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1

Retentive Force of FRC Posts Inserted with Core Build-up Composites and Resin Cements  

Microsoft Academic Search

The aim of this study was to determine the retentive forces of fiber-reinforced composite (FRC) posts luted with different core build-up composite resins, and resin cements. Extracted single-rooted teeth were restored using FRC posts luted with the core build-up composites Build-It, Culmat, Flow White, Luxacore, Multi-Core Flow, Rebilda DC and luted with the resin cements Calibra, Cement-It, Multilink, and RelyX

P. Schmage; F. Yalcin Cakir; I. Nergiz; S. Selcuk; P. Pfeiffer

2011-01-01

2

Microhardness of different resin cement shades inside the root canal  

PubMed Central

Objectives: To compare microhardness along the root canal post space of two resin cements in different shades and a dual-cure resin core material. Study Design: Root canals of 21 bovine incisors were prepared for post space. Translucent posts (X•Post, Dentsply DeTrey) were luted using one the following resin luting agent: Calibra (Dentsply DeTrey) in Translucent, Medium and Opaque shades, RelyX Unicem (3M ESPE) in Translucent, A2 and A3 shades and the dual-cure resin core material Core•X flow. All materials were applied according to manufacturers’ instructions and were all photopolymerized (Bluephase LED unit, Ivoclar Vivadent, 40s). After 24 hours, roots were transversally cut into 9 slices 1 mm thick from the coronal to apical extremes, three corresponding to each root third. Then, VHNs were recorded (100 gf, 30 s) on the resin luting materials along the adhesive interface in all sections. Data were analyzed by two-way ANOVA and SNK tests (?=0.05). Results: A significant influence on microhardness of resin luting material in their respective shades (p<0.001), root third (p<0.001) and interactions between them was detected (p<0.001). RelyX Unicem cement showed the highest microhardness values and Calibra the lowest, regardless of the shade selected. All resin luting materials tested exhibited a significantly higher microhardness in the cervical third. Conclusions: Microhardness of resin luting agents tested inside the canal is dependent on material brand and resin cement shade seems to be a less relevant factor. Microhardness decreased along the root canal, regardless of the shade selected. Key words:Cement shade, degree of conversion, dual-cured resin cements, fiber posts, microhardness, root thirds.

Vignolo, Valeria; Fuentes, Maria V.; Garrido, Miguel A.; Rodriguez, Jesus

2012-01-01

3

Inorganic composition and filler particles morphology of conventional and self-adhesive resin cements by SEM/EDX.  

PubMed

The purpose of this study was to characterize the inorganic components and morphology of filler particles of conventional and self-adhesive, dual-curing, resin luting cements. The main components were identified by energy dispersive X-ray spectroscopy microanalysis (EDX), and filler particles were morphologically analyzed by scanning electron microscopy (SEM). Four resin cements were used in this study: two conventional resin cements (RelyX ARC/3M ESPE and Clearfil Esthetic Cement/Kuraray Medical) and two self-adhesive resin cements (RelyX Unicem/3M ESPE and Clearfil SA Luting/Kuraray Medical). The materials (n = 5) were manipulated according to manufacturers' instructions, immersed in organic solvents to eliminate the organic phase and observed under SEM/EDX. Although EDX measurements showed high amount of silicon for all cements, differences in elemental composition of materials tested were identified. RelyX ARC showed spherical and irregular particles, whereas other cements presented only irregular filler shape. In general, self-adhesive cements contained higher filler size than conventional resin luting cements. The differences in inorganic components and filler particles were observed between categories of luting material and among them. All resin cements contain silicon, however, other components varied among them. PMID:22628243

Aguiar, Thaiane Rodrigues; Di Francescantonio, Marina; Bedran-Russo, Ana Karina; Giannini, Marcelo

2012-10-01

4

Evaluation of a commercial primer for bonding of zirconia to two different resin composite cements.  

PubMed

Purpose: To evaluate the effects of a commercial zirconia primer (Choice or RelyX Unicem) on shear bond strength (SBS) of two different resin composite cements - Choice (a conventional bis-GMA-based resin cement) and RelyX Unicem (self-adhesive resin cement) - to zirconia. Materials and Methods: Zirconia blocks were manufactured and randomly divided into 5 main groups (n = 20) that received surface treatments and cements as follows: no surface treatment, Choice and RelyX Unicem (groups C and U, resp.); tribochemical silica coating followed by silanization, Choice (group SSC); application of a zirconia primer, Choice and RelyX Unicem (groups ZC and ZU, resp.). Light-curing composite resin cylinders were prepared and bonded on the prepared zirconia blocks using the two different resin cements. Half of the specimens in each group were stored in water for 24 h, and half were aged by 50 days of water storage followed by thermocycling (12,000 cycles between 5°C and 55°C). Thereafter, all of them were submitted to the SBS test. Fourier transmission infrared (FT-IR) spectrum analysis and gas mass spectrometry (MS) analysis were adopted for characterization of the zirconia primer. Results: Statistical analysis of the SBS test showed that group C presented the lowest SBS values and group SSC the highest (p < 0.01). Artificial aging exerted no influence on the SBS of groups U, SSC, ZC, or ZU. FT-IR analysis suggested that benzene rings and carboxylic groups exist in the zirconia primer. MS analysis detected that 2-hydroxyethyl methacrylate, triethylamine, ethyl-4-dimethylaminobenzoate, ethanol, and water are contained in the primer. Conclusion: The zirconia primer and self-adhesive resin cement increased the SBS of zirconia. PMID:24683591

Chen, Chen; Xie, Haifeng; Song, Xin; Burrow, Michael Francis; Chen, Gang; Zhang, Feimin

2014-04-01

5

Changes in degree of conversion and microhardness of dental resin cements.  

PubMed

There are few studies available on the post-light activation or post-mix polymerization of dental resin cements as a function of time. This in vitro study evaluated the successive changes in the degree of conversion (DC) and microhardness during polymerization of six commercial resin cements (light-cured [Choice 2, RelyX Veneer], chemical-cured [Multilink, C&B Cement] and dual-cured [Calibra, RelyX ARC]) within the first 24 hours and up to seven days. Resin specimens were prepared for Fourier transform infrared (FTIR) spectroscopy and microhardness testing to determine the DC and Vickers hardness (VH), respectively. The light-cured materials or mixed pastes of the dual-cured materials were irradiated with a light-curing unit (Elipar TriLight) through a precured composite overlay for 40 seconds. The FTIR spectra and microhardness readings were taken at specified times: 1, 2, 5, 10, 15, 30 and 60 minutes; 24 hours and after two days and seven days. According to the FTIR study, most of the curing reaction of Choice 2 and RelyX Veneer occurred within 10 and 30 minutes, respectively. Multilink, C&B Cement and Calibra exhibited gradual increases in the DC up to 24 hours, with no further statistically significant increase (p > 0.05). RelyX ARC attained a DC value within five minutes, similar to that at seven days (p > 0.05). Choice 2 and RelyXARC showed gradual increases in the VH, up to 15 minutes, with no further significant change over the remaining observation time (p > 0.05). For RelyX Veneer, Multilink, C&B Cement and Calibra, there were no significant increases in the VH value after 24 hours (p > 0.05). The light-cured materials produced significantly higher DC values than the chemical-cured materials (p < 0.05). The DC values of the two dual-cured resin cements were significantly different from each other (p < 0.001). The results suggest that the significant polymerization reaction was finished within 24 hours post-mix or post-light activation for all resin cements tested. PMID:20420064

Yan, Yong Li; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub

2010-01-01

6

Bond strength of self-adhesive resin cements to composite submitted to different surface pretreatments  

PubMed Central

Objectives Extensively destroyed teeth are commonly restored with composite resin before cavity preparation for indirect restorations. The longevity of the restoration can be related to the proper bonding of the resin cement to the composite. This study aimed to evaluate the microshear bond strength of two self-adhesive resin cements to composite resin. Materials and Methods Composite discs were subject to one of six different surface pretreatments: none (control), 35% phosphoric acid etching for 30 seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane + adhesive (n = 6). A silicone mold containing a cylindrical orifice (1 mm2 diameter) was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.) self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesive cement cylinders were submitted to shear loading. Data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Results Independent of the cement used, the PA + Silane + Adhesive group showed higher microshear bond strength than those of the PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Conclusions Pretreatments of the composite resin surface might have an effect on the bond strength of self-adhesive resin cements to this substrate.

dos Santos, Victor Hugo; Griza, Sandro; de Moraes, Rafael Ratto

2014-01-01

7

Influence of matrix metalloproteinase synthetic inhibitors on dentin microtensile bond strength of resin cements.  

PubMed

This study evaluated the effect of dentin pretreatment with 2% chlorhexidine (CHX) or 24% ethylenediamine tetra-acetic acid gel (EDTA) on the dentin microtensile bond strength (?TBS) of resin cements. Composite blocks were luted to superficial noncarious human dentin (n=10) using two resin cements (RelyX ARC [ARC] and RelyX U100 [U100]) and three dentin pretreatments (without pretreatment-control, CHX, and EDTA). CHX was applied for 60 seconds on the acid-etched dentin in the ARC/CHX group, and for the same time on smear layer-covered dentin in the U100/CHX group. EDTA was applied for 45 seconds on smear-covered dentin in the U100/EDTA group, and it replaced phosphoric acid conditioning in the ARC/EDTA group for 60 seconds. After storage in water for 24 hours, specimens were prepared for microtensile bond strength testing. The results were submitted to two-way analysis of variance (ANOVA) followed by Tukey test. ARC produced significantly higher ?TBS (p<0.05) compared to the U100, except when EDTA was used. For ARC, no pretreatment and CHX produced higher ?TBS than EDTA. For U100, EDTA produced higher ?TBS; no statistical difference occurred between CHX pretreatment and when no pretreatment was performed. While CHX did not affect immediate dentin bond strength of both cements, EDTA improved bond strength of U100, but it reduced dentin bond strength of ARC. PMID:22335305

Stape, T H S; Menezes, M S; Barreto, B C F; Aguiar, F H B; Martins, L R; Quagliatto, P S

2012-01-01

8

Radiopacity Evaluation of Contemporary Luting Cements by Digitization of Images  

PubMed Central

Objective. The aim of this study was to evaluate the radiopacity of two conventional cements (Zinc Cement and Ketac Cem Easymix), one resin-modified glass ionomer cement (RelyX Luting 2) and six resin cements (Multilink, Bistite II DC, RelyX ARC, Fill Magic Dual Cement, Enforce and Panavia F) by digitization of images. Methods. Five disc-shaped specimens (10 × 1.0?mm) were made for each material, according to ISO 4049. After setting of the cements, radiographs were made using occlusal films and a graduated aluminum stepwedge varying from 1.0 to 16?mm in thickness. The radiographs were digitized, and the radiopacity of the cements was compared with the aluminum stepwedge using the software VIXWIN-2000. Data (mmAl) were submitted to one-way ANOVA and Tukey's test (? = 0.05). Results. The Zinc Cement was the most radiopaque material tested (P < 0.05). The resin cements presented higher radiopacity (P < 0.05) than the conventional (Ketac Cem Easymix) or resin-modified glass ionomer (RelyX Luting 2) cements, except for the Fill Magic Dual Cement and Enforce. The Multilink presented the highest radiopacity (P < 0.05) among the resin cements. Conclusion. The glass ionomer-based cements (Ketac Cem Easymix and RelyX Luting 2) and the resin cements (Fill Magic Dual Cement and Enforce) showed lower radiopacity values than the minimum recommended by the ISO standard.

Reis, Jose Mauricio dos Santos Nunes; Jorge, Erica Gouveia; Ribeiro, Joao Gustavo Rabelo; Pinelli, Ligia Antunes Pereira; Abi-Rached, Filipe de Oliveira; Tanomaru-Filho, Mario

2012-01-01

9

Durability of the bond strength of self-adhesive resin cements to human dentin.  

PubMed

This study subjected two self-adhesive resin cements and two conventional resin cements to dry and aging conditions, to compare their microtensile bond strengths (microTBS) to dentin. Using four different luting systems (n = 10), 40 composite resin blocks (each 5 x 5 x 4 mm) were cemented to flat human crown dentin surfaces. The specimens were stored in water for 24 hours (37 degrees C), at which point each specimen was sectioned along two axes to obtain beams that were divided randomly into two groups: dry samples, which were tested immediately, and samples that were subjected to accelerated aging conditions (12,000 thermocycles followed by storage for 150 days). The microTBS results were affected significantly by the luting system used (P < 0.0001). Only the microTBS of Rely-X Unicem was reduced significantly after aging; the microTBS remained stable or increased for the other self-adhesive resin cement and the two conventional cements. PMID:19903614

de Melo, Renata Marques; Amaral, Regina; Galhano, Graziela; Vanderlei, Aleska; Bottino, Marco Antonio; Valandro, Luiz Felipe

2009-01-01

10

In vitro evaluation of the bonding durability of self-adhesive resin cement to titanium using highly accelerated life test.  

PubMed

The purpose of this in vitro study was to evaluate the bonding durability of three self-adhesive resin cements to titanium using the Highly Accelerated Life Test (HALT). The following self-adhesive resin cements were used to bond pairs of titanium blocks together according to manufacturers' instructions: RelyX Unicem, Breeze, and Clearfil SA Luting. After storage in water at 37°C for 24 h, bonded specimens (n=15) immersed in 37°C water were subjected to cyclic shear load testing regimes of 20, 30, or 40 kg using a fatigue testing machine. Cyclic loading continued until failure occurred, and the number of cycles taken to reach failure was recorded. The bonding durability of a self-adhesive resin cement to titanium was largely influenced by the weight of impact load. HALT showed that Clearfil SA Luting, which contained MDP monomer, yielded the highest median bonding lifetime to titanium. PMID:22123007

Lin, Jie; Shinya, Akikazu; Gomi, Harunori; Matinlinna, Jukka Pekka; Shinya, Akiyoshi

2011-11-25

11

Influence of curing mode and time on degree of conversion of one conventional and two self-adhesive resin cements.  

PubMed

This study evaluated the effect of curing mode (auto- and dual-polymerizing mode) and time interval (5, 10 and 15 minutes) on the degree of conversion of resin cements. One conventional dual-cured resin cement (Panavia F 2.0 [Kuraray Medical Inc]) and two self-adhesive cements (RelyX Unicem [3M ESPE] and BisCem [BISCO, Inc]) were evaluated. The products (n = 5) were manipulated according to the manufacturer's instructions and applied to the surface of a horizontal attenuated reflectance unit attached to an infrared spectrometer. The materials were either light-cured for 40 seconds (dual-polymerizing mode) or allowed to auto-polymerize. The degree of conversion was calculated according to changes in the aliphatic-to-aromatic peak ratios prior to and 5, 10 and 15 minutes after light-activation or after mixing when the specimens were allowed to auto-polymerize. Data (%) were analyzed by two-way repeated measure ANOVA (curing mode and time interval) and Tukey's post-hoc test (alpha = 0.05%). The light-activating mode led to a higher degree of conversion values than the self-curing mode in self-adhesive cements (RelyX Unicem and BisCem), while there was no difference in the degree of conversion between the self- and light-cured groups of Panavia F 2.0 resin cement. All products showed a higher degree of conversion at 15 minutes postcuring than any other evaluation interval. The self-adhesive cements provide a higher degree of conversion values when light-activated. After 15 minutes of polymerization initiation, the degree of conversion was higher in all resin cements, regardless of the curing mode. PMID:20533629

Aguiar, Thaiane Rodrigues; Di Francescantonio, Marina; Arrais, Cesar A G; Ambrosano, Gláucia Maria Bovi; Davanzo, Celso; Giannini, Marcelo

2010-01-01

12

Effect of different surface treatments on shear bond strength of zirconia to three resin cements  

NASA Astrophysics Data System (ADS)

Statement of problem: There are no standard guidelines for material selection to obtain acceptable bonding to high-strength zirconium oxide ceramic. Studies suggest resin cements in combination with MDP-containing primer is a reasonable choice, however, the other cements cannot be rejected and need further investigation. Objective: The purpose of this in vitro study was the evaluation of the shear bond strength of three composite resin cements to zirconia ceramic after using different surface conditioning methods. Materials and methods: One hundred and twenty sintered Y-TZP ceramic (IPS e.max ZirCAD) squares (8 x 8 x 4 mm) were embedded in acrylic molds, then divided into three groups (n=40) based on the type of cement used. Within each group, the specimens were divided into four subgroups (n=10) and treated as follows: (1) Air abrasion with 50microm aluminum oxide (Al2O 3) particles (ALO); (2) Air abrasion + Scotchbond Universal adhesive (SBU); (3) Air abrasion + Monobond Plus (MBP); (4) Air abrasion + Z-Prime Plus (ZPP). Composite cylinders were used as carriers to bond to conditioned ceramic using (1) RelyX Ultimate adhesive resin cement (RX); (2) Panavia SA self-adhesive resin cement (PSA); (3) Calibra esthetic cement (CAL). The bonded specimens were submerged in distilled water and subjected to 24-hour incubation period at 37°C. All specimens were stressed in shear at a constant crosshead speed of 0.5 mm/min until failure. Statistical analysis was performed by ANOVA. The bond strength values (MPa), means and standard deviations were calculated and data were analyzed using analysis of variance with Fisher's PLSD multiple comparison test at the 0.05 level of significance. The nature of failure was recorded. Results: The two-way ANOVA showed Panavia SA to have the highest strength at 44.3 +/- 16.9 MPa (p<0.05). The combination of Scotchbond Universal surface treatment with Panavia SA cement showed statistically higher bond strength (p=0.0054). The highest bond strengths for all three cements were observed with Scotchbond Universal surface treatment (p=0.0041). Calibra in combination with aluminum oxide air abrasion resulted in statistically lowest bond strength at 12.0 +/- 3.9 MPa. The predominant mode of failure was cohesive with cement remaining principally on the zirconium oxide samples in 57.5% of the specimens, followed by cement found on both the zirconium oxide samples and composite rods (mixed) in 32.5% of the samples. Only 10% of the specimens were found with cement on the composite rods (adhesive failure). Conclusions: Within the limitations of this in vitro study, the MDP-containing resin cement, Panavia SA, yielded the strongest bond to Y-TZP ceramic when compared to adhesive (RelyX Ultimate) or esthetic (Calibra) resin cements. Air abrasion particle + Scotchbond Universal surface treatment demonstrated the highest bond strength regardless of the cement. Significance: The variation of surface conditioning methods yielded different results in accordance with the cement types. Overall, Scotchbond Universal adhesive + air abrasion yielded the highest bond strengths among all three surface treatments. The phosphate monomer-containing luting system, Panavia SA, is acceptable for bonding to zirconia ceramics.

