single cone as a core material. The roots were prepared for SEM evaluation, and serial scanning electron photomicrographs were taken at ×50, ×100, ×500, and ×1000 magnifications. The gaps between the root canal sealer and canal walls were detected and measured in coronal, middle, and apical thirds. For each section, the highest value among the detected gap formations was recorded. Statistical Analysis: Mann–Whitney U-test, Freidman, and Wilcoxon tests were used. Results: The statistical analysis showed no significant difference between two sealers in terms of gap formation (P > 0.05). Conclusions: MTA Fillapex has a similar dentinal wall adaptation ability as AH Plus does. PMID:27217633

  3. Wettability of dentin after Yb:KYW thin-disk femtosecond ablation.

    PubMed

    Liu, Jing; Lü, Peijun; Sun, Yuchun; Wang, Yong

    2015-08-01

    The aim of this study was to quantitatively evaluate the wettability of dentin after Yb:KYW thin-disk femtosecond-pulsed laser ablation by measuring the contact angle. Different laser parameters were used including different fluences (F), scanning speeds, and scanning line spacings. Crowns of 15 extracted human teeth were cut longitudinally into slices approximately 1.5-mm thick with a cutting instrument. The samples were randomly divided into ten groups (n = 3/group). Samples in groups 1-8 were irradiated with a femtosecond-pulsed laser. The dentin samples were fixed on a stage at the focal plane, and the laser beam irradiated the samples through a galvanometric scanning system so rectangular movement could be achieved. Samples in groups 9 and 10 were prepared with grinding instruments. Following ablation and preparation, the samples were examined for contact angle with an optical contact angle measuring instrument. The results showed that scanning speed and scanning line spacing had little influence on the wettability of dentin following femtosecond-pulsed laser ablation, except when F = 6 J/cm(2). For six out of the eight laser ablation groups, when a lower fluence was used, the dentin contact angle was higher and vice versa. Most of the dentin which had been ablated using the femtosecond-pulsed laser had improved wettability compared to samples prepared with the grinding instruments. This study showed that various laser fluences, scanning speeds, and scanning line spacings can alter dentin wettability. Therefore, adequate parameters should be chosen to achieve proper therapeutic benefits.

  4. 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.

  5. Chelating and antibacterial properties of chitosan nanoparticles on dentin

    PubMed Central

    Bramante, Clovis Monteiro; Duarte, Marco Antonio Hungaro; de Moura, Marcia Regina; Aouada, Fauze Ahmad; Kishen, Anil

    2015-01-01

    Objectives The use of chitosan nanoparticles (CNPs) in endodontics is of interest due to their antibiofilm properties. This study was to investigate the ability of bioactive CNPs to remove the smear layer and inhibit bacterial recolonization on dentin. Materials and Methods One hundred bovine dentin sections were divided into five groups (n = 20 per group) according to the treatment. The irrigating solutions used were 2.5% sodium hypochlorite (NaOCl) for 20 min, 17% ethylenediaminetetraacetic acid (EDTA) for 3 min and 1.29 mg/mL CNPs for 3 min. The samples were irrigated with either distilled water (control), NaOCl, NaOCl-EDTA, NaOCl-EDTA-CNPs or NaOCl-CNPs. After the treatment, half of the samples (n = 50) were used to assess the chelating effect of the solutions using portable scanning electronic microscopy, while the other half (n = 50) were infected intra-orally to examine the post-treatment bacterial biofilm forming capacity. The biovolume and cellular viability of the biofilms were analysed under confocal laser scanning microscopy. The Kappa test was performed for examiner calibration, and the non-parametric Kruskal-Wallis and Dunn tests (p < 0.05) were used for comparisons among the groups. Results The smear layer was significantly reduced in all of the groups except the control and NaOCl groups (p < 0.05). The CNPs-treated samples were able to resist biofilm formation significantly better than other treatment groups (p < 0.05). Conclusions CNPs could be used as a final irrigant during root canal treatment with the dual benefit of removing the smear layer and inhibiting bacterial recolonization on root dentin. PMID:26295022

  6. Effect of dentin dehydration and composite resin polymerization mode on bond strength of two self-etch adhesives

    PubMed Central

    Samimi, Pooran; Alizadeh, Mehdi; Shirban, Farinaz; Davoodi, Amin; Khoroushi, Maryam

    2016-01-01

    Background: Dual-cured composite resins are similar to self-cured composite resins in some of their clinical applications due to inadequate irradiation, lack of irradiation, or delayed irradiation. Therefore, incompatibility with self-etch adhesives (SEAs) should be taken into account with their use. On the other, the extent of dentin dehydration has a great role in the quality of adhesion of these resin materials to dentin. The aim of this study was to investigate the effect of dentin dehydration and composite resin polymerization mode on bond strength of two SEAs. Materials and Methods: A total of 120 dentinal specimens were prepared from extracted intact third molars. Half of the samples were dehydrated in ethanol with increasing concentrations. Then Clearfil SE Bond (CSEB) and Prompt L-Pop (PLP) adhesives were applied in the two groups. Cylindrical composite resin specimens were cured using three polymerization modes: (1) Immediate light-curing, (2) delayed light-curing after 20 min, and (3) self-curing. Bond strength was measured using universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with two-way ANOVA and Duncan post hoc tests. Statistical significance was defined at P < 0.05. Results: There were no significant differences for CSEB subgroups with hydrated and dehydrated dentin samples between the three different curing modes (P > 0.05). PLP showed significant differences between subgroups with the lowest bond strength in hydrated dentin with delayed light-curing and self-cured mode of polymerization. Conclusion: Within the limitations of this study, a delay in composite resin light-curing or using chemically cured composite resin had a deleterious effect on dentin bond strength of single-step SEAs used in the study. PMID:27041894

  7. Hydration and dynamic fatigue of dentin.

    PubMed

    Arola, D; Zheng, W

    2006-04-01

    An experimental investigation on the dynamic fatigue response of dentin was conducted to examine the influence of stress rate on the strength and energy to fracture. Rectangular beams were prepared from the coronal dentin of bovine maxillary molars and subjected to four-point flexure to failure. The dentin beams were examined in the fully hydrated and dehydrated condition at stress rates (sigma) ranging from 0.01 to 100 MPa/s. Results for the hydrated dentin showed that the flexure strength, energy to fracture, and flexure modulus all increased with increasing stress rate; the flexure strength increased from 100 MPa ((sigma) = 0.01 MPa/s) to 250 MPa ((sigma) = 100 MPa/s). In contrast, the elastic modulus and strength of the dehydrated dentin decreased with increasing stress rate; the flexural strength of the dehydrated dentin deceased from 170 MPa ((sigma) = 0.01 MPa/s) to 100 MPa ((sigma) = 100 MPa/s). While the hydrated dentin behaved more like a brittle material at low stress rates, the strain to fracture was found to be nearly independent of (sigma). According to the experimental results, restorative conditions that cause development of static stresses within the tooth could promote a decrease in the damage tolerance of dentin.

  8. Management of dentinal hypersensitivity: a review.

    PubMed

    Parolia, Abhishek; Kundabala, M; Mohan, Mandakini

    2011-03-01

    Dentinal hypersensitivity is a very common clinical finding that can cause considerable concern for the patient. Clinicians must understand the various etiological factors, their complexities, and numerous treatment options available. This article reviews the etiology, management, and prevention of dentinal hypersensitivity. PMID:21563596

  9. Selective excavation of human carious dentin using a nanosecond pulsed laser with a wavelength of 5.85 μm

    NASA Astrophysics Data System (ADS)

    Kita, Tetsuya; Ishii, Katsunori; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2013-06-01

    Less-invasive treatment of caries has been needed in laser dentistry. Based on the absorption property of dentin substrates, 6 μm wavelength range shows specific absorptions and promising characteristics for the excavation. In our previous study, 5.8 μm wavelength range was found to be effective for selective excavation of carious dentin and restoration treatment using composite resin from the irradiation experiment with bovine sound and demineralized dentin. In this study, the availability of 5.8 μm wavelength range for selective excavation of human carious dentin was investigated for clinical application. A mid-infrared tunable nanosecond pulsed laser by difference-frequency generation was used for revealing the ablation property of human carious dentin. Irradiation experiments indicated that the wavelength of 5.85 μm and the average power density of 30 W/cm2 realized the selective excavation of human carious dentin, but ablation property was different with respect to each sample because of the different caries progression. In conclusion, the wavelength of 5.85 μm could realize the selective excavation of human carious dentin, but it was necessary to evaluate the stage of caries progression in order to control the ablation property.

  10. 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.

  11. Dentine caries: take it or leave it?

    PubMed

    Banerjee, A; Watson, T F; Kidd, E A

    2001-04-01

    In modern dentistry the primary aim when excavating carious dentine is to eradicate only the highly infected, irreversibly demineralised and denatured biomass in order to allow effective restoration of the cavity, restoration of the surface anatomy of the tooth and to prevent disease progression. However, the boundary between this superficial zone of dentine requiring excavation and the deeper, affected but repairable tissue is not always obvious either in the clinic or in the research laboratory. The inherent subjectivity in detecting this excavation boundary can result in clinically significant differences in the quality and quantity of dentine removed by different operators and makes the in vitro comparison of newer excavation techniques more difficult. This article discusses the rationale behind carious dentine excavation and the criteria available to the dentist, both clinical and laboratory, to help identify the dentine requiring removal. PMID:11436234

  12. Dentine caries: take it or leave it?

    PubMed

    Banerjee, A; Watson, T F; Kidd, E A

    2000-01-01

    In modern dentistry the primary aim when excavating carious dentine is to eradicate only the highly infected, irreversibly demineralized and denatured biomass in order to allow effective restoration of the cavity, restoration of the surface anatomy of the tooth and to prevent disease progression. However, the boundary between this superficial zone of dentine requiring excavation and the deeper, affected but repairable tissue is not always obvious either in the clinic or in the research laboratory. The inherent subjectivity in detecting this excavation boundary can result in clinically significant differences in the quality and quantity of dentine removed by different operators and makes the in vitro comparison of newer excavation techniques more difficult. This article discusses the rationale behind carious dentine excavation and the criteria available to the dentist, both clinical and laboratory, to help identify the dentine requiring removal. PMID:11218463

  13. 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.

  14. 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. PMID:12120777

  15. Cervical microleakage in root canals treated with Er:YAG and Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Sponchiado, Emilio C., Jr.; Azevedo, Lidiany K.; Marchesan, Melissa; Brugnera, Aldo, Jr.; Silva-Sousa, Yara T.; Alfredo, Edson; Sousa Neto, Manoel D.

    2005-03-01

    Cervical microleakage was evaluated in sealed root canals previously treated with Er:YAG and Nd:YAG lasers. Ninety-two single-rooted maxillary human canines were prepared with the crown-down technique and irrigated with distilled and deionized water. The samples were distributed randomly into 9 groups of 10 teeth each. One tooth was used as a positive control and one as a negative control. In group I, 1.2 ml of EDTAC was applied during 5 min. In groups II to V, radicular dentine was irradiated with Er:YAG laser (Opus 20, Opus Dent, Israel) at the following parameters: 200 mJ and 8 Hz, 200 mJ and 16 Hz, 400 mJ and 8 Hz, or 400 mJ and 16Hz, respectively, for 60 s. In groups VI to IX, radicular dentine was irradiated with Nd:YAG laser (Fotona Medical Lasers, Slovenia) at 10 Hz and 1 W, 10 Hz and 2 W, 15 Hz and 1 W, or 15 Hz and 2 W, respectively, for 60 s. The canals were then sealed by the lateral condensation technique with an epoxy resin-based sealer. The roots were immersed in India ink for 15 days and then cleared to visualize the level of cervical microleakage with a measurement microscope. The results were evaluated by the Kruskal-Wallis test, which showed no statistical significance (p>0.01) for parameter variations of the Er:YAG laser when compared to the control group. However, the increase in frequency and potency for Nd:YAG laser decreased the microleakage when compared to the control group.

  16. Comparative study of age estimation using dentinal translucency by digital and conventional methods

    PubMed Central

    Bommannavar, Sushma; Kulkarni, Meena

    2015-01-01

    Introduction: Estimating age using the dentition plays a significant role in identification of the individual in forensic cases. Teeth are one of the most durable and strongest structures in the human body. The morphology and arrangement of teeth vary from person-to-person and is unique to an individual as are the fingerprints. Therefore, the use of dentition is the method of choice in the identification of the unknown. Root dentin translucency is considered to be one of the best parameters for dental age estimation. Traditionally, root dentin translucency was measured using calipers. Recently, the use of custom built software programs have been proposed for the same. Objectives: The present study describes a method to measure root dentin translucency on sectioned teeth using a custom built software program Adobe Photoshop 7.0 version (Adobe system Inc, Mountain View California). Materials and Methods: A total of 50 single rooted teeth were sectioned longitudinally to derive a 0.25 mm uniform thickness and the root dentin translucency was measured using digital and caliper methods and compared. The Gustafson's morphohistologic approach is used in this study. Results: Correlation coefficients of translucency measurements to age were statistically significant for both the methods (P < 0.125) and linear regression equations derived from both methods revealed better ability of the digital method to assess age. Conclusion: The custom built software program used in the present study is commercially available and widely used image editing software. Furthermore, this method is easy to use and less time consuming. The measurements obtained using this method are more precise and thus help in more accurate age estimation. Considering these benefits, the present study recommends the use of digital method to assess translucency for age estimation. PMID:25709325

  17. 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 dentin in thermal effects from the Nd:YAG laser. Enamel had lower maximum surface temperatures than dentin for all laser powers and times. The surface temperature ranged from 34 +/- 1 degree(s)C to 110 +/- 4 degree(s)C on enamel and 62 +/- 5 degree(s)C to 392 +/- 82 degree(s)C on dentin. As power and time of exposure increased, both the maximum surface temperature and thermal penetration distance increased. The greatest length of thermal effect on the surface (11.0 +/- 0.9 mm) and thermal penetration distance (4.7 +/- 0.4 mm) recorded were caused by the air-cooled turbine drill on dentin. Surface temperatures were much higher for the Nd:YAG laser applied to enamel

  18. Wavelength and average power density dependency of the recrystallization of tooth dentin using a MIR-FEL

    NASA Astrophysics Data System (ADS)

    Heya, Manabu; Awazu, Kunio

    2002-04-01

    Recrystallization of tooth dentin by the application of mid- infrared (MIR) pulsed-laser irradiation is one candidate for a novel, non-invasive treatment for the prevention of tooth decay. Recrystallized dentin functions in a similar way to dental enamel. To recrystallize the dentin effectively and non-invasively it is essential to estimate quantitatively and qualitatively the laser parameters, such as the wavelength and the average power density, required for recrystallization. The laser-tissue interaction is initiated effectively by selective excitation of phosphate acid ions (PO4) in the dentin. Using a tunable, MIR Free Electron Laser (FEL) in the wavelength region of 8.8- 10.6micrometers , corresponding to intense absorption bands due to PO4 vibration modes, we have investigated macroscopically extent of surface modification of dentin, and we have obtained experimental results related to the ablation depth, the MIR absorption spectrum, and the elemental chemical composition. From these results, it was found that (1) the laser parameters at which efficient surface modification, without enhanced ablation effects, occurred were estimated to be approximately in the wavelength and average power density regions of ~9.4- 10.3micrometers and ~10-20 W/cm2, and that (2) in this region PO4 vibration modes with lower binding energy were preferentially excluded from the dentin.

  19. Neural crest deletion of Dlx3 leads to major dentin defects through down-regulation of Dspp.

    PubMed

    Duverger, Olivier; Zah, Angela; Isaac, Juliane; Sun, Hong-Wei; Bartels, Anne K; Lian, Jane B; Berdal, Ariane; Hwang, Joonsung; Morasso, Maria I

    2012-04-01

    During development, Dlx3 is expressed in ectodermal appendages such as hair and teeth. Thus far, the evidence that Dlx3 plays a crucial role in tooth development comes from reports showing that autosomal dominant mutations in DLX3 result in severe enamel and dentin defects leading to abscesses and infections. However, the normal function of DLX3 in odontogenesis remains unknown. Here, we use a mouse model to demonstrate that the absence of Dlx3 in the neural crest results in major impairment of odontoblast differentiation and dentin production. Mutant mice develop brittle teeth with hypoplastic dentin and molars with an enlarged pulp chamber and underdeveloped roots. Using this mouse model, we found that dentin sialophosphoprotein (Dspp), a major component of the dentin matrix, is strongly down-regulated in odontoblasts lacking Dlx3. Using ChIP-seq, we further demonstrate the direct binding of Dlx3 to the Dspp promoter in vivo. Luciferase reporter assays determined that Dlx3 positively regulates Dspp expression. This establishes a regulatory pathway where the transcription factor Dlx3 is essential in dentin formation by directly regulating a crucial matrix protein.

  20. In vitro biofilm formation on the surface of resin-based dentine adhesives.

    PubMed

    Rolland, Sarah L; McCabe, John F; Robinson, Colin; Walls, Angus W G

    2006-06-01

    Prevention of root caries on exposed root surfaces in the aging population is a significant challenge. Bonding resins can be applied to exposed root surfaces as sealants; however, minimal data exists regarding biofilm formation on the surface of these resins. We hypothesized that an antibacterial dentine-bonding resin containing methacryloxydodecyl-pyridiniumbromide (MDPB) may reduce biofilm formation. Biofilms were produced in pooled stimulated natural whole saliva, supplemented with 1% sucrose, on the surface of 5 dentine-bonding resins (Clearfil SE, OptiBond Solo, Protect Bond, Protect Bond Primer, and Xeno III) using untreated root surfaces as controls. Biofilms were stained using the Live:Dead Baclight bacterial viability stain, viewed with confocal microscopy, and analyzed using ImageJ image-analysis software. Resin surfaces encouraged attachment of live bacteria compared with root surfaces. All resins showed similar bacterial colonization in sections adjacent to the resin surface, but in the central and outer portions of biofilms, Xeno III and Protect Bond Primer showed a viable bacterial load similar to that of the root surface. Fluoride-releasing resins (OptiBond Solo/Protect Bond) did not show reduced biofilm formation. Thus, antibacterial agents within the resins have a minimal effect on biofilm formation, particularly when directly adjacent to the root surface.

  1. Dentin hypersensitivity: differential diagnosis, tests, and etiology.

    PubMed

    Trushkowsky, Richard D; Garcia-Godoy, Franklin

    2014-02-01

    Dentin hypersensitivity (DHS) is a painful condition that affects up to 57 percent of the adult population. It occurs as a result of exposure of dentin to the oral environment. Ensuring the correct diagnosis of this condition is based on history and examination. An oral screening for DHS should encompass such elements as patient history, clinical examination that includes radiographs, a variety of tests, identification of risk factors, and a differential diagnosis. An understanding of dentinal fluid and odontoblasts is also beneficial for diagnosis. PMID:24571559

  2. Morphological aspects and physical properties of enamel and dentine of Sus domesticus: A tooth model in laboratory research.

    PubMed

    Fagundes, Nathalia Carolina Fernandes; Cardoso, Miquéias André Gomes; Miranda, Mayara Sabrina Luz; Silva, Raira de Brito; Teixeira, Francisco Bruno; Nogueira, Bárbara Catarina Lima; Nogueira, Brenna Magdalena Lima; de Melo, Sara Elisama Silva; da Costa, Natacha Malu Miranda; Lima, Rafael Rodrigues

    2015-11-01

    This study aims to describe and analyze morphological and physical properties of deciduous teeth of Sus domesticus. Ultrastructural analysis, mineral composition and microhardness of enamel and dentine tissues were performed on 10 skulls of S. domesticus. External anatomic characteristics and the internal anatomy of the teeth were also described. Data regarding microhardness and ultrastructural analysis were subjected to statistical tests. For ultrastructural analysis, we used the analysis of variance (ANOVA) with Tukey's post hoc (p≤0.05) test. In the analysis of microhardness, the difference between the enamel and dentine tissues was analyzed by a Student's t test. Values were expressed as mean with standard error. The results of ultrastructural analysis showed the presence of an enamel prism pattern. A dentinal tubule pattern was also observed, with a larger diameter in the pulp chamber and the cervical third, in comparison to middle and apical thirds. We observed an average microhardness of 259.2kgf/mm(2) for enamel and 55.17kgf/mm(2) for dentine. In porcine enamel and dentine, the chemical elements Ca and P showed the highest concentration. The analysis of internal anatomy revealed the presence of a simple root canal system and the occurrence of main canals in the roots. The observed features are compatible with the functional demand of these animals, following a pattern very similar to that seen in other groups of mammals, which can encourage the development of research using dental elements from the pig as a substitute for human teeth in laboratory research.

  3. Near tubule and intertubular bovine dentin mapped at the 250 nm level

    PubMed Central

    Stock, S. R.; Veis, A.; Telser, A.; Cai, Z.

    2011-01-01

    In this study, simultaneous diffraction and fluorescence mapping with a (250 nm)2, 10.1 keV synchrotron x-ray beam investigated the spatial distribution of carbonated apatite (cAp) mineral and elemental Ca (and other cations including Zn) around dentin tubules. In 1 μm thick sections of near-pulp root dentin, where peritubular dentin (PTD) is newly forming, high concentrations of Zn, relative to those in intertubular dentin (ITD), were observed adjacent to and surrounding the tubule lumens. Some but not all tubules exhibited hypercalcified collars (high Ca signal relative to the surrounding ITD), and, when present, the zone of high Ca did not extend around the tubule. Diffraction rings from cAp 00.2 and 11.2+21.1+30.0 reflections were observed, and cAp was the only crystal phase detected. Profiles of Ca, Zn and cAp diffracted intensities showed the same transitions from solid to tubule lumen, indicating the same cAp content and organization in ITD far from the tubules and adjacent to them. Further, the matching Ca and diffraction profiles demonstrated that all of the Ca is in cAp or that any noncrystalline Ca was uniformly distributed throughout the dentin. Variation of 00.2 and 11.2+21.1+30.0 diffracted intensity was consistent with the expected biaxial crystallographic texture. Extension of x-ray mapping from near 1 μm resolution to the 250 nm level, performed here for dentin and its tubules, will provide new understanding of other mineralized tissues. PMID:21821132

  4. Degradation in the Dentin-Composite Interface Subjected to Multi-Species Biofilm Challenges

    PubMed Central

    Li, Yuping; Carrera, Carola; Chen, Ruoqiong; Li, Jianying; Patricia, Lenton; Rudney, Joel. D.; Jones, Robert S.; Aparicio, Conrado; Fok, Alex

    2013-01-01

    Oral biofilms can degrade the components in dental resin-based composite restorations, thus compromising marginal integrity and leading to secondary caries. In this study, we investigated the mechanical integrity of the dentin-composite interface challenged with multi-species oral biofilms. While most studies used single-species biofilms, we used a more realistic, diverse biofilm model produced directly from plaques collected from donors with a history of early childhood caries. Dentin–composite disks were made using bovine incisor roots filled with Z100™ or Filtek™ LS (3M ESPE). The disks were incubated for 72hr in paired CDC biofilm reactors, using a previously published protocol. One reactor was pulsed with sucrose, and the other was not. A sterile saliva-only control group was run with sucrose pulsing. The disks were fractured under diametral compression to evaluate their interfacial bond strength. Surface deformation of the disks was mapped using digital image correlation (DIC) to ascertain fracture origin. Fracture surfaces were examined using SEM/EDS to assess demineralization and interfacial degradation. Dentin demineralization was greater under sucrose-pulsed biofilms, as the pH dropped below 5.5 during pulsing, with LS and Z100 specimens suffering similar degrees of surface mineral loss. Biofilm growth with sucrose pulsing also caused preferential degradation of the composite-dentin interface, depending on the composite/adhesive system used. Specifically, Z100 specimens showed greater bond strength reduction and more frequent cohesive failure in the adhesive layer. This was attributed to the inferior dentin coverage by Z100 adhesive which possibly led to a higher level of chemical and enzymatic degradation. The results suggested that factors other than dentin demineralization were also responsible for interfacial degradation. We have thus developed a clinically relevant in vitro biofilm model which would allow us to effectively assess the

  5. Efficacy of stannous, fluoride and their their combination in dentin erosion prevention in vitro.

    PubMed

    Algarni, Amnah Abdullah; Lippert, Frank; Hara, Anderson Takeo

    2015-01-01

    The aim of this study was to compare the protective effects of solutions containing stannous (Sn), fluoride (F) and their combination in the prevention of dentin erosion. Forty bovine root dentin specimens (4'4'2 mm(3)) were prepared and randomly assigned to 4 groups (n = 10): SnCl2 (800 ppm/6.7 mM Sn), NaF (250 ppm/13 mM F), NaF/SnCl2 (800 ppm/6.7 mM Sn; 250 ppm/13 mM F), and deionized water (DIW) as a negative control. An acquired pellicle was formed on dentin samples by incubation in clarified, pooled, stimulated human saliva for 24 hours. The specimens were subjected to 5 daily cycles, each consisting of 5 of min demineralization (0.3%/15.6 mM citric acid, pH 2.6, 6'/day) and 60 min of re-mineralization in clarified human saliva. Thirty minutes after the 1st, 3rd and 5th demineralization episodes of each day, the specimens were treated with one of the test solutions for 2 min. Surface loss was measured via optical profilometry. Mixed-model ANOVA followed by Tukey's test were used for the statistical analysis. Sn, F, and their combination significantly reduced the dentin surface loss by 23%, 36%, and 60% compared with DIW, respectively. All groups were significantly different (p < 0.05). The combination of Sn and F significantly reduced the amount of dentin surface loss compared with all other groups. The F group also significantly reduced surface loss compared with Sn and DIW, followed by the Sn group, which showed significantly greater protection compared with the DIW control. The daily use of a combined fluoride and stannous solution is promising for preventing dentin erosion.

  6. Efficacy of stannous, fluoride and their their combination in dentin erosion prevention in vitro.

    PubMed

    Algarni, Amnah Abdullah; Lippert, Frank; Hara, Anderson Takeo

    2015-01-01

    The aim of this study was to compare the protective effects of solutions containing stannous (Sn), fluoride (F) and their combination in the prevention of dentin erosion. Forty bovine root dentin specimens (4'4'2 mm(3)) were prepared and randomly assigned to 4 groups (n = 10): SnCl2 (800 ppm/6.7 mM Sn), NaF (250 ppm/13 mM F), NaF/SnCl2 (800 ppm/6.7 mM Sn; 250 ppm/13 mM F), and deionized water (DIW) as a negative control. An acquired pellicle was formed on dentin samples by incubation in clarified, pooled, stimulated human saliva for 24 hours. The specimens were subjected to 5 daily cycles, each consisting of 5 of min demineralization (0.3%/15.6 mM citric acid, pH 2.6, 6'/day) and 60 min of re-mineralization in clarified human saliva. Thirty minutes after the 1st, 3rd and 5th demineralization episodes of each day, the specimens were treated with one of the test solutions for 2 min. Surface loss was measured via optical profilometry. Mixed-model ANOVA followed by Tukey's test were used for the statistical analysis. Sn, F, and their combination significantly reduced the dentin surface loss by 23%, 36%, and 60% compared with DIW, respectively. All groups were significantly different (p < 0.05). The combination of Sn and F significantly reduced the amount of dentin surface loss compared with all other groups. The F group also significantly reduced surface loss compared with Sn and DIW, followed by the Sn group, which showed significantly greater protection compared with the DIW control. The daily use of a combined fluoride and stannous solution is promising for preventing dentin erosion. PMID:26106907

  7. Energy-dependent RBE of neutrons to induce micronuclei in root-tip cells of Allium cepa onion irradiated as dry dormant seeds and seedlings.

    PubMed

    Zhang, Wenyi; Fujikawa, Kazuo; Endo, Satoru; Ishikawa, Masayori; Ohtaki, Megu; Ikeda, Hideo; Hoshi, Masaharu

    2003-06-01

    The relative biological effectiveness (RBE) of various energy neutrons produced from a Schenkel-type accelerator at the Research Institute for Radiation Biology and Medicine, Hiroshima University (HIRRAC), compared with 60Co gamma-ray radiation was determined. The neutron radiations and gamma-ray radiation produced good linear changes in the frequency of micronuclei induced in the root-tip cells of Allium cepa onion irradiated as dry dormant seeds (seed assay) and seedlings (seedling assay) with varying radiation doses. Therefore the RBE for radiation-induced micronuclei can be calculated as the ratio of the slopes of the fitted linear dose response for the neutron radiations and the 60Co gamma-ray radiation. The RBE values by seed assay and seedling assay decreased to 174 +/- 7, from 216 +/- 9, and to 31.4 +/- 1.0, from 45.3 +/- 1.3 (one standard error), respectively, when neutron energies increased to 1.0 MeV, from 0.2 MeV, in the present study. Furthermore, the ratio of the micronucleus induction rates of seed assay to seedling assay by gamma-ray radiation was much lower than that by neutron radiations.

  8. Evaluation of dentin permeability after light activated internal dental bleaching.

    PubMed

    Carrasco, Laise Daniela; Zanello Guerisoli, Danilo M; Pécora, Jesus Djalma; Fröner, Izabel Cristina

    2007-02-01

    The aim of this in vitro study was to assess quantitatively the dentin permeability of human teeth after intracoronal bleaching therapy with 35% hydrogen peroxide activated by LEDs, halogen lamp or using the walking bleach technique. Forty human maxillary central incisors had standard access cavities performed and the cervical thirds of the canals were prepared with Gates-Glidden drills up to a size 130. Roots were resected between the coronal and middle thirds and the apical portions were discarded. A glass ionomer, 2 mm thick cervical plug was placed inside the canal, at the cement-enamel junction level. Group I received 35% hydrogen peroxide gel activated by LEDs. Group II was submitted to 35% hydrogen peroxide gel activated by halogen lamp. Group III received 35% hydrogen peroxide gel and the walking bleach technique was followed. Group IV (control) received a dry cotton pellet inside the pulp chamber with temporary restoration. Dentinal permeability was quantified by copper ion penetration. Linear measurements were obtained by analysis of digital images under x 5 magnification. Mean values and SD for the experimental groups were: I, 7.1% (+/-3.2%); II, 8.4% (+/-3.0%); III, 9.1% (+/-3.0%); IV, 1.3% (+/-2.8%). One-way ANOVA was used to analyze the results. Results showed an increase of permeability values for groups I, II and III when compared to group IV (control); however, no statistical differences were found between the three tested bleaching techniques. It can be concluded that 35% hydrogen peroxide activated by LED, halogen lamp or used following the walking bleach technique produced similar increase in dentinal permeability. PMID:17227378

  9. Pulp-dentin Regeneration: Current State and Future Prospects.

    PubMed

    Cao, Y; Song, M; Kim, E; Shon, W; Chugal, N; Bogen, G; Lin, L; Kim, R H; Park, N-H; Kang, M K

    2015-11-01

    The goal of regenerative endodontics is to reinstate normal pulp function in necrotic and infected teeth that would result in reestablishment of protective functions, including innate pulp immunity, pulp repair through mineralization, and pulp sensibility. In the unique microenvironment of the dental pulp, the triad of tissue engineering would require infection control, biomaterials, and stem cells. Although revascularization is successful in resolving apical periodontitis, multiple studies suggest that it alone does not support pulp-dentin regeneration. More recently, cell-based approaches in endodontic regeneration based on pulpal mesenchymal stem cells (MSCs) have demonstrated promising results in terms of pulp-dentin regeneration in vivo through autologous transplantation. Although pulpal regeneration requires the cell-based approach, several challenges in clinical translation must be overcome-including aging-associated phenotypic changes in pulpal MSCs, availability of tissue sources, and safety and regulation involved with expansion of MSCs in laboratories. Allotransplantation of MSCs may alleviate some of these obstacles, although the long-term stability of MSCs and efficacy in pulp-dentin regeneration demand further investigation. For an alternative source of MSCs, our laboratory developed induced MSCs (iMSCs) from primary human keratinocytes through epithelial-mesenchymal transition by modulating the epithelial plasticity genes. Initially, we showed that overexpression of ΔNp63α, a major isoform of the p63 gene, led to epithelial-mesenchymal transition and acquisition of stem characteristics. More recently, iMSCs were generated by transient knockdown of all p63 isoforms through siRNA, further simplifying the protocol and resolving the potential safety issues of viral vectors. These cells may be useful for patients who lack tissue sources for endogenous MSCs. Further research will elucidate the level of potency of these iMSCs and assess their

  10. Dentine chips produced by nickel-titanium rotary instruments.

    PubMed

    Guppy, D R; Curtis, R V; Ford, T R

    2000-12-01

    This study aimed to compare the cross-sectional shape of two nickel-titanium rotary instruments, namely ProFile and Quantec files, both ISO 25, 0.06 taper, and sought to relate this to the chips produced by cutting dentine. A limited comparison was made with stainless steel engine reamers. First, five files of each type were sectioned transversely at 12 mm, 8 mm and 4 mm from the tip and examined by scanning electron microscopy. The cutting angles were assessed by a direct measurement technique which allowed for the inclination of a cutting edge to the root canal. Second, eight samples of cutting debris were collected from instrumentation by each type of nickel-titanium file and four samples from the engine reamers. The major and minor axis, area and roundness of the dentine chips in each sample were measured using computerized particle analysis. The results demonstrated that all files had a negative cutting angle which varied at the different levels (ProFiles range 69.4 degrees to 58.4 degrees and Quantec range 74.8 degrees to 56.8 degrees). The consistency within files of the same type was good as demonstrated by low standard deviations, except for Quantec files at the 4 mm level where higher standard deviations of 4.1 degrees and 5.5 degrees for the two blades were found. The chip analysis showed significant differences between chips produced by ProFile and Quantec files (P < 0.05). The latter were larger and rounder. The chips from the ProFile and the engine reamer chips were similar in dimension (P > 0.05). No simple relationship existed between file geometry and the dentine chips produced during instrumentation. PMID:11202891

  11. Shear bond strength and ultrastructural interface analysis of different adhesive systems to Er:YAG laser-prepared dentin.

    PubMed

    Guven, Yeliz; Aktoren, Oya

    2015-02-01

    The aim of this study was to evaluate the shear bond strength (SBS) of a microhybrid composite resin bonded with three different adhesive systems to Er:YAG laser- (EL) or bur-prepared dentin surfaces and to analyze the quality and ultrastructure of the adhesive-dentin interfaces by scanning electron microscopy (SEM). The specimens prepared for SBS test and SEM analysis were randomly assigned to eight groups (G1-G8): G1, EL (Fidelis PlusIII, Fotona) + Clearfil S3 Bond (C3S); G2, EL + AdperSE Plus (SE); G3, EL + laser etch + Adper Single Bond2 (SB2); G4, EL + acid etch + SB2; G5, EL + SB2 (no etching); G6, bur + acid etch + SB2; G7, bur + S3; G8, bur + SE. Laser was used in very short pulse mode at a setting of 200 mJ/20 Hz for dentin preparation and at 80 mJ/10 Hz for dentin etching. Bond strength test: 3.5 × 2.0 mm cylindrical molds were placed onto adhesives and filled with the composites. After 24 h in distilled water, SBS was tested at a crosshead speed of 0.5 mm/min. SEM analysis: The dentin-adhesive interfaces were evaluated for the ultrastructure of hybrid layer. Data of SBS (MPa) were statistically analyzed by ANOVA and Tukey HSD. ER:YAG laser-prepared dentin has demonstrated significantly more SBS (p < 0.01) for SE when compared to bur-prepared dentin. No significancies (p > 0.05) in SBS have been determined between the total-etch adhesive applied groups with regard to etching types. SEM analysis revealed that hybrid layers obtained in Er:YAG laser-irradiated dentin exhibited more irregular and non-homogeneous pattern than the conventionally prepared dentin. In conclusion, SE Bond demonstrated superior results in Er:YAG laser-ablated dentin compared to bur-prepared dentin. PMID:23982720

  12. Dentin bond strength after ablation using a CO2 laser operating at high pulse repetition rates

    NASA Astrophysics Data System (ADS)

    Hedayatollahnajafi, Saba; Staninec, Michal; Watanabe, Larry; Lee, Chulsung; Fried, Daniel

    2009-02-01

    Pulsed CO2 lasers show great promise for the rapid and efficient ablation of dental hard tissues. Our objective was to demonstrate that CO2 lasers operated at high repetition rates can be used for the rapid removal of dentin without excessive thermal damage and without compromising adhesion to restorative materials. Human dentin samples (3x3mm2) were rapidly ablated with a pulsed CO2 laser operating at a wavelength of 9.3-µm, pulse repetition rate of 300-Hz and an irradiation intensity of 18-J/cm2. The bond strength to composite was determined by the modified single plane shear test. There were 8 test groups each containing 10 blocks: negative control (non-irradiated non-etched), positive control (non-irradiated acid-etched), and six laser treated groups (three etched and three non-etched sets). The first and second etched and non-etched sets were ablated at a speed of 25 mm/sec and 50 mm/sec with water, respectively. The third set was also ablated at 50 mm/sec without application of water during laser irradiation. Minimal thermal damage was observed on the dentin surfaces for which water cooling was applied. Bond strengths exceeded 20 MPa for laser treated surfaces that were acid-etched after ablation (25-mm/sec: 29.9-MPa, 50-mm/sec: 21.3-MPa). The water-cooled etched laser groups all produced significantly stronger bonds than the negative control (p<0.001) and a lower bond strength than the positive control (p<0.05). These measurements demonstrate that dentin surfaces can be rapidly ablated by a CO2 lasers with minimal peripheral thermal damage. Additional studies are needed to determine if a lower bond strength than the acid-etched control samples is clinically significant where durability of these bonded restoration supersedes high bond strength.

  13. Isolated dentinogenesis imperfecta and dentin dysplasia: revision of the classification.

    PubMed

    de La Dure-Molla, Muriel; Philippe Fournier, Benjamin; Berdal, Ariane

    2015-04-01

    Dentinogenesis imperfecta is an autosomal dominant disease characterized by severe hypomineralization of dentin and altered dentin structure. Dentin extra cellular matrix is composed of 90% of collagen type I and 10% of non-collagenous proteins among which dentin sialoprotein (DSP), dentin glycoprotein (DGP) and dentin phosphoprotein (DPP) are crucial in dentinogenesis. These proteins are encoded by a single gene: dentin sialophosphoprotein (DSPP) and undergo several post-translational modifications such as glycosylation and phosphorylation to contribute and to control mineralization. Human mutations of this DSPP gene are responsible for three isolated dentinal diseases classified by Shield in 1973: type II and III dentinogenesis imperfecta and type II dentin dysplasia. Shield classification was based on clinical phenotypes observed in patient. Genetics results show now that these three diseases are a severity variation of the same pathology. So this review aims to revise and to propose a new classification of the isolated forms of DI to simplify diagnosis for practitioners.

  14. Biomechanical Perspective on the Remineralization of Dentin

    PubMed Central

    Bertassoni, L.E.; Habelitz, S.; Kinney, J.H.; Marshall, S.J.; Marshall, G.W.

    2009-01-01

    The objective of this article is to critically evaluate the methods that are used to assess outcomes of remineralization of dentin. Currently, the most used assessment methods fall either into quantitative analysis of the mineral content of the remineralized structures or dry measurements of their mechanical properties. Properties obtained from the dehydrated organic dentin matrix may not reflect the true mechanical behavior of the remineralized tissue under physiological and hydrated conditions. Here we seek to clarify the biomechanical aspects of remineralization of dentin, pointing out the effects of hydration and dehydration on the mechanical properties of treated tissues. We also emphasize that a more appropriate endpoint to evaluate the effectiveness of remineralization in dentin should be associated with the recovery of the mechanical properties of the hydrated tissue, which is presumed to correlate well with its overall functionality. PMID:19208991

  15. Substantivity of Chlorhexidine to Human Dentin

    PubMed Central

    Carrilho, Marcela R.; Carvalho, Ricardo M.; Sousa, Ethan N.; Nicolau, José; Breschi, Lorenzo; Mazzoni, Annalisa; Tjäderhane, Leo; Tay, Franklin R.; Agee, Kelli; Pashley, David H.

    2010-01-01

    Objectives To better comprehend the role of CHX in the preservation of resin-dentin bonds, this study investigated the substantivity of CHX to human dentin. Material and Methods Dentin disks (n= 45) were obtained from the mid-coronal portion of human third molars. One-third of dentin disks were kept mineralized (MD), while the other two-thirds had one of the surfaces partially demineralized with 37% phosphoric acid for 15 s (PDD) or they were totally demineralized with 10% phosphoric acid (TDD). Disks of hydroxyapatite (HA) were also prepared. Specimens were treated with: 1) 10 μL of distilled water (controls), 2) 10 μL of 0.2% chlorhexidine diacetate (0.2% CHX) or 3) 10 μL of 2% chlorhexidine diacetate (2% CHX). Then, they were incubated in 1 mL of PBS (pH 7.4, 37 °C). Substantivity was evaluated as a function of the CHX-applied dose after: 0.5h, 1h, 3h, 6h, 24h, 168h (1wk), 672h (4wks) and 1344h (8wks) of incubation. CHX concentration in eluates was spectrophotometrically analyzed at 260 nm. Results Significant amounts of CHX remained retained in dentin substrates (MD, PPD or TDD), independent on the CHX-applied dose or time of incubation (p<0.05). High amounts of retained CHX onto HA were observed only for specimens treated with the highest concentration of CHX (2%) (p<0.05). Conclusion The outstanding substantivity of CHX to dentin and its reported effect on the inhibition of dentinal proteases may explain why CHX can prolong the durability of resin-dentin bonds. PMID:20472282

  16. Power toothbrushes, gender, and dentin hypersensitivity.

    PubMed

    Hefti, A F; Stone, C

    2000-06-01

    Power toothbrushes require less force for plaque removal than manual brushes. In addition, in vitro studies have indicated that brushing with low force could occlude patent dentin tubules by formation of a smear layer. Hence, lessening the force necessary to remove plaque may reduce dentin hypersensitivity. However, it was recently suggested that the use of an oscillating/rotating power toothbrush could decrease tooth sensitivity as compared to a sonic power toothbrush. Therefore, the objective of the present research was to compare the effect on dentin hypersensitivity of two different types of power brushes, the Optiva Sonicare and the Braun Oral B Ultra Plaque Remover. The null hypothesis was tested in an 8-week, randomized, parallel group, examiner-blind clinical trial. Fifty-nine subjects with a history of dentin hypersensitivity participated. Dentin hypersensitivity-associated pain was elicited using tactile and evaporative stimuli and assessed using a visual analog scale (VAS) instrument. Clinical examinations were carried out at screening and baseline and repeated after 8 weeks of twice daily use of the power brushes. Data analysis was performed on VAS scores obtained at the final visit following adjustment for group differences at baseline. A 35% to 40% reduction in pain as compared to baseline was observed in both treatment groups. Treatment-related differences were not statistically significant. A gender-related effect on dentin hypersensitivity was observed using the tactile stimulus and may merit further investigation.

  17. Biodentine-a novel dentinal substitute for single visit apexification.

    PubMed

    Nayak, Gurudutt; Hasan, Mohammad Faiz

    2014-05-01

    Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.

  18. Ablation of human carious dentin with a nanosecond pulsed laser at a wavelength of 5.85 μm: relationship between hardness and ablation depth

    NASA Astrophysics Data System (ADS)

    Ishii, Katsunori; Kita, Tetsuya; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2014-02-01

    Less invasive treatment and preservation of teeth, referred to as minimal intervention, are strong requirements in dentistry. In our previous study, the fundamental ablation properties of human dentin at wavelengths around 5.8 μm were investigated, and the results indicated that the wavelength of 5.85 μm was optimal for selective removal of carious dentin with less damage to normal dentin. The purpose of this study was to investigate the relationship between the ablation depth and hardness of human dentin including carious lesion. A nanosecond pulsed laser produced by difference-frequency generation was used for irradiations to human carious dentin. It was observed that correlation between ablation depth and Vickers hardness after 2 s laser irradiation at the wavelength of 5.85 μm and the average power density of 30 W/cm2. On the other hand, ablations did not depend on Vickers hardness at the wavelength of 6.00 μm. A nanosecond pulsed laser with the wavelength at 5.85 μm is useful for selective ablation of human carious dentin in accordance with the hardness.