Dadjoo, Nisa

13

Nanoleakage for Self-Adhesive Resin Cements used in Bonding CAD/CAD Ceramic Material to Dentin  

PubMed Central

Objectives: To determine nanoleakage of CAD/CAM ceramic blocks bonded to dentin with self-adhesive resin cement. Methods: Eighteen sound extracted human molars were sterilized and sectioned into 3 mm-thick dentin sections. Trilux Cerec Vitablocks (Vita) were also sectioned into 3 mm sections, surface-treated using 5% hydrofluoric acid-etchant, and then coated with silane primer (Vita). Trilux and dentin sections were cemented together by means of three resin cements: Rely-X Unicem (3M/ESPE), BisCem (Bisco), and Calibra (Dentsply), according to manufacturers’ recommendations. Calibra was used in conjunction with Prime/Bond-NT adhesive (Dentsply), while the other two are self-adhesive. The bonded specimens were stored for 24h in distilled water at 37°C. Specimens were vertically sectioned into 1 mm-thick slabs, yielding up to six per specimen. Two central slabs were randomly chosen from each specimen making up the cement groups (n=12). Each group was subdivided into two subgroups (n=6), a control and a thermocycled subgroup (5–55°C) for 500 cycles. Slabs were coated with nail polish up to 1 mm from the interface, immersed in a 50% silver nitrate solution for 24h, and tested for nanoleakage using Quanta Environmental SEM and EDAX. Data were statistically analyzed using two-way ANOVA and Tukey’s post-hoc tests. Results: Rely-X Unicem and Calibra groups demonstrated no significant difference in the percentage of silver penetration, while the BisCem group revealed a significantly higher percentage (P?.05). Thermocycling (500 cycles) did not have a statistically significant effect on the percentage of silver penetration (P>.05). Conclusions: One self-adhesive-resin cement demonstrated a similar sealing ability when compared with a standard resin cement. Thermo-cycling did not significantly increase dye penetration under the test conditions.

El-Badrawy, Wafa; Hafez, Randa Mohamed; El Naga, Abeer Ibrahim Abo; Ahmed, Doaa Ragai

2011-01-01

14

Light transmittance of zirconia as a function of thickness and microhardness of resin cements under different thicknesses of zirconia  

PubMed Central

Objective: The objective of this study was to compare microhardness of resin cements under different thicknesses of zirconia and the light transmittance of zirconia as a function of thickness. Study design: A total of 126 disc-shaped specimens (2 mm in height and 5 mm in diameter) were prepared from dual-cured resin cements (RelyX Unicem, Panavia F and Clearfil SA cement). Photoactivation was performed by using quartz tungsten halogen and light emitting diode light curing units under different thicknesses of zirconia. Then the specimens (n=7/per group) were stored in dry conditions in total dark at 37°C for 24 h. The Vicker’s hardness test was performed on the resin cement layer with a microhardness tester. Statistical significance was determined using multifactorial analysis of variance (ANOVA) (alpha=.05). Light transmittance of different thicknesses of zirconia (0.3, 0.5 and 0.8 mm) was measured using a hand-held radiometer (Demetron, Kerr). Data were analyzed using one-way ANOVA test (alpha=.05). Results: ANOVA revealed that resin cement and light curing unit had significant effects on microhardness (p < 0.001). Additionally, greater zirconia thickness resulted in lower transmittance. There was no correlation between the amount of light transmitted and microhardness of dual-cured resin cements (r = 0.073, p = 0.295). Conclusion: Although different zirconia thicknesses might result in insufficient light transmission, dual-cured resin cements under zirconia restorations could have adequate microhardness. Key words:Zirconia, microhardness, light transmittance, resin cement.

Egilmez, Ferhan; Ergun, Gulfem; Kaya, Bekir M.

2013-01-01

15

Immediate and delayed photoactivation of self-adhesive resin cements and retention of glass-fiber posts.  

PubMed

The aim of this study was to evaluate the effect of immediate and delayed photoactivation of self-adhesive resin cements (SARCs) on the retention of glass-fiber posts luted into root canals. Bovine incisors were endodontically treated, and post holes of 9 mm in depth were prepared. Fiber posts were luted using one of two SARCs, BisCem? (Bisco Inc., Schaumburg, USA) or RelyX Unicem clicker (3M ESPE, Saint Paul, USA), or a regular (etch-and-rinse) resin cement (AllCem; FGM, Joinvile, Brazil). Photoactivation was performed immediately, or at 5 or 10 min after cementation. Root/post specimens were transversely sectioned 7 days after luting into 1-mm-thick slices, which were submitted to push-out testing in a mechanical testing machine. Bond strength data were analyzed by two-way ANOVA and Student-Newman-Keuls' method (? = 0.05). Immediate photoactivation resulted in the highest bond strength for Unicem. BisCem? demonstrated higher bond strength values when photoactivated after a 10-min delay. Immediate photoactivation yielded the lowest bond strengths for AllCem, although no differences in bond strength were observed between photoactivation delayed by 5 and 10 min. In conclusion, the moment of resin cement photoactivation may affect the intraradicular retention of fiber posts, depending upon the resin cement used for luting. PMID:25006624

Faria-e-Silva, André Luis; Peixoto, Aline Carvalho; Borges, Marcela Gonçalves; Menezes, Murilo de Sousa; Moraes, Rafael Ratto de

2014-01-01

16

Intra-radicular dentin treatments and retention of fiber posts with self-adhesive resin cements.  

PubMed

The aim of this study was to evaluate the effect of treating intraradicular dentin with irrigating solutions on the retention of glass-fiber posts luted with self-adhesive resin cement. Bovine incisors were endodontically treated, and 9-mm-deep postholes were prepared. Before inserting the cement, the root canals were irrigated with various solutions: 11.5% polyacrylic acid for 30 s, 17% EDTA for 60 s, or 5% NaOCl for 60 s, respectively. Irrigation with distilled water was used in the control group. After all specimens had been rinsed with distilled water, the excess moisture was removed and the posts were luted using either BisCem (Bisco) or RelyX Unicem clicker (3M ESPE). Seven days after luting, the specimens were sectioned transversally into 1-mm-thick slices, which were submitted to push-out testing on a mechanical testing machine. Bond strength data (n = 6 per group) were analyzed by two-way ANOVA and Student-Newman-Keuls' test (? = 0.05). For Unicem, EDTA showed lower bond strength than the other solutions, which had similar results. For BisCem, EDTA showed higher bond strength than the other treatments, while application of NaOCl yielded higher bond strength than polyacrylic acid whereas the control group had intermediate results. In conclusion, irrigating root canals before insertion of self-adhesive resin cements, especially EDTA, might interfere with retention of the fiber posts. PMID:23306622

Faria-e-Silva, André Luis; Menezes, Murilo de Sousa; Silva, Fernanda Pereira; Reis, Giselle Rodrigues dos; Moraes, Rafael Ratto de

2013-01-01

17

Influence of preheating the bonding agent of a conventional three-step adhesive system and the light activated resin cement on dentin bond strength  

PubMed Central

Aims: to evaluate the influence of preheating the bonding agent (Scotchbond Multipurpose Adhesive/3M ESPE) and the light-activated resin cement (RelyX Venner/3M ESPE) on dentin microtensile bond strength. Materials and Methods: The exposed flat dentin surface of 40 human third molars were randomly distributed into four groups for cementation (SR Adoro/Ivoclar Vivadent) (n = 10): G1-bond and resin cement, both at room temperature (22°C), G2-bond preheated to 58°C and cement at room temperature (22°C), G3-bond at room temperature (22°C) and the cement preheated to 58°C, G4-bond preheated to 58°C and cement preheated to 58°C. Sticks of dentin/block set measuring approximately 1 mm2 were obtained and used for the microtensile bond strength test. All sticks had their failure mode classified. Statistical analysis used: Factorial analysis of variance was applied, 2 × 2 (bond × cement) (P < 0.05). Results: Preheating the bonding agent (P = 0.8411) or the cement (P = 0.7155), yielded no significant difference. The interaction bond × cement was not significant (P = 0.9389). Conclusions: Preheating the bond and/or the light-activated resin cement did not influence dentin bond strength or fracture failure mode.

Holanda, Daniel Brandao Vilela; Franca, Fabiana Mantovani Gomes; do Amaral, Flavia Lucisano Botelho; Florio, Flavia Martao; Basting, Roberta Tarkany

2013-01-01

18

Push-out bond strengths of fiber-reinforced composite posts with various resin cements according to the root level  

PubMed Central

PURPOSE The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni.

Chang, Hoon-Sang; Noh, Young-Sin; Lee, Yoon; Min, Kyung-San

2013-01-01

19

Qualitative evaluation of scanning electron microscopy methods in a study of the resin cement/dentine adhesive interface.  

PubMed

Sample preparation and imaging techniques for scanning electron microscopy (SEM) of dehydrated dental samples can hinder the structural analyses. This study qualitatively evaluated images obtained with two different protocols of SEM preparation and analysis to assess the dentine adhesive interface. The crown and root dentine of 12 bovine incisors were subjected to cementation with the resin cement RelyX U100 or RelyX ARC/SBMP (n = 6). After storage for 7 days in a moist environment at 37 ± 1°C, the dentine samples were dehydrated in an ascending alcohol series, and three specimens from each group were coated with gold or carbon and examined in a high-vacuum (JEOL JSM-6360LV, 10 kV) or low-vacuum (FEI Quanta 200F, 15-30 kV) microscope. Images were obtained at magnifications between 50 and 2,000×, but with different working distances. The use of high vacuum for carbon and gold coating and SEM visualization led to cracks in the samples. A small number of cracks can be described in the specimens subjected to the low-vacuum technique. The protocol for SEM imaging in low vacuum was considered more appropriate for preservation of the integrity of the evaluated structures. PMID:24188716

Pereira, Carolina N D B; Daleprane, Bruno; Barbosa, Paola F; Moreira, Allyson N; de Magalhães, Cláudia S

2014-02-01

20

Degree of conversion of a resin cement light-cured through ceramic veneers of different thicknesses and types.  

PubMed

During the cementation of ceramic veneers the polymerization of resin cements may be jeopardized if the ceramics attenuate the irradiance of the light-curing device. The aim of this study was to evaluate the effect of different types and thicknesses of ceramic veneers on the degree of conversion of a light-cured resin-based cement (RelyX Veneer). The cement was light-cured after interposing ceramic veneers [IPS InLine, IPS Empress Esthetic, IPS e.max LT (low translucency) and IPS e.max HT (high translucency) - Ivoclar Vivadent] of four thicknesses (0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm). As control, the cement was light-cured without interposition of ceramics. The degree of conversion was evaluated by FTIR spectroscopy (n=5). Data were analyzed with one-way ANOVA and Tukey's test (?=0.05). Significant differences were observed among groups (p<0.001). The degree of conversion was similar to the control for all light-cured groups with interposition of ceramics of 0.5 mm and 1.0 mm (p>0.05). Among 1.5-mm-thick veneers, IPS e.max LT was the only one that showed different results from the control (p<0.05). At the thickness of 2.0 mm, only the IPS e.max LT and HT veneers were able to produce cements with degrees of conversion similar to the control (p>0.05). The degree of conversion of the evaluated light-cured resin cement depends on the thickness and type of ceramics employed when veneers thicker than 1.5 mm are cemented. PMID:24789290

Runnacles, Patrício; Correr, Gisele Maria; Baratto Filho, Flares; Gonzaga, Carla Castiglia; Furuse, Adilson Yoshio

2014-01-01

21

Influence of surface treatments and resin cement selection on bonding to zirconia.  

PubMed

This study aimed to evaluate the surface changes caused in zirconia by different surface treatments and the influence of the surface treatment and cement selection on bonding to zirconia under aging. Sintered zirconia specimens were divided into five groups (n = 31) based on the surface treatment, namely, control, air abrasion, silica coating, laser and air abrasion + laser. After surface treatment, surface roughness and microscope analyses were performed on one specimen of each group. Composite cylinders were then bonded to conditioned ceramics using RelyX U100 (RXU), Clearfil Esthetic Cement (CEC) and Panavia F (PF) (n = 10). After 24 h, the bonded specimens were subjected to thermal cycling (6,000 times), and then, a shear bond strength test was conducted. The roughness values were analysed using Kruskal-Wallis and Mann-Whitney U tests, and the bond strengths were analysed by two-way analysis of variance and Duncan's test. The relationship between the roughness and the bond strength was determined by Spearman's correlation analysis. Specimens subjected to surface treatments were rougher than the control specimen (p < 0.000). However, there were no significant differences between the air abrasion and air abrasion + laser groups and the silica coating and laser groups. Specimens treated with laser showed lower bond strengths irrespective of the resin cement used. CEC and/or PF showed higher bond strengths than RXU for each surface treatment group. No significant relationship was observed between the roughness and the bond strength. The results of this study showed that all the surface treatments, except for laser irradiation, were suitable for treating zirconia ceramics. Cement selection was found to be more important than surface treatment, and phosphate monomer-containing cements were suitable for cementing zirconia. PMID:23139070

Suba??, Meryem Gülce; Inan, Özgür

2014-01-01

22

Solidification of ion exchange resin wastes in hydraulic cement  

SciTech Connect

Work has been conducted to investigate the solidification of ion exchange resin wastes with portland cements. These efforts have been directed toward the development of acceptable formulations for the solidification of ion exchange resin wastes and the characterization of the resultant waste forms. This paper describes formulation development work and defines acceptable formulations in terms of ternary phase compositional diagrams. The effects of cement type, resin type, resin loading, waste/cement ratio and water/cement ratio are described. The leachability of unsolidified and solidified resin waste forms and its relationship to full-scale waste form behavior is discussed. Gamma irradiation was found to improve waste form integrity, apparently as a result of increased resin crosslinking. Modifications to improve waste form integrity are described. 3 tables.

Neilson, R.M. Jr.; Kalb, P.; Fuhrmann, M.; Colombo, P.

1982-01-01

23

Bond strength of self-adhesive resin cements to dry and moist dentin.  

PubMed

This study evaluated the effects of humidity conditions and evaluation times on the dentin bond strength (DBS) of two self-adhesive resin cements (RC). The RC used were: RelyX Unicem (3M ESPE) and Clearfil SA Cement (Kuraray Med.). One hundred and twenty coronal portions of bovine incisors (n = 10) were used. Buccal surfaces were abraded in order to expose a flat dentinal surface (180-grit SiC) and to standardize the smear layer formation (600-grit SiC). The humidity conditions tested were: dry (air-dried for 10 s), slightly moist (water application with disposable applicator on dried dentin and water excess removed with absorbent paper), and moist (same application without water removal). The RC were used according to the manufacturers' recommendations and were applied to prepolymerized resin discs (2 mm thick; Sinfony, 3M ESPE), which were subsequently bonded to the dentin surfaces. After 24 h, half of the teeth were prepared for the microtensile bond strength test, while the other half were stored in water for 6 months and tested in tension (0.5 mm/min) until failure. A 3-way analysis of variance and the Tukey test were performed (preset alpha of 0.05). No RC showed any reduction of DBS after 6 months, and no significant difference was observed between them. The moist dentin increased the bond strength of Clearfil SA Cement for both periods of time. Humidity conditions can change the DBS; however, the study's results were product-dependent. PMID:24036976

André, Carolina Bosso; Aguiar, Thaiane Rodrigues; Ayres, Ana Paula Almeida; Ambrosano, Glaucia Maria Bovi; Giannini, Marcelo

2013-01-01

24

Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics  

PubMed Central

Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pre-treated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after NaOClaq immersion. Conclusions: Resin-ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. The MDP-containing and the self-adhesive resin cements were both suitable for luting CAD/CAM ceramics. Despite both cements being prone to degradation, RXU luted to zirconia or untreated or sandblasted alumina showed the most stable interfaces. CAL experimented spontaneous debonding in all tested groups. Key words:CAD/CAM ceramic, alumina, zirconia, resin cement, surface pre-treatment, sandblasting, silica-coating, chemical aging, bond degradation, microtensile bond strength.

Osorio, Raquel; Monticelli, Francesca; Osorio, Estrella; Toledano, Manuel

2012-01-01

25

In vitro study of resin-modified glass ionomer cements for cementation of orthodontic bands  

Microsoft Academic Search

The aim of this in vitro study was to investigate different light-cured and chemically cured resin-modified glass ionomer cements used for the cementation of orthodontic bands and to analyze various factors influencing the adhesive strength between enamel, cement and stainless steel.

Saskia M. Liebmann; Paul-Georg Jost-Brinkmann

1999-01-01

26

Effect of immediate and delayed light activation on the mechanical properties and degree of conversion in dual-cured resin cements.  