  19. The Role of Host-derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

    PubMed Central

    Zhang, Shan-chuan; Kern, Matthias

    2009-01-01

    Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength. Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modern self-etch and etch-and-rinse adhesives. The aim of this review is to summarize the current knowledge of the role of dentinal host-derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability. PMID:20690420

  20. Dentinal permeability of the dog canine after exposure of a cervical cavity to the beam of a CO2 laser.

    PubMed

    Bonin, P; Boivin, R; Poulard, J

    1991-03-01

    The dentinal permeability of the axial wall of a class V cavities in the canine of the dog was analyzed before and after its laser CO2 irradiation at two energy levels: 285 J per cm2 and 570 J per cm2. The sealing of the exposed dentin was verified by means of a pellet of cotton wool placed in contact with the axial wall and on which 20 microliters of a 50 mg per ml solution of noradrenaline was injected with a micrometric syringe. The transdentinal passage of noradrenaline induces a vasoconstriction of the pulp which is attested by a drop in its blood pressure. The absence of any variation in the pulpal pressure is an indication of the sealing to noradrenaline of the dentinal wall irradiated with an energy level of 570 J per cm2. This experimentation illustrates that it is possible to obtain dentinal sealing by means of laser irradiation without affecting the underlying pulp. The quality of this reduction in permeability is dependent upon the different factors which define the energy level.

  1. Comparison of dentinal damage induced by different nickel-titanium rotary instruments during canal preparation: An in vitro study

    PubMed Central

    Garg, Shiwani; Mahajan, Pardeep; Thaman, Deepa; Monga, Prashant

    2015-01-01

    Aim: To compare dentinal damage caused by hand and rotary nickel-titanium instruments using ProTaper, K3 Endo, and Easy RaCe systems after root canal preparation. Materials and Methods: One hundred and fifty freshly extracted mandibular premolars were randomly divided into five experimental groups of 30 teeth each and biomechanical preparation was done: Group 1 with unprepared teeth; Group 2 were prepared with hand files; Group 3 with ProTaper rotary instruments; Group 4 with K3 rotary; Group 5 with Easy RaCe rotary instruments. Then, roots were cut horizontally at 3, 6, and 9 mm from apex and were viewed under stereomicroscope. The presence of dentinal defects was noted. Statistical analysis: Groups were analyzed with the Chi-square test. Results: Significant difference was seen between groups. No defects were found in unprepared roots and those prepared with hand files. ProTaper, K3 rotary, and Easy RaCe preparations resulted in dentinal defects in 23.3%, 10%, and 16.7% of teeth, respectively. More defects were shown in coronal and middle sections, and no defect was seen in apical third. Conclusion: The present study revealed that use of rotary instruments could result in an increased chance for dentinal defects as compared to hand instrumentation. PMID:26180415

  2. CBX7 deficiency plays a positive role in dentin and alveolar bone development.

    PubMed

    Zhou, Zhixuan; Yin, Ying; Jiang, Fei; Niu, Yuming; Wan, Shujian; Chen, Ning; Shen, Ming

    2016-08-01

    To clarify the role of CBX7 deficiency in dentin and alveolar bone development, the dental and mandibular phenotypes of homozygous CBX7-knockout (CBX7(-/-)) mice were compared with their wild-type (WT) counterparts at 3 weeks age. In contrast to WT littermates, dental volume and dentin sialoprotein-positive area were significantly increased, whereas the area ratio of predentin to dentin was decreased markedly in CBX7(-/-) mice. Mineral density, cortical thickness, alveolar bone volume, type I collagen and osterix-immunopositive area, osteoblast number and activity, protein expression and mRNA level of Runt-related transcription factor 2 (Runx2), alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2 (BMP2) were all remarkably increased, while osteoclast number and activity, and mRNA expression ratio of NF-κB ligand (RANKL) to osteoprotegerin (opg) were all decreased significantly in the alveolar bone of CBX7(-/-) mice compared with their WT counterparts. Moreover, proliferating cell nuclear antigen (PCNA)-positive cells were found more in Hertwig' s epithelial root sheath of CBX7(-/-) mice, and their protein level of cyclin E1, cyclin-dependent kinase 2 (CDK2) were correspondingly increased in contrast to WT mice. Taken together, these results of this study suggest that CBX7 deficiency plays a positive role in dentin and alveolar bone formation. PMID:27271093

  3. Effects of human vascular endothelial growth factor on reparative dentin formation

    PubMed Central

    ZHANG, JUAN; LIU, XIA; YU, WEIXIAN; ZHANG, YINGLI; SHI, CE; NI, SHILEI; LIU, QILIN; LI, XIANGWEI; SUN, YINGJIAN; ZHENG, CHANGYU; SUN, HONGCHEN

    2016-01-01

    It is a challenge for dentists to save dental pulp in patients with pulp disease without resorting to root canal therapy. Formation of tertiary dentin to maintain pulp vitality is a key odontoblast response to dental pulp injury. Vascular endothelial growth factor (VEGF) is the most potent angiogenic and vasculogenic factor involved in tertiary dentin formation. It was hypothesized that VEGF may be used to treat pulp diseases such as pulpitis. To explore this hypothesis, the first step was to assess whether VEGF affects dental pulp cells to promote reparative dentin formation. In the current study, an AdCMV-hVEGF vector was constructed to deliver hVEGF into dental pulp cells of exfoliated deciduous teeth (hDPCs) in vitro and dental pulp cells in a rat model in vivo. The collected data clearly demonstrated that hVEGF increased alkaline phosphatase and mineralization by enzymatic activity. RT-qPCR data demonstrated that hVEGF significantly increased the expression levels of genes commonly involved in osteogenesis/odontogenesis. Data from the in vivo assays indicated that hVEGF enhanced pulp cell proliferation and neovascularization, and markedly increased formation of reparative dentin in dental pulp. The in vitro and in vivo data suggest that hVEGF may have potential clinical applications, thus may aid in the development of novel treatment strategies for dental pulpitis. PMID:26647730

  4. Age, dehydration and fatigue crack growth in dentin.

    PubMed

    Bajaj, Devendra; Sundaram, Naryana; Nazari, Ahmad; Arola, D

    2006-04-01

    A preliminary study of the effects from age and dehydration on fatigue crack growth in human dentin was conducted. Compact tension (CT) fatigue specimens of coronal dentin were prepared from extracted molars and subjected to high cycle fatigue (10(5)dentin (mean age=25+/-7 years), old hydrated dentin (mean age=55+/-14 years) and young dehydrated dentin (mean age=20+/-2 years) were examined. Fatigue crack growth rates were quantified according to the Paris Law in terms of the crack growth exponent (m) and coefficient (C). The average fatigue crack growth exponent for the young hydrated dentin (m=13.3+/-1.1) was significantly less than that for the hydrated old (m=21.6+/-5.2; p<0.003) and dehydrated young dentin (m=18.8+/-2.8; p<0.01). Fatigue cracks in the old dentin underwent initiation at a lower stress intensity range than in young dentin and propagated at as significantly faster rate (over 100x). Differences in the microscopic features of the fracture surfaces from the old and young dentin suggested that particular mechanisms contributing to energy dissipation and crack growth resistance in the young hydrated dentin were not present in the old dentin. Based on results of this study, the fatigue crack growth resistance of human dentin decreases with both age of the tissue and dehydration.

  5. Regulation of reactionary dentin formation by odontoblasts in response to polymicrobial invasion of dentin matrix

    PubMed Central

    Charadram, Nattida; Farahani, Ramin M; Harty, Derek; Rathsam, Catherine; Swain, Michael V; Hunter, Neil

    2011-01-01

    Odontoblast synthesis of dentin proceeds through discrete but overlapping phases characterized by formation of a patterned organic matrix followed by remodelling and active mineralization. Microbial invasion of dentin in caries triggers an adaptive response by odontoblasts, culminating in formation of a structurally altered reactionary dentin, marked by biochemical and architectonic modifications including diminished tubularity. Scanning electron microscopy of the collagen framework in reactionary dentin revealed a radically modified yet highly organized meshwork as indicated by fractal and lacunarity analyses. Immuno-gold labelling demonstrated increased density and regular spatial distribution of dentin sialoprotein (DSP) in reactionary dentin. DSP contributes putative hydroxyapatite nucleation sites on the collagen scaffold. To further dissect the formation of this altered dentin matrix, the associated enzymatic machinery was investigated. Analysis of extracted dentin matrix indicated increased activity of matrix metalloproteinase-2 (MMP-2) in the reactionary zone referenced to physiologic dentin. Likewise, gene expression analysis of micro-dissected odontoblast layer revealed up-regulation of MMP-2. Parallel up-regulation of tissue inhibitor of metalloproteinase-2 (TIMP-2) and membrane type 1- matrix metalloproteinase (MT1-MMP) was observed in response to caries. Next, modulation of odontoblastic dentinogenic enzyme repertoire was addressed. In the odontoblast layer expression of Toll-like receptors was markedly altered in response to bacterial invasion. In carious teeth TLR-2 and the gene encoding the corresponding adaptor protein MyD88 were down-regulated whereas genes encoding TLR-4 and adaptor proteins TRAM and Mal/TIRAP were up-regulated. TLR-4 signalling mediated by binding of bacterial products has been linked to up-regulation of MMP-2. Further, increased expression of genes encoding components of the TGF-β signalling pathway, namely SMAD-2 and SMAD-4

  6. Regulation of reactionary dentin formation by odontoblasts in response to polymicrobial invasion of dentin matrix.

    PubMed

    Charadram, Nattida; Farahani, Ramin M; Harty, Derek; Rathsam, Catherine; Swain, Michael V; Hunter, Neil

    2012-01-01

    Odontoblast synthesis of dentin proceeds through discrete but overlapping phases characterized by formation of a patterned organic matrix followed by remodelling and active mineralization. Microbial invasion of dentin in caries triggers an adaptive response by odontoblasts, culminating in formation of a structurally altered reactionary dentin, marked by biochemical and architectonic modifications including diminished tubularity. Scanning electron microscopy of the collagen framework in reactionary dentin revealed a radically modified yet highly organized meshwork as indicated by fractal and lacunarity analyses. Immuno-gold labelling demonstrated increased density and regular spatial distribution of dentin sialoprotein (DSP) in reactionary dentin. DSP contributes putative hydroxyapatite nucleation sites on the collagen scaffold. To further dissect the formation of this altered dentin matrix, the associated enzymatic machinery was investigated. Analysis of extracted dentin matrix indicated increased activity of matrix metalloproteinase-2 (MMP-2) in the reactionary zone referenced to physiologic dentin. Likewise, gene expression analysis of micro-dissected odontoblast layer revealed up-regulation of MMP-2. Parallel up-regulation of tissue inhibitor of metalloproteinase-2 (TIMP-2) and membrane type 1- matrix metalloproteinase (MT1-MMP) was observed in response to caries. Next, modulation of odontoblastic dentinogenic enzyme repertoire was addressed. In the odontoblast layer expression of Toll-like receptors was markedly altered in response to bacterial invasion. In carious teeth TLR-2 and the gene encoding the corresponding adaptor protein MyD88 were down-regulated whereas genes encoding TLR-4 and adaptor proteins TRAM and Mal/TIRAP were up-regulated. TLR-4 signalling mediated by binding of bacterial products has been linked to up-regulation of MMP-2. Further, increased expression of genes encoding components of the TGF-β signalling pathway, namely SMAD-2 and SMAD-4

  7. Temperature Rise during Primer, Adhesive, and Composite Resin Photopolymerization of a Low-Shrinkage Composite Resin under Caries-Like Dentin Lesions.

    PubMed

    Mousavinasab, Sayed-Mostafa; Khoroushi, Maryam; Moharreri, Mohammadreza

    2012-01-01

    Objective. This study evaluated temperature rise of low-shrinkage (LS) self-etch primer (P), LS self-etch adhesive (A), and P90 silorane-based composite resin systems, photopolymerized under normal and artificially demineralized dentin. Methods. Forty 1.5 mm-thick dentin discs were prepared from sound human molars, half of which were demineralized. Temperature rise was measured during photopolymerization using a K-type thermocouple under the discs: 10 s and 40 s irradiation of the discs (controls/groups 1 and 2); 10 s irradiation of primer (P), 10 s irradiation of adhesive (A), 40 s irradiation of P90 without P and A, and 40 s irradiation of P90 with P and A (groups 3 to 6, resp.). The samples were photopolymerized using an LED unit under 550 mW/cm(2) light intensity. Data was analyzed using repeated measures ANOVA and paired-sample t-test (α = 0.05). Results. There were no significant differences in temperature rise means between the two dentin samples for each irradiation duration (P > 0.0001), with significant differences between the two irradiation durations (P > 0.0001). Temperature rise measured with 40 s irradiation was significantly higher than that of 10 s duration for undemineralized and demineralized dentin P < 0.0001). Conclusions. Light polymerization of P90 low-shrinkage composite resin resulted in temperature rise approaching threshold value under artificially demineralized and undemineralized dentin. PMID:23320185

  8. Adhesion to chondroitinase ABC treated dentin

    PubMed Central

    Mazzoni, Annalisa; Pashley, David H.; Ruggeri, Alessandra; Vita, Francesca; Falconi, Mirella; Di Lenarda, Roberto; Breschi, Lorenzo

    2013-01-01

    Dentin bonding relies on complete resin impregnation throughout the demineralised hydrophilic collagen mesh. Chondroitin sulphate-glycosaminoglycans are claimed to regulate the three-dimensional arrangement of the dentin organic matrix and its hydrophilicity. The aim of this study was to investigate bond strength of two etch-and-rinse adhesives to chondroitinase ABC treated dentin. Human extracted molars were treated with chondroitinase ABC and a double labelling immunohistochemical technique was applied to reveal type I collagen and chondroitin 4/6 sulphate distribution under field emission in-lens scanning electron microscope. The immunohistochemical technique confirmed the effective removal of chondroitin 4/6 sulphate after the enzymatic treatment. Dentin surfaces exposed to chondroitinase ABC and untreated specimens prepared on untreated acid-etched dentin were bonded with Adper Scotchbond Multi-Purpose or Prime & Bond NT. Bonded specimens were submitted to microtensile testing and nanoleakage interfacial analysis under transmission electron microscope. Increased mean values of microtensile bond strength and reduced nanoleakage expression were found for both adhesives after chondroitinase ABC treatment of the dentin surface. Adper Scotchbond Multi-Purpose increased its bond strength about 28%, while bonding made with Prime & Bond NT almost doubled (92% increase) compared to untreated specimens. This study supports the hypothesis that adhesion can be enhanced by removal of chondroitin 4/6 sulphate and dermatan sulphate, probably due to a reduced amount of water content and enlarged interfibrillar spaces. Further studies should validate this hypothesis investigating the stability of chondroitin 4/6 and dermatan sulphate-depleted dentin bonded interface over time. PMID:18161809

  9. 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. PMID:7983255

  10. Effects of Tetracycline, EDTA and Citric Acid Application on Nonfluorosed and Fluorosed Dentin: An In Vitro Study

    PubMed Central

    Sadanand, K.; Vandana, K. L.

    2016-01-01

    Fluorosis is one of the factors that may bring about mineralization changes in teeth. Routine treatment of root biomodification is commonly followed during Periodontal therapy. Background: The Purpose of the present study was to compare and evaluate the morphological changes in fluorosed and nonfluorosed root dentin subsequent to the application of Tetracycline, EDTA and Citric acid. Both fluorosed and nonfluorosed teeth comprising of periodontally healthy and diseased were included in this study. Method: Each of them was grouped into Tetracycline Hydrochloride, EDTA and Citric acid treatment groupes. Using scanning electron microscope (SEM), the photomicrographs of dentin specimens were obtained. Results: Showed that there was no significant difference in exposure of number of tubules in different groups, while significant increase in the tubular width and tubular surface area was seen in fluorosed healthy, followed by fluorosed diseased groups, nonfluorosed healthy and nonfluorosed diseased groups after root biomodification procedure using various root conditioning agents. The root biomodification procedure brings in definite difference between fluorosed and nonfluorosed dentin specimens. PMID:27335611

  11. Morphometric evaluation and planning of anticurvature filing in roots of maxillary and mandibular molars.

    PubMed

    Oliveira, Maria Antonieta Veloso Carvalho; Venâncio, Jessyca Figueira; Raposo, Luís Henrique Araújo; Barbosa Júnior, Nelson; Biffi, João Carlos Gabrielli

    2015-01-01

    This study aimed to guide the planning of anticurvature filing using pre-determined anatomical points on teeth to establish directions for proper implementation of the technique. Two hundred digital periapical radiographs of human molar teeth were selected and divided into two groups (n = 100): MX (maxillary) and MD (mandibular) molars. Mesiobuccal roots were considered for the MX group and mesial roots for the MD group. Pre-determined anatomical points required for planning the anticurvature filing on the root canal path were located, and the distances between these points obtained. The anticurvature filing was simulated in two different protocols for each group, and the region of dentin removal and the remaining dentin thickness were measured in the safety and danger zones of the root canals. Statistical analysis was carried out at a significance level of 5%. The distances between the anatomical points and the thickness of remaining dentin showed significant differences when the two groups were compared (p < 0.001). No significant differences were found between the two experimental groups regarding the area of dentin removal at the root region, but differences were detected in comparison with dentin removal at the crown (p < 0.001). In terms of wear produced after simulation of both anticurvature filing protocols, significant differences were verified for all regions, except for the dentin remaining at the danger zone. The radiographic location of anatomical points allows for planning and implementation of controlled and efficient anticurvature filing and can be performed in the same manner for maxillary and mandibular molars.

  12. Dentin caries zones: mineral, structure, and properties.

    PubMed

    Pugach, M K; Strother, J; Darling, C L; Fried, D; Gansky, S A; Marshall, S J; Marshall, G W

    2009-01-01

    Caries Detector staining reveals 4 zones in dentin containing caries lesions, but characteristics of each zone are not well-defined. We therefore investigated the physical and microstructural properties of carious dentin in the 4 different zones to determine important differences revealed by Caries Detector staining. Six arrested dentin caries lesions and 2 normal controls were Caries-Detector-stained, each zone (pink, light pink, transparent, apparently normal) being analyzed by atomic force microscopy (AFM) imaging for microstructure, by AFM nano-indentation for mechanical properties, and by transverse digital microradiography (TMR) for mineral content. Microstructure changes, and nanomechanical properties and mineral content significantly decreased across zones. Hydrated elastic modulus and mineral content from normal dentin to pink Caries-Detector-stained dentin ranged from 19.5 [10.6-25.3] GPa to 1.6 [0.0-5.0] GPa and from 42.9 [39.8-44.6] vol% to 12.4 [9.1-14.2] vol%, respectively. Even the most demineralized pink zone contained considerable residual mineral.

  13. 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. PMID:25665859

  14. The effect of early weaning on dentin formation and dentinal caries in rats.

    PubMed

    Hietala, E L; Autio, J; Larmas, M

    1997-08-01

    The effect of early weaning on caries progression, dentin formation, and dentin mineralization was examined in four groups of rats. Two groups received a normal diet and were weaned on day 18 or 21, and another two received a sucrose-rich diet and were weaned on day 18 or 21. At age 35 days the lower molars were sectioned sagittally, and the areas of dentin formation and of the dentinal caries were quantified. The width of the predentin zone was measured from histologically stained sections of maxillary molars. Early weaning reduced dentin formation in the group on the high-sucrose diet only the first days; later this effect was partially caught up with. A high-sucrose diet significantly increased caries frequency and extension of caries lesions compared with a normal diet in both early weaned and normally weaned groups. The effect of early weaning on caries frequency and extension in the high-sucrose group was insignificant compared with the normally weaned group on a high-sucrose diet. The predentin zone was wider in the sucrose groups than in the control groups at the end of the experiment. These results indicate that the effect of sucrose on dentin formation was dependent on the stage of physiologic dentin formation, but early weaning as such did not affect this.

  15. Plasma treatment of dentin surfaces for improving self-etching adhesive/dentin interface bonding

    PubMed Central

    Dong, Xiaoqing; Li, Hao; Chen, Meng; Wang, Yong; Yu, Qingsong

    2015-01-01

    This study is to evaluate plasma treatment effects on dentin surfaces for improving self-etching adhesive and dentin interface bonding. Extracted unerupted human third molars were used after crown removal to expose dentin. One half of each dentin surface was treated with atmospheric non-thermal argon plasmas, while another half was untreated and used as the same tooth control. Self-etching adhesive and universal resin composite was applied to the dentin surfaces as directed. After restoration, the adhesive-dentin bonding strength was evaluated by micro-tensile bonding strength (μTBS) test. Bonding strength data was analyzed using histograms and Welch’s t-test based on unequal variances. μTBS test results showed that, with plasma treatment, the average μTBS value increased to 69.7±11.5 MPa as compared with the 57.1±17.5 MPa obtained from the untreated controls. After 2 months immersion of the restored teeth in 37 °C phosphate buffered saline (PBS), the adhesive-dentin bonding strengths of the plasma-treated specimens slightly decreased from 69.7±11.5 MPa to 63.9±14.4 MPa, while the strengths of the untreated specimens reduced from 57.1±17.5 MPa to 48.9±14.6 MPa. Water contact angle measurement and scanning electron microscopy (SEM) examination verified that plasma treatment followed by water rewetting could partially open dentin tubules, which could enhance adhesive penetration to form thicker hybrid layer and longer resin tags and consequently improve the adhesive/dentin interface quality. PMID:26273561

  16. Surface energy of bovine dentin and enamel by means of inverse gas chromatography.

    PubMed

    Okulus, Zuzanna; Strzemiecka, Beata; Czarnecka, Beata; Buchwald, Tomasz; Voelkel, Adam

    2015-04-01

    Adhesion between tooth tissues and dental fillings depends on the surface energy of both connected materials. Bond strength can be determined directly or indirectly as a work of adhesion on the basis of values of surface energy of these materials. Inverse gas chromatography (IGC) is one of the methods of surface energy examination. In this study the values of total surface energy components of wet and dry teeth fragments (enamel, crown dentin and root dentin) were determined with the use of inverse gas chromatography. Inverse gas chromatography has never been used for investigation of surface energy of natural tooth tissues. Different storage conditions were examined - wet and dry. Different values of surface energy are observed according to the type of tooth tissue (dentin or enamel), occurring place (crown or root) and storage conditions (dry or wet). The effect of tissue type and occurring place was the greatest, while storage conditions were of secondary importance. Surface energy depends on composition of tissue, its surface area and the presence of pores.