PubMed

We evaluated the effect of activation mode (immediate or delayed light activation vs. no light activation) on diametral tensile strength (DTS), elastic modulus, ultimate tensile strength (UTS), and degree of conversion (DC) in dual-cured resin cements. Three resin cements were evaluated: Enforce, RelyX ARC, and Panavia F. The mixed cements were inserted into circular molds for the DTS test and into dumbbell-shaped molds for the UTS test. Inside the molds, the cements were light-activated either immediately or after 5 min (delayed light activation). If no light activation was performed, the materials were protected from light exposure (control). The DTS and UTS tests were performed until fracture. The elastic modulus was calculated using data from the DTS test, and DC was evaluated 24 h after manipulation using near-infrared spectroscopy. Data for each variable were individually analyzed by two-way ANOVA and the post-hoc Tukey test (? = 0.05). Regarding DTS, activation mode influenced only Panavia Fspecimens, which had the lowest DTS values in the absence of light activation. Activation mode did not influence the elastic modulus or UTS of any resin cement evaluated. Immediate light activation yielded higher DC values as compared with the absence of light activation. PMID:23047037

Faria-e-Silva, André L; Piva, Evandro; Lima, Giana S; Boaro, Letícia C; Braga, Roberto R; Martins, Luis R M

2012-09-01

27

Early Hardness and Shear Bond Strength of Dual-cure Resin Cement Light Cured Through Resin Overlays With Different Dentin-layer Thicknesses.  

PubMed

SUMMARY The purpose of this study was to investigate whether dentin-layer thickness of resin overlays could affect the early hardness and shear bond strength of dual-cure resin cement (DCRC, RelyX ARC) after light curing with light curing units (LCUs) of various power densities: Optilux 360 (360), Elipar Freelight 2 (FL2), and Elipar S10 (S10). Resin overlays were fabricated using an indirect composite resin (Sinfony) with a dentin layer, an enamel layer, and a translucent layer of 0.5 mm thickness each (0.5-0.5-0.5) or of 0.2 mm, 0.5 mm, and 0.8 mm thickness (0.2-0.5-0.8), respectively. The DCRC was light cured for 40 seconds through the overlays, and surface hardness and shear bond strength to bovine dentin were tested 10 minutes after the start of light curing. Surface hardness was higher when the DCRC was light cured through the 0.2-0.5-0.8 combination than when the DCRC was light cured through the 0.5-0.5-0.5 combination with all LCUs. The ratio of upper surface hardness of DCRC light cured through resin overlays relative to the upper surface hardness of DCRC light cured directly was more than 90% only when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination. The shear bond strength value was higher when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination than when light cured with S10 through the 0.5-0.5-0.5 combination. This study indicates that reducing the dentin-layer thickness while increasing the translucent-layer thickness of resin inlays can increase the photopolymerization of DCRC, thereby increasing the early bond strength of resin inlays to dentin. PMID:24191869

Chang, H-S; Kim, J-W

2014-01-01

28

Effect of light energy density on conversion degree and hardness of dual-cured resin cement.  

PubMed

This study evaluated the effect of different light energy densities on conversion degree (CD) and Knoop hardness number (KHN) of RelyX ARC (RLX) resin cement. After manipulation according to the manufacturer's instructions, RLX was inserted into a rubber mold (0.8 mm x 5 mm) and covered with a Mylar strip. The tip of the light-curing unit (LCU) was positioned in contact with the Mylar surface. Quartz-tungsten-halogen (QTH) and light-emitting diode (LED) LCUs with light densities of 10, 20 and 30 J/cm2 were used to light-cure the specimens. After light curing, the specimens were stored dry in lightproof containers at 37 degrees C. After 24 hours, the CD was analyzed by FT-Raman and, after an additional 24-hours, samples were submitted to Knoop hardness testing. The data of the CD (%) and KHN were submitted to two-way ANOVA and the Tukey's test (alpha = 0.05). QTH and LED were effective light curing units. For QTH, there were no differences among the light energy densities for CD or KHN. For LED, there was a significant reduction in CD with the light energy density set at 10 J/cm2. KHN was not influenced by the light-curing unit and by its light energy density. PMID:20166419

Komori, Paula Carolina de Paiva; de Paula, Andréia Bolzan; Martin, Airton Abr?o; Tango, Rubens Nisie; Sinhoreti, Mario Alexandre Coelho; Correr-Sobrinho, Lourenço

2010-01-01

29

Statistical failure analysis of adhesive resin cement bonded dental ceramics  

PubMed Central

The goal of this work is to quantitatively examine the effect of adhesive resin cement on the probability of crack initiation from the internal surface of ceramic dental restorations. The possible crack bridging mechanism and residual stress effect of the resin cement on the ceramic surface are examined. Based on the fracture-mechanics-based failure probability model, we predict the failure probability of glass-ceramic disks bonded to simulated dentin subjected to indentation loads. The theoretical predictions match experimental data suggesting that both resin bridging and shrinkage plays an important role and need to be considered for accurate prognostics to occur.

Wang, Yaou; Katsube, Noriko; Seghi, Robert R; Rokhlin, Stanislav I.

2007-01-01

30

Study of Mechanical and Physicochemical Properties of Cementated Spent Ion-Exchange-Resins.  

National Technical Information Service (NTIS)

As first part of a study on the possibilities, to immobilize spent ion exchange resins, for final disposal, the dependence of compressive strength from the composition of cement - resin mixtures was detected. Powdered resins, bead resins and ashes from th...

P. Patek

1981-01-01

31

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

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. PMID:22313828

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

2011-01-01

32

Bonding Effectiveness of Two Adhesive Luting Cements to Glass Fiber Posts: Pull-Out Evaluation of Three Different Post Surface Conditioning Methods  

PubMed Central

The purpose of this study was to evaluate the bond strength at the post/resin-cement interface with 3 different surface treatments of glass fiber posts and with 2 different luting resin cements. Sixty glass fiber posts (RelyX Fiber Post) were randomly divided into 3 groups (n = 20) and were luted with a dual-polymerizing self-adhesive universal resin cement (RelyX Unicem) and with a dual-polymerizing resin cement (RelyX ARC). This was carried out in association with a dual-polymerizing adhesive (Scotchbond Multi-Purpose Plus) in simulated plexiglass root canals after receiving three different pretreatment procedures. A pull-out test was performed on each sample to measure bond strengths. Data were analyzed with two-way ANOVA. Two samples from each group were processed for SEM observations in order to investigate the morphologic aspect of the post/cement interface. Both resin cements demonstrated significant different bond strength values (P < 0.0001). The surface treatment result was also statistically significant (P = 0.0465). SEM examination showed a modification of the post surface after pretreatment with methyl methacrylate. The dual-polymerizing self-adhesive universal resin cement achieved higher MPa bond strength values. The use of methyl methacrylate as a surface treatment of glass fiber posts provided a significant increase in bond strengths between the posts and both luting materials.

Calabrese, Marco

2014-01-01

33

Bonding effectiveness of two adhesive luting cements to glass fiber posts: pull-out evaluation of three different post surface conditioning methods.  

PubMed

The purpose of this study was to evaluate the bond strength at the post/resin-cement interface with 3 different surface treatments of glass fiber posts and with 2 different luting resin cements. Sixty glass fiber posts (RelyX Fiber Post) were randomly divided into 3 groups (n = 20) and were luted with a dual-polymerizing self-adhesive universal resin cement (RelyX Unicem) and with a dual-polymerizing resin cement (RelyX ARC). This was carried out in association with a dual-polymerizing adhesive (Scotchbond Multi-Purpose Plus) in simulated plexiglass root canals after receiving three different pretreatment procedures. A pull-out test was performed on each sample to measure bond strengths. Data were analyzed with two-way ANOVA. Two samples from each group were processed for SEM observations in order to investigate the morphologic aspect of the post/cement interface. Both resin cements demonstrated significant different bond strength values (P < 0.0001). The surface treatment result was also statistically significant (P = 0.0465). SEM examination showed a modification of the post surface after pretreatment with methyl methacrylate. The dual-polymerizing self-adhesive universal resin cement achieved higher MPa bond strength values. The use of methyl methacrylate as a surface treatment of glass fiber posts provided a significant increase in bond strengths between the posts and both luting materials. PMID:24987418

Graiff, Lorenzo; Rasera, Laura; Calabrese, Marco; Vigolo, Paolo

2014-01-01

34

Progress in Solidification of Radioactive Waste Resins Using Specific Cement  

SciTech Connect

A kind of special cement (Named as ASC) was used in radioactive spent resins solidification in China. A prescription of X ASC cement + 0.5 X waste resins (50% water hold) + 0.35 X water was obtained first. In order to control the temperature rise caused by hydration of cement in 200 L solidification matrix, various supplementary materials were tried. Based on compressive strength tests and center temperature rise, super powered zeolite was selected. In addition, more resins were added to reduce the center temperature rise. A superior combination was obtained as ASC 35 wt.%, zeolite 7 wt.% to mix 42 wt.% of resins (50% water hold) with 16 wt.% of water. The microstructures of hydrated OPC, ASC and ASC with different zeolite addition were compared by means of Scanning Electron Microscopy (SEM). From the SEM pictures, the structures of the needles or spines can be seen in ASC matrices and the needles structure of ASC change into flake structure gradually with more zeolite added. The simulated leaching tests showed that inclusion of zeolite in ASC reduced the leaching rates of radionuclides significantly. From 200 L matrix test, the centre temperature curve was measured, and the highest temperature was lower than 90 deg. C. No thermal cracks were found in the final solidified products. (authors)

Li, J.F.; Ye, Y.C.; Wang, J.L. [Institute of Nuclear and New Energy Technology - INET, Tsinghua University, Beijing 100084 (China)

2006-07-01

35

The effect of dentin desensitizers and Nd:YAG laser pre-treatment on microtensile bond strength of self-adhesive resin cement to dentin  

PubMed Central

PURPOSE The purpose of this study is to evaluate if pre-treatment with desensitizers have a negative effect on microtensile bond strength before cementing a restoration using recently introduced self-adhesive resin cement to dentin. MATERIALS AND METHODS Thirty-five human molars' occlusal surfaces were ground to expose dentin; and were randomly grouped as (n=5); 1) Gluma-(Glutaraldehyde/HEMA) 2) Aqua-Prep F-(Fluoride), 3) Bisblock-(Oxalate), 4) Cervitec Plus-(Clorhexidine), 5) Smart protect-(Triclosan), 6) Nd:YAG laser, 7) No treatment (control). After applying the selected agent, RelyX U200 self-adhesive resin cement was used to bond composite resin blocks to dentin. All groups were subjected to thermocycling for 1000 cycles between 5-55?. Each bonded specimen was sectioned to microbars (6 mm × 1 mm × 1 mm) (n=20). Specimens were submitted to microtensile bond strength test at a crosshead speed of 0.5 mm/min. Kolmogorov-Smirnov, Levene's test, Kruskal-Wallis One-way Analysis of Variance, and Conover's nonparametric statistical analysis were used (P<.05). RESULTS Gluma, Smart Protect and Nd:YAG laser treatments showed comparable microtensile bond strengths compared with the control group (P>.05). The microtensile bond strengths of Aqua-Prep F, and Cervitec Plus were similar to each other but significantly lower than the control group (P<.05). Bisblock showed the lowest microtensile bond strength among all groups (P<.001). Most groups showed adhesive failure. CONCLUSION Within the limitation of this study, it is not recommended to use Aqua-prep F, Cervitec Plus and Bisblock on dentin when used with a self-adhesive resin cement due to the decrease they cause in bond strength. Beside, pre-treatment of dentin with Gluma, Smart protect, and Nd:YAG laser do not have a negative effect.

Tuncer, Duygu; Yuzugullu, Bulem; Celik, Cigdem

2014-01-01

36

Hardening of new resin cements cured through a ceramic inlay.  

PubMed

This study investigated the degree of hardening achieved through self-curing only and through dual-curing a group of eight new resin-based cements. In addition, the effect of ceramic inlay thickness on cement hardness was determined. Disk specimens measuring 6 mm in diameter and 2.5 mm thick were prepared from eight cements: Adherence, Choice, Duolink, Enforce, Lute-It, Nexus, Resinomer, and Variolink. Eight specimens were prepared from each material; half were self-cured, while the remainder were dual-cured. Knoop hardness measurements were then made at 1-hour, 1-day, and 1-week intervals. In addition 12 specimens of the same dimensions were prepared from each cement and were dual-cured through ceramic spacers of varying thickness (1-6 mm). Hardness measurements were made as above. ANOVA showed significant differences in hardness of self-cured versus dual-cured specimens for all cements (P < 0.0001). Significant differences were also found in the hardness of specimens dual-cured through ceramic spacers 2-3 mm in thickness or more compared with those that were dual-cured without spacer. It is concluded that for some materials self-curing alone was not adequate to achieve sufficient hardening; cement hardness was significantly reduced when ceramic inlay thickness was 2-3 mm or more. PMID:10337297

el-Mowafy, O M; Rubo, M H; el-Badrawy, W A

1999-01-01

37

Immobilization of caesium-loaded ion exchange resins in zeolite-cement blends  

Microsoft Academic Search

Water leaching of caesium (Cs)-loaded cemented ion exchange resin and the mechanism of Cs immobilization were studied in the cement-resin-zeolite (mainly clinoptilolite) system. Present work focuses on the reduction of significant Cs leaching (in terms of the total Cs adsorbed on the resin) by blending natural untreated and chemically treated zeolites to the cement. Addition of natural zeolites decreased Cs

Sandor Bagosi; Laszlo J Csetenyi

1999-01-01

38

Leachability of Decontamination Ion-Exchange Resins Solidified in Cement at Operating Nuclear Power Plants,  

National Technical Information Service (NTIS)

Data are presented on the release of radionuclides, stable metals, and organic reagents from decontamination ion-exchange resin wastes solidified in Portland cement. Both solidified and unsolidified decontamination resin waste samples were collected from ...

C. V. McIsaac J. W. Mandler

1989-01-01

39

Immobilization of caesium-loaded ion exchange resins in zeolite-cement blends  

SciTech Connect

In several countries, low-level radioactive waste immobilization strategies are based on cementitious materials. Water leaching of caesium (Cs)-loaded cemented ion exchange resin and the mechanism of Cs immobilization were studied in the cement-resin-zeolite (mainly clinoptilolite) system. Present work focuses on the reduction of significant Cs leaching (in terms of the total Cs adsorbed on the resin) by blending natural untreated and chemically treated zeolites to the cement. Addition of natural zeolites decreased Cs release by up to 70--75% (of the quantity originally bonded in the resin) in the course of a 3-year leaching period.

Bagosi, S.; Csetenyi, L.J. [Univ. of Veszprem (Hungary). Dept. of Silicate and Materials Engineering] [Univ. of Veszprem (Hungary). Dept. of Silicate and Materials Engineering

1999-04-01

40

Microhardness of resin cements in the intraradicular environment: Effects of water storage and softening treament  

Microsoft Academic Search

ObjectivesTo analyze the microhardness of four dual-cure resin cements used for cementing fiber-reinforced posts under the following conditions: after 7 days of storage in water, after additional 24h of immersion in 75% ethanol, and after 3 months of storage in water. Hardness measurements were taken at the cervical, middle and apical thirds along the cement line.

Ana Paula R. V. Pedreira; Luiz Fernando Pegoraro; Mario Fernando de Góes; Thiago Amadei Pegoraro; Ricardo Marins Carvalho

2009-01-01

41

Association of different primers and resin cements for adhesive bonding to zirconia ceramics.  

PubMed

Purpose: To evaluate the shear bond strength (SBS) to zirconia ceramics using different associations of primers and resin cements. Materials and Methods: Two blocks of LAVA zirconia (3Y-TZP) were randomly submitted to an application of three different commercially available primers: Alloy Primer (AP), Z-Prime Plus (ZP), and Signum Zirconia Bond (SZB). Nonprimed specimens were considered controls. After treatment, the 80 specimens (5 mm × 5 mm × 2 mm) were randomly cemented with one of the resin cements: Panavia F, Multilink, seT, and NX3. For cementation, cylinders of resin cement were built on the ceramic surfaces using the SDI SBS apparatus. The specimens were submitted to the SBS test. Fractured surfaces were observed under stereomicroscopy to determine the failure mode, and mean bond strength values were analyzed using the Kruskal-Wallis and Mann-Whitney tests (? = 0.05). Results: Signum Zirconia Bond had the highest SBS compared to all other primers and the control group, regardless of the resin cement used. The highest values were obtained when associating Panavia F with Signum Zirconia Bond. Alloy Primer increased bonding values when associated with seT cement only. When no primer was used, no statistical difference was observed among resin cements. All specimens fractured due to adhesive failure. Conclusion: Signum Zirconia Bond is capable of increasing bonding values of resin cements to zirconia ceramics. Its association with Panavia F shows enhanced results when considering short-term adhesion to zirconia. PMID:24779024

Maeda, Fernando Akio; Bello-Silva, Marina Stella; Eduardo, Carlos de; Miranda Junior, Walter Gomes; Cesar, Paulo Francisco

2014-06-01

42

Method to determine the thermal expansion of epoxies, inorganic cements and polyester resins at cryogenic temperatures  

NASA Astrophysics Data System (ADS)

An apparatus for measuring the integral thermal expansions at cryogenic temperatures is described. The thermal expansions are given for a number of commercial epoxy resins, commercial polyester resins and inorganic cements. A method to reduce the thermal expansion of the resins by the use of quartz powder fillers is reported.

Sereinig, W.; Gross, F.

43

Bone-like apatite layer formation on the new resin-modified glass-ionomer cement  

Microsoft Academic Search

In this study, the apatite-forming ability of the new resin-modified glass-ionomer cement was evaluated by soaking the cement\\u000a in the simulated body fluid. The Fourier Transform Infrared (FTIR) spectrometer and X-Ray Diffraction (XRD) patterns of the\\u000a soaked cement pointed to the creation of poorly crystalline carbonated apatite. It was found that the releasing of calcium\\u000a ions from the soaked cement

Jhamak Nourmohammadi; S. K. Sadrnezhaad; A. Behnam Ghader

2008-01-01

44

Mechanical properties and biochemical activity of remineralizing resin-based Ca–PO 4 cements  

Microsoft Academic Search

Objectives. This study examined strength and bioactive (remineralizing) properties of a powder\\/liquid formulation (Cement I) and a more practical two-paste formulation (Cement II) of a fluoride-releasing resin-based Ca–PO4 cement.Methods. For the remineralization potential, the dissolution of calcium, total ionic phosphate and fluoride from set cement specimens were determined in buffered saline and saliva-like solution (SLS). Artificial caries lesions were produced

Sabine H Dickens; Glenn M Flaim; Shozo Takagi

2003-01-01

45

Influence of cement thickness on resin-zirconia microtensile bond strength  

PubMed Central

PURPOSE The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 µm, storage: thermocycled or not). They were cut into microbeams and stored in 37? distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (?=95%). RESULTS All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength.

Lee, Tae-Hoon; Ahn, Jin-Soo; Shim, June-Sung; Han, Chong-Hyun

2011-01-01

46

Solubility of a resin-modified glass ionomer cement.  

PubMed

Thirty standardized discs were fabricated from a resin-modified glass ionomer cement (Vitremer -3M) using three different powder/liquid ratios. All specimens were immediately weighed. Specimens were stored in artificial saliva for thirty days. Twice each day the specimens received a 30-min. artificial caries challenge (pH 4.4) and were returned to artificial saliva. At the end of the thirty-day experimental period, the specimens were dried and weighed again. Duncan's Multiple Range Test indicated that the 145 mg powder/35 mg liquid ratio had significantly less weight loss than the 145 mg powder/105 mg liquid ratio (p < 0.05). The results appear to demonstrate that solubility decreases as the aluminosilicate glass powder increases. PMID:9795733

Quackenbush, B M; Donly, K J; Croll, T P

1998-01-01

47

Resins and non-portland cements for construction in the cold  

NASA Astrophysics Data System (ADS)

A laboratory investigation was conducted to assess the potential of some resins and non-portland cements for structural concrete at low temperatures. The resins investigated were urethane (non-hydrophilic), epoxy and polyester, as well as a polysulfide polymer. Two non-portland (modified) cements were also tested. The curability of the resins, when mixed with fine aggregate, showed that they had potential for low temperature use in the following decreasing order: urethane, polyester, and epoxy. Of the non-portland cement materials, mixed as individual neat slurries, one showed potential for low temperature use at -10 C (using 3.9 C water).

Johnson, R.

1980-09-01

48

Evaluation of the rat tissue reaction to experimental new resin cement and mineral trioxide aggregate cement  

PubMed Central

Objectives New resin cement (NRC) has been developed as a root repairing material and the material is composed of organic resin matrix and inorganic powders. The aim of this study was to compare the rat subcutaneous tissue response to NRC and mineral trioxide aggregate (MTA) cement and to investigate the tissue toxicity of both materials. Materials and Methods Sixty rats received two polyethylene tube-implants in dorsal subcutaneous regions, MTA and NRC specimens. Twenty rats were sacrificed respectively at 1, 4 and 8 wk after implantation and sectioned to 5 µm thickness and stained with Hematoxylin-Eosin (H-E) or von-Kossa staining. The condition of tissue adjacent to the implanted materials and the extent of inflammation to each implant were evaluated by two examiners who were unaware of the type of implanted materials in the tissues. Data were statistically analyzed with paired t-test (p < 0.05). Results In specimens implanted with both NRC and MTA, severe inflammatory reactions were present at one wk, which decreased with time. At eighth wk, MTA implanted tissue showed mild inflammatory reaction, while there were moderate inflammatory reactions in NRC implanted tissue, respectively. In NRC group, von-Kossa staining showed more calcification materials than MTA group at eighth wk. Conclusions It was concluded that the calcium reservoir capability of NRC may contribute to mineralization of the tissues.

Yang, Won-Kyung; Ko, Hyun-Jung

2012-01-01

49

Evaluation of the flexural strength of dual-cure composite resin cements.  

PubMed

The aim of this study was to evaluate of flexural strength of some adhesive resin cements. Three dual-cure composite resin cements (Nexus 3; Variolink II, Panavia F) were prepared. The manufacturer's mixing directions for the cements were followed. Adhesive resin cement was mixed, placed in the rectangular portion of the mold. Fifteen specimens were prepared for each cements. The cements were light-activated with light lamp for 40 s on both and top and bottom surfaces. The each cement specimens were divided into three groups according to time of storage and stored in distilled water for 24 h, 15, and 30 days. Total 45 specimens were stored at 37°C (98.6 0F) in distilled water for 24 h, 15, and 30 days prior to tests. The flexural strength was tested w?th a universal testing machine at a crosshead speed of 0.5 mm/min (0.02 in.) The maximum load was recorded as MPa. The results were analyzed by Analysis of Variance and Duncan test. The Panavia F resin cements content Bisphenol A was showed the highest flexural strength (80.80 MPa) (11.71 ksi) for 24 h. The lowest flexural strength was observed in Nexus 3 (51.00 MPa) (7.39 ksi). It was found significant interaction of material and time (p < 0.05). The types of cement and time of storage was statistically significant on the flexural strengths (p < 0.001). PMID:23359518

Duymus, Zeynep Yesil; Yaniko?lu, Nuran Dinckal; Alkurt, Murat

2013-07-01

50

Leachability of Cesium from Cemented Evaporator Concentrates and Ion-Exchange Resins.  

National Technical Information Service (NTIS)

Leachabilities of cesium from cemented evaporator concentrates and ion-exchange resins were measured. The standard draft of the International Organization for Standardization (ISO, 1979) for long-term leach testing was followed in the research. Three resi...

A. Muurinen

1985-01-01

51

Tensile bond strength of a composite resin cement for bonded prosthesis to various dental alloys.  

PubMed

The development of composite resin cements that chemically bond to dental alloys has improved the construction of resin-bonded prostheses. Composite resins can be selected for various situations, but specific clinical situations may require different alloys. This study evaluated the ability of a composite resin cement to bond to various dental alloys of different compositions. Ten pairs of disks for each alloy (two NiCr, two NiCrBe, one CuAl, one gold type IV, and one gold for metal ceramic) were bonded to a composite resin cement after air abrasion was performed with aluminum oxide. The disks were then rinsed in tap water and were ultrasonically cleaned in distilled water for 2 minutes. The tensile tests exhibited greater values for alloys ultrasonically cleaned, and the best results were recorded by NiCr and NiCrBe alloys. PMID:7473275

Rubo, J H; Pegoraro, L F

1995-09-01

52

Resin-modified glass ionomer cements for bonding orthodontic retainers.  

PubMed

The aims of this study were to evaluate the shear bond strength (SBS), fracture mode, and wire pull out (WPO) resistance between resin-modified glass ionomer cement (RMGIC) and conventional orthodontic composite used as a lingual retainer adhesive. Forty lower human incisors were randomly divided into two equal groups. To determine the SBS, either Transbond-LR or Fuji Ortho-LC was applied to the lingual surface of the teeth by packing the material into cylindrical plastic matrices with an internal diameter of 2.34 mm and a height of 3 mm (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prepared for each composite where the wire was embedded in the composite material and cured, 20 seconds for Transbond-LR and 40 seconds for Fuji Ortho-LC. The ends of the wire were then drawn up and tensile stress was applied until failure of the resin. A Student's t-test for independent variables was used to compare the SBS and WPO data. Fracture modes were analyzed using Pearson chi-square test. Significance was determined at P < 0.05. The SBS values were 24.7 +/- 9.2 and 10.2 +/- 5.5 MPa and the mean WPO values 19.8 +/- 4.6 and 11.1 +/- 5.7 N for Transbond-LR and Fuji Ortho-LC, respectively. Statistical analysis showed that the SBS and WPO values of Transbond-LR and Fuji Ortho-LC were significantly different (P < 0.001). No significant differences were present among the groups in terms of fracture mode. However, the RMGIC resulted in a significant decrease in SBS and WPO; it produced sufficient SBS values on the etched enamel surfaces, when used as a bonded orthodontic retainer adhesive. PMID:19793779

Baysal, Asli; Uysal, Tancan

2010-06-01

53

The effect of tooth-preparation cleansing protocol on the bond strength of self-adhesive resin cement to dentin contaminated with a hemostatic agent.  

PubMed

This study evaluated the effect of tooth-preparation cleansing protocols on the bond strength of a self-adhesive resin cement to dentin contaminated with two different types of hemostatic agents. The occlusal surface of extracted third molars was flattened to expose the dentin surface and prepared for a full crown. Acrylic temporary crowns were fabricated and placed using temporary cement. The specimens were stored at 100% relative humidity for seven days. Following removal of the temporary crowns, the specimens were surface debrided using aluminum oxide abrasion with a particle size of 27 ?m at 40 psi. The specimens were randomly assigned to three groups, according to the hemostatic agents: Group I–an agent containing aluminum chloride was applied to the tooth surface; Group II–an agent containing ferric sulfate was applied to the tooth surface and Group III–uncontaminated (control). The contaminated specimens were then further subdivided into three subgroups (A–C; n=12): Group A–tooth surface cleansing with water spray; Group B–tooth surface cleansing with phosphoric acid etch and Group C–tooth surface cleansing with aluminum oxide abrasion with a particle size of 27 ?m at 40 psi. Ceramic blocks were treated with a 9.5% hydrofluoric acid-etch and silanized prior to being cemented with self-adhesive resin luting agent (RelyX Unicem) to the prepared dentin. The shear bond strength was determined at a crosshead speed of 0.5 mm/minute. The data were analyzed with two-way ANOVA, followed by the Duncan multiple range test, to determine any significant differences between the testing groups. The microstructure morphology of the tooth surface was evaluated using SEM analysis. The results revealed that there was a significant difference between the bond strength of the control and the contaminated testing groups (p<0.05). A tooth preparation cleansing protocol using particle abrasion with low-pressure aluminum oxide particles provided a significant improvement in bond strength to contaminated dentin, while rinsing with water spray resulted in the lowest mean bond strength of the self-adhesive resin cement to dentin (p<0.05). PMID:21488725

Chaiyabutr, Y; Kois, J C

2011-01-01

54

Casting Granular Ion Exchange Resins with Medium-Active Waste in Cement.  

National Technical Information Service (NTIS)

Medium active waste from nuclear power stations in Sweden is trapped in granular ion exchange resins. The resin is mixed with cement paste and cast in a concrete shell which is cubic and has an edge dimension of 1.2 m. In some cases the ion exchange cemen...

O. Beijer

1980-01-01

55

Advances in cement solidification technology for waste radioactive ion exchange resins: A review  

Microsoft Academic Search

Treatment and disposal of waste radioactive ion exchange resins is one of the most urgent problems for nuclear industries in China. Cement solidification technology has many advantages, such as requiring simple equipment, easy scaling-up, low working temperature, no trouble of gas cleaning and low cost. It is a suitable technology for treatment of waste radioactive resins, and has been widely

Junfeng Li; Jianlong Wang

2006-01-01

56

Effects of different surface treatments on bond strength between resin cements and zirconia ceramics.  

PubMed

This study compares the bond strength of resin cement and yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic with different surface conditioning methods. Two hundred presintered Y-TZP ceramic specimens were prepared, sintered (4 × 4 × 4 mm), and randomly assigned to four equal groups as control (C, no conditioning); airborne particle abraded (APA, air abrasion with 11 ?m Al2O3); tribochemical silica coating/silane coupling system (TSC, Rocatec, air abrasion with 110 ?m Al2O3, 30 ?m silica-coated Al2O3 and silane); and laser (L, Er:YAG laser irradiation treated at a power setting of 200 mJ). After specimen preparation, composite resin cylinders were prepared and cemented with resin cements (Clearfil Esthetic, Panavia F 2.0, Rely X-U100, Super Bond C&B, and Multilink Automix) on the ceramic surfaces and kept in an incubator at 37°C for 60 days. All specimens were tested for shear bond strength with a universal testing machine, and fractured surfaces were evaluated by environmental scanning electron microscopy. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U-tests (?=0.05). The bond strengths for C and L groups were not significantly different according to adhesive resin cement. APA and TSC resulted in increased bond strength for Panavia F 2.0 and Rely X-U100 resin cements. Additionally, TSC presented higher bond strength with Multilink Automix. Adhesive fracture between the ceramic and resin cement was the most common failure. Complete cohesive fracture at the ceramic or composite cylinders was not observed. Regardless of the adhesive resin cement used, laser treatment did not improve resin bond strength. PMID:24299447

Erdem, A; Akar, G C; Erdem, A; Kose, T

2014-01-01

57

An in vitro study to compare the effect of two etching techniques on the tensile bond strength of resin cement bonded to base metal alloy and enamel.  

PubMed

Resin-bonded retainers are being preferred for anterior restorations. To increase the retentive strength of the metal fixed to the tooth, the retainer surface has to be etched. Different etching techniques are described in the literature with different researchers expressing the superiority of one technique over the other. This study was conducted to compare electro chemical and chemical etching techniques and the mode of bond failure. Twenty human maxillary premolars with the crown portion separated from root were embedded in resin block such that mesial or distal portion of it was exposed on the top of the block. 4 × 5 mm area was marked on the tooth, and wax pattern was prepared to cover the exact area, with the opposite end having a hook like structure which was later attached to universal testing machine. Wiron99 Ni-Cr alloy was used for casting. Once the casting and etching procedures were finished, wax patterns were invested, casted and half the samples were etched chemically using Aqua-regia and the other half samples were etched electrochemically. The castings were cleaned and cemented to tooth structure using Rely-X ARC (3 M ESPE, USA) resin cement. Specimens were fixed to universal testing machine and de-bonded. The load required to de-bond and mode of de-bonding was noted. Results were subjected to five different statistical tests, each test specific to the variable being tested. The mean failure load was calculated as 5.95 kg for electrochemically etched samples and that of chemically etched samples was calculated as 11.15 kg. The standard deviation of the force required to debond the specimens (Kgf) was calculated and found to be 0.65 for electrochemically etched samples and 1.11 for chemically etched samples. The following conclusions have been drawn from the study. 1. Chemical etching of the samples created better retentive surfaces than electrochemical etching. 2. The results of mode of de-bonding show that in case of chemical etching maximum debonding occurred at resin-enamel interface and in electrochemical type it occurred at resin-metal interface. PMID:24431780

Sudheer, Arunachalam; Shetty, Gautam

2013-12-01

58

Treatment of a vertical root fracture using dual-curing resin cement: a case report.  

PubMed

Introduction. Vertical root fracture (VRF) is one of the most frustrating complications of root canal treatment. The prognosis of the root with VRF is poor therefore tooth extraction and root amputation are usually the only treatment options. However, bonding of the fracture line with adhesive resin cement during the intentional replantation procedure was recently suggested as an alternative to tooth extraction. Methods. A vertically fractured left maxillary incisor was carefully extracted, fracture line was treated with adhesive resin cement, a retrograde cavity was produced and filled with calcium-enriched mixture (CEM) cement, and tooth was replanted. Results. After 12 months the tooth was asymptomatic. The size of periapical radiolucency was noticeably reduced and there was no clinical sign of ankylosis. Conclusion. Using adhesive resin cement to bond the fracture lines extraorally in roots with VRF and intentional replantation of the reconstructed teeth could be considered as an alternative to tooth extraction, especially for anterior teeth. PMID:23316397

Moradi Majd, Nima; Akhtari, Farshid; Araghi, Solmaz; Homayouni, Hamed

2012-01-01

59

Treatment of a Vertical Root Fracture Using Dual-Curing Resin Cement: A Case Report  

PubMed Central

Introduction. Vertical root fracture (VRF) is one of the most frustrating complications of root canal treatment. The prognosis of the root with VRF is poor therefore tooth extraction and root amputation are usually the only treatment options. However, bonding of the fracture line with adhesive resin cement during the intentional replantation procedure was recently suggested as an alternative to tooth extraction. Methods. A vertically fractured left maxillary incisor was carefully extracted, fracture line was treated with adhesive resin cement, a retrograde cavity was produced and filled with calcium-enriched mixture (CEM) cement, and tooth was replanted. Results. After 12 months the tooth was asymptomatic. The size of periapical radiolucency was noticeably reduced and there was no clinical sign of ankylosis. Conclusion. Using adhesive resin cement to bond the fracture lines extraorally in roots with VRF and intentional replantation of the reconstructed teeth could be considered as an alternative to tooth extraction, especially for anterior teeth.

Moradi Majd, Nima; Akhtari, Farshid; Araghi, Solmaz; Homayouni, Hamed

2012-01-01

60

Effects of layering technique on the shade of resin overlays and the microhardness of dual cure resin cement.  