  17. Dentine microhardness after different methods for detection and removal of carious dentine tissue

    PubMed Central

    MOLLICA, Fernanda Brandão; TORRES, Carlos Rocha Gomes; GONÇALVES, Sergio Eduardo de Paiva; MANCINI, †Maria Nadir Gasparoto

    2012-01-01

    There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. Objectives The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. Material and methods The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10), according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. Results ANOVA and Tukey's test (α=0.05) were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7±105.0; a), Caries-detector dye (370.5±78.3; ab), Tactile method (322.8±51.5; bc). Results for the remaining dentin microhardness were: "Papacárie" (42.2±10.5; bc), Caries-detector dye (44.6±11.8; abc), Tactile method (24.3±9.0; d). Conclusions DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values. PMID:23032207

  18. Dentin Matrix Proteins in Bone Tissue Engineering.

    PubMed

    Ravindran, Sriram; George, Anne

    2015-01-01

    Dentin and bone are mineralized tissue matrices comprised of collagen fibrils and reinforced with oriented crystalline hydroxyapatite. Although both tissues perform different functionalities, they are assembled and orchestrated by mesenchymal cells that synthesize both collagenous and noncollagenous proteins albeit in different proportions. The dentin matrix proteins (DMPs) have been studied in great detail in recent years due to its inherent calcium binding properties in the extracellular matrix resulting in tissue calcification. Recent studies have shown that these proteins can serve both as intracellular signaling proteins leading to induction of stem cell differentiation and also function as nucleating proteins in the extracellular matrix. These properties make the DMPs attractive candidates for bone and dentin tissue regeneration. This chapter will provide an overview of the DMPs, their functionality and their proven and possible applications with respect to bone tissue engineering.

  19. Fate of HERS during Tooth Root Development

    PubMed Central

    Huang, Xiaofeng; Bringas, Pablo; Slavkin, Harold C.; Chai, Yang

    2009-01-01

    Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS cells are attached to the surface of the cementum, and others separate to become the epithelial rest of Malasez. HERS cells secrete extracellular matrix components onto the surface of the dentin before dental follicle cells penetrate the HERS network to contact dentin. HERS cells also participate in the cementum development and may differentiate into cementocytes. During root development, the HERS is not interrupted, and instead the HERS cells continue to communicate with each other through the network structure. Furthermore, HERS cells interact with cranial neural crest derived mesenchyme to guide root development. Taken together, the network of HERS cells is crucial for tooth root development. PMID:19576204

  20. Effects of adsorbed and templated nanosilver in mesoporous calcium-silicate nanoparticles on inhibition of bacteria colonization of dentin.

    PubMed

    Fan, Wei; Wu, Daming; Tay, Franklin R; Ma, Tengjiao; Wu, Yujie; Fan, Bing

    2014-01-01

    Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for controlled drug delivery and mineralization induction. Nanosilver-incorporated MCSNs (Ag-MCSNs) were prepared in the present study using both the adsorption and template methods. Both versions of Ag-MCSNs showed characteristic morphology of mesoporous materials and exhibited sustained release of ions over time. In antibacterial testing against planktonic Enterococcus faecalis, Ag-MCSNs showed significantly better antibacterial effects when compared with MCSNs (P<0.05). The Ag-MCSNs aggregated on the dentin surface of root canal walls and infiltrated into dentinal tubules after ultrasound activation, significantly inhibiting the adherence and colonization of E. faecalis on dentin (P<0.05). Despite this, Ag-MCSNs with templated nanosilver showed much lower cytotoxicity than Ag-MCSNs with adsorbed nanosilver (P<0.05). The results of the present study indicated that nanosilver could be incorporated into MCSNs using the template method. The templated nanosilver could release silver ions and inhibit the growth and colonization of E. faecalis both in the planktonic form and as biofilms on dentin surfaces as absorbed nanosilver. Templated Ag-MCSNs may be developed into a new intracanal disinfectant for root canal disinfection due to their antibacterial ability and low cytotoxicity, and as controlled release devices for other bioactive molecules to produce multifunctional biomaterials.

  1. Effects of adsorbed and templated nanosilver in mesoporous calcium-silicate nanoparticles on inhibition of bacteria colonization of dentin

    PubMed Central

    Fan, Wei; Wu, Daming; Tay, Franklin R; Ma, Tengjiao; Wu, Yujie; Fan, Bing

    2014-01-01

    Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for controlled drug delivery and mineralization induction. Nanosilver-incorporated MCSNs (Ag-MCSNs) were prepared in the present study using both the adsorption and template methods. Both versions of Ag-MCSNs showed characteristic morphology of mesoporous materials and exhibited sustained release of ions over time. In antibacterial testing against planktonic Enterococcus faecalis, Ag-MCSNs showed significantly better antibacterial effects when compared with MCSNs (P<0.05). The Ag-MCSNs aggregated on the dentin surface of root canal walls and infiltrated into dentinal tubules after ultrasound activation, significantly inhibiting the adherence and colonization of E. faecalis on dentin (P<0.05). Despite this, Ag-MCSNs with templated nanosilver showed much lower cytotoxicity than Ag-MCSNs with adsorbed nanosilver (P<0.05). The results of the present study indicated that nanosilver could be incorporated into MCSNs using the template method. The templated nanosilver could release silver ions and inhibit the growth and colonization of E. faecalis both in the planktonic form and as biofilms on dentin surfaces as absorbed nanosilver. Templated Ag-MCSNs may be developed into a new intracanal disinfectant for root canal disinfection due to their antibacterial ability and low cytotoxicity, and as controlled release devices for other bioactive molecules to produce multifunctional biomaterials. PMID:25419127

  2. AFM Investigation of mechanical properties of dentin

    SciTech Connect

    Cohen, Sidney R; Apter, Nathan; Jesse, Stephen; Kalinin, Sergei V; Barlam, David; Peretz, Adi Idit; Ziskind, Daniel; Wagner, H. Daniel

    2008-01-01

    Mechanical properties of peritubular dentin were investigated using scanning probe microscopy techniques, namely Nanoindentation and Band Excitation. Particular attention was directed to the possible existence of a gradient in these properties moving outward from the tubular lumen to the junction with the intertubular dentin. Finite element analysis showed that the influence of the boundaries is small relative to the effects observed. Thus, these results strongly support the concept of a lowering of modulus and hardness from the tubular exterior to its periphery, which appear to correlate with graded changes in the mineral content.

  3. Observations on pulpal response to carbon dioxide laser drilling of dentine in healthy human third molars.

    PubMed

    Nair, P N R; Baltensperger, M; Luder, H U; Eyrich, G K H

    2005-01-01

    Preservation of pulpal health is the primary prerequisite for successful application of laser systems in the hard tissue management of vital teeth. The purpose of this study was to investigate the short and long-term pulpal effects to cavity preparations in healthy human teeth using carbon dioxide (CO2) laser. A total of seven, healthy, third molars that were scheduled to be removed due to space problems were used. After the laser drilling, the occlusal cavities were closed temporarily, and the teeth were extracted 7 days (n=5) and 3 months (n=2) after the operation. The specimens were fixed, decalcified, subdivided and processed for light and transmission electron microscopy. Seven days postoperatively all the five teeth that had been irradiated with the CO2 laser did not reveal any pathological changes in the pulpo-dentine complex. Three months postoperatively the two teeth that were prepared with the laser showed subtle but distinct apposition of tertiary dentine that was lined with intact odontoblasts. One of the specimens at 3 months revealed the presence of a mild, but very circumscribed, pulpal infiltration of chronic inflammatory cells subjacent to the cavity preparation. The latter is unlikely to be due to a direct effect of the laser irradiation but a possible consequence of microleakage of oral antigens and/or other tissue-irritating molecules through the temporary restoration and the remaining dentine thickness (RDT). Although these preliminary histological results suggest that the CO2 laser under investigation induced only minimal response of the dentine-pulp complex when used as a hard-tissue drilling tool, with specific energy settings, pulse duration within thermal relaxation time and emitting radiations at 9.6 microm of wavelength, larger clinical trials involving various types of teeth are necessary to reach definite conclusions for large-scale clinical application of the laser device. PMID:15647971

  4. Accumulation of advanced glycation end-products in human dentine.

    PubMed

    Miura, Jiro; Nishikawa, Kantaro; Kubo, Mizuho; Fukushima, Shuichiro; Hashimoto, Mamoru; Takeshige, Fumio; Araki, Tsutomu

    2014-02-01

    Cross-linking of collagen by Advanced Glycation End-products (AGEs) occurs by non-enzymatic glycation (Maillard reaction). The purpose of this study was to examine whether AGEs are formed in human dentinal collagen, and to consider any possible influence of AGEs on dentinal physiology. Mechanical characteristics, fluorescence spectra and immunohistochemical analyses of demineralized dentine sections from young subjects were compared with those of aged ones. The same investigations were performed with young dentine artificially glycated by incubation in 0.1M ribose solution. Indentation measurement indicated that the sections from aged dentine were mechanically harder than those from young dentine. The hardness of young dentine increased after incubation in ribose solution. Fluorescence peak wavelength of the young dentine was shorter than that of the aged one, but shifted towards the peak wavelength of the aged one after incubation in ribose solution. These changes were considered to be due to accumulation of AGEs. Existence of AGEs in dentinal collagen was confirmed by immunohistochemical analysis. The obtained results suggest that AGEs accumulation occurs in dentinal collagen and is affected by both human age and physiological conditions such as glucose level in blood because dentinal collagen receives nourishment via dental pulp and tubules. PMID:24370182

  5. An in vitro comparison of the intraradicular dentin bond strength of Resilon and gutta-percha.

    PubMed

    Skidmore, Lance J; Berzins, David W; Bahcall, James K

    2006-10-01

    The purpose of this study was to compare the micropush-out bond strength of Resilon to that of gutta-percha. Extracted human anterior teeth were used for evaluation. The crowns were removed and the root canals were instrumented with Gates Glidden drills and 0.06 Profile rotary files. Instrumentation was performed with 5.25% sodium hypochlorite irrigation and a final rinse of 17% EDTA. The teeth were randomly divided into two groups. Gutta-percha group: obturation with gutta-percha and Kerr Pulp Canal Sealer EWT. Resilon group: obturation with Resilon points, Epiphany Primer, and Root Canal Sealant. The teeth were cut perpendicular to their long axis to obtain a series of 1.0 mm thick disks (n = 15 per group). Micropush-out bond strengths to root canal dentin were measured. The results show that the mean bond strength to root canal dentin was significantly higher (p < 0.05) in the Resilon/Epiphany group as compared to the gutta-percha/Kerr Pulp Canal Sealer EWT group.

  6. Efficient Rutin and Quercetin Biosynthesis through Flavonoids-Related Gene Expression in Fagopyrum tataricum Gaertn. Hairy Root Cultures with UV-B Irradiation

    PubMed Central

    Huang, Xuan; Yao, Jingwen; Zhao, Yangyang; Xie, Dengfeng; Jiang, Xue; Xu, Ziqin

    2016-01-01

    Transformed hairy roots had been efficiently induced from the seedlings of Fagopyrum tataricum Gaertn. due to the infection of Agrobacterium rhizogenes. Hairy roots were able to display active elongation with high root branching in 1/2 MS medium without growth regulators. The stable introduction of rolB and aux1 genes of A. rhizogenes WT strain 15834 into F. tataricum plants was confirmed by PCR analysis. Besides, the absence of virD gene confirmed hairy root was bacteria-free. After six different media and different sources of concentration were tested, the culturing of TB7 hairy root line in 1/2 MS liquid medium supplemented with 30 g l-1 sucrose for 20 days resulted in a maximal biomass accumulation (13.5 g l-1 fresh weight, 1.78 g l-1 dry weight) and rutin content (0.85 mg g-1). The suspension culture of hairy roots led to a 45-fold biomass increase and a 4.11-fold rutin content increase in comparison with the suspension culture of non-transformed roots. The transformation frequency was enhanced through preculturing for 2 days followed by infection for 20 min. The UV-B stress treatment of hairy roots resulted in a striking increase of rutin and quercetin production. Furthermore, the hairy root lines of TB3, TB7, and TB28 were chosen to study the specific effects of UV-B on flavonoid accumulation and flavonoid biosynthetic gene expression by qRT-PCR. This study has demonstrated that the UV-B radiation was an effective elicitor that dramatically changed in the transcript abundance of ftpAL, FtCHI, FtCHS, FtF3H, and FtFLS-1 in F. tataricum hairy roots. PMID:26870075

  7. Efficient Rutin and Quercetin Biosynthesis through Flavonoids-Related Gene Expression in Fagopyrum tataricum Gaertn. Hairy Root Cultures with UV-B Irradiation.

    PubMed

    Huang, Xuan; Yao, Jingwen; Zhao, Yangyang; Xie, Dengfeng; Jiang, Xue; Xu, Ziqin

    2016-01-01

    Transformed hairy roots had been efficiently induced from the seedlings of Fagopyrum tataricum Gaertn. due to the infection of Agrobacterium rhizogenes. Hairy roots were able to display active elongation with high root branching in 1/2 MS medium without growth regulators. The stable introduction of rolB and aux1 genes of A. rhizogenes WT strain 15834 into F. tataricum plants was confirmed by PCR analysis. Besides, the absence of virD gene confirmed hairy root was bacteria-free. After six different media and different sources of concentration were tested, the culturing of TB7 hairy root line in 1/2 MS liquid medium supplemented with 30 g l(-1) sucrose for 20 days resulted in a maximal biomass accumulation (13.5 g l(-1) fresh weight, 1.78 g l(-1) dry weight) and rutin content (0.85 mg g(-1)). The suspension culture of hairy roots led to a 45-fold biomass increase and a 4.11-fold rutin content increase in comparison with the suspension culture of non-transformed roots. The transformation frequency was enhanced through preculturing for 2 days followed by infection for 20 min. The UV-B stress treatment of hairy roots resulted in a striking increase of rutin and quercetin production. Furthermore, the hairy root lines of TB3, TB7, and TB28 were chosen to study the specific effects of UV-B on flavonoid accumulation and flavonoid biosynthetic gene expression by qRT-PCR. This study has demonstrated that the UV-B radiation was an effective elicitor that dramatically changed in the transcript abundance of ftpAL, FtCHI, FtCHS, FtF3H, and FtFLS-1 in F. tataricum hairy roots. PMID:26870075

  8. Effects of endodontic tri-antibiotic paste on bond strengths of dentin adhesives to coronal dentin

    PubMed Central

    Mirzakoucheki, Parvin; Walter, Ricardo; Jahromi, Maryam Zare; Mirsattari, Sanaz; Akbarzadeh, Navid

    2015-01-01

    Objectives The aim of this study was to evaluate the effects of tri-antibiotic paste (TAP) on microtensile bond strengths (MTBS) of dental adhesives to dentin. Materials and Methods Sixty extracted molars had their occlusal surfaces flattened to expose dentin. They were divided into two groups, i.e., control group with no dentin treatment and experimental group with dentin treatment with TAP. After 10 days, specimens were bonded using self-etch (Filtek P90 adhesive) or etch-and-rinse (Adper Single Bond Plus) adhesives and restored with composite resin. Teeth were sectioned into beams, and the specimens were subjected to MTBS test. Data were analyzed using two-way ANOVA and post hoc Tukey tests. Results There was a statistically significant interaction between dentin treatment and adhesive on MTBS to coronal dentin (p = 0.003). Despite a trend towards worse MTBS being noticed in the experimental groups, TAP application showed no significant effect on MTBS (p = 0.064). Conclusions The etch-and-rinse adhesive Adper Single Bond Plus presented higher mean bond strengths than the self-etch adhesive Filtek P90, irrespective of the group. The superior bond performance for Adper Single Bond when compared to Filtek P90 adhesive was confirmed by a fewer number of adhesive failures. The influence of TAP in bond strength is insignificant. PMID:25984475

  9. Dentin Biomodification Potential Depends on Polyphenol Source

    PubMed Central

    Aguiar, T.R.; Vidal, C.M.P.; Phansalkar, R.S.; Todorova, I.; Napolitano, J.G.; McAlpine, J.B.; Chen, S.N.; Pauli, G.F.; Bedran-Russo, A.K.

    2014-01-01

    Although proanthocyanidins (PACs) modify dentin, the effectiveness of different PAC sources and the correlation with their specific chemical composition are still unknown. This study describes the chemical profiling of natural PAC-rich extracts from 7 plants using ultra high pressure/performance liquid chromatography (UHPLC) to determine the overall composition of these extracts and, in parallel, comprehensively evaluate their effect on dentin properties. The total polyphenol content of the extracts was determined (as gallic acid equivalents) using Folin-Ciocalteau assays. Dentin biomodification was assessed by the modulus of elasticity, mass change, and resistance to enzymatic biodegradation. Extracts with a high polyphenol and PAC content from Vitis vinifera, Theobroma cacao, Camellia sinensis, and Pinus massoniana induced a significant increase in modulus of elasticity and mass. The UHPLC analysis showed the presence of multiple types of polyphenols, ranging from simple phenolic acids to oligomeric PACs and highly condensed tannins. Protective effect against enzymatic degradation was observed for all experimental groups; however, statistically significant differences were observed between plant extracts. The findings provide clear evidence that the dentin bioactivities of PACs are source dependent, resulting from a combination of concentration and specific chemical constitution of the complex PAC mixtures. PMID:24574140

  10. Effects of aging on the mechanical behavior of human dentin.

    PubMed

    Arola, D; Reprogel, R K

    2005-06-01

    An experimental study on the mechanical behavior of human dentin and the influence of age was conducted. Beams with rectangular cross-section were sectioned from the coronal dentin of virgin extracted molars (N = 76) that were obtained from (N = 70) patients between 17 and 80 years of age. The beams were loaded in either quasi-static 4-point flexure or 4-point flexural fatigue to failure and the stiffness, strength and fatigue properties were evaluated. In characterizing the fatigue response the beams were divided into two age groups that were regarded as young (17 < or = age < or = 30, mean +/- std. dev. = 25 +/- 5 years) and old (50 < or = age < or = 80, mean +/- std. dev. = 64 +/- 9 years) dentin. Results from monotonic loading showed that both the flexural strength and strain to fracture of dentin decreased significantly with age. The fatigue life of dentin increased with a reduction in cyclic stress amplitude and the fatigue strength of young dentin was greater than that of old dentin at all cyclic stress amplitudes. The endurance strength of young dentin (at 10(7) cycles) was approximately 44 MPa, whereas the old dentin exhibited an endurance strength of approximately 23 MPa. Based on differences in the mechanical behavior and microscopic features of the fracture surfaces from the young and old specimens, aging appears to result in an increase in both the rate of damage initiation and propagation in dentin.

  11. Extracellular matrix proteins and the dynamics of dentin formation.

    PubMed

    Butler, William T; Brunn, Jan C; Qin, Chunlin; McKee, Marc D

    2002-01-01

    Dentinogenesis involves controlled reactions that result in conversion of unmineralized predentin to dentin when apatite crystals are formed. This process is dynamic: Maturation events occur within predentin beginning at the proximal layer and progressing to the predentin-dentin (PD) border. One type of controlled reaction is the proteolytic processing of dentin sialophosphoprotein (DSPP) to dentin sialoprotein (DSP) and dentin phosphoprotein (DPP), by cleavage of at least three highly conserved peptide bonds. We postulate that this processing event represents an activation step, resulting in release of DPP, which is active in its effects on formation and growth of apatite crystals. Dentin matrix protein 1 (DPM1), present as a processed fragment (57-kD protein) in bone, is seen in dentin on sodium dodecyl sulfate polyacrylamide gel electrophoresis as one intact protein of 150-200 kD. Anti-57-kD antibodies elicit immunoreactivity in bone, dentin, and cellular cementum. In bone, the reactivity is associated with osteocytes and their cell processes. Similarly, dentin shows reactivity in odontoblasts, predentin, and the odontoblast processes. In summary, the processing of large sialic acid-rich proteins into smaller fragments may be an important part of the controlled conversion of predentin to dentin and osteoid to bone.

  12. Surface microanalysis and chemical imaging of early dentin remineralization.

    PubMed

    Toledano, Manuel; Cabello, Inmaculada; Vílchez, Miguel Angel Cabrerizo; Fernández, Miguel Angel; Osorio, Raquel

    2014-02-01

    This study reports physical and chemical changes that occur at early dentin remineralization stages. Extracted human third molars were sectioned to obtain dentin discs. After polishing the dentin surfaces, three groups were established: (1) untreated dentin (UD), (2) 37% phosphoric acid application for 15 s (partially demineralized dentin-PDD), and (3) 10% phosphoric acid for 12 h at 25° C (totally demineralized dentin-TDD). Five different remineralizing solutions were used: chlorhexidine (CHX), artificial saliva (AS), phosphate solution (PS), ZnCl2, and ZnO. Wettability (contact angle), ζ potential and Raman spectroscopy analysis were determined on dentin surfaces. Demineralization of dentin resulted in a higher contact angle. Wettability decreased after immersion in all solutions. ζ potential analysis showed dissimilar performance ranging from -6.21 mV (TDD + AS) up to 3.02 mV (PDD + PS). Raman analysis showed an increase in mineral components after immersing the dentin specimens, in terms of crystallinity, mineral content, and concentration. This confirmed the optimal incorporation and deposition of mineral on dentin collagen. Organic content reflected scarce changes, except in TDD that appeared partially denatured. Pyridinium, as an expression of cross-linking, appeared in all spectra except in specimens immersed in PS. PMID:24160361

  13. A Case of Dentinogenesis Imperfecta Treated with Submerged Root Technique.

    PubMed

    Uday, Ginjupally; Chandar, Bhanu; Srilakshmi, J; Khaitan, Tanya; Babu, B Balaji

    2015-09-01

    Dentinogenesis imperfecta (DGI), an autosomal dominant trait, is one of the most common hereditary disorders affecting both the formation and mineralization of dentin. Either or both primary and permanent dentition is affected by it. Here, we present a case report of a 13-year-old female patient affected with DGI who had undergone prosthetic rehabilitation with submerged root technique.