PubMed

The purpose of this study was to assess the color of layered resin overlays and to test the early microhardness of dual cure resin cement (DCRC) light cured through the layered resin overlays. Resin overlays of 1.5 mm thickness were fabricated with the A3 shade of Z350 (Group 1L), the A3B and A3E shades of Supreme XT (Group 2L), and the A3, E3, and T1 shades of Sinfony (Group 3L) using one, two, and three layers, respectively (n=7). Each layer of the resin overlays was set in equal thickness. The color of the resin overlays was measured with a colorimeter and compared with an A3 shade resin denture tooth. DCRC was light cured through the resin overlays, and the early microhardness of the DCRC was measured. The ?E value between the denture tooth and the resin overlays and the Vickers hardness number (VHN) of the DCRC were analyzed with one-way ANOVA and Tukey's HSD test. The color differences were 8.9±0.5, 5.3±1.0, and 7.3±0.5 and the VHNs were 19.4±1.1, 21.1±0.9, and 29.3±0.6 for Groups 1L, 2L, and 3L, respectively. Therefore, to match the designated tooth color of resin inlays and to increase the early microhardness of DCRC, layered resin inlays are more appropriate than single-dentin-layer resin inlays. However, the translucent layer should be used cautiously because the color difference of resin inlays with a translucent layer was affected more than those without a translucent layer. PMID:24918368

Chang, Hoon-Sang; Hong, Sung-Ok

2014-01-01

61

Influence of cement type and thickness on polyfiber post adhesion  

PubMed Central

Introduction: To evaluate the effect of two different post space diameters and related resin cement film thicknesses on the bond strength of a polyfiber post. Materials and Methods: A total of 48 premolars were randomly divided into two according to the post space diameter: 1.1 mm and 1.5 mm. Then each group was divided into three sub-groups according to luting cement used: RelyX U100, Panavia F2.0/ED primer, Clearfil SA cement. Spirapost was then luted into the canal using luting cements. Two slices were obtained from each root specimen. Push-out tests were performed. Data was analyzed with Kruskal-Wallis and Connover post-hoc and Mann-Whitney U-test (P < 0.05). Results: Push-out bond strength was found to vary significantly according to type of adhesive system and post space diameter size (P < 0.05). The self-adhesive resin cement RelyX U100 had significantly higher bond strengths compared with the other adhesive system (P < 0.05). The self-etch adhesive system (Panavia F2.0) showed significantly lower bond strengths compared with the other systems (P < 0.05). There was a significant interaction between the luting systems and post space diameter (P < 0.05). Conclusion: The increases in post space diameter significantly reduced the bond strength of Spirapost to root dentine for both groups.

Uzunoglu, Emel; Turker, Sevinc Aktemur; Yilmaz, Zeliha

2014-01-01

62

Preliminary Study Of The Permeability Of Cement-Resin Admixture For Water Storage  

NASA Astrophysics Data System (ADS)

Admixtures of cement and polymer resin were prepared for water storage in an aquifer layer. Water to cement (w/c) ratio was in the range of 6/7 to 10/7 and the resin added was between 10 and 60 ml. Samples were formed in two ways: by injecting the admixture into a box of 80×60×60 cm3 with a pressure of 6 bar and by molding to fit a certain dimension based on the requirements of the standard measurement. It was found that the increase of water to cement ratio enhances the coefficient of permeability. In addition, the coefficient of permeability decreases with increasing the volume of resin. An attempt to make a relationship between the permeability and the porosity showed that a power law would hold. However, more data are required for confirming the power law.

Putra, Ardian; Handayani, Gunawan; Satira, Suparno; Viridi, Sparisoma; Nugraha, Nirwan

2010-12-01

63

Cementation of ILW ion exchange resins: Impact of sulfate ions released by radiolysis on hydrated matrix  

NASA Astrophysics Data System (ADS)

Some of the ion exchange resins used during treatment of spent nuclear fuels are intermediate level radioactive wastes which may be damaged by radiolysis process, releasing sulfate ions directly into the cement-based encapsulating material. This work consists in an experimental study of the resulting sulfate attack on the properties of the hydrated matrix: dimensional stability, mineralogy and microstructure of the samples, as well as variations in the chemical composition of the curing solution, were studied during six months. Three sites of delayed ettringite formation were detected: into the cement matrix near the surface exposed to solution, localized in the interfacial transition zone between cement matrix and resins, or progressively replacing the portlandite that initially fulfilled the cracks of anionic resins. During the experiment period, the ettringite precipitation and the expansion detected were moderate, and did not lead to cracking. The material involved was considered as having a good resistance to sulfate attack.

Frizon, F.; Cau-dit-Coumes, C.

2006-12-01

64

Adhesion of conventional and simplified resin-based luting cements to superficial and deep dentin  

Microsoft Academic Search

This study evaluated the bond strengths of conventional (chemically and dual-polymerized) and simplified resin-based luting\\u000a cements with their corresponding adhesives to superficial dentin (SD) and deep dentin (DD). Recently extracted third molars\\u000a (N?=?70, n?=?10 per group) were obtained and prepared for testing procedures. After using their corresponding etchants, primers, and\\/or\\u000a adhesive systems, the conventional and simplified cements (Variolink II [group

Mutlu Özcan; Ayse Mese

65

Etching conditions for resin-modified glass ionomer cement for orthodontic brackets.  

PubMed

This study reports the tensile bond strength of orthodontic eyelets (RMO, Inc, Denver, Colo) bonded to human extracted teeth with a resin-modified glass ionomer cement (RMGIC) (Fuji Ortho LC, GC America, Alsip, Ill) and various acid etchants (Etch-37 and All-Etch, Bisco, Schaumburg, Ill; Ultra Etch, 3M Unitek, St Paul, Minn) for enamel preparation before bonding. The enamel etch conditions were as follows: 37% phosphoric acid with silica; 37% phosphoric acid, silica-free; 10% phosphoric acid, silica-free; 10% polyacrylic acid; and unetched enamel. Bond strength was measured by pulling in tension on the eyelet with a 0.018-in steel wire perpendicular to the enamel surface with a testing machine (Instron model 1125, Canton, Mass) at a speed of 2 mm/min. A light-cured resin cement (Transbond XT, 3M Unitek, Monrovia, Calif) applied to enamel etched with 37% phosphoric acid containing silica served as a control. Each group included 30 specimens. The Weibull distribution (m) was used for statistical analysis with a 90% CI. The different etchants used with RMGIC did not affect tensile bond strength. The resin cement group had the highest tensile strength. Significantly lower bond strengths were observed when glass ionomer cement was used to bond orthodontic attachments to nonetched teeth. However, unlike resin cement, RMGIC can bond effectively to etched teeth in a moist environment without an additional bonding agent. PMID:12045770

Valente, Rudolfo M; De Rijk, Waldemar G; Drummond, James L; Evans, Carla A

2002-05-01

66

Effects of surface treatments, thermocycling, and cyclic loading on the bond strength of a resin cement bonded to a lithium disilicate glass ceramic.  

PubMed

SUMMARY Objectives : The aim of this present study was to investigate the effect of two surface treatments, fatigue and thermocycling, on the microtensile bond strength of a newly introduced lithium disilicate glass ceramic (IPS e.max Press, Ivoclar Vivadent) and a dual-cured resin cement. Methods : A total of 18 ceramic blocks (10 mm long × 7 mm wide × 3.0 mm thick) were fabricated and divided into six groups (n=3): groups 1, 2, and 3-air particle abraded for five seconds with 50-?m aluminum oxide particles; groups 4, 5, and 6-acid etched with 10% hydrofluoric acid for 20 seconds. A silane coupling agent was applied onto all specimens and allowed to dry for five seconds, and the ceramic blocks were bonded to a block of composite Tetric N-Ceram (Ivoclar Vivadent) with RelyX ARC (3M ESPE) resin cement and placed under a 500-g static load for two minutes. The cement excess was removed with a disposable microbrush, and four periods of light activation for 40 seconds each were performed at right angles using an LED curing unit (UltraLume LED 5, Ultradent) with a final 40 second light exposure from the top surface. All of the specimens were stored in distilled water at 37°C for 24 hours. Groups 2 and 5 were submitted to 3,000 thermal cycles between 5°C and 55°C, and groups 3 and 6 were submitted to a fatigue test of 100,000 cycles at 2 Hz. Specimens were sectioned perpendicular to the bonding area to obtain beams with a cross-sectional area of 1 mm(2) (30 beams per group) and submitted to a microtensile bond strength test in a testing machine (EZ Test) at a crosshead speed of 0.5 mm/min. Data were submitted to analysis of variance and Tukey post hoc test (p?0.05). Results : The microtensile bond strength values (MPa) were 26.9 ± 6.9, 22.2 ± 7.8, and 21.2 ± 9.1 for groups 1-3 and 35.0 ± 9.6, 24.3 ± 8.9, and 23.9 ± 6.3 for groups 4-6. For the control group, fatigue testing and thermocycling produced a predominance of adhesive failures. Fatigue and thermocycling significantly decreased the microtensile bond strength for both ceramic surface treatments when compared with the control groups. Etching with 10% hydrofluoric acid significantly increased the microtensile bond strength for the control group. PMID:22856682

Guarda, G B; Correr, A B; Gonçalves, L S; Costa, A R; Borges, G A; Sinhoreti, M A C; Correr-Sobrinho, L

2013-01-01

67

Bonding all-ceramic restorations with two resins cement techniques: a clinical report of three-year follow-up.  

PubMed

Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceramic crowns and two laminates veneers were placed in the maxillary incisors and cemented with a self-adhesive resin luting cement and conventional resin luting cement, respectively. After a three-year follow-up, the restorations and cement/teeth interface were clinically perfect with no chipping, fractures or discoloration. Proper use of different resin luting cements shows clinical appropriate behavior after a three-year follow-up. Self-adhesive resin luting cement may be used for cementing all-ceramic crowns with high predictability of success, mainly if there is a large dentin surface available for bonding and no enamel at the finish line. Otherwise, conventional resin luting agent should be used for achieving an adequate bonding strength to enamel. PMID:21912505

Anchieta, Rodolfo Bruniera; Rocha, Eduardo Passos; de Almeida, Erika Oliveira; Junior, Amilcar Chagas Freitas; Martini, Ana Paula

2011-08-01

68

Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste  

NASA Astrophysics Data System (ADS)

Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums. The corrosion rate of the steel in contact with cemented ion-exchange resins in the absence of contaminants or in the presence of 2.3 wt.% sulphate content remains low (less than 0.1 ?m/year) during the whole period of the study (900 days). The presence of chloride ions increases the corrosion rate of the steel at the beginning of the exposure but, after 1 year, the corrosion rate drops abruptly reaching a value close to 0.1 ?m/year. This is probably due to the lack of water to sustain the corrosion process. When applying the results obtained in the present work to estimate the corrosion depth of the steel drums containing the cemented radioactive waste after a period of 300 years, it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums. Cementation of ion-exchange resins does not seem to pose special risks regarding the corrosion of the steel drums that contained them; even in the case the matrix is highly contaminated with chloride ions.

Duffó, G. S.; Farina, S. B.; Schulz, F. M.

2013-07-01

69

Effect of Self-adhesive Resin Cement and Tribochemical Treatment on Bond Strength to Zirconia  

PubMed Central

Aim To evaluate the interactive effects of different self-adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated: Maxcem (MA), Smartcem (SM), Rely X Unicem Aplicap (UN), Breeze (BR), Biscem (BI), Set (SE), and Clearfil SA luting (CL). The specimens were grouped according to conditioning as follows: Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 µm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating + silanization. Specimens were stored in distilled water at 37°C for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, BI, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP-containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.

Lin, Jie; Shinya, Akikazu; Gomi, Harunori; Shinya, Akiyoshi

2010-01-01

70

Radiopacity of different resin-based and conventional luting cements compared to human and bovine teeth.  

PubMed

This study evaluated the radiopacity of different resin-based luting materials and compared the results to human and bovine dental hard tissues. Disc specimens (N=130, n=10 per group) (diameter: 6 mm, thickness: 1 mm) were prepared from 10 resin-based and 3 conventional luting cements. Human canine dentin (n=10), bovine enamel (n=10), bovine dentin (n=10) and Aluminium (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted and equivalent Al thickness values were determined for radiopacity measurements of each material. The radiopacity values of conventional cements and two resin luting materials (Rely X Unicem and Variolink II), were significantly higher than that of bovine enamel that could be preferred for restorations cemented on enamel. Since all examined resin-based luting materials showed radiopacity values equivalent to or greater than that of human and bovine dentin, they could be considered suitable for the restorations cemented on dentin. PMID:22277608

Pekkan, Gürel; Ozcan, Mutlu

2012-02-01

71

Micro-shear bond strength of dual-cured resin cement to glass ceramics  

Microsoft Academic Search

Objectives: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration.Methods: A cast glass ceramic (Olympas Castable Ceramics) with a crystalline phase consisting of mica and ?-spondumene was selected as the substrate material. The

Yasushi Shimada; Saori Yamaguchi; Junji Tagami

2002-01-01

72

Influence of composite inlay/onlay thickness on hardening of dual-cured resin cements.  

PubMed

This investigation evaluated the effect of resin composite inlay/onlay thickness on the hardness of a group of eight dual-cure resin-based cements. Fourteen disc specimens measuring 6 mm in diameter and 2.5 mm thick were prepared from each of eight dual-cure cements: Adherence, Choice, Duolink, Enforce, Lute-It, Nexus, Resinomer and Variolink. Two specimens from each material were directly light-cured while the remainder of the specimens were light-cured through resin composite spacers varying in thickness from 1 mm to 6 mm. Curing through the spacers always resulted in a decrease in the Knoop hardness number. For some cements, hardness values were reduced by 50% or more when the resin composite spacer thickness was 4 mm or greater even when measurements were made one week after dual-curing. Low hardness values indicate the presence of a weak chemical-curing mechanism that may compromise cement quality in areas of the cavity not readily accessible to the curing light. PMID:10859728

El-Mowafy, O M; Rubo, M H

2000-03-01

73

Carbon fiber post adhesion to resin luting cement in the restoration of endodontically treated teeth  

Microsoft Academic Search

Carbon fiber posts (CFP) are widely used in the restoration of endodontically treated teeth to enhance the mechanical behavior in spite of metallic posts and to prevent vertical fractures of the tooth under chewing loads. The post is cemented inside the canal lumen using polymer resins with Young's modulus lower than Dentine. In this conditions the stress concentration is located

R. De Santis; D. Prisco; A. Apicella; L. Ambrosio; S. Rengo; L. Nicolais

2000-01-01

74

Bond strength of two resin cements to titanium after different surface conditioning methods.  

PubMed

This study evaluated the bond strength of two resin cements (Panavia F and Super Bond) to titanium after various surface conditioning techniques. The cements were applied using polyethylene tubes. After thermocycling, the specimens were tested in a universal testing machine for shear bond strength. Panavia F demonstrated significantly higher bond strength values than Super Bond. Of the conditioning techniques, Al2O3+Silane+Sinfony and Silano Pen+AP demonstrated significantly lower bond strength values than Al2O3+Cesead II Opaque Primer and 110 µm SiOx+Silane. The combination of Panavia and 110 µm SiOx+Silane, Al2O3+AP, or Al2O3+Cesead II, and the combination of Super Bond and 110 µm SiOx+Silane or Al2O3+Cesead II, can be recommended for improving the bond strength of resin cement to titanium. PMID:22313994

Ozcan, Mutlu; Valandro, Luiz Felipe

2012-01-01

75

Effects of curing mode of resin cements on the bond strength of a titanium post: An intraradicular study  

PubMed Central

Aim: To compare push-out bond strength between self-cured and dual-cured resin cement using a titanium post. Background: Dual-cured resin cements have been found to be less polymerized in the absence of light; thus the bond strength of cements would be compromised due to the absence of light with a metallic post. Materials and Methods: Ten extracted teeth were prepared for cement titanium PARAPOST, of five specimens each, with Panavia F [dual-cured (PF)] and Rely×Luting 2 [self-cured resin-modified glass ionomer luting cement (RL)]; the push-out bond strength (PBS) at three different levels of the sectioned roots was measured. The failure modes were observed and the significance of the differences in bond strength of the two types of cement at each level and at different levels of the same type was analyzed with non-parametric tests. Results: The push-out bond strength of the RL group was greater at all the three levels; with significant differences at the coronal and middle levels (P<0.05). No significant differences in PBS at different levels of the same group were observed. Cement material around the post was obvious in the PF group. The failure mode was mostly adhesive between the post and resin cement in the RL group. Conclusion: Bond strength was greater with self-cured, resin-modified glass ionomer luting cement, using titanium post.

Reza, Fazal; Lim, Siau Peng

2012-01-01

76

Influence of ultrasound, with and without water spray cooling, on removal of posts cemented with resin or glass ionomer cements: An in-vitro study  

PubMed Central

Aims/objectives: To evaluate in vitro the ultrasonic vibration efficacy with and without water spray cooling on the reduction of the amount of force necessary to dislodge the cast posts cemented with resin cement and to compare it with those cemented with GIC Type I luting cement. Materials and Methods: Sixty samples were divided into six groups: groups 1, 2, 3, posts cemented with GIC; groups 4, 5, 6, posts cemented with resin; groups 1 and 4 (controls), no ultrasound; groups 2 and 5, ultrasound without water spray; and groups 3 and 6, ultrasound with water spray. Instron testing machine was used to dislodge the posts from the root canals and the data was statistically analyzed. Results: Ultrasound with water spray (group 3) among the GIC groups reduced the traction force necessary to extract posts by 53.33% whereas ultrasound without water spray (group 5) among the resin groups reduced by 59.5% compared to control. Conclusion: Ultrasound with water is more effective in removing posts cemented with GIC because of the ultrasonic energy being transferred to the post. Ultasonics without water is more effective in removing posts fixed with resin cement probably by the indirect action of heat production.