  14. A Case of Dentinogenesis Imperfecta Treated with Submerged Root Technique

    PubMed Central

    Chandar, Bhanu; Srilakshmi, J.; Khaitan, Tanya; Babu, B. Balaji

    2015-01-01

    Dentinogenesis imperfecta (DGI), an autosomal dominant trait, is one of the most common hereditary disorders affecting both the formation and mineralization of dentin. Either or both primary and permanent dentition is affected by it. Here, we present a case report of a 13-year-old female patient affected with DGI who had undergone prosthetic rehabilitation with submerged root technique. PMID:26501025

  15. Selective removal of carious dentin using a nanosecond pulsed laser with a wavelength of 6.02 μm

    NASA Astrophysics Data System (ADS)

    Ishii, Katsunori; Saiki, Masayuki; Yasuo, Kenzo; Yamamoto, Kazuyo; Yoshikawa, Kazushi; Awazu, Kunio

    2010-04-01

    Conventional laser light sources for the treatment of a hard tissue in dental (Er:YAG laser, Er,Cr:YSGG laser and CO2 laser etc.) are good for removal of caries. However these lasers cannot achieve to give a selective treatment effect for caries without a side effect for normal tissue. The objective of this study is to develop the less-invasive treatment technique of carious dentin by selective absorption effect using the laser with a wavelength of 6.02 μm which corresponds to an absorption peak of organic matters called amide 1 band. Mid-infrared nanosecond pulsed laser by difference-frequency generation was used for the experiment of selective treatment. A tunable wavelength range, pulse width and repetition rate is from 5.5 to 10 μm, 5 ns and Hz, respectively. The laser with a wavelength of 6.02 μm and predetermined energy parameters was irradiated to the plate of carious dentin model which is made by soaking in lactic acid solution. After laser irradiation, the surface and cross-sectional surface of samples were observed by a scanning electron microscope (SEM). Average power density about 15 W/cm2 realized to excavate a demineralized region (carious dentin model) selectively in a SEM observation. In the same energy condition, serious side effect was not observed on the surface of normal dentin. A wavelength of 6.02 μm realizes a selective excavation of carious dentin. Using 6.02 μm is a novel and promising technique toward to next-generation dental treatment procedure for realizing MI.

  16. The effect of CPP-ACP and Nd:YAG laser on the bond strength of softened dentin.

    PubMed

    Kamozaki, Maria Beatriz Beber; Prakki, Anuradha; Perote, Letícia Carvalho Coutinho Costa; Gutierrez, Natalia Cortez; Pagani, Clovis

    2015-01-01

    The purpose of this study was to investigate the effect of CPP-ACP treatment and Nd:YAG laser on microtensile bond strength (µTBS) of softened dentin. Sixty samples were obtained from thirty sound third molars. All samples were submitted to dentin softening procedure, by the immersion of the specimens in 30 mL of Sprite Zero for 30 min. Afterwards, the samples were randomly divided according to the CPP-ACP treatment: CG-Control group; MP-treated with CPP-ACP paste (MI Paste); MPP-treated with CPP-ACP+900 ppm NaF paste (MI Paste Plus). Each group was further divided according to bonding procedure: NL-No laser; L-Laser irradiation after adhesive application and before polymerization. The laser parameters used were 1.4 W, 10 Hz, 140 mJ/pulse, with an optic fiber of 320 µm, generating energy of 174 J/cm(2) per pulse. All samples were restored with Clearfil SE Bond/Filtek Z350 XT. After 24 h, the restored samples were cut into beams (± 1 mm(2) adhesive interface area) and subjected to a µTBS test. Data were analyzed by two-way ANOVA test and Holm-Sidak post-hoc method (α = 0.05). The treatment with CPP-ACP pastes did not significantly affect softened dentin µTBS (p = 0.070). Statistic revealed significant reduction on µTBS values for CG/L, leading to the rejection of the second null hypothesis (p < 0.001). Both CPP-ACP based pastes did not affect µTBS of softened dentin for the adhesive system utilized. The Nd:YAG laser irradiation after application of adhesive system did affect µTBS values of softened dentin samples untreated with CPP-ACP based pastes. PMID:26083086

  17. Dynamic intratubular biomineralization following root canal obturation with pozzolan-based mineral trioxide aggregate sealer cement.

    PubMed

    Yoo, Yeon-Jee; Baek, Seung-Ho; Kum, Kee-Yeon; Shon, Won-Jun; Woo, Kyung-Mi; Lee, WooCheol

    2016-01-01

    The application of mineral trioxide aggregates (MTA) cement during the root canal obturation is gaining concern due to its bioactive characteristic to form an apatite in dentinal tubules. In this regard, this study was to assess the biomineralization of dentinal tubules following root canal obturation by using pozzolan-based (Pz-) MTA sealer cement (EndoSeal MTA, Maruchi). Sixty curved roots (mesiobuccal, distobuccal) from human maxillary molars were instrumented and prepared for root canal obturation. The canals were obturated with gutta-percha (GP) and Pz-MTA sealer by using continuous wave of condensation technique. Canals obturated solely with ProRoot MTA (Dentsply Tulsa Dental) or Pz-MTA sealer were used for comparison. In order to evaluate the biomineralization ability under different conditions, the PBS pretreatment before the root canal obturation was performed in each additional samples. At dentin-material interfaces, the extension of intratubular biomineralization was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy. When the root canal was obturated with GP and Pz-MTA sealer, enhanced biomineralization of the dentinal tubules beyond the penetrated sealer tag was confirmed under the SEM observation (p < 0.05). Mineralized apatite structures (calcium/phosphorous ratio, 1.45-1.89) connecting its way through the dentinal tubules were detected at 350-400 μm from the tubule orifice, and the pre-crystallization seeds were also observed along the intra- and/or inter-tubular collagen fiber. Intratubular biomineralization depth was significantly enhanced in all PBS pretreated canals (p < 0.05). Pz-MTA cement can be used as a promising bioactive root canal sealer to enhance biomineralization of dentinal tubules under controlled environment.

  18. Monoblocks in root canals - a hypothetical or a tangible goal

    PubMed Central

    Tay, Franklin R.; Pashley, David H.

    2007-01-01

    The term “monoblock” has become a familiar term in the endodontic literature with recent interest in the application of dentin adhesive technology to endodontics. Endodontic “monoblocks” have generated controversial discussions among academicians and clinicians as to whether they are able to improve the quality of seal in root fillings and to strengthen roots. This review attempts to provide a broader meaning to the term “monoblock” and see how this definition may be applied to the materials that have been used in the past and present for rehabilitation of the root canal space. The potential of currently available bondable materials to achieve mechanically homogeneous units with root dentin is then discussed in relation to the classical concept in which the term “monoblock” was first employed in restorative dentistry, and subsequently in endodontics. PMID:17368325

  19. Porcine enamel matrix derivative enhances the formation of reparative dentine and dentine bridges during wound healing of amputated rat molars.

    PubMed

    Igarashi, Rie; Sahara, Takako; Shimizu-Ishiura, Miho; Sasaki, Takahisa

    2003-01-01

    We examined the biological effects of porcine enamel matrix derivative (EMD; Emdogain) on the formation of reparative dentine and dentine bridges in rat molars after pulp amputation. The pulp chambers of upper molars of Wistar rats were perforated and the amputated pulp surfaces were directly capped with either EMD or its carrier propylene glycol alginate (PGA) as control. The cavities were then restored with glass-ionomer cement. On post-amputation days 4-30, the dissected maxillae were examined by light and electron microscopy. In PGA-capped pulp, reparative dentine had been formed over the dentine walls under the prepared cavity on day 7 post-amputation and its thickness extended until day 30. On day 30, as well as reparative dentine formation, diffuse calcification had occurred beneath the amputated wound surfaces. Dentine bridge formation under the amputated coronal pulp surface was observed in 18.2% of amputated pulp on day 30. In EMD-capped pulp, reparative dentine had already been formed by odontoblast-like cells over the dentine walls, already on day 4 post-amputation, and its thickness extended until day 30. The Ca and P weight % and Ca/P ratio of reparative dentine matrix were similar to those of pre-existing dentine matrix, and these values were not different between PGA and EMD-capped pulp. Dentine bridge formation was observed in 27.3% of EMD-capped pulp on day 30. Our results suggest that EMD enhances the formation of both reparative dentine and dentine bridges during wound healing of amputated rat molar pulp. PMID:12868593

  20. Effect of postponed polishing on marginal adaptation of resin used with dentin-bonding agent.

    PubMed

    Hansen, E K; Asmussen, E

    1988-06-01

    Dentin cavities, prepared in extracted human teeth, were treated with two different dentin-bonding agents and filled with a light-activated microfilled resin. The maximum width of the contraction gap (MG) and the extent of the gap (GP) were then measured, using a light microscope, approximately 0.1 mm below the original free surface of the filling. The contraction gap was measured 30 s, 10 min or 60 min, and remeasured 65 min, after stop of irradiation. A positive correlation was found between the two variables, MG and GP. The product of MG and GP was chosen as basis for the statistical analyses. This "marginal index" was significantly reduced when polishing of the marginal area was postponed for 10 min with one of the dentin-bonding agents and for 60 min with the other. Even though the improvement in marginal adaptation was statistically significant, this improvement was considered clinically irrelevant. It is concluded that polishing of the marginal area should not be done before the hygroscopic expansion of the resin restoration has closed the contraction gap.

  1. MEPE Localization in the Craniofacial Complex and Function in Tooth Dentin Formation.

    PubMed

    Gullard, Angela; Gluhak-Heinrich, Jelica; Papagerakis, Silvana; Sohn, Philip; Unterbrink, Aaron; Chen, Shuo; MacDougall, Mary

    2016-04-01

    Matrix extracellular phosphoglycoprotein (MEPE) is an extracellular matrix protein found in dental and skeletal tissues. Although information regarding the role of MEPE in bone and disorders of phosphate metabolism is emerging, the role of MEPE in dental tissues remains unclear. We performed RNA in situ hybridization and immunohistochemistry analyses to delineate the expression pattern of MEPE during embryonic and postnatal development in craniofacial mineralizing tissues. Mepe RNA expression was seen within teeth from cap through root formation in association with odontoblasts and cellular cementoblasts. More intense expression was seen in the alveolar bone within the osteoblasts and osteocytes. MEPE immunohistochemistry showed biphasic dentin staining in incisors and more intense staining in alveolar bone matrix and in forming cartilage. Analysis of Mepe null mouse molars showed overall mineralized tooth volume and density of enamel and dentin comparable with that of wild-type samples. However, Mepe(-/-) molars exhibited increased thickness of predentin, dentin, and enamel over controls and decreased gene expression of Enam, Bsp, Dmp1, Dspp, and Opnby RT-PCR. In vitro Mepe overexpression in odontoblasts led to significant reductions in Dspp reporter activity. These data suggest MEPE may be instrumental in craniofacial and dental matrix maturation, potentially functioning in the maintenance of non-mineralized matrix.

  2. Tissue dissolution and modifications in dentin composition by different sodium hypochlorite concentrations

    PubMed Central

    TARTARI, Talita; BACHMANN, Luciano; MALIZA, Amanda Garcia Alves; ANDRADE, Flaviana Bombarda; DUARTE, Marco Antonio Hungaro; BRAMANTE, Clovis Monteiro

    2016-01-01

    ABSTRACT Sodium hypochlorite (NaOCl) remains the most used irrigation solution during root canal preparation because of characteristics such as wide-spectrum antimicrobial activity and organic tissue dissolution capacity. However, these solutions can alter dentin composition and there is no consensus on the optimal concentration of NaOCl to be used. Objectives To determine the organic matter dissolution and changes in dentin chemical composition promoted by different concentrations of NaOCl over time. Material and Methods: Fragments of bovine muscle tissue were weighed before and after 5, 10, and 15 min of immersion in the groups (n=10): G1- 0.9% saline solution; G2- 1% NaOCl; G3- 2.5% NaOCl; and G4- 5% NaOCl. Bovine dentin fragments were subjected to the same irrigants and absorption spectra were collected by Attenuated Total Reflectance of Fourier Transform Infrared Spectroscopy (ATR-FTIR) before and after 0,5, 1, 2, 3, 5, 8, and 10 min of immersion in the solutions. The ratios of the amide III/phosphate and carbonate/phosphate absorption bands were determined. The tissue dissolution and carbonate/phosphate ratios were submitted to the two-way analysis of variance (ANOVA) with Tukey’s multiple-comparison test (α<0.05) and to the one-way analysis of variance with Tukey’s (α<0.05). The amide III/phosphate ratio was analyzed by Friedman test (α<0.05) and the Kruskal-Wallis test with Dunn’s post-hoc (α<0.05). Results The increase in NaOCl concentration and contact time intensified the dissolution of organic matter and dentin collagen with reduction in the amide III/phosphate ratio. Significant differences between all groups (p<0.05) were observed in the dissolution of organic matter at 10 min and in the amide III/phosphate ratio between the saline solution and 5% NaOCl at 5 min. The carbonate/phosphate ratio decreased significantly in G2, G3, and G4 after 0,5 min of immersion (p<0.05), but more alterations did not occur in the subsequent periods (p>0

  3. Microbiological assessment of dentin stained with a caries detector dye.

    PubMed

    Zacharia, M A; Munshi, A K

    1995-01-01

    The purpose of this study was to assess microbiologically the efficacy of 1% acid red in propylene glycol dye to stain carious dentin. Thirty teeth with primary carious lesions involving dentin were chosen. Cavity preparation using the conventional visual and tactile criteria was done and the dye was applied to the prepared cavity. Dentin samples were collected, from carious dentin prior to cavity preparation, dye stained areas and unstained areas. The total colony forming units (CFU) in each sample were then assessed microbiologically. The results showed a highly significant difference in the total colony forming units in dye stained and dye unstained dentin samples. The 1% acid red dye in propylene glycol dye was found to be effective as an adjunctive aid in the diagnosis of carious dentin.

  4. Changes in matrix phosphorylation during bovine dentin development.

    PubMed

    Verdelis, Kostas; Lukashova, Lyudmilla; Yamauchi, Mitsuo; Atsawasuwan, Peter; Wright, John T; Peterson, Margaret G E; Jha, Divya; Boskey, Adele L

    2007-08-01

    Phosphorylation of the organic matrix proteins of dentin is important for the initiation of mineralization, but its relevance in later mineralization stages is controversial. The objective of this study was to analyze changes in the total matrix phosphate content during dentin development and to identify their origin. Amino acid and total matrix phosphate analyses of microdissected developing mantle and circumpulpal fetal bovine dentin specimens were performed. The amino acid composition showed few changes during mantle and circumpulpal dentin maturation. However, the total matrix phosphate content showed a significant, positive correlation with tissue maturation in both mantle and circumpulpal dentin, with a two- and a three-fold increase, respectively, being observed. The data indicate that changes occur in the pattern of phosphorylation of matrix proteins during dentin maturation, which we suggest may play a functional role in later stages of tooth mineralization.

  5. Dentin phosphoprotein compound mutation in dentin sialophosphoprotein causes dentinogenesis imperfecta type III.

    PubMed

    Dong, Juan; Gu, TingTing; Jeffords, Leticia; MacDougall, Mary

    2005-01-30

    A rare compound mutation involving a 36 bp deletion and 18 bp insertion within exon 5 of the dentin sialophosphoprotein (DSPP) gene has been identified in a family with dentinogenesis imperfecta type III (DGI-III). The DSPP gene encodes two major tooth matrix proteins dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). DSPP mutations associated with DGI-III results in an in frame truncation of the serine aspartic acid triplet repeat found in DPP near the highly conserved carboxyl terminal region shortening the protein by six amino acids. Clinically this family presents with discolored amber opalescent teeth and severe attrition of the tooth structure. This study is the first report of a mutation within DPP associated with a genetic dentin disease. Our study indicates that DGI-III is allelic with some forms of DGI-II with and without progressive hearing loss and dentin dysplasia type II that have been shown to be caused by mutations within the DSP coding or signal peptide regions.

  6. SEM evaluation of nanoparticulate silver penetration into dentine collagen matrix

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Bilenko, David I.; Venig, Sergey B.

    2014-01-01

    In the present study a novel approach to caries management based on the application of nanoparticles of different nature to increase the mineral phase of demineralized dentin has been developed. Silver nanoparticles have been tested as a material for dentine matrix infiltration. Research findings clearly show that collagen fibers of demineralized dentine could be considered as a scaffold for mineral component delivery and the place where mineral growth can occur.

  7. 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

  8. In vitro study on selective removal of bovine demineralized dentin using nanosecond pulsed laser at wavelengths around 5.8 μm for realizing less invasive treatment of dental caries.

    PubMed

    Kita, Tetsuya; Ishii, Katsunori; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2015-04-01

    In the treatment of dental caries, less invasive methods are strongly required. However, conventional dental lasers cannot always achieve selective removal of caries or good bonding with a composite resin. Based on the optical absorption characteristics of dentin, wavelengths around 6 μm are promising in this regard. Our previous study indicated the possibility of selective removal of demineralized dentin using a nanosecond pulsed laser at wavelengths around 6 μm. In the present study, the optimal laser irradiation conditions were investigated for achieving selective removal of demineralized dentin. Bovine dentin was used, and its laser ablation characteristics were evaluated. The results indicated that demineralized dentin could be selectively removed, without causing cracking or damage to sound dentin, at laser wavelengths of 5.75 and 5.80 μm and average power densities of 30-40 W/cm(2). These optimal laser irradiation conditions also realized higher bonding strength with a composite resin than was possible using an Er:YAG laser. The use of nanosecond pulses allowed the thermal confinement condition to be satisfied, leading to a reduction in tissue damage, including degradation of dental pulp vitality. Thus, a nanosecond pulsed laser at 5.8 μm was found to be effective for less invasive caries treatment.

  9. Preventive effect of toothpastes with MMP inhibitors on human dentine erosion and abrasion in vitro

    PubMed Central

    Hannas, Angelica Reis; Kato, Melissa Thiemi; Cardoso, Cristiane de Almeida Baldini; Magalhães, Ana Carolina; Pereira, José Carlos; Tjäderhane, Leo; Buzalaf, Marília Afonso Rabelo

    2016-01-01

    ABSTRACT The use of gels and mouthrinses with MMP inhibitors (chlorhexidine, and green tea extract) was shown to prevent erosive wear. The aim of this study was to analyze the protective effect of toothpastes containing MMP inhibitors on dentine loss induced by erosion in vitro. Material and Methods Five groups each containing 12 specimens of human root dentine were prepared. The specimens were subjected to 1 min erosion by immersion in a cola drink, 4 times a day, for 5 d. Each day, after the first and last erosive challenges, the specimens were brushed for 15 s with a slurry of dentifrice and water (1:3) containing placebo, 1,100 ppm fluoride, 0.61% green tea extract, 0.12% chlorhexidine or 0.004% chlorhexidine (commercial toothpaste). Between the acid challenges, the specimens were stored in artificial saliva with remineralizing potential until the next treatment. Dentine loss was determined using profilometry. Data were analyzed using one-way ANOVA after log transform (p<0.05). Results The mean wear values (μm) were as follows: placebo 1.83±0.53; 0.61% green tea extract 1.00±0.21; fluoride 1.27±0.43; 0.12% chlorhexidine 1.19±0.30; and 0.004% chlorhexidine 1.22±0.46. There was a significant difference in wear between placebo and all the treatment toothpastes, which did not differ from each other. Conclusion The results suggest that toothpastes containing MMP inhibitors are as effective as those based on NaF in preventing dentine erosion and abrasion. PMID:27008258

  10. 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.

  11. Effect of the clinical application of the diode laser (810 nm) in the treatment of dentine hypersensitivity

    PubMed Central

    2014-01-01

    Background Dentine hypersensitivity is a common clinical finding with a wide variation in prevalence values. The aim of this study was to evaluate the use of diode laser (810 nm) in the treatment of cervical dentine hypersensitivity. Methods Five patients, with at least two sensitive teeth were selected. A total of 14 teeth were included in this trial. By using Visual Analogous Scale the pain of dentine hyper sensitivity was detected and the pre- treatment readings were recorded. The Diode laser (810 nm), was irradiated on (non contact) mode at the cervical region. The samples were divided into two groups according to exposure duration: For Group 1 exposure duration was 30 seconds and for group 2 exposure duration was one minute. The efficiency of the treatment was assessed at two examination period :15 minutes after first application and 7 days after first application, the degree of sensitivity was determined by using Visual Analogous Scale. Results The results show significant reduction of pain after 15 minutes of laser application in the group with 30 seconds exposure duration (P = .001), and the pain completely fade away after one week in the same group, while in the group with 1 minute exposure duration the pain completely disappeared (visual analogous scale = (0)) after 15 minutes and one week of laser application (P = 0.001). Conclusion The study concluded that application of diode laser (810 nm) was effective for the reduction of dentine hypersensitivity. PMID:24411005

  12. 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.

  13. Photosensitizer and light diffusion through dentin in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Nogueira, Ana C.; Graciano, Ariane X.; Nagata, Juliana Y.; Fujimaki, Mitsue; Terada, Raquel S. S.; Bento, Antonio C.; Astrath, Nelson G. C.; Baesso, Mauro L.

    2013-05-01

    Photodynamic therapy has been considered a potential antimicrobial modality against oral infections, including dental caries. A model to estimate the penetration of both photosensitizers and light through human dentin, a factor of interest in photodynamic therapy, is proposed. The photoacoustic spectroscopy technique was used to evaluate in vitro dentin permeability of three different photosensitizers. Using the dentin optical absorption and scattering coefficients, it was possible to propose a semi-quantitative model predicting both photosensitizer and light doses within dentin. The graphic illustrations obtained provided guidelines that may be useful in photodynamic therapy protocols used as antimicrobial tools in caries lesions.

  14. Vitamin D receptor deficiency affects dentin maturation in mice.

    PubMed

    Zhang, Xueming; Rahemtulla, Firoz G; MacDougall, Mary J; Thomas, Huw F

    2007-12-01

    Mutation of vitamin D receptors (vdr) results in resistance to the vitamin's normal effects which may compromise dentin formation. The objective of this study was to investigate the effect of vdr deficiency on post-natal dentin maturation in mice. The dentin in mandibular incisors of 70.5-day-old vdr wild-type and vdr knockout mice was compared at different levels along the long axis. Expression of biglycan and decorin was detected by immunolocalisation. Scanning electron microscopy was used to observe the ultrastructure of the dentin, and micro-computerised tomography was used to determine the degree of dentin mineralisation density. In the vdr knockout mice, the pulp chamber was larger and the dentin wall was thinner compared with the wild-type mice. In addition, the pre-dentin layer was thickened with an irregular front line and diffuse expression of biglycan and decorin. Fewer tubules, lower mineralisation density and pore-like defects were observed in the dentin at the eruptive region and level with the first molar. In conclusion, vdr deficiency compromises dentin maturation.

  15. Effect of UVA-activated riboflavin on dentin bonding.

    PubMed

    Cova, A; Breschi, L; Nato, F; Ruggeri, A; Carrilho, M; Tjäderhane, L; Prati, C; Di Lenarda, R; Tay, F R; Pashley, D H; Mazzoni, A

    2011-12-01

    Recent studies have reported collagen cross-linking after exposure to riboflavin followed by ultraviolet-A (UVA) exposure. This study is the first to investigate the effect of a riboflavin-containing primer on adhesive interface stability and dentinal matrix metalloproteinase activity. Human dentin was etched with 35% phosphoric acid, treated with 0.1% riboflavin, exposed to UVA for 2 min, and bonded with a two-step etch-and-rinse adhesive. Adhesive was applied to control specimens without riboflavin/UVA. Specimens were subjected to microtensile bond strength tests and pulled to failure after storage for 24 hrs, 6 mos, or 1 yr. Interfacial nanoleakage was evaluated by light and transmission electron microscopy. To investigate dentinal matrix metalloproteinase activity, we performed correlative zymographic assays on protein extracts obtained from phosphoric-acid-etched dentin powder with or without riboflavin/UVA treatment and XP Bond. Ultraviolet-activated riboflavin treatment increased the immediate bond strength to dentin at all aging intervals (p < 0.05 vs. control) and decreased interfacial nanoleakage in aged specimens (1 yr; p < 0.05). Zymograms revealed that riboflavin/UVA pre-treatment inhibited dentinal matrix metalloproteinase activity (especially MMP-9). In conclusion, dentinal collagen cross-linking induced by riboflavin/UVA increased immediate bond strength, stabilized the adhesive interface, and inhibited dentin matrix metalloproteinases, thereby increasing the durability of resin-dentin bonds. PMID:21940521

  16. Effect of cleaning dentine with soap and pumice on shear bond strength of dentine-bonding agents.

    PubMed

    Bachmann, M; Paul, S J; Lüthy, H; Schärer, P

    1997-06-01

    This in vitro study reports on the cleaning effect of different soaps on the shear bond strength of various dentine-bonding agents. Human teeth were coated with provisional cements for 24 h or for 14 days. After removing the provisional cements with a scaler, the dentinal surface was cleaned with a cotton pellet and non-fluoridated flour of pumice and soap for 10 sec. Different dentine-bonding agents and a luting resin were bonded to the dentinal surface according to manufacturers' instructions with the bonding agent and the composite material being light-cured at the same time. The bonding agents were tested under intrapulpal pressure and with thermal cycling to imitate physiological conditions. Compared with cleaning the dentine with water and pumice, all soaps investigated in this study decreased the shear bond strength values of the tested dentine-bonding agents considerably.

  17. A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding

    PubMed Central

    Dong, Xiaoqing; Chen, Meng; Wang, Yong; Yu, Qingsong

    2014-01-01

    Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm−1 and amide II at 1550 cm−1, which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding. PMID:25267936

  18. Dentin hypersensitivity: Recent trends in management.

    PubMed

    Miglani, Sanjay; Aggarwal, Vivek; Ahuja, Bhoomika

    2010-10-01

    Dentinal hypersensitivity (DH) is a common clinical condition usually associated with exposed dentinal surfaces. It can affect patients of any age group and most commonly affects the canines and premolars of both the arches. This article concisely reviews the patho-physiology, mechanism and clinical management of the DH. Treatment of DH should start with an accurate diagnosis. Differential diagnosis should be made and all other probable causes should be excluded. An often neglected phase of clinical management of DH is the identification and treatment of the causative factors of DH. By removing the etiological factors, the condition can be even prevented from occurring or recurring. There are various treatment modalities available which can be used at home or may be professionally applied. The "at home" desensitizing agents include toothpastes, mouthwashes or chewing gums and they act by either occluding the dentinal tubules or blocking the neural transmission. This article also discusses the recent treatment options like bioglass, Portland cement, lasers and casein phosphopeptide.

  19. Caries-resistant bonding layer in dentin

    PubMed Central

    Zhou, Wei; Niu, Li-na; Hu, Lin; Jiao, Kai; Chang, Gang; Shen, Li-juan; Tay, Franklin R.; Chen, Ji-hua

    2016-01-01

    The present study examined the mechanism for caries resistance and the pulp responses in vital teeth following the use of the augmented-pressure adhesive displacement technique. Dentin adhesives were applied to the surface of sound dentin disks in 4 experimental groups: non-antibacterial adhesive and gentle adhesive displacement (N-G), non-antibacterial adhesive and augmented-pressure adhesive displacement (N-H), antibacterial adhesive and gentle adhesive displacement (A-G), antibacterial adhesive and augmented-pressure adhesive displacement (A-H). The depth of demineralization induced by biological or chemical demineralization models was measured using confocal laser scanning microscopy and analyzed with two-way ANOVA. Pulp responses of vital dog’s teeth to the augmented-pressure adhesive displacement technique were evaluated using light microscopy. Depth of demineralization was significantly affected by “adhesive type” and “intensity of adhesive displacement” for biological demineralization. For chemical demineralization, only “intensity of adhesive displacement” showed significant influence on lesion depth. Pulp response of 0.1, 0.2 and 0.3 MPa groups showed only moderate disorganization of the odontoblast layer at 24 hours that completely re-organized after 3 weeks. Augmented-pressure adhesive displacement improves the caries resistance property of bonded dentin and does not cause irreversible pulpal damage to vital teeth when the air pressure employed is equal or smaller than 0.3 MPa. PMID:27599621

  20. Chlorhexidine Preserves Dentin Bond in vitro

    PubMed Central

    Carrilho, M. R. O.; Carvalho, R. M.; de Goes, M. F.; di Hipólito, V.; Geraldeli, S.; Tay, F. R.; Pashley, D. H.; Tjäderhane, L.

    2008-01-01

    Loss of hybrid layer integrity compromises resin-dentin bond stability. Matrix metalloproteinases (MMPs) may be partially responsible for hybrid layer degradation. Since chlorhexidine inhibits MMPs, we hypothesized that chlorhexidine would decelerate the loss of resin-dentin bonds. Class I preparations in extracted third molars were sectioned into two halves. One half was customarily restored (etch-and-rinse adhesive/resin composite), and the other was treated with 2% chlorhexidine after being acid-etched before restoration. Specimens were stored in artificial saliva with/without protease inhibitors. Microtensile bond strengths and failure mode distribution under SEM were analyzed immediately after specimens' preparation and 6 months later. With chlorhexidine, significantly better preservation of bond strength was observed after 6 months; protease inhibitors in the storage medium had no effect. Failure analysis showed significantly less failure in the hybrid layer with chlorhexidine, compared with controls after 6 months. In conclusion, this in vitro study suggests that chlorhexidine might be useful for the preservation of dentin bond strength. PMID:17189470

  1. Radiopacities in dentine under amalgam restorations.

    PubMed

    Rudolphy, M P; van Amerongen, J P; ten Cate, J M

    1994-01-01

    Radiopacities, caused by tin or zinc deposits in partly demineralized dental tissue, are frequently seen under amalgam restorations. The aim of this study was to determine to what extent these radiopaque areas could be identified by Caries Detector (1% acid red in propylene glycol) which is claimed to stain the irreversibly demineralized dentine. Twenty-eight extracted teeth showing radiopacities under amalgam fillings were selected. The restorations were removed, and Caries Detector was applied. Caries was excavated until the dentine did no longer stain with the Caries Detector. Standardized radiographs were taken at different stages. In all teeth the radiopaque areas stained with the Caries Detector. Visual inspection of the radiographs, taken after excavation, revealed that the radiopacities had disappeared completely in 6 teeth; in 5 teeth a very small part of the radiopaque area remained; in 17 teeth the cavity floor appeared as a thin white line on X-ray. Overall, line scan analysis confirmed the data obtained by visual observation. The residual radiopacities and radiopaque lines were a very small fraction of the initial radiopacities. Therefore, it is concluded that the radiopaque zone under amalgam fillings represents almost entirely an area of irreversibly demineralized dentine as indicated by the Caries Detector.

  2. In vitro quality testing of dentin adhesives.

    PubMed

    Oilo, G; Austrheim, E K

    1993-08-01

    A tensile and a shear bond strength test are compared, using two well-known and two more recently marketed dentin adhesive systems: Gluma (Bayer), Scotchbond 2 (3M), Scotchbond Multi-Purpose (3M), and Syntac (Vivadent). The adhesives were used to bond composite resins to the buccal surface of human third molars. Specimens stored for 24 h before testing did not show significant differences between bond strength values obtained by either the tensile or the shear test method for any of the materials. The bond strength of thermocycled specimens did not differ for Gluma, was significantly lower for Scotchbond 2, and significantly higher for Scotchbond Multi-Purpose and Syntac. SEM observations showed increasing amounts of cohesive failure in resin with increasing bond strength values. Cohesive fractures in dentin were also observed. It is concluded that either the tensile or the shear test method can be used for quality testing of dentin adhesives. Thermocycling may provide interesting information about the quality of a bond.

  3. Glycosaminoglycan chain of dentin sialoprotein proteoglycan.

    PubMed

    Zhu, Q; Sun, Y; Prasad, M; Wang, X; Yamoah, A K; Li, Y; Feng, J; Qin, C

    2010-08-01

    Dentin sialophosphoprotein (DSPP) is processed into dentin sialoprotein (DSP) and dentin phosphoprotein. A molecular variant of rat DSP, referred to as "HMW-DSP", has been speculated to be a proteoglycan form of DSP. To determine if HMW-DSP is the proteoglycan form of DSP and to identify the glycosaminoglycan side-chain attachment site(s), we further characterized HMW-DSP. Chondroitinase ABC treatment reduced the migration rate for portions of rat HMW-DSP to the level of DSP. Disaccharide analysis showed that rat HMW-DSP contains glycosaminoglycan chains made of chondroitin-4-sulfate and has an average of 31-32 disaccharides/mol. These observations confirmed that HMW-DSP is the proteoglycan form of DSP (renamed "DSP-PG"). Edman degradation and mass spectrometric analyses of tryptic peptides from rat DSP-PG, along with substitution analyses of candidate Ser residues in mouse DSPP, confirmed that 2 glycosaminoglycan chains are attached to Ser(241) and Ser(253) in the rat, or Ser(242) and Ser(254) in the mouse DSPP sequence.

  4. Caries-resistant bonding layer in dentin

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Niu, Li-Na; Hu, Lin; Jiao, Kai; Chang, Gang; Shen, Li-Juan; Tay, Franklin R.; Chen, Ji-Hua

    2016-09-01

    The present study examined the mechanism for caries resistance and the pulp responses in vital teeth following the use of the augmented-pressure adhesive displacement technique. Dentin adhesives were applied to the surface of sound dentin disks in 4 experimental groups: non-antibacterial adhesive and gentle adhesive displacement (N-G), non-antibacterial adhesive and augmented-pressure adhesive displacement (N-H), antibacterial adhesive and gentle adhesive displacement (A-G), antibacterial adhesive and augmented-pressure adhesive displacement (A-H). The depth of demineralization induced by biological or chemical demineralization models was measured using confocal laser scanning microscopy and analyzed with two-way ANOVA. Pulp responses of vital dog’s teeth to the augmented-pressure adhesive displacement technique were evaluated using light microscopy. Depth of demineralization was significantly affected by “adhesive type” and “intensity of adhesive displacement” for biological demineralization. For chemical demineralization, only “intensity of adhesive displacement” showed significant influence on lesion depth. Pulp response of 0.1, 0.2 and 0.3 MPa groups showed only moderate disorganization of the odontoblast layer at 24 hours that completely re-organized after 3 weeks. Augmented-pressure adhesive displacement improves the caries resistance property of bonded dentin and does not cause irreversible pulpal damage to vital teeth when the air pressure employed is equal or smaller than 0.3 MPa.

  5. Cigarette smoke affects bonding to dentin.

    PubMed

    Almeida e Silva, Junio S; de Araujo, Edson Medeiro; Araujo, Elito

    2010-01-01

    This in vitro study evaluated the microtensile bond strength (muTBS) of composite resin bonded to dentin that had been contaminated by cigarette smoke. Ten extracted unerupted human third molars were used: Six molars were prepared for muTBS testing, while the other four molars were assigned to pre- and post-etching scanning electronic microscopy (SEM) analysis. The 20 specimens obtained from the 10 coronal portions were distributed into two experimental groups so that each tooth served as its own control. Group 1 underwent a daily toothbrushing simulation and exposure to a smoking simulation chamber, while Group 2 received only a daily simulated toothbrushing. Student's t-test demonstrated that Group 1 samples demonstrated significantly lower bond strength (49.58 MPa) than Group 2 samples (58.48 MPa). Pre and postetching SEM analysis revealed the presence of contaminants on the dentinal surfaces of the Group 1 specimens. It was concluded that contamination by cigarette smoke decreases the bond strength between dentin and composite resin.

  6. Diagnosis and treatment of dentinal hypersensitivity.

    PubMed

    Porto, Isabel C C M; Andrade, Ana K M; Montes, Marcos A J R

    2009-09-01

    This bibliographic review provides a general view of the etiology, characteristics and treatment of dentinal hypersensitivity, so that professionals can use this information in the therapeutic management of this clinical condition. For this purpose, the authors have analyzed whole texts of relevant articles on the subject. This study showed that the predisposing factors associated with the causes of dentinal hypersensitivity must be controlled or eliminated, by educating the patient regarding the excessive intake of acidic food, as well as providing guidance on the proper tooth brushing technique and analysis of occlusion. Effective treatment must be preceded by a proper diagnosis, established after the exclusion of any other possible causes of the pain. These cases must be managed efficiently, quickly and permanently. The availability of a wide variety of treatment could be an indicator that there is still no effective desensitizing agent to completely resolve the patient's discomfort, or that it is difficult to treat, irrespective of the available treatment options. Even with the large number of published studies, it has not been possible to reach a consensus about the product that represents the gold standard in the treatment of dentinal hypersensitivity. PMID:19776498

  7. Dentin hypersensitivity: Recent trends in management.

    PubMed

    Miglani, Sanjay; Aggarwal, Vivek; Ahuja, Bhoomika

    2010-10-01

    Dentinal hypersensitivity (DH) is a common clinical condition usually associated with exposed dentinal surfaces. It can affect patients of any age group and most commonly affects the canines and premolars of both the arches. This article concisely reviews the patho-physiology, mechanism and clinical management of the DH. Treatment of DH should start with an accurate diagnosis. Differential diagnosis should be made and all other probable causes should be excluded. An often neglected phase of clinical management of DH is the identification and treatment of the causative factors of DH. By removing the etiological factors, the condition can be even prevented from occurring or recurring. There are various treatment modalities available which can be used at home or may be professionally applied. The "at home" desensitizing agents include toothpastes, mouthwashes or chewing gums and they act by either occluding the dentinal tubules or blocking the neural transmission. This article also discusses the recent treatment options like bioglass, Portland cement, lasers and casein phosphopeptide. PMID:21217949

  8. Caries-resistant bonding layer in dentin.

    PubMed

    Zhou, Wei; Niu, Li-Na; Hu, Lin; Jiao, Kai; Chang, Gang; Shen, Li-Juan; Tay, Franklin R; Chen, Ji-Hua

    2016-01-01

    The present study examined the mechanism for caries resistance and the pulp responses in vital teeth following the use of the augmented-pressure adhesive displacement technique. Dentin adhesives were applied to the surface of sound dentin disks in 4 experimental groups: non-antibacterial adhesive and gentle adhesive displacement (N-G), non-antibacterial adhesive and augmented-pressure adhesive displacement (N-H), antibacterial adhesive and gentle adhesive displacement (A-G), antibacterial adhesive and augmented-pressure adhesive displacement (A-H). The depth of demineralization induced by biological or chemical demineralization models was measured using confocal laser scanning microscopy and analyzed with two-way ANOVA. Pulp responses of vital dog's teeth to the augmented-pressure adhesive displacement technique were evaluated using light microscopy. Depth of demineralization was significantly affected by "adhesive type" and "intensity of adhesive displacement" for biological demineralization. For chemical demineralization, only "intensity of adhesive displacement" showed significant influence on lesion depth. Pulp response of 0.1, 0.2 and 0.3 MPa groups showed only moderate disorganization of the odontoblast layer at 24 hours that completely re-organized after 3 weeks. Augmented-pressure adhesive displacement improves the caries resistance property of bonded dentin and does not cause irreversible pulpal damage to vital teeth when the air pressure employed is equal or smaller than 0.3 MPa. PMID:27599621

  9. SEM evaluation of resin-carious dentin interfaces formed by two dentin adhesive systems

    PubMed Central

    Hsu, Kuang-Wei; Marshall, Sally J.; Pinzon, Lilliam M.; Watanabe, Larry; Saiz, Eduardo; Marshall, Grayson W.

    2008-01-01

    Objectives We investigated the influence of dentin tubule direction and identifiable zone of carious dentin on the microstructure and the thickness of the hybrid-like layer (HL) formed by self-etch and etch-rinse adhesive systems. Methods An etch-rinse and a self-etching adhesive were bonded to dentin carious zones divided into groups with parallel or perpendicular orientation relative to the dentin tubules at the resin-carious dentin interface (N = 5/variable). Bonds were prepared to each of the four zones of carious dentin apparent after staining with Caries Detector: pink, light pink, transparent and apparently normal Six non-carious third molars were controls. The microstructure and thickness of the HL were determined by SEM.and compared using three-way ANOVA and Tukey's multiple comparisons (p<0.05). Results Etch-rinse controls gave thicker HLs than self-etching systems; ; orientation did not affect thickness for the self-etch system. Perpendicular orientations gave thicker HLs than parallel for the pink zone bonded with the etch-rinse system. For both adhesives, HL thickness in the pink zone were significantly greater than in light pink for the perpendicular group, but no significant differences were found among other variables. HL microstructure was more granular and rougher for the etch rinse than for the self etching system. Pores and cracks were obvious in the more demineralized zones, Resin tags were shorter and irregular in the transparent zone and often were completely absent in the outer demineralized zones (pink, light pink). Significance Microstructure of bonded interfaces varies markedly depending on adhesive system, tubule orientation and carious zone. PMID:18155289

  10. Identification of full-length dentin matrix protein 1 in dentin and bone.

    PubMed

    Huang, Bingzhen; Maciejewska, Izabela; Sun, Yao; Peng, Tao; Qin, Disheng; Lu, Yongbo; Bonewald, Lynda; Butler, William T; Feng, Jian; Qin, Chunlin

    2008-05-01

    Dentin matrix protein 1 (DMP1) has been identified in the extracellular matrix (ECM) of dentin and bone as the processed NH(2)-terminal and COOH-terminal fragment. However, the full-length form of DMP1 has not been identified in these tissues. The focus of this investigation was to search for the intact full-length DMP1 in dentin and bone. We used two types of anti-DMP1 antibodies to identify DMP1: one type specifically recognizes the NH(2)-terminal region and the other type is only reactive to the COOH-terminal region of the DMP1 amino acid sequence. An approximately 105-kDa protein, extracted from the ECM of rat dentin and bone, was recognized by both types of antibodies; and the migration rate of this protein was identical to the recombinant mouse full-length DMP1 made in eukaryotic cells. We concluded that this approximately 105-kDa protein is the full-length form of DMP1, which is considerably less abundant than its processed fragments in the ECM of dentin and bone. We also detected the full-length form of DMP1 and its processed fragments in the extract of dental pulp/odontoblast complex dissected from rat teeth. In addition, immunofluorescence analysis showed that in MC3T3-E1 cells the NH(2)-terminal and COOH-terminal fragments of DMP1 are distributed differently. Our findings indicate that the majority of DMP1 must be cleaved within the cells that synthesize it and that minor amounts of uncleaved DMP1 molecules are secreted into the ECM of dentin and bone.

  11. Temperature changes inside the molar pulp chamber and on the enamel and root surfaces induced by the CO2 laser beam, in vitro

    NASA Astrophysics Data System (ADS)

    Anic, Ivica; Dzubur, A.; Skala, Karolj; Sutalo, Jozo

    1993-12-01

    The application of the CO2 laser continuous wave to hard dental tissue causes temperature changes on the impact area, on the adjacent area and inside the pulp chamber. The purpose of this study was to investigate the thermal effects induced by the CO2 laser continuous wave, and the temperature flow through adjacent areas. Forty healthy molars, 15 molars with class II amalgam restoration and 10 canines with cervical caries extracted for periodontal reasons were irradiated with laser beam. On the occlusal surface the class I preparation was made just beyond the dentine-enamel junction. Temperature changes were measured at the enamel, root surface and at the cross section of the previously prepared holes 3 mm in diameter which were made 2 mm above the bifurcation level.

  12. Stable nitrogen isotope analysis of dentine serial sections elucidate sex differences in weaning patterns of wild chimpanzees (Pan troglodytes).

    PubMed

    Fahy, Geraldine E; Richards, Michael P; Fuller, Benjamin T; Deschner, Tobias; Hublin, Jean-Jacques; Boesch, Christophe

    2014-04-01

    Offspring provisioning is one of the most energetically demanding aspects of reproduction for female mammals. Variation in lactation length and weaning strategies between chimpanzees (Pan troglodytes), our closest living relative, and modern human societies have been reported. When and why these changes occurred is frequently debated. Our study used stable nitrogen isotope data of tooth root dentine from wild Western chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire, to quantify weaning in these chimpanzees and explore if infant sex plays a role in maternal investment. We analyzed serial sections of deciduous lateral incisor root dentine from four Taï chimpanzees to establish the δ(15) N signal of nursing infants; we then analyzed serial sections of first permanent mandibular molar root dentine from 12 Taï chimpanzees to provide quantitative δ(15) N data on weaning in this population. Up to 2 years of age both sexes exhibited dentine δ(15) N values ≈2-3‰ higher than adult female Taï chimpanzees, consistent with a nursing signal. Thereafter a steady decrease in δ(15) N values consistent with the onset, and progression, of weaning, was visible. Sex differences were also evident, where male δ(15) N values decreased at a significantly slower rate compared to females. Confirmation of sex differences in maternal investment among Taï chimpanzees, demonstrates the viability of using isotope analysis to investigate weaning in non-human primates. Additionally, assuming that behaviors observed in the Taï chimpanzees are illustrative of the ancestral pattern, our results provide a platform to enable the trajectory of weaning in human evolution to be further explored.