Adarsha, M S; Lata, D A

2010-01-01

77

Influence of Curing Light Attenuation Caused by Aesthetic Indirect Restorative Materials on Resin Cement Polymerization  

PubMed Central

Objectives: To verify the effect of interposing different indirect restorative materials on degree of conversion (DC), hardness, and flexural strength of a dual-cure resin cement. Methods: Discs (2 mm-thick, n=5) of four indirect restorative materials were manufactured: a layered glass-ceramic (GC); a heat-pressed lithium disilicate-based glass-ceramic veneered with the layered glass-ceramic (LD); a micro-hybrid (MH); and a micro-filled (MF) indirect composite resin. The light transmittance of these materials was determined using a double-beam spectrophotometer with an integrating sphere. Bar-shaped specimens of a dual-cure resin cement (Nexus 2/SDS Kerr), with (dual-cure mode) and without the catalyst paste (light-cure mode), were photoactivated through the discs using either a quartz-tungsten-halogen (QTH) or a light-emitting diode (LED) unit. As a control, specimens were photoactivated without the interposed discs. Specimens were stored at 37ºC for 24h before being submitted to FT-Raman spectrometry (n=3), Knoop microhardness (n=6) and three-point bending (n=6) tests. Data were analyzed by ANOVA/Tukey’s test (?=0.05). Results: MH presented the highest transmittance. The DC was lower in light-cure mode than in dual-cure mode. All restorative materials reduced the cement microhardness in light-cure mode. GC and LD with QTH and GC with LED decreased the strength of the cement for both activation modes compared to the controls. Curing units did not affect DC or microhardness, except when the dual-cure cement was photoactivated through LD (LED>QTH). Flexural strength was higher with QTH compared to LED. Conclusions: Differences in transmittance among the restorative materials significantly influenced cement DC and flexural strength, regardless of the activation mode, as well as the microhardness of the resin cement tested in light-cure mode. Microhardness was not impaired by the interposed materials when the resin cement was used in dual-cure mode.

Pick, Barbara; Gonzaga, Carla Castiglia; Junior, Washington Steagall; Kawano, Yoshio; Braga, Roberto Ruggiero; Cardoso, Paulo Eduardo Capel

2010-01-01

78

Adhesion of conventional and simplified resin-based luting cements to superficial and deep dentin.  

PubMed

This study evaluated the bond strengths of conventional (chemically and dual-polymerized) and simplified resin-based luting cements with their corresponding adhesives to superficial dentin (SD) and deep dentin (DD). Recently extracted third molars (N = 70, n = 10 per group) were obtained and prepared for testing procedures. After using their corresponding etchants, primers, and/or adhesive systems, the conventional and simplified cements (Variolink II [group A, conventional], Bifix QM [group B, conventional], Panavia F2.0 [group C, conventional], Multilink Automix [group D, simplified], Superbond C&B [group E, conventional], Clearfil Esthetic Cement [group F, simplified], Ketac-Fil [group G, conventional]) were adhered incrementally onto the dentin surfaces using polyethylene molds (inner diameter 3.5 mm, height 5 mm) and polymerized accordingly. Resin-modified glass-ionomer cement (RMGIC) acted as the control material. Shear bond strengths (1 mm/min) were determined after 500 times of thermocycling. Kruskal-Wallis and Mann-Whitney tests were used to analyze the data (? = 0.05). Bond strength (MPa) results were significantly affected by the cement types and their corresponding adhesive systems (p ? 0.05). The shear bond strengths (MPa ± SD) for groups A-G were 14.6 ± 3.8, 18.9 ± 3.9, 5.5 ± 4.5, 3.1 ± 3.6, 1.1 ± 2.5, 15.5 ± 2.6, 7 ± 4.3 and 7.1 ± 5.8, 15.1 ± 7.8, 8.4 ± 7.3, 7.5 ± 7.3, 4.9 ± 5.1, 12.5 ± 2.1, 6 ± 2.6 for SD and DD, respectively. The level of dentin depth did not decrease the bond strength significantly (p > 0.05) for all cements, except for Variolink II (p < 0.05). On the SD, bond strength of resin cements with "etch-and-rinse" adhesive systems (Variolink II, Bifix QM, Super-Bond C&B) showed similar results being higher than those of the simplified ones. Simplified cements and RMGIC as control material showed inferior adhesion to superficial and deep dentin compared to conventional resin cements tested. PMID:21833482

Özcan, Mutlu; Mese, Ayse

2012-08-01

79

Dentin adhesion and microleakage of a resin-based calcium phosphate pulp capping and basing cement.  

PubMed

An experimental resin-based bioactive calcium phosphate cement, intended as a pulp capping and basing material, was evaluated for dentin shear bond strength and microleakage. The interfacial morphology was examined by scanning electron microscopy (SEM). For microleakage, dentin cavities without (Group A) or after (Group B) acid etching were restored with the calcium phosphate cement. A resin-based calcium hydroxide (VLC Dycal; Group C) was used as control material according to the manufacturer's instructions. After water storage and thermocycling, the microleakage was scored using a AgNO(3) staining procedure. For the shear bond strength, flat exposed dentin surfaces were treated as for the microleakage test. Metal irises pressed against the dentin surface were filled with the cements, which were photocured. Both tests were carried out after 1 wk. While acid etching did not result in significantly greater microleakage, it led to higher shear bond strength, and allowed, as shown by SEM, the formation of a hybrid layer and resin tags. Both groups treated with the calcium phosphate cement had significantly lower microleakage scores and higher mean shear bond strength values than the groups treated with the control material. PMID:15458506

Dickens, Sabine H; Kelly, Sean R; Flaim, Glenn M; Giuseppetti, Anthony A

2004-10-01

80

Effects of post surface conditioning before silanization on bond strength between fiber post and resin cement  

PubMed Central

PURPOSE Post surface conditioning is necessary to expose the glass fibers to enable bonding between fiber post and resin cement. The purpose of the present study was to evaluate the effect of different surface conditioning on tensile bond strength (TBS) of a glass fiber reinforced post to resin cement. MATERIALS AND METHODS In this in vitro study, 40 extracted single canal central incisors were endodontically treated and post spaces were prepared. The teeth were divided into four groups according to the methods of post surface treatment (n=10): 1) Silanization after etching with 20% H2O2, 2) Silanization after airborne-particle abrasion, 3) Silanization, and 4) No conditioning (Control). Adhesive resin cement (Panavia F 2.0) was used for cementation of the fiber posts to the root canal dentin. Three slices of 3 mm thick were obtained from each root. A universal testing machine was used with a cross-head speed of 1 mm/minute for performing the push-out tests. Two-way ANOVA and Tukey post hoc tests were used for analyzing data (?=0.05). RESULTS It is revealed that different surface treatments and root dentin regions had significant effects on TBS, but the interaction between surface treatments and root canal regions had no significant effect on TBS. There was significant difference among H2O2 + Silane Group and other three groups. CONCLUSION There were significant differences among the mean TBS values of different surface treatments. Application of hydrogen peroxide before silanization increased the bond strength between resin cements and fiber posts. The mean TBS mean values was significantly greater in the coronal region of root canal than the middle and apical thirds.

Ranjbarian, Parisa

2013-01-01

81

Polymer Resins as Admixtures in Portland Cement Mortar and Concrete.  

National Technical Information Service (NTIS)

The report covers the studies made of two admixtures for concrete that were investigated primarily for their use as overlays or as patching materials for bridge decks. The first, Epoxon, is a mixture of pozzolan and a two-component epoxy resin emulsion. T...

R. G. Pike R. E. Hay

1972-01-01

82

A Comparative Evaluation of the Effect of Resin based Sealers on Retention of Crown Cemented with Three Types of Cement - An In Vitro Study.  

PubMed

Aim: In an effort to control postoperative sensitivity, dentin sealers are being applied following crown preparations, with little knowledge of how crown retention might be affected. A previous study demonstrated no adverse effect when using a gluteraldehyde-based sealer, and existing studies have shown conflicting results for resin-based products. This study determined the retention of the casting cemented with three types of cement, with and without use of resin sealers and it determined the mode of failure. Materials and Methods: Extracted human molars (n=60) were prepared with a flat occlusal, 20-degree taper, and 4-mm axial length. The axial surface area of each preparation was determined and specimens were distributed equally among groups (n=10). A single-bottle adhesive system (one step single bottle adhesive system) was used to seal dentin, following tooth preparation. Sealers were not used on the control specimens. The test castings were prepared by using Ni-Cr alloy for each specimen and they were cemented with a seating force of 20 Kg by using either Zinc Phosphate (Harvard Cement), Glass Ionomer (GC luting and lining cement,GC America Inc.) and modified-resin cement (RelyXTMLuting2). Specimens were thermocycled for one month and were then removed along the path of insertion by using a Universal Testing Machine at 0.5 mm/min. A single-factor ANOVA was used with a p value of .05. The nature of failure was recorded and the data was analyzed by using Chi-square test. Results: Mean dislodgement stress for Zinc phosphate (Group A) was 24.55±1.0 KgF and that for zinc phosphate with sealer (Group D) was 14.65±0.8 KgF. For glass ionomer (Group B) without sealer, the mean value was 32.0±1.0 KgF and mean value for glass ionomer with sealer (Group E) was 37.90±1.0 KgF. The mean value for modified resin cement (Group C) was 44.3±1.0KgF and that for modified resins with sealer (Group F) was 57.2±1.2 KgF. The tooth failed before casting dislodgement in 8 to 10 specimens cemented with modified-resin cement. Conclusion: Resin sealer decreased casting retentive stress by 46% when it was used with Zinc phosphate. However, sealer use resulted in 60% increased retention when it was used with Glass ionomer cement. The modified-resin cement produced the highest mean dislodgement stress, which nearly always exceeded the strength of the tooth. PMID:24783150

Sharma, Sumeet; Patel, J R; Sethuraman, Rajesh; Singh, Sarbjeet; Wazir, Nikhil Dev; Singh, Harvinder

2014-03-01

83

A Comparative Evaluation of the Effect of Resin based Sealers on Retention of Crown Cemented with Three Types of Cement - An In Vitro Study  

PubMed Central

Aim: In an effort to control postoperative sensitivity, dentin sealers are being applied following crown preparations, with little knowledge of how crown retention might be affected. A previous study demonstrated no adverse effect when using a gluteraldehyde-based sealer, and existing studies have shown conflicting results for resin-based products. This study determined the retention of the casting cemented with three types of cement, with and without use of resin sealers and it determined the mode of failure. Materials and Methods: Extracted human molars (n=60) were prepared with a flat occlusal, 20-degree taper, and 4-mm axial length. The axial surface area of each preparation was determined and specimens were distributed equally among groups (n=10). A single-bottle adhesive system (one step single bottle adhesive system) was used to seal dentin, following tooth preparation. Sealers were not used on the control specimens. The test castings were prepared by using Ni-Cr alloy for each specimen and they were cemented with a seating force of 20 Kg by using either Zinc Phosphate (Harvard Cement), Glass Ionomer (GC luting and lining cement,GC America Inc.) and modified-resin cement (RelyXTMLuting2). Specimens were thermocycled for one month and were then removed along the path of insertion by using a Universal Testing Machine at 0.5 mm/min. A single-factor ANOVA was used with a p value of .05. The nature of failure was recorded and the data was analyzed by using Chi-square test. Results: Mean dislodgement stress for Zinc phosphate (Group A) was 24.55±1.0 KgF and that for zinc phosphate with sealer (Group D) was 14.65±0.8 KgF. For glass ionomer (Group B) without sealer, the mean value was 32.0±1.0 KgF and mean value for glass ionomer with sealer (Group E) was 37.90±1.0 KgF. The mean value for modified resin cement (Group C) was 44.3±1.0KgF and that for modified resins with sealer (Group F) was 57.2±1.2 KgF. The tooth failed before casting dislodgement in 8 to 10 specimens cemented with modified-resin cement. Conclusion: Resin sealer decreased casting retentive stress by 46% when it was used with Zinc phosphate. However, sealer use resulted in 60% increased retention when it was used with Glass ionomer cement. The modified-resin cement produced the highest mean dislodgement stress, which nearly always exceeded the strength of the tooth.

Sharma, Sumeet; Patel, J.R.; Sethuraman, Rajesh; Singh, Sarbjeet; Wazir, Nikhil Dev; Singh, Harvinder

2014-01-01

84

Effect of etch-and-rinse and self-etching adhesive systems on hardness uniformity of resin cements after glass fiber post cementation  

PubMed Central

Objective To evaluate the effects of etch-and-rinse and self-etching adhesive systems on Vickers hardness (VHN) uniformity of dual-cured resin cements after fiber post cementation. Methods: Fifty glass fiber posts were cemented into bovine roots using the following cementing systems: Prime&Bond 2.1 Dual Cure and Enforce with light-activation (PBDC-LCEN); Prime&Bond 2.1 and Enforce with light-activation (PB-CLEN); Prime&Bond 2.1 Dual Cure and Enforce without light exposure (PBDC-SCEN); ED Primer and Panavia 21 (ED-SCPN); and Clearfil SE Bond and Panavia 21 (CF-SCPN). The roots were stored in distilled water for 72 h and transversely sectioned into thirds (coronal, medium, and apical). The VHN values of the resin cement layers were measured close to the post and to the dentin wall on the transversely sectioned flat surfaces. The results were analyzed by three-way repeated measures analysis of variance (ANOVA) and Tukey’s post-hoc test (pre-set alpha of 5%). Results: Most resin cements presented higher VHN values near the post than near the dentin wall. The ED-SCPN group showed the highest VHN values regardless of the root third, while the self-cured group PBDC-SCEN exhibited the lowest values. The resin cements from the light-activated groups PBDC-LCEN and PB-LCEN showed lower VHN values at the apical third than at the coronal third. The VHN values were not influenced by the root third in self-cured groups PBDC-SCEN, ED-SCPN, and ED-SCPN. Conclusion: Depending on the product, bonding agents might promote changes in hardness uniformity of resin cements after post cementation.

Grande da Cruz, Fernanda Zander; Grande, Christiana Zander; Roderjan, Douglas Augusto; Galvao Arrais, Cesar Augusto; Buhrer Samra, Adriana Postiglione; Calixto, Abraham Lincoln

2012-01-01

85

Knoop hardness of dental resin cements: Effect of veneering material and light curing methods  

Microsoft Academic Search

This study evaluated the Knoop hardness of one resin cement (dual-cure mode or light-cure mode) when illuminated directly or through restorative materials—ceramic (HeraCeram) or composite (Artglass)—by two light curing units. Light curing was carried out using a conventional quartz tungsten halogen (QTH) light source (XL2500) for 40s, and a light emitting diodes (LED) light source (Ultrablue Is) for 40s. Bovine

Rubens Nisie Tango; Mário Alexandre Coelho Sinhoreti; Américo Bortolazzo Correr; Luis Felipe Jochims Schneider; Estevão Tomomitsu Kimpara; Lourenço Correr-Sobrinho

2007-01-01

86

In vivo Cariostatic Effect of Resin Modified Glass lonomer Cement and Amalgam on Dentine  

Microsoft Academic Search

Fluoride-releasing materials have been reported to be bactericidal in vitro. This may be of benefit to modern dentistry, which is directed to the preservation of tooth tissue during restorative treatment. Little is known about in vivo effects. The aim is to investigate the influence of a resin-modified glass ionomer cement (RM-GIC) on carious dentine that remains under restorations, compared to

C. M. Kreulen; J. J. Soet; K. L. Weerheijm; W. E. van Amerongen

1997-01-01

87

Cytotoxicity Comparison of Harvard Zinc Phosphate Cement Versus Panavia F2 and Rely X Plus Resin Cements on Rat L929-fibroblasts  

PubMed Central

Objective: Resin cements, regardless of their biocompatibility, have been widely used in restorative dentistry during the recent years. These cements contain hydroxy ethyl methacrylate (HEMA) molecules which are claimed to penetrate into dentinal tubules and may affect dental pulp. Since tooth preparation for metal ceramic restorations involves a large surface of the tooth, cytotoxicity of these cements would be more important in fixed prosthodontic treatments. The purpose of this study was to compare the cytotoxicity of two resin cements (Panavia F2 and Rely X Plus) versus zinc phosphate cement (Harvard) using rat L929-fibroblasts in vitro. Materials and Methods: In this experimental study, ninety hollow glass cylinders (internal diameter 5-mm, height 2-mm) were made and divided into three groups. Each group was filled with one of three experimental cements; Harvard Zinc Phosphate cement, Panavia F2 resin cement and Rely X Plus resin cement. L929- Fibroblast were passaged and subsequently cultured in 6-well plates of 5×105 cells each. The culture medium was RPMI_ 1640. All samples were incubated in CO2. Using enzyme-linked immune-sorbent assay (ELISA) and (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay, the cytotoxicity of the cements was investigated at 1 hour, 24 hours and one week post exposure. Statistical analyses were performed via two-way ANOVA and honestly significant difference (HSD) Tukey tests. Results: This study revealed significant differences between the three cements at the different time intervals. Harvard cement displayed the greatest cytotoxicity at all three intervals. After 1 hour Panavia F2 showed the next greatest cytotoxicity, but after 24-hours and oneweek intervals Rely X Plus showed the next greatest cytotoxicity. The results further showed that cytotoxicity decreased significantly in the Panavia F2 group with time (p<0.005), cytotoxicity increased significantly in the Rely X Plus group with time (p<0.001), and the Harvard cement group failed to showed no noticeable change in cytotoxicity with time. Conclusion: Although this study has limitations, it provides evidence that Harvard zinc phosphate cement is the most cytotoxic product and Panavia F2 appears to be the least cytotoxic cement over time.

Mahasti, Sahabi; Sattari, Mandana; Romoozi, Elham; Akbar-zadeh Baghban, Alireza

2011-01-01

88

Bond strength of selected composite resin-cements to zirconium-oxide ceramic  

PubMed Central

Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test for more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (?=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-W<0.001). The worst techniques were Lava TM + sandblasting + Silane + Rely X; Lava TM + sandblasting + Silane + Multilink and Lava TM + CoJet + silane + Multilink. Adhesive failure (separation of cement and ceramic) was produced at a lesser force than cohesive failure (fracture of cement) (p-value M-W<0.001). Electron microscopy confirmed that the surface treatments modified the zirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Key words:Shear bond strength, silica coating, surface treatment, zirconia ceramics, phosphate monomer.

Fons-Font, Antonio; Amigo-Borras, Vicente; Granell-Ruiz, Maria; Busquets-Mataix, David; Panadero, Ruben A.; Sola-Ruiz, Maria F.

2013-01-01

89

Nanoindentation Study of Resin Impregnated Sandstone and Early-Age Cement Paste Specimens  

NASA Astrophysics Data System (ADS)

Nanoindentation testing requires well prepared samples with a good surface finish. Achieving a good surface finish is difficult for heterogeneous materials, particularly those with weak and fragile structures/phases, which are easily damaged or lost during preparation. The loss of weak structures can be drastically reduced by impregnating the sample with a resin before cutting and polishing. This technique is commonly used in SEM microscopy but has not been used for nanoindentation-testing before. This paper reports an investigation to extract micro-mechanical properties of different phases in resin impregnated sandstone and 1-day hydrated cement samples. The results appeared to show that it is feasible to use resin impregnated specimens for nanoindentation study of both materials.

Zhu, W.; Fonteyn, M. T. J.; Hughes, J.; Pearce, C.

90

Push-out bond strength of a fiber post system with two resin cements  

PubMed Central

Introduction: Debonding is a common cause of failure encountered with fiber-reinforced composite (FRC) posts, and usually occurs along the post space-dentin adhesive interface. The aim of this in vitro study is to evaluate the regional push-out bond strength of a fiber-reinforced post system, using two resin cements. Materials and Methods: In this in vitro study 20 maxillary central incisors were decoronated and the roots were endodontically treated. Following post space preparation, the roots were divided into two groups of 10 specimens each. Fiber-reinforced composite posts were cemented with two resin cement systems: (a) Self-etch system (Panavia F2.0/ED-primer II) and (b) conventional system (Variolink II/Excite DSC). Three slices of each root, with a thickness of 3 mm, were prepared. The push-out test was performed with a universal testing machine at a crosshead speed of 1 mm/minute, and bond strength values were calculated. The data were analyzed with a two-way Analysis of variance (ANOVA) and Scheffe tests (?=.05). Results: There were no significant differences between the mean push-out bond strengths of two experimental groups (Panavia F: 12.59±5.44, Variolink II: 12.49±4.52 MPa) (P=0.920), but there were significant differences between the mean push out bond strengths of the root dentin regions (P<0.001). Conclusion: Under the conditions of this study, there was no significant difference between the mean push out bond strength of self-etching and the conventional resin cement systems. The coronal region of the root dentin showed a significantly higher bond strength than the apical region.

Mosharraf, Ramin; Haerian, Alireza

2011-01-01

91

Shear bond strength of resin cement to an acid etched and a laser irradiated ceramic surface  

PubMed Central

PURPOSE To evaluate the effects of hydrofluoric acid etching and Er,Cr:YSGG laser irradiation on the shear bond strength of resin cement to lithium disilicate ceramic. MATERIALS AND METHODS Fifty-five ceramic blocks (5 mm × 5 mm × 2 mm) were fabricated and embedded in acrylic resin. Their surfaces were finished with 1000-grit silicon carbide paper. The blocks were assigned to five groups: 1) 9.5% hydrofluoric-acid etching for 60 s; 2-4), 1.5-, 2.5-, and 6-W Er,Cr:YSGG laser applications for 60 seconds, respectively; and 5) no treatment (control). One specimen from each group was examined using scanning electron microscopy. Ceramic primer (Rely X ceramic primer) and adhesive (Adper Single Bond) were applied to the ceramic surfaces, followed by resin cement to bond the composite cylinders, and light curing. Bonded specimens were stored in distilled water at 37? for 24 hours. Shear bond strengths were determined by a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests (?=0.05). RESULTS Adhesion was significantly stronger in Group 2 (3.88 ± 1.94 MPa) and Group 3 (3.65 ± 1.87 MPa) than in Control group (1.95 ± 1.06 MPa), in which bonding values were lowest (P<.01). No significant difference was observed between Group 4 (3.59 ± 1.19 MPa) and Control group. Shear bond strength was highest in Group 1 (8.42 ± 1.86 MPa; P<.01). CONCLUSION Er,Cr:YSGG laser irradiation at 1.5 and 2.5 W increased shear bond strengths between ceramic and resin cement compared with untreated ceramic surfaces. Irradiation at 6 W may not be an efficient ceramic surface treatment technique.

Motro, Pelin Fatma Karagoz; Yurdaguven, Haktan

2013-01-01

92

Comparing the effect of a resin based sealer on crown retention for three types of cements: an in vitro study.  

PubMed

To determine the effect of resin based sealer on retention of casting cemented with three different luting agents. 55 extracted molar teeth were prepared with a flat occlusal surface, 20° taper and 4 mm axial height. The axial surface of each specimen was determined. The specimen were then distributed into five groups based on decreasing surface area, so each cementation group contained 11 specimens with similar mean axial surface area. A two-step, single bottle universal adhesive system (One-Step-Resinomer, Bisco) was used to seal dentin after the tooth preparation. Sealer was not used on the control specimens except for the modified-resin cement (Resinomer, Bisco) specimens that required use of adhesive with cementation. Using ceramometal (Wirobond(®), BEGO), a casting was produced for each specimen and cemented with either zinc phosphate (Harvard), glass ionomer (Vivaglass) or modified resin cement (Resinomer) with single bottle adhesive. All the castings were cemented with a force of 20 kg. Castings were thermal cycled at 5 and 55 °C for 2,500 cycles and were then removed along the path of insertion using a universal testing machine at 0.5 mm/min. A single-factor ANOVA was used with a = 0.05. The nature of failure was also recorded. The mean stress removal for non sealed zinc phosphate, sealed zinc phosphate, non sealed glass ionomer, sealed glass ionomer and modified resin cement was found to be 3.56, 1.92, 2.40, 4.26, 6.95 MPa respectively. Zinc phosphate cement remained principally on the castings when the tooth surface was treated with the sealer and was found on both the tooth and the casting when the sealer was not used. Fracture of root before dislodgement was seen in 9 of 11 specimens with modified resin cement. Resin sealer decreases the retention of the castings when used with zinc phosphate and increases it when used with glass ionomer cement. The highest mean dislodgement force was measured with modified resin cement. PMID:24431752

Patel, Pankaj; Thummar, Mansukh; Shah, Dipti; Pitti, Varun

2013-09-01

93

In vitro effects of different moisture level and curing method on microleakage of resin cements to pulp chamber dentine.  

PubMed

This study evaluated the microleakage of resin cements in the pulp chamber dentin. Fifty specimens of sound human molars were divided into five groups. Composite cores cemented using Clearfil SA Luting in the first group to a dried dentin and in the second group to a moistened dentin and then light-cured. In third and fourth groups, cement was placed on dried and moistened dentin and self-cured respectively. In fifth group, composite cores were cemented by Panavia F2.0. After thermocycling, microleakage was evaluated using fluid filtration technique. The highest microleakage mean value was observed in the group with light-cured to a dry dentin. The mode of curing in contrast to moisture value had significant effect on microleakage. The microleakage of self- adhesive resin cement used in this study was lower in case of self cured than in case of light-cured and was not related to the dentin surface moisture. PMID:24922999

Moosavi, H; Darvishzadeh, F; Sadr, A; Salary, S

2014-03-01

94

Effect of different light curing systems on the shear bond strength of resin-modified glass ionomer cement and polyacid-modified composite resin  

Microsoft Academic Search

The aim of this study was to determine in vitro shear bond strength of resin-modified glass ionomer cement (RMGIC) and polyacid-modified composite resin (PMCR) polymerized with conventional halogen light curing unit (LCU) or light emitting diode (LED). Twenty-four mandibular molar teeth were used. Enamel was removed from buccal and lingual surfaces of the teeth to expose superficial dentin. Teeth were

Oya Bala; Hacer Deniz Arisu; Bagdagul Helvacioglu Kivanc; Sara Samur

95

Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin  

PubMed Central

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin (1 mm below the dentine-enamel junction), deep dentin (1 mm above the highest pulp horn) and cervical dentin (0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction). Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mm/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin (P < 0.001). Micro-tensile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions (P < 0.001). Immediate micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements (P < 0.001). It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.

Ali, Abdelraheem Mohamed; Hamouda, Ibrahim Mohamed; Ghazy, Mohamed Hamed; Abo-Madina, Manal Mohamed

2013-01-01

96

Effect of curing mode on the micro-mechanical properties of dual-cured self-adhesive resin cements.  

PubMed

Light supplying to luting resin cements is impeded in several clinical situations, causing us to question whether materials can properly be cured to achieve adequately (or adequate) mechanical properties. The aim of this study was therefore to analyse the effect of light on the micro-mechanical properties of eight popular dual-cured self-adhesive resin cements by comparing them with two conventional, also dual-cured, resin cements. Four different curing procedures were applied: auto-polymerisation (dark curing) and light curing (LED unit, Freelight 2, 20 s) by applying the unit directly on the samples' surface, at a distance of 5 and 10 mm. Twenty minutes after curing, the samples were stored for 1 week at 37°C in a water-saturated atmosphere. The micro-mechanical properties-Vickers hardness, modulus of elasticity, creep and elastic/plastic deformation-were measured. Data were analysed with multivariate ANOVA followed by Tukey's test and partial eta-squared statistics (p?cement-conventional or self-adhesive-was generally low. The influence of light on the polymerisation process was material dependent, with four different behaviour patterns to be distinguished. As a material category, significantly higher micro-mechanical properties were measured for the conventional compared to the self-adhesive resin cements, although this difference was low. Within the self-adhesive resin cements group, the variation in micro-mechanical properties was high. The selection of suitable resin cements should be done by considering, besides its adhesive properties, its micro-mechanical properties and curing behaviour also. PMID:21350865

Ilie, Nicoleta; Simon, Alexander

2012-04-01

97

In-vitro evaluation of an experimental method for bonding of orthodontic brackets with self-adhesive resin cements  

PubMed Central

Background Self-adhesive resin cements do not require the surface treatment of teeth and are said to release fluoride, which makes them suitable candidates for bonding of orthodontic brackets. The objectives of this study was to investigate the shear bond strength (SBS) of self-adhesive resin cements on etched on non-etched surfaces in vitro and to assess their fluoride release features. Materials and Methods Four fluoride-releasing dual-cure self-adhesive resin cements were investigated. For SBS experiment, 135 freshly extracted human maxillary premolars were used and divided into nine groups of 15 teeth. In the control group, brackets were cemented by Transbond XT (3M Unitek, USA), in four groups self-adhesive resin cements were used without acid-etching and in four groups self-adhesive cements were applied on acid-etched surfaces and the brackets were then deboned in shear with a testing machine. Adhesive remnant index (ARI) scores were also calculated. For fluoride release investigation, 6 discs were prepared for each self-adhesive cement. Transbond XT and Fuji Ortho LC (GC, Japan) served as negative and positive control groups, respectively. The fluoride release of each disc into 5 ml of deionized water was measured at days 1, 2, 3, 7, 14, 28, and 56 using a fluoride ion-selective electrode connected to an ion analyzer. To prevent cumulative measurements, the storage solutions were changed daily. Results The SBS of brackets cemented with Transbond XT were significantly higher compared to self-adhesives applied on non-etched surfaces (P<0.001). However, when the self-adhesive resin cements were used with enamel etching, no significant differences was found in the SBS compared to Transbond XT, except for Breeze. The comparisons of the ARI scores indicated that bracket failure modes were significantly different between the etched and non-etched groups. All self-adhesive cements released clinically sufficient amounts of fluoride for an extended period of time. Conclusion For the tested cements, the strongest bonds were obtained by enamel acid-etching prior to bracket bonding. All the self-adhesive resin cements had significant long-term fluoride release and could be recommended as suitable fluoride-releasing orthodontic bonding materials.

Ramazanzadeh, Barat Ali; Merati, Mohsen; Shafaee, Hooman; Dogon, Leon; Sohrabi, Keyvan

2013-01-01

98

Bonding of Y-TZP to Dentin: Effects of Y-TZP Surface Conditioning, Resin Cement Type, and Aging.  

PubMed

SUMMARY Purpose : To evaluate the effects of two surface treatments, aging, and two resin cements on shear bond strength between dentin and yttrium-stabilized tetragonal zirconia polycrystal ceramic (Y-TZP). Materials and Methods : Eighty human molars were embedded in acrylic resin and sectioned 3 mm below the occlusal plane. These teeth and 80 cylindrical Y-TZP specimens (height, 4 mm; diameter, 3.4 mm) were divided into eight groups (n=10) using the following factors: Y-TZP surface treatment (Vi: low-fusing porcelain [vitrification] + hydrofluoric acid etching + silanization or Si: tribochemical silicatization); cementation strategies (PF: Panavia or CC: Clearfil); and storage (nonaging or aging). Bonding surfaces of 40 Y-TZP specimens received Vi treatment, and the rest received Si treatment. Half of the ceramic-tooth assemblies were cemented with Panavia, the rest with Clearfil. Shear tests were executed using 0.4-mm-thick wire at 0.5 mm/min. Data were analyzed by three-way analysis of variance and Tukey test (?=0.05). Fractures were analyzed. Results : Y-TZP surface treatments did not affect bond strength (p=0.762, Vi = Si), while resin cements (p<0.001, Panavia > Clearfil) and aging (p=0.006, nonaging > aging) showed a significant effect. Most failures were in adhesive at dentin-cement interfaces; no failure occurred between zirconia and cement. Conclusion : When Y-TZP ceramic is bonded to dentin, the weakest interface is that between dentin and resin cement. The resin cement/Y-TZP interface was less susceptible to failures, owing to Y-TZP surface treatments. PMID:24147749

Bottino, Ma; Bergoli, C; Lima, Eg; Marocho, Sms; Souza, Ro; Valandro, Lf

2014-01-01

99

Influence of inorganic filler content on the radiopacity of dental resin cements.  

PubMed

Digital radiography was used to measure the radiopacity of 18 resin cements to determine the influence of inorganic filler content on radiopacity. Four disk specimens (n=4) of each light-curing cement were digitally radiographed alongside an aluminum step wedge using an intraoral sensor (XIOS Plus, Sirona, Germany), and their mean gray value measured. Percentage of filler by weight was determined using an analytical combustion furnace. Data were statistically analyzed using one-way ANOVA and Tukey's test (?=0.05). All materials were more radiopaque than dentin and 12 materials were more radiopaque than enamel. Filler percentage ranged between 17.36 to 53.56 vol% and radiopacity between 1.02 to 3.40 mm Al. There were no statistically significant differences in inorganic filler percentage and radiopacity among the different shades of the same material (p>0.05), but the highest radiopacity was measured for the material which contained a higher percentage of filler. PMID:22447061

Furtos, Gabriel; Baldea, Bogdan; Silaghi-Dumitrescu, Laura; Moldovan, Marioara; Prejmerean, Cristina; Nica, Luminita

2012-01-01

100

Surgical management of invasive cervical resorption using resin-modified glass ionomer cement.  

PubMed

Invasive cervical resorption is an external resorption that begins below the epithelial attachment. It is caused primarily by dental trauma, orthodontic treatment, or dental bleaching. This case report involved an invasive Class III cervical resorption resulting from trauma to the superior right central incisor. Root canal treatment was followed by surgical intervention. The resorptive defect was debrided, and part of the tooth was restored with resin-modified glass ionomer cement. Postoperative follow-up revealed complete healing and healthy gingival attachment. PMID:24192742

Tavares, Warley Luciano Fonseca; Lopes, Renata Carvalho Portes; Oliveira, Ricardo Reis; Souza, Rodrigo Goncalves de; Henriques, Luiz Carlos Feitosa; Ribeiro-Sobrinho, Antonio Paulino

2013-01-01

101

Bonding of Resin Cement to Zirconia with High Pressure Primer Coating  

PubMed Central

Objectives To investigate the effect of air-drying pressure during ceramic primer coating on zirconia/resin bonding and the surface characteristics of the primed zirconia. Methods Two ceramic primers (Clearfil Ceramic Primer, CCP, Kuraray Medical Inc. and Z-Prime Plus, ZPP, Bisco Inc.) were applied on the surface of air-abraded zirconia (Katana zirconia, Noritake) and dried at 4 different air pressures (0.1–0.4 MPa). The primed zirconia ceramic specimens were bonded with a resin-based luting agent (SA Luting Cement, Kuraray). Micro-shear bond strengths of the bonded specimens were tested after 3 days of water storage or 5,000× thermocycling (n?=?12). Failure modes of the fractured specimens were examined with scanning electron miscopy. The effects of air pressure on the thickness of the primer layers and the surface roughness (Sa) of primed zirconia were evaluated using spectroscopic ellipsometry (n?=?6), optical profilometry and environmental scanning electron microscopy (ESEM) (n?=?6), respectively. Results Clearfil Ceramic Primer air-dried at 0.3 and 0.4 MPa, yielding significantly higher µSBS than gentle air-drying subgroups (p<0.05). Compared to vigorous drying conditions, Z-Prime Plus air-dried at 0.2 MPa exhibited significantly higher µSBS (p<0.05). Increasing air-drying pressure reduced the film thickness for both primers. Profilometry measurements and ESEM showed rougher surfaces in the high pressure subgroups of CCP and intermediate pressure subgroup of ZPP. Conclusion Air-drying pressure influences resin/zirconia bond strength and durability significantly. Higher air-drying pressure (0.3-0.4 MPa) for CCP and intermediate pressure (0.2 MPa) for ZPP are recommended to produce strong, durable bonds between resin cement and zirconia ceramics.