  13. Effects of dentin surface treatments on the fracture toughness and tensile bond strength of a dentin-composite adhesive interface.

    PubMed

    Tam, L E; Pilliar, R M

    1994-09-01

    It has been proposed that the fracture toughness test provides an appropriate method for assessing the fracture resistance of the dentin-composite interface. The plane-strain fracture toughness test was therefore applied to a dentin-composite interface, with use of a specific dentinal adhesive, so that the effects of various dentin surface treatments on dentin-bond integrity could be studied. Interfacial fracture toughness (KIC) values were determined following 24h and 180 days of specimen aging in distilled water at 37 degrees C. Tensile bond strength (TBS) results following 24-hour aging were also obtained for comparison with the 24-hour KIC results. In general, the fracture resistance of the dentin-composite interface was highest when the dentin surface was conditioned with acid but not air-dried, intermediate when the dentin surface was conditioned with acid and subsequently air-dried, and lowest when the dentin was not conditioned with acid. The tensile bond strength results differed from the fracture toughness results in indicating differences in surface preparation effects and the type of interfacial failure observed.

  14. Dentin matrix protein 1 and dentin sialophosphoprotein in human sound and carious teeth: an immunohistochemical and colorimetric assay.

    PubMed

    Martini, D; Trirè, A; Breschi, L; Mazzoni, A; Teti, G; Falconi, M; Ruggeri, A

    2013-10-29

    Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) are extracellular matrix proteins produced by odontoblasts involved in the dentin mineralization. The aim this study was to compare the distribution of DMP1 and DSPP in human sound dentin vs human sclerotic dentin. Sixteen sound and sixteen carious human molars were selected, fixed in paraformaldehyde and processed for immunohistochemical detection of DMP1 and DSPP by means of light microscopy, transmission electron microscopy (TEM) and high-resolution field emission in-lens scanning electron microscopy (FEI-SEM). Specimens were submitted to a pre-embedding or a post-embedding immunolabeling technique using primary antibodies anti DMP1 and anti-DSPP and gold-conjugated secondary antibodies. Other samples were processed for the detection of DMP1 and DSPP levels. Dentin from these samples was mechanically fractured to powder, then a protein extraction and a protein level detection assay were performed. DMP1 and DSPP were more abundant in carious than in sound samples. Immunohistochemical analyses in sclerotic dentin disclosed a high expression of DMP1 and DSPP inside the tubules, suggesting an active biomineralization of dentin by odontoblasts. Furthermore, the detection of small amounts of these proteins inside the tubules far from the carious lesion, as shown in the present study, is consistent with the hypothesis of a preventive defense of all dentin after a noxious stimulus has undermined the tooth.

  15. The nano-hardness and elastic modulus of sound deciduous canine dentin and young premolar dentin--preliminary study.

    PubMed

    Hosoya, Y; Marshall, G W

    2005-01-01

    The purpose of this study was to compare the nano-hardness and elastic modulus among deciduous and permanent dentin, buccal and lingual sides, incisal, center and cervical areas, and outer, middle and inner layers. Three premolars and three deciduous canines were bucco lingually (BL) sectioned, and three deciduous canines were mesio-distally (MD) sectioned parallel to the long axis at the center of the tooth. Hardness (H), plastic hardness (PH) and Young's modulus (Y) were measured using a nano-indentation tester. The H, PH and Y values from the deciduous canine dentin were significantly lower than those from the premolar dentin at most sites. For deciduous canine dentin, the H and PH values of the MD sectioned dentin were significantly higher than those of the BL sectioned dentin in many layers of many areas. Generally deciduous canine dentin had H, PH and Y values that decreased from outer toward the inner layers and significant differences were obtained among the layers in many areas. For MD sectioned deciduous canine and BD sectioned premolar dentin, the H, PH and Y values of the cervical area were significantly lower than those of the incisal and center areas in many layers. It is possible that optimum bonding may require different treatments for deciduous and permanent dentin and perhaps also for different intratooth locations.

  16. Effects of Chemical Cross-linkers on Caries-affected Dentin Bonding

    PubMed Central

    Macedo, G.V.; Yamauchi, M.; Bedran-Russo, A.K.

    2009-01-01

    The achievement of a strong and stable bond between composite resin and dentin remains a challenge in restorative dentistry. Over the past two decades, dental materials have been substantially improved, with better handling and bonding characteristics. However, little attention has been paid to the contribution of collagen structure/stability to bond strength. We hypothesized that the induction of cross-linking in dentin collagen improves dentin collagen stability and bond strength. This study investigated the effects of glutaraldehyde- and grape seed extract-induced cross-linking on the dentin bond strengths of sound and caries-affected dentin, and on the stability of dentin collagen. Our results demonstrated that the application of chemical cross-linking agents to etched dentin prior to bonding procedures significantly enhanced the dentin bond strengths of caries-affected and sound dentin. Glutaraldehyde and grape seed extract significantly increased dentin collagen stability in sound and caries-affected dentin, likely via distinct mechanisms. PMID:19892915

  17. Coinvasion of dentinal tubules by Porphyromonas gingivalis and Streptococcus gordonii depends upon binding specificity of streptococcal antigen I/II adhesin.

    PubMed

    Love, R M; McMillan, M D; Park, Y; Jenkinson, H F

    2000-03-01

    Cell wall-anchored polypeptides of the antigen I/II family are produced by many species of oral streptococci. These proteins mediate adhesion of streptococci to salivary glycoproteins and to other oral microorganisms and promote binding of cells to collagen type I and invasion of dentinal tubules. Since infections of the root canal system have a mixed anaerobic bacterial etiology, we investigated the hypothesis that coadhesion of anaerobic bacteria with streptococci may facilitate invasive endodontic disease. Porphyromonas gingivalis ATCC 33277 cells were able to invade dentinal tubules when cocultured with Streptococcus gordonii DL1 (Challis) but not when cocultured with Streptococcus mutans NG8. An isogenic noninvasive mutant of S. gordonii, with production of SspA and SspB (antigen I/II family) polypeptides abrogated, was deficient in binding to collagen and had a 40% reduced ability to support adhesion of P. gingivalis. Heterologous expression of the S. mutans SpaP (antigen I/II) protein in this mutant restored collagen binding and tubule invasion but not adhesion to P. gingivalis or the ability to promote P. gingivalis coinvasion of dentin. An isogenic afimbrial mutant of P. gingivalis had 50% reduced binding to S. gordonii cells but was unaffected in the ability to coinvade dentinal tubules with S. gordonii wild-type cells. Expression of the S. gordonii SspA or SspB polypeptide on the surface of Lactococcus lactis cells endowed these bacteria with the abilities to bind P. gingivalis, penetrate dentinal tubules, and promote P. gingivalis coinvasion of dentin. The results demonstrate that collagen-binding and P. gingivalis-binding properties of antigen I/II polypeptides are discrete functions. Specificity of antigen I/II polypeptide recognition accounts for the ability of P. gingivalis to coinvade dentinal tubules with S. gordonii but not with S. mutans. This provides evidence that the specificity of interbacterial coadhesion may influence directly the etiology

  18. Growth Factor Liberation and DPSC Response Following Dentine Conditioning.

    PubMed

    Sadaghiani, L; Gleeson, H B; Youde, S; Waddington, R J; Lynch, C D; Sloan, A J

    2016-10-01

    Liberation of the sequestrated bioactive molecules from dentine by the action of applied dental materials has been proposed as an important mechanism in inducing a dentinogenic response in teeth with viable pulps. Although adhesive restorations and dentine-bonding procedures are routinely practiced, clinical protocols to improve pulp protection and dentine regeneration are not currently driven by biological knowledge. This study investigated the effect of dentine (powder and slice) conditioning by etchants/conditioners relevant to adhesive restorative systems on growth factor solubilization and odontoblast-like cell differentiation of human dental pulp progenitor cells (DPSCs). The agents included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH <1), citric acid (10%, pH 1.5), and polyacrylic acid (25%, pH 3.9). Growth factors were detected in dentine matrix extracts drawn by EDTA, phosphoric acid, and citric acid from powdered dentine. The dentine matrix extracts were shown to be bioactive, capable of stimulating odontogenic/osteogenic differentiation as observed by gene expression and phenotypic changes in DPSCs cultured in monolayer on plastic. Polyacrylic acid failed to solubilize proteins from powdered dentine and was therefore considered ineffective in triggering a growth factor-mediated response in cells. The study went on to investigate the effect of conditioning dentine slices on growth factor liberation and DPSC behavior. Conditioning by EDTA, phosphoric acid, and citric acid exposed growth factors on dentine and triggered an upregulation in genes associated with mineralized differentiation, osteopontin, and alkaline phosphatase in DPSCs cultured on dentine. The cells demonstrated odontoblast-like appearances with elongated bodies and long extracellular processes extending on dentine surface. However, phosphoric acid-treated dentine appeared strikingly less populated with cells, suggesting a detrimental impact on cell

  19. A novel bioactive glass-ceramic for treating dentin hypersensitivity.

    PubMed

    Tirapelli, Camila; Panzeri, Heitor; Soares, Rodrigo Gongalves; Peitl, Oscar; Zanotto, Edgar Dutra

    2010-01-01

    Dentin hypersensitivity (DH) is a painful response to stimulus applied to the open dentinal tubules of a vital tooth. It's a common oral condition, however, without an ideal treatment available yet. This work evaluated in vitro the effect of micron-sized particles from a novel bioactive glass-ceramic (Biosilicate) in occluding open dentinal tubules. A dentin disc model was employed to observe comparatively, using scanning electron microscopy (SEM), dentinal tubule occlusion by different products and deposition of hydroxyl carbonate apatite (HCA) on dentin surface by Biosilicate, after a single application: G1 - Dentifrice with potassium nitrate and fluoride; G2 - Two-step calcium phosphate precipitation treatment; G3 - Water-free gel containing Biosilicate particles (1%); G4 - Biosilicate particles mixed with distilled water in a 1:10 ratio; all of them after 1, 12 and 24 hours of immersion in artificial saliva. Fourier transform infrared spectroscopy (FTIR) was performed to detect HCA formation on dentin discs filled with Biosilicate after 2 minutes, 30 minutes and 12 hours of immersion in artificial saliva. SEM showed a layer of HCA formed on dentin surface after 24 hours by G4. G1, G2 and G3 promoted not total occlusion of open dentinal tubules after 24 hours. FTIR showed HCA precipitation on the dentin surface induced by Biosilicate after 30 minutes. The micron-sized particles from the bioactive glass-ceramic thus were able to induce HCA deposition in open dentinal tubules in vitro. This finding suggests that Biosilicate may provide a new option for treating DH. PMID:21180956

  20. A novel bioactive glass-ceramic for treating dentin hypersensitivity.

    PubMed

    Tirapelli, Camila; Panzeri, Heitor; Soares, Rodrigo Gongalves; Peitl, Oscar; Zanotto, Edgar Dutra

    2010-01-01

    Dentin hypersensitivity (DH) is a painful response to stimulus applied to the open dentinal tubules of a vital tooth. It's a common oral condition, however, without an ideal treatment available yet. This work evaluated in vitro the effect of micron-sized particles from a novel bioactive glass-ceramic (Biosilicate) in occluding open dentinal tubules. A dentin disc model was employed to observe comparatively, using scanning electron microscopy (SEM), dentinal tubule occlusion by different products and deposition of hydroxyl carbonate apatite (HCA) on dentin surface by Biosilicate, after a single application: G1 - Dentifrice with potassium nitrate and fluoride; G2 - Two-step calcium phosphate precipitation treatment; G3 - Water-free gel containing Biosilicate particles (1%); G4 - Biosilicate particles mixed with distilled water in a 1:10 ratio; all of them after 1, 12 and 24 hours of immersion in artificial saliva. Fourier transform infrared spectroscopy (FTIR) was performed to detect HCA formation on dentin discs filled with Biosilicate after 2 minutes, 30 minutes and 12 hours of immersion in artificial saliva. SEM showed a layer of HCA formed on dentin surface after 24 hours by G4. G1, G2 and G3 promoted not total occlusion of open dentinal tubules after 24 hours. FTIR showed HCA precipitation on the dentin surface induced by Biosilicate after 30 minutes. The micron-sized particles from the bioactive glass-ceramic thus were able to induce HCA deposition in open dentinal tubules in vitro. This finding suggests that Biosilicate may provide a new option for treating DH.

  1. Remineralization of root caries monitored using cross polarization optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Darling, Cynthia L.; Staninec, Michal; Chan, Kenneth H.; Kang, Hobin; Fried, Daniel

    2012-01-01

    Previous studies have demonstrated that polarization sensitive optical coherence tomography (PS-OCT) can be used to image caries lesions in dentin, measure nondestructively the severity of dentin demineralization, and determine the efficacy of intervention with anticaries agents including fluoride and lasers. However, those studies were limited to artificial lesions on dentin and roots surfaces. The objective of this study is to determine if a cross polarization OCT system (CP-OCT) can be used to nondestructively measure a reduction in the reflectivity of natural root caries lesions after exposure to a remineralization solution. CPOCT images of 11 teeth with existing root lesions were acquired before and after exposure to a remineralizing solution for 20 days. The integrated reflectivity was calculated after integrating to a fixed depth of 200-μm. There was a significant decrease in the integrated reflectivity after exposure to the remineralizing solution.

  2. In Vitro assessment of dentin erosion after immersion in acidic beverages: surface profile analysis and energy-dispersive X-ray fluorescence spectrometry study.

    PubMed

    Caneppele, Taciana Marco Ferraz; Jeronymo, Raffaela Di Iorio; Di Nicoló, Rebeca; de Araújo, Maria Amélia Máximo; Soares, Luís Eduardo Silva

    2012-01-01

    The aim of this study was to investigate the effects of some acidic drinks on dentin erosion, using methods of surface profile (SP) analysis and energy-dispersive X-ray fluorescence spectrometry (EDXRF). One hundred standardized dentin slabs obtained from bovine incisor roots were used. Dentin slabs measuring 5x5 mm were ground flat, polished and half of each specimen surface was protected with nail polish. For 60 min, the dentin surfaces were immersed in 50 mL of 5 different drinks (Gatorade®, Del Valle Mais orange juice®, Coca-Cola®, Red Bull® and white wine), 20 blocks in each drink. The pH of each beverage was measured. After the erosive challenge, the nail polish was removed and SP was analyzed. The mineral concentration of dentin surfaces was determined by means of EDXRF. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). SP analysis showed that Red-Bull had the highest erosive potential (p<0.05). EDXRF results exhibited a decrease in phosphate in the groups immersed in Red-Bull, orange juice and white wine (p<0.05), and no significant difference in calcium content between the reference surface and eroded surface. In conclusion, this study demonstrated that all studied beverages promoted erosion on root dentin and Red Bull had the highest erosive potential. There was no correlation between pH of beverages and their erosive potential and only the P content changed after erosive challenge. PMID:23207852

  3. In Vitro assessment of dentin erosion after immersion in acidic beverages: surface profile analysis and energy-dispersive X-ray fluorescence spectrometry study.

    PubMed

    Caneppele, Taciana Marco Ferraz; Jeronymo, Raffaela Di Iorio; Di Nicoló, Rebeca; de Araújo, Maria Amélia Máximo; Soares, Luís Eduardo Silva

    2012-01-01

    The aim of this study was to investigate the effects of some acidic drinks on dentin erosion, using methods of surface profile (SP) analysis and energy-dispersive X-ray fluorescence spectrometry (EDXRF). One hundred standardized dentin slabs obtained from bovine incisor roots were used. Dentin slabs measuring 5x5 mm were ground flat, polished and half of each specimen surface was protected with nail polish. For 60 min, the dentin surfaces were immersed in 50 mL of 5 different drinks (Gatorade®, Del Valle Mais orange juice®, Coca-Cola®, Red Bull® and white wine), 20 blocks in each drink. The pH of each beverage was measured. After the erosive challenge, the nail polish was removed and SP was analyzed. The mineral concentration of dentin surfaces was determined by means of EDXRF. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). SP analysis showed that Red-Bull had the highest erosive potential (p<0.05). EDXRF results exhibited a decrease in phosphate in the groups immersed in Red-Bull, orange juice and white wine (p<0.05), and no significant difference in calcium content between the reference surface and eroded surface. In conclusion, this study demonstrated that all studied beverages promoted erosion on root dentin and Red Bull had the highest erosive potential. There was no correlation between pH of beverages and their erosive potential and only the P content changed after erosive challenge.

  4. Fracture mechanics analysis of vertical root fracture from condensation of gutta-percha.

    PubMed

    Chai, Herzl; Tamse, Aviad

    2012-06-01

    A two-dimensional fracture mechanics analysis of vertical root fracture (VRF) in single-canal roots from apical condensation of gutta-percha (gp) is developed. The resulting analytic relation for apical load causing VRF agrees with major trends reported in in-vitro tests on roots subjected to either continuous or, the more clinically relevant, repeating vertical condensation of gp. The model explicitly exposes the role of root canal morphology and dentin fracture toughness on VRF. Ovoid and irregular canals are prone to fracture while the effect of mean root canal radius is modest. Canal taper and instrumentation details may affect VRF only marginally and indirectly. The model predicts dentinal cracks to occur following root canal instrumentation and obturation, which may pose long-term threats to tooth integrity. PMID:22503579

  5. 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

  6. 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

  7. External Dentin Stimulation Induces ATP Release in Human Teeth.

    PubMed

    Liu, X; Wang, C; Fujita, T; Malmstrom, H S; Nedergaard, M; Ren, Y F; Dirksen, R T

    2015-09-01

    ATP is involved in neurosensory processing, including nociceptive transduction. Thus, ATP signaling may participate in dentin hypersensitivity and dental pain. In this study, we investigated whether pannexins, which can form mechanosensitive ATP-permeable channels, are present in human dental pulp. We also assessed the existence and functional activity of ecto-ATPase for extracellular ATP degradation. We further tested if ATP is released from dental pulp upon dentin mechanical or thermal stimulation that induces dentin hypersensitivity and dental pain and if pannexin or pannexin/gap junction channel blockers reduce stimulation-dependent ATP release. Using immunofluorescence staining, we demonstrated immunoreactivity of pannexin 1 and 2 in odontoblasts and their processes extending into the dentin tubules. Using enzymatic histochemistry staining, we also demonstrated functional ecto-ATPase activity within the odontoblast layer, subodontoblast layer, dental pulp nerve bundles, and blood vessels. Using an ATP bioluminescence assay, we found that mechanical or cold stimulation to the exposed dentin induced ATP release in an in vitro human tooth perfusion model. We further demonstrated that blocking pannexin/gap junction channels with probenecid or carbenoxolone significantly reduced external dentin stimulation-induced ATP release. Our results provide evidence for the existence of functional machinery required for ATP release and degradation in human dental pulp and that pannexin channels are involved in external dentin stimulation-induced ATP release. These findings support a plausible role for ATP signaling in dentin hypersensitivity and dental pain. PMID:26130258

  8. External Dentin Stimulation Induces ATP Release in Human Teeth

    PubMed Central

    Wang, C.; Fujita, T.; Malmstrom, H.S.; Nedergaard, M.; Ren, Y.F.; Dirksen, R.T.

    2015-01-01

    ATP is involved in neurosensory processing, including nociceptive transduction. Thus, ATP signaling may participate in dentin hypersensitivity and dental pain. In this study, we investigated whether pannexins, which can form mechanosensitive ATP-permeable channels, are present in human dental pulp. We also assessed the existence and functional activity of ecto-ATPase for extracellular ATP degradation. We further tested if ATP is released from dental pulp upon dentin mechanical or thermal stimulation that induces dentin hypersensitivity and dental pain and if pannexin or pannexin/gap junction channel blockers reduce stimulation-dependent ATP release. Using immunofluorescence staining, we demonstrated immunoreactivity of pannexin 1 and 2 in odontoblasts and their processes extending into the dentin tubules. Using enzymatic histochemistry staining, we also demonstrated functional ecto-ATPase activity within the odontoblast layer, subodontoblast layer, dental pulp nerve bundles, and blood vessels. Using an ATP bioluminescence assay, we found that mechanical or cold stimulation to the exposed dentin induced ATP release in an in vitro human tooth perfusion model. We further demonstrated that blocking pannexin/gap junction channels with probenecid or carbenoxolone significantly reduced external dentin stimulation–induced ATP release. Our results provide evidence for the existence of functional machinery required for ATP release and degradation in human dental pulp and that pannexin channels are involved in external dentin stimulation–induced ATP release. These findings support a plausible role for ATP signaling in dentin hypersensitivity and dental pain. PMID:26130258

  9. Can interaction of materials with the dentin-pulp complex contribute to dentin regeneration?

    PubMed

    Ferracane, Jack L; Cooper, Paul R; Smith, Anthony J

    2010-02-01

    Understanding outcomes of the interaction between a dental material and tooth tissue is important in terms not only of biocompatibility but also of the potential for the material to modulate the response of the tissue. This interaction is influenced by many factors, including the chemistry of the material and any of its eluted components or degradation products, and the manner in which the tissue responds to these agents. Past studies of this interaction have primarily been aimed at identifying cytotoxic effects. More recently, investigations have focused on specific cellular responses, and in particular, on understanding how the materials themselves actually may contribute to regenerative processes in the tooth. Recent work has demonstrated the solubilization of proteins from dentin exposed to certain materials, such as calcium hydroxide, mineral trioxide aggregate, and acidic solutions that relate to those used in dentin bonding agents, with the subsequent modulation by these proteins of gene expression in odontoblast-like cells. This work suggests that dentin bridge formation under such materials may be stimulated through this process. Thus, there is much merit in examining both how new dental materials can be developed and how more traditional ones can be modified to preferentially stimulate regenerative processes when preferred. This review summarizes current knowledge about the potential beneficial effects derived from the interaction of dental materials with the dentin-pulp complex, as well as potential future developments in this exciting field.

  10. Dentin noncollagenous matrix proteins in familial hypophosphatemic rickets.

    PubMed

    Gaucher, Céline; Boukpessi, Tchilalo; Septier, Dominique; Jehan, Frédéric; Rowe, Peter S; Garabédian, Michèle; Goldberg, Michel; Chaussain-Miller, Catherine

    2009-01-01

    Familial hypophosphatemic rickets is transmitted in most cases as an X-linked dominant trait and results from the mutation of the PHEX gene predominantly expressed in osteoblast and odontoblast. Patients with rickets have been reported to display important dentin defects. Our purpose was to explore the structure, composition and distribution of noncollagenous proteins (NCPs) of hypophosphatemic dentin. We collected teeth from 10 hypophosphatemic patients whose mineralization occurred either in a hypophosphatemic environment or in a corrected phosphate and vitamin environment. Teeth were examined by scanning electron microscopy, immunohistochemistry and Western blot analysis. An abnormal distribution (accumulation in interglobular spaces) and cleavage of the NCPs and particularly of matrix extracellular phosphoglycoprotein were observed in deciduous dentin. In contrast, it was close to normal in permanent dentin mineralized under corrected conditions. In conclusion, dentin mineralization in a corrected phosphate and vitamin D environment compensates the adverse effect of PHEX mutation.

  11. Bone Induction by Demineralized Dentin Matrix in Nude Mouse Muscles

    PubMed Central

    Kim, Kyung-Wook

    2014-01-01

    Purpose: This study examined the osteoinductive activity of demineralized human dentin matrix for nude mice. Methods: Twenty healthy nude mice weighing about 15 to 20 g were used for study. Demineralized human dentin matrix was prepared and implanted into the dorsal portion of nude mice (subcutaneous), which were sacrificed at two, four, and eight weeks after demineralized dentin matrix grafting and evaluated histologically by H&E and Masson trichrome staining. The specimens were also evaluated histomorphometrically. Results: The demineralized dentin matrix induced bone and cartilage formation independently in soft tissues. Histological examination showed bone-forming cells such as osteoblasts and fibroblasts at two, four, and eight weeks. Conclusion: These results suggest that demineralized human dentin matrix has osteoinductive ability, and is a good alternative to autogenous bone graft materials. PMID:27489810

  12. Cryopreserved dentin matrix as a scaffold material for dentin-pulp tissue regeneration.

    PubMed

    Jiao, Liang; Xie, Li; Yang, Bo; Yu, Mei; Jiang, Zongting; Feng, Lian; Guo, Weihua; Tian, Weidong

    2014-06-01

    Cryopreservation has been identified as an efficient approach to preserve tissue engineered products for a long term. Our prior studies have suggested that the treated dentin matrix (TDM) could be an ideal bioactive scaffold for dental tissue regeneration. In this study, we hypothesize that the cryopreservation could effectively maintain the survival and viability of dentinogenesis-related proteins of TDM and the cryopreserved dentin matrix (CDM) would provide the suitable biological scaffold and inductive microenvironment for the regeneration of dentin-pulp like tissue. CDM-3 and CDM-6 were prepared by cryopreserving TDM in liquid nitrogen (-196 °C) with cryoprotectant for 3 months and 6 months, respectively. Various biological characteristics of CDM, including mechanical properties, cell proliferation, and odontogenesis ability, were investigated. To further evaluate the inductive capacity of CDM, human dental follicle cells were encapsulated within CDM, and implanted the scaffold into a mouse model for 8 weeks, and the grafts were harvested and assessed histologically. The CDM showed superior mechanical properties than TDM. Compared to TDM, CDM can release more dentinogenesis-related proteins due to the larger pore diameter. Cell proliferation with the addition of CDM extract liquid was similar to that of TDM in the first five days. Human dental follicle cells, under the effect of CDM extract liquid, highly expressed bone sialoprotein, collagen-1, alkaline phosphatase, indicating that CDM, regarded as the inductive microenvironment, plays an important role in odontogenesis. Most importantly, in vivo, CDM could induce dental follicle cells to regenerate new dentin-pulp like tissues, such as dentinal tubules, predentin, collagen fibers, nerves, and blood vessels which were positive for dentin sialophosphoprotein, dental matrix protein-1, Tubulin, and collagen-1. In conclusion, CDM is an ideal biological scaffold material for human dentin-pulp like tissue

  13. Influence of Ultrasonic Irrigation and Chloroform on Cleanliness of Dentinal Tubules During Endodontic Retreatment-An Invitro SEM Study

    PubMed Central

    Singhal, Anurag; Gurtu, Anuraag; Vinayak, Vineet

    2015-01-01

    Background Ultrasonic irrigation has been proved for its remarkable cleaning efficiency in the field of endodontics. But its role in endodontic re-treatment has been understated. There is not much data available to understand the effect of ultrasonic irrigation for the evaluation of cleanliness of dentinal tubules when it is used with or without chloroform, a gutta percha solvent during endodontic retreatment. Aim To compare the influence of ultrasonic irrigation with syringe irrigation on cleanliness of dentinal tubules after gutta perch removal for endodontic retreatment with or without the use of chloroform a gutta percha solvent using scanning electron microscope (SEM). Materials and Methods Freshly extracted 45 human mandibular premolar teeth for periodontal and orthodontic reasons were taken and were occlusally adjusted to a working length of 19 mm. The root canals of all teeth were prepared chemo mechanically to a master apical file size 40 and were divided in various groups. In Group 1 (n = 5; control group), the canals remained unfilled. In Groups 2 and 3 (n = 20 each), the canals were filled using lateral compaction with gutta-percha and AH plus sealer, removal of root fillings was undertaken after 2 weeks using Gates Glidden drills and H files without chloroform in Group 2 and with chloroform in group 3. The specimen of Group 2 and 3 were further divided into two subgroups I and II (n=10). In subgroup I, irrigation was done using side vented needles and sodium hypochlorite. In subgroup II irrigation was done using passive ultrasonic irrigation with sodium hypochlorite. Thereafter, the roots were split and the sections were observed under SEM. The number of occluded dentinal tubules /total number of dentinal tubules were calculated for the coronal, middle and apical third of each root half. Statistical analysis was performed using one-way ANOVA followed by Tukey’s test using standardized technique. Result Results indicated that the cleanest dentinal

  14. Tertiary Dentin Formation after Indirect Pulp Capping Using Protein CPNE7.

    PubMed

    Choung, H W; Lee, D S; Lee, Ji-Hyun; Shon, W J; Lee, Jong-Ho; Ku, Y; Park, J C

    2016-07-01

    If there is a partial loss of dentin, the exposed dentinal surface should be protected by an indirect pulp capping (IPC) procedure to preserve pulp vitality and prevent symptoms of dentin hypersensitivity. In our previous study, copine7 (CPNE7) induced odontoblast differentiation in vitro and promoted dentin formation in vivo. The aim of this study was to investigate the possibility of IPC therapy using the CPNE7 protein at the exposed dentinal surface and the resulting effects on tertiary dentin formation in a beagle model. CPNE7 promoted mineralization of odontoblasts and had high calcium ion-binding capacity. The in vivo IPC model with canine teeth showed that regeneration of physiologic reactionary dentin with dentinal tubule structures was clearly observed beneath the remaining dentin in the CPNE7 group, whereas irregular features of reparative dentin were generated in the mineral trioxide aggregate (MTA) group. The CPNE7+MTA group also showed typical reactionary dentin without reparative dentin, showing synergistic effects of CPNE7 with MTA. A scanning electron microscopy analysis showed that dentinal tubules beneath the original dentin were occluded by the deposition of peritubular dentin in the CPNE7 and CPNE7+MTA groups, whereas those in the control group were opened. Therefore, CPNE7 may be able to serve as a novel IPC material and improve symptoms of dentin hypersensitivity. PMID:27013639

  15. Identification of new rat dentin proteoglycans utilizing C18 chromatography.

    PubMed

    Steinfort, J; van de Stadt, R; Beertsen, W

    1994-09-01

    Although only one small PG has been identified in dentin until now, a preliminary investigation has shown indications of the presence of several new proteoglycans (PGs) in rat incisor dentin. The aim of the present investigation was to isolate and characterize these PGs, which were labeled with 35S to facilitate the analysis. C18 chromatography resolved five dentin PGs. Based on SDS-polyacrylamide gel electrophoresis, their size varied from 100 to 400 kDa. The core proteins of the first four PGs appeared as 25, 40, 70, and 115 kDa bands. They stained turquoise with Stains All but did not stain with Coomassie Brilliant Blue. The core protein of the fifth PG appeared at about 45 kDa. This core protein stained with Coomassie Brilliant Blue but not with Stains All. In all PGs, the glycosaminoglycans consisted mainly of chondroitin 4-sulfate. To investigate their incorporation into predentin (young dentin that is not yet mineralized) and dentin, rat dentin PGs were pulse-labeled by injecting rats with [35S]sulfate at 5, 28, 55, or 177 h before killing the animals. Radiolabeling of predentin PGs was highest after 5 h and decreased rapidly (76%) over the next 50 h. In dentin PGs, a large percentage (34%) of the final quantity of incorporated 35S (at 177 h) was already present at 5 h. C18 chromatography of dentin PGs for each of the four time intervals showed similar 35S distribution patterns representing all five PGs, whereas the predentin appeared to contain mainly the fifth PG. This study demonstrates the existence of several apparently novel PGs in dentin that can be resolved by the use of a new method. These PGs were found in mineralized dentin and are thought to be rapidly transported toward the mineralization front. Part of the predentin PGs, on the other hand, seems to be lost as mineralization proceeds.

  16. Astacin proteases cleave dentin sialophosphoprotein (Dspp) to generate dentin phosphoprotein (Dpp).

    PubMed

    Tsuchiya, Shuhei; Simmer, James P; Hu, Jan C-C; Richardson, Amelia S; Yamakoshi, Fumiko; Yamakoshi, Yasuo

    2011-01-01

    Dentin sialophosphoprotein (Dspp) is critical for proper dentin biomineralization because genetic defects in DSPP cause dentin dysplasia type II and dentinogenesis imperfecta types II and III. Dspp is processed by proteases into smaller subunits; the initial cleavage releases dentin phosphoprotein (Dpp). We incubated fluorescence resonance energy transfer (FRET) peptides containing the amino acid context of the Dpp cleavage site (YEFDGKSMQGDDPN, designated Dspp-FRET) or a mutant version of that context (YEFDGKSIEGDDPN, designated mutDspp-FRET) with BMP-1, MEP1A, MEP1B, MMP-2, MMP-8, MMP-9, MT1-MMP, MT3-MMP, Klk4, MMP-20, plasmin, or porcine Dpp and characterized the peptide cleavage products. Only BMP-1, MEP1A, and MEP1B cleaved Dspp-FRET at the G-D peptide bond that releases Dpp from Dspp in vivo. We isolated Dspp proteoglycan from dentin power and incubated it with the three enzymes that cleaved Dspp-FRET at the G-D bond. In each case, the released Dpp domain was isolated, and its N-terminus was characterized by Edman degradation. BMP-1 and MEP1A both cleaved native Dspp at the correct site to generate Dpp, making both these enzymes prime candidates for the protease that cleaves Dspp in vivo. MEP1B was able to degrade Dpp when the Dpp was at sufficiently high concentration to deplete free calcium ion concentration. Immunohistochemistry of developing porcine molars demonstrated that astacins are expressed by odontoblasts, a result that is consistent with RT-PCR analyses. We conclude that during odontogenesis, astacins in the predentin matrix cleave Dspp before the DDPN sequence at the N-terminus of Dpp to release Dpp from the parent Dspp protein.

  17. Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 2. Root-canal-filling materials.

    PubMed

    Hauman, C H J; Love, R M

    2003-03-01

    Root-canal-filling materials are either placed directly onto vital periapical tissues or may leach through dentine. The tissue response to these materials therefore becomes important and may influence the outcome of endodontic treatment. This paper is a review of the biocompatibility of contemporary orthograde and retrograde root-canal-filling materials. PMID:12657140

  18. Effect of addition of lycopene to calcium hydroxide and chlorhexidine as intracanal medicament on fracture resistance of radicular dentin at two different time intervals: An in vitro study

    PubMed Central

    Madhusudhana, Koppolu; Archanagupta, Kasamsetty; Suneelkumar, Chinni; Lavanya, Anumula; Deepthi, Mandava

    2015-01-01

    Background: Long-term use of intracanal medicaments such as calcium hydroxide (CH) reduces the fracture resistance of dentin. The present study was undertaken to evaluate the fracture resistance of radicular dentin on long-term use of CH, chlorhexidine (CHX) with lycopene (LP). Aim: To compare the fracture resistance of radicular dentin when intracanal medicaments such as CH, CHX with LP were used for 1-week and 1-month time interval. Settings and Design: Sixty single-rooted extracted human permanent premolars were collected, and complete instrumentation was done. Samples were divided into three groups based on intracanal medicament used. Materials and Methods: Group 1 - no medicament was placed (CON), group 2 - mixture of 1.5 g of CH and 1 ml of 2% CHX (CHCHX), group 3 - mixture of 1.5 g of CH, 1 ml of CHX and 1 ml of 5% LP solution (CHCHXLP). After storage period of each group for 1-week and 1-month, middle 8 mm root cylinder was sectioned and tested for fracture resistance. Statistical Analysis: Results were analyzed using paired t-test. Results: At 1-month time interval, there was a statistically significant difference in fracture resistance between CHCHX and CHCHXLP groups. Conclusion: Addition of LP has not decreased the fracture resistance of radicular dentin after 1-month. PMID:26069405

  19. Dynamic intratubular biomineralization following root canal obturation with pozzolan‐based mineral trioxide aggregate sealer cement

    PubMed Central

    Yoo, Yeon‐Jee; Baek, Seung‐Ho; Kum, Kee‐Yeon; Shon, Won‐Jun; Woo, Kyung‐Mi

    2015-01-01

    Summary The application of mineral trioxide aggregates (MTA) cement during the root canal obturation is gaining concern due to its bioactive characteristic to form an apatite in dentinal tubules. In this regard, this study was to assess the biomineralization of dentinal tubules following root canal obturation by using pozzolan‐based (Pz‐) MTA sealer cement (EndoSeal MTA, Maruchi). Sixty curved roots (mesiobuccal, distobuccal) from human maxillary molars were instrumented and prepared for root canal obturation. The canals were obturated with gutta‐percha (GP) and Pz‐MTA sealer by using continuous wave of condensation technique. Canals obturated solely with ProRoot MTA (Dentsply Tulsa Dental) or Pz‐MTA sealer were used for comparison. In order to evaluate the biomineralization ability under different conditions, the PBS pretreatment before the root canal obturation was performed in each additional samples. At dentin‐material interfaces, the extension of intratubular biomineralization was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy. When the root canal was obturated with GP and Pz‐MTA sealer, enhanced biomineralization of the dentinal tubules beyond the penetrated sealer tag was confirmed under the SEM observation (p < 0.05). Mineralized apatite structures (calcium/phosphorous ratio, 1.45–1.89) connecting its way through the dentinal tubules were detected at 350–400 μm from the tubule orifice, and the pre‐crystallization seeds were also observed along the intra‐ and/or inter‐tubular collagen fiber. Intratubular biomineralization depth was significantly enhanced in all PBS pretreated canals (p < 0.05). Pz‐MTA cement can be used as a promising bioactive root canal sealer to enhance biomineralization of dentinal tubules under controlled environment. SCANNING 38:50–56, 2016. © 2015 The Authors. Scanning Published by Wiley Periodicals, Inc. PMID:26179659

  20. Effect of chitosan-ethylenediamine tetraacetic acid on Enterococcus faecalis dentinal biofilm and smear layer removal

    PubMed Central

    Geethapriya, Nagarajan; Subbiya, Arunajatesan; Padmavathy, Kesavaram; Mahalakshmi, Krishnan; Vivekanandan, Paramasivam; Sukumaran, Virudhachalam Ganapathy

    2016-01-01

    Objective: The objective of the study was to evaluate the effectiveness of chitosan and chitosan-ethylenediamine tetraacetic acid (EDTA) (3:1,1:1,1:3) in comparison with 5.2% sodium hypochlorite (NaOCl) in disinfecting Enterococcus faecalis biofilm on root canal dentin and in the removal of smear layer with minimal erosion. Materials and Methods: Seventy single-rooted extracted human mandibular premolars (n = 70) were selected for the study. Forty tooth samples were biomechanically prepared, vertically sectioned, and sterilized by autoclaving. The tooth sections were artificially infected with E. faecalis (ATCC 29212 [n = 35] and clinical isolate [SBEF2, n = 35]) to form mature dentinal biofilm in vitro. The tooth samples were treated with the test solutions: chitosan and chitosan-EDTA (3:1, 1:1, 1:3), and the killing time was determined. The smear layer removal ability of the test solutions (Group A: chitosan-EDTA [1:1], Group B: EDTA, Group C: control) (n = 10 tooth/group) was assessed. Results: Chitosan and chitosan-EDTA (3:1, 1:1, 1:3) exhibited antibacterial activity against both the strains of E. faecalis. Chitosan and chitosan-EDTA caused 3 log reduction in the viable count of the sessile cells of E. faecalis at 15 min while 5.2% NaOCl exhibited 99.98% inhibition at 15 min. Chitosan-EDTA (1:1) was found to be effective in removing the smear layer and showed lesser erosion than EDTA at the coronal and middle portions. Conclusion: Chitosan-EDTA (1:1) is a potential root canal irrigant that performs a dual role – root canal disinfection and smear layer removal. PMID:27656070

  1. Effect of chitosan-ethylenediamine tetraacetic acid on Enterococcus faecalis dentinal biofilm and smear layer removal

    PubMed Central

    Geethapriya, Nagarajan; Subbiya, Arunajatesan; Padmavathy, Kesavaram; Mahalakshmi, Krishnan; Vivekanandan, Paramasivam; Sukumaran, Virudhachalam Ganapathy

    2016-01-01

    Objective: The objective of the study was to evaluate the effectiveness of chitosan and chitosan-ethylenediamine tetraacetic acid (EDTA) (3:1,1:1,1:3) in comparison with 5.2% sodium hypochlorite (NaOCl) in disinfecting Enterococcus faecalis biofilm on root canal dentin and in the removal of smear layer with minimal erosion. Materials and Methods: Seventy single-rooted extracted human mandibular premolars (n = 70) were selected for the study. Forty tooth samples were biomechanically prepared, vertically sectioned, and sterilized by autoclaving. The tooth sections were artificially infected with E. faecalis (ATCC 29212 [n = 35] and clinical isolate [SBEF2, n = 35]) to form mature dentinal biofilm in vitro. The tooth samples were treated with the test solutions: chitosan and chitosan-EDTA (3:1, 1:1, 1:3), and the killing time was determined. The smear layer removal ability of the test solutions (Group A: chitosan-EDTA [1:1], Group B: EDTA, Group C: control) (n = 10 tooth/group) was assessed. Results: Chitosan and chitosan-EDTA (3:1, 1:1, 1:3) exhibited antibacterial activity against both the strains of E. faecalis. Chitosan and chitosan-EDTA caused 3 log reduction in the viable count of the sessile cells of E. faecalis at 15 min while 5.2% NaOCl exhibited 99.98% inhibition at 15 min. Chitosan-EDTA (1:1) was found to be effective in removing the smear layer and showed lesser erosion than EDTA at the coronal and middle portions. Conclusion: Chitosan-EDTA (1:1) is a potential root canal irrigant that performs a dual role – root canal disinfection and smear layer removal.

  2. Resistance to compression of weakened roots subjected to different root reconstruction protocols

    PubMed Central

    ZOGHEIB, Lucas Villaça; SAAVEDRA, Guilherme de Siqueira Ferreira Anzaloni; CARDOSO, Paula Elaine; VALERA, Márcia Carneiro; de ARAÚJO, Maria Amélia Máximo

    2011-01-01

    Objective This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45º in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (α=0.05). Results Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol. PMID:22231002

  3. Site specific properties of carious dentin matrices biomodified with collagen cross-linkers

    PubMed Central

    Bedran-Russo, Ana K.; Karol, Sachin; Pashley, David H.; Viana, Grace

    2014-01-01

    Purpose To assess in non-cavitated carious teeth the mechanical properties of dentin matrix by measuring its reduced modulus of elasticity and the effect of dentin biomodification strategies on three dentin matrix zones: caries-affected, apparently normal dentin below caries-affected zone and sound dentin far from carious site. Methods Nano-indentations were performed on dentin matrices of carious molars before and after surface modification using known cross-linking agents (glutaraldehyde, proanthocyanidins from grape seed extract and carbodiimide). Results Statistically significant differences were observed between dentin zones of demineralized dentin prior to surface biomodification (P< 0.05). Following surface modification, there were no statistically significant differences between dentin zones (P< 0.05). An average increase of 30-fold, 2-fold and 2.2-fold of the reduced modulus of elasticity was observed following treatments of the three dentin zones with proanthocyanidin, carbodiimide and glutaraldehyde, respectively. PMID:24479274

  4. Micromechanical testing of the dentin hybrid zone formed by all-in-one adhesive system in sound human dentin

    NASA Astrophysics Data System (ADS)

    Koytchev, E.; Datcheva, M.; Iankov, R.

    2015-10-01

    This study explored the spatial variations in mechanical behavior of the dentin hybrid layer formed by a single step (one bottle) dentin adhesive system. Objective. The objectives were to: (1) evaluate the mechanical behavior of the hybrid zone formed by a single sep dentin adhesive system using nanoindentation technique, (2) compare the indentation moduli (EIT) and indentation hardness (HIT) of human dentin and the hybrid zone, and (3) assess the importance of specimen hydration on the nanoindentation response. Methods. Specimens of human dentin, treated with commercial single step resin adhesive and restored with composite material were evaluated using a nanoindenter in a load-displacement control mode. The load and displacement responses were used to perform nanoindentation characterization of dentin and the hybrid layer and estimate EIT and HIT, using Oliver & Pharr approximation method. Results. In hydrated state, EIT for dentin and hybrid layer were 18.214 ± 1.30 GPa and 12.535 ± 0.19 GPa respectively. For HIT, also in hydrated state, the values in dentin and hybrid layer were 0.56 ± 0.06 GPa and 0.36 ± 0.005 GPa respectively. Viscoelastic deformation of the dentin hybrid zone exceeded that occuring in regions of uniform dentin tissue. The load displacement curves of the two zones were also estimated and analyzed. They generally follow the same pattern without any noticeable pop-ins or irregularities. Significance. The microstructure and hydration play critical roles on the mechanical behavior of the hybrid layer and nanoindentation provides a potent measurment tool for identifying the spatial variations.