Wang, Ying-jie; Jiao, Kai; Liu, Yan; Zhou, Wei; Shen, Li-juan; Fang, Ming; Li, Meng; Zhang, Xiang; Tay, Franklin R.; Chen, Ji-hua

2014-01-01

102

Water sorption of resin-modified glass-ionomer cements photoactivated with LED.  

PubMed

The Light Emitting Diodes (LED) technology has been used to photoactivate composite resins and there is a great number of published studies in this area. However, there are no studies regarding resin-modified glass-ionomer cements (RMGIC), which also need photoactivation. Therefore, the aim of this study was to evaluate water sorption of two RMGIC photoactivated with LED and to compare this property to that obtained with a halogen light curing unit. A resin composite was used as control. Five specimens of 15.0 mm in diameter x 1.0 mm in height were prepared for each combination of material (Fuji II LC Improved, Vitremer, and Filtek Z250) and curing unit (Radii and Optilight Plus) and transferred to desiccators until a constant mass was obtained. Then the specimens were immersed into deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Water sorption was calculated based on weight and volume of specimens. The data were analyzed by two-way ANOVA and Tukey test (p < 0.05). Specimens photocured with LED presented significantly more water sorption than those photocured with halogen light. The RMGIC absorbed statistically significant more water than the resin composite. The type of light curing unit affected water sorption characteristics of the RMGIC. PMID:17242796

Cefaly, Daniela Francisca Gigo; Wang, Linda; de Mello, Liliam Lucia Carrara Paes; dos Santos, Janaína Lima; dos Santos, Jean Rodrigo; Lauris, José Roberto Pereira

2006-01-01

103

FTIR investigation of polymerisation and polyacid neutralisation kinetics in resin-modified glass-ionomer dental cements  

Microsoft Academic Search

A new diamond ATR FTIR method has been developed to quantify the processes occurring in the resin-modified glass-ionomer cement (RMGIC), Fuji II LC (Improved), at 1mm depth from the cement\\/water interface. With Fuji II LC (Improved) various changes in the spectra due to 90% monomer polymerisation were observed within 1min after 20s exposure to a dental light. Following polymerisation further

A. M. Young

2002-01-01

104

Effect of acid and laser etching on shear bond strength of conventional and resin-modified glass-ionomer cements to composite resin.  

PubMed

Success in sandwich technique procedures can be achieved through an acceptable bond between the materials. The aim of this study was to compare the effect of 35% phosphoric acid and Er,Cr:YSGG laser on shear bond strength of conventional glass-ionomer cement (GIC) and resin-modified glass-ionomer cement (RMGIC) to composite resin in sandwich technique. Sixty-six specimens were prepared from each type of glass-ionomer cements and divided into three treatment groups as follows: without pretreatment, acid etching by 35% phosphoric acid for 15 s, and 1-W Er,Cr:YSGG laser treatment for 15 s with a 600-?m-diameter tip aligned perpendicular to the target area at a distance of 1 mm from the surface. Energy density of laser irradiation was 17.7 J/cm(2). Two specimens in each group were prepared for evaluation under a scanning electron microscope (SEM) after surface treatment and the remainder underwent bonding procedure with a bonding agent and composite resin. Then the shear bond strength was measured at a crosshead speed of 0.5 mm/min. Two-factor analysis of variance and post-hoc Tukey test showed that the cement type, surface treatment method, and the interaction of these two factors significantly affect the shear bond strength between glass-ionomer cements and composite resin (p < 0.05). Surface treatment with phosphoric acid or Er,Cr:YSGG laser increased the shear bond strength of GIC to composite resin; however, in RMGIC only laser etching resulted in significantly higher bond strength. These findings were supported by SEM results. The fracture mode was evaluated under a stereomicroscope at ×20. PMID:21234634

Navimipour, Elmira Jafari; Oskoee, Siavash Savadi; Oskoee, Parnian Alizadeh; Bahari, Mahmoud; Rikhtegaran, Sahand; Ghojazadeh, Morteza

2012-03-01

105

Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement  

Microsoft Academic Search

This study evaluated the Knoop hardness and polymerization depth of a dual-cured resin cement, light-activated at different distances through different thicknesses of composite resin. One bovine incisor was embedded in resin and its buccal surface was flattened. Dentin was covered with PVC film where a mold (0.8-mm-thick and 5 mm diameter) was filled with cement and covered with another PVC

Andréia Bolzan de Paula; Rubens Nisie Tango; Mário Alexandre Coelho Sinhoreti; Marcelo Corrêa Alves; Regina M. Puppin-Rontani

2010-01-01

106

Optical fiber sensors and their application in monitoring stress build-up in dental resin cements  

NASA Astrophysics Data System (ADS)

The field of optical fiber sensing is highly diverse and this diversity is perceived as a great advantage over more conventional sensors in that an optical sensor can be tailored to measure any of a myriad of physical parameters. In this paper we present a niche application for optical fiber sensors in the domain of biophotonics, namely the monitoring of stress build-up during the curing process of dental resin cements. We discuss the origin of this stress build-up and the problems it can cause when treating patients. Optical fiber sensors aim at excelling in two kind of applications: firstly to perform quality control on batch produced dental cements and measure their total material shrinkage, secondly to monitor the hardening of the cement during in-vivo measurements resulting in the dynamic measurement of the shrinkage and to control the stress in a facing based restoration. We therefore investigated two types of optical fiber sensors as alternatives to conventional measurement techniques; namely polarimetric optical fiber sensors and fiber Bragg gratings written in polarization maintaining fibers. After discussing the results obtained with both optical fiber sensors, we will conclude with a critical assessment of the suitability of the two proposed sensing configurations for multi-parameter stress monitoring.

Ottevaere, H.; Tabak, M.; Fernandez Fernandez, A.; Berghmans, F.; Thienpont, H.

2005-09-01

107

Adhesion of 10-MDP containing resin cements to dentin with and without the etch-and-rinse technique  

PubMed Central

PURPOSE This study evaluated the adhesion of 10-MDP containing self-etch and self-adhesive resin cements to dentin with and without the use of etch-and-rinse technique. MATERIALS AND METHODS Human third molars (N=180) were randomly divided into 6 groups (n=30 per group). Conventional (Panavia F2.0, Kuraray-PAN) and self-adhesive resin cements (Clearfil SA, Kuraray-CSA) were bonded to dentin surfaces either after application of 3-step etch-and-rinse (35% H3PO4 + ED Primer) or two-step self-etch adhesive resin (Clearfil SE Bond). Specimens were subjected to shear bond strength test using the universal testing machine (0.5 mm/min). The failure types were analyzed using a stereomicroscope and quality of hybrid layer was observed under a scanning electron microscope. The data (MPa) were analyzed using two-way ANOVA and Tukey's tests (?=.05). RESULTS Overall, PAN adhesive cement showed significantly higher mean bond strength (12.5 ± 2.3 - 14.1 ± 2.4 MPa) than CSA cement (9.3 ± 1.4 - 13.9 ± 1.9 MPa) (P<.001). Adhesive failures were more frequent in CSA cement groups when used in conjunction with two-step self-adhesive (68%) or no adhesive at all (66%). Hybrid layer quality was inferior in CSA compared to PAN cement in all conditions. CONCLUSION In clinical situations where bonding to dentin substrate is crucial, both conventional and self-adhesive resin cements based on 10-MDP can benefit from etch-and-rinse technique to achieve better quality of adhesion in the early clinical period.

Sen, Deniz; Tuncelli, Betul; Ozcan, Mutlu

2013-01-01

108

Comparison of bracket debonding force between two conventional resin adhesives and a resin-reinforced glass ionomer cement: an in vitro and in vivo study.  

PubMed

The purpose of this study was to compare the debonding force of orthodontic brackets bonded with two conventional resin adhesives (Resilience L3 and Light Bond) and a resin-reinforced glass ionomer cement (Fuji Ortho LC). For the in vitro part of the study, 80 extracted premolars were randomly divided into four groups. In groups A and B, brackets were bonded to unetched enamel using Fuji Ortho LC cement in wet and dry conditions, respectively. In groups C and D, brackets were bonded to etched enamel using Resilience L3 and Light Bond, respectively. Debonding force was determined using a servohydraulic testing machine at a crosshead speed of 1 mm/min. Data was analyzed using the ANOVA and Tukey-Kramer multiple comparison test at p<0.05. A significant difference was found in debonding force between unetched Fuji Ortho LC and the two conventional resins. There was no significant difference between the two conventional resins or between unetched resin-reinforced glass ionomer in the wet and dry conditions. For the in vivo part of the study, 30 patients were randomly assigned to one of the three bonding material groups. Bracket survival rates and distributions were obtained by following these patients for 1.2 years. Data was analyzed using the Kaplan-Meier product-limit estimates of survivorship function. Bond failure interface was determined using a modified adhesive remnant index (ARI). These results showed no significant difference between survival rates and distributions among the three bonding materials with respect to the type of malocclusion, type of orthodontic treatment, or location of bracket. There were significant differences between survival distributions of males and females in the unetched Fuji Ortho LC group and among type of teeth in the conventional resin groups. The predominant mode of bracket failure for the unetched Fuji Ortho LC cement was at the enamel-adhesive interface, and for conventional resins, the enamel-adhesive interface and the bracket-adhesive interface. These results suggest that resin-reinforced glass ionomer cement can withstand occlusal and orthodontic forces despite having a bond strength lower than that of conventional resin adhesives. PMID:10515145

Shammaa, I; Ngan, P; Kim, H; Kao, E; Gladwin, M; Gunel, E; Brown, C

1999-10-01

109

Comparison of Microleakage and Thickness of Resin Cement in Ceramic Inlays with Various Temperatures  

PubMed Central

Background and aims. Microleakage is still one of the major problems of composite-based restorations.This study compared the microleakage and thickness of resin cement in ceramic inlays with various temperatures. Materials and methods. Class V cavities were prepared on the buccal and lingual aspects of thirty human molars with occlusal margins in enamel and gingival margins in dentin (3 mm wide, 5 mm long and 2 mm deep). Laboratory-made inlays (LMI) were used for buccal cavities, and CAD/CAM inlays (CMI) were used for lingual cavities. All the cavities were divided into six groups (n=10): 1) LMI at -5°C; 2) LMI at 50°C; 3) LMI at room temperature (25°C); 4) CMI at -5°C; 5) CMI at 50°C; 6) CMI at room temperature (25°C). Inlays were bonded to cavities in a pulp pressure- and temperature-simulating device. After thermocycling and dye penetration, the teeth were divided into two mesiodistal halves. Amount of dye penetration and film thickness were measured under a stereomicroscope and analyzed with Kruskal-Wallis, Wilcoxon and Spearman's correlation tests ( = 0.05). Results. There were no statistically significant differences in leakage between different inlay temperatures (P > 0.05). The mean cement thickness in laboratory-made inlays (gingival margin, 83.7 ± 11 and occlusal margin, 84.7 ± 19) was greater than that in CAD/CAM inlays (gingival margin, 69 ± 16 and occlusal margin, 84.7 ± 16). No correlation was found be-tween cement thickness and microleakage either in enamel or dentin for any of the ceramic systems. Conclusion. Differences in inlay temperature had no effect on microleakage. CAD/CAM inlays had lower cement thickness than laboratory-made inlays, but this was not related to their microleakage.

Alaghemand, Homayoun; Abolghasemzadeh, Faezeh; Pakdel, Farzaneh; Judi Chelan, Reza

2014-01-01

110

Characterization of the kinetic behavior of resin modified Glass-ionomer cements by DSC, TMA and ultrasonic wave propagation  

Microsoft Academic Search

In this study the isothermal kinetic behavior of two resin modified glass ionomer cements (RMGIC) and a dental composite have been compared by differential scanning calorimetry (DSC) and thermo-mechanical analysis (TMA). The simultaneous evolution of the multiple reactions occurring in RMGIC has been analyzed not only by DSC and TMA but also by ultrasonic wave propagation using the pulse-echo technique.

F. Micelli; A. Maffezzoli; R. Terzi; V. A. M. Luprano

2001-01-01

111

Sealing ability of mineral trioxide aggregate, glass ionomer cement and composite resin when repairing large furcal perforations  

Microsoft Academic Search

Objective To evaluate the sealing ability of different repair materials and the pathway of bacterial penetration after closure of large pulp chamber floor perforations. Materials and methods Perforations were made in the furcation area of extracted human molars and sealed with either mineral trioxide aggregate (MTA), glass ionomer cement or resin composite. The bacterial leakage method was used with Enterococcus

M. Kleivmyr; E. Bruzell; D. Ørstavik; G. Lodiene

2011-01-01

112

Si-based thin film coating on Y-TZP: Influence of deposition parameters on adhesion of resin cement  

NASA Astrophysics Data System (ADS)

This study evaluated the influence of deposition parameters for Si-based thin films using magnetron sputtering for coating zirconia and subsequent adhesion of resin cement. Zirconia ceramic blocks were randomly divided into 8 groups and specimens were either ground finished and polished or conditioned using air-abrasion with alumina particles coated with silica. In the remaining groups, the polished specimens were coated with Si-based film coating with argon/oxygen magnetron discharge at 8:1 or 20:1 flux. In one group, Si-based film coating was performed on air-abraded surfaces. After application of bonding agent, resin cement was bonded. Profilometry, goniometry, Energy Dispersive X-ray Spectroscopy and Rutherford Backscattering Spectroscopy analysis were performed on the conditioned zirconia surfaces. Adhesion of resin cement to zirconia was tested using shear bond test and debonded surfaces were examined using Scanning Electron Microscopy. Si-based film coating applied on air-abraded rough zirconia surfaces increased the adhesion of the resin cement (22.78 ± 5.2 MPa) compared to those of other methods (0-14.62 MPa) (p = 0.05). Mixed type of failures were more frequent in Si film coated groups on either polished or air-abraded groups. Si-based thin films increased wettability compared to the control group but did not change the roughness, considering the parameters evaluated. Deposition parameters of Si-based thin film and after application of air-abrasion influenced the initial adhesion of resin cement to zirconia.

Queiroz, José Renato Cavalcanti; Nogueira Junior, Lafayette; Massi, Marcos; Silva, Alecssandro de Moura; Bottino, Marco Antonio; Sobrinho, Argemiro Soares da Silva; Özcan, Mutlu

2013-10-01

113

The retentive effects of pre-fabricated posts by luting cements.  

PubMed

The purpose of this study was to compare the retention of two different pre-fabricated posts cemented to the root canal with four different adhesive luting cements and a zinc phosphate cement. The crowns of 100 freshly extracted human mandibular central and lateral incisors were removed at the cementoenamel junction and divided into two main groups (A = ParaPost and B = Flexi-Post) and further divided into five subgroups to evaluate the effects of five different cements (Rely-X ARC, Panavia F, ParaPost Cement, Flexi-Flow Natural and Adhesor) each with 10 samples. Post-holes were prepared on all of the roots following the manufacturer's instructions. Each sample was placed into a specialized jig and tensile strength tests performed by using testing machine with a crosshead speed of 0.638 cm min(-1) and force applied until failure. The data were analysed with one-way anova (Post Hoc a Scheffe's S test) and two-way anova (P < 0.001). The Flexi-Post dowels had a mean of 54.21 kg (s.d. = 9.37) and demonstrated statistically higher retention than ParaPost dowels with a mean of 33.93 kg (s.d. = 10.69) for all of the cement groups (P < 0.001). In Flexi-Post and ParaPost dowel groups; Rely-X ARC was statistically higher than the Panavia F, ParaPost Cement, Flexi-Flow Natural and Adhesor (P < 0.05). Adhesor was significantly lower than the other subgroups (P < 0.05). Resin luting cements have demonstrated very high tensile strength potential for a strong bond to dentin. PMID:15189317

Sen, D; Poyrazoglu, E; Tuncelli, B

2004-06-01

114

Shear bond strength of self-adhesive resins compared to resin cements with etch and rinse adhesives to enamel and dentin in vitro  

Microsoft Academic Search

Self-adhesive resin cements should ease the placement of dental restorations. The purpose of this study was to evaluate their\\u000a shear bond strength to enamel and dentin. Sixty molars were randomly assigned to 12 test groups (each n?=?10), and the approximal surfaces were ground flat to get an enamel and dentin surface with a diameter of at least 4 mm.\\u000a Ceramic specimens

A.-K. Lührs; S. Guhr; H. Günay; W. Geurtsen

2010-01-01

115

Effectiveness of surface protection of resin modified glass ionomer cements evaluated spectrophotometrically.  

PubMed

The effectiveness of four surface protectors for resin-modified glass ionomer cements was evaluated by spectrophotometrically determining dye uptake. Ninety specimens, 3.0 mm in diameter and 1.0 mm in height, were made with Photac-Fil, Fuji II LC and Vitremer and divided into six groups for each material. Positive and negative controls were not protected while experimental specimens were protected with proprietary glaze, nail varnish, flowable resin and glaze. The discs were immersed in 0.1% methylene blue solution for 10 minutes after mixing, except for those negative control specimens that were immersed in deionized-water. After 24 hours, the specimens were washed and the protectors trimmed with Sof-Lex discs. The specimens were then removed from the matrixes and individually placed in 1.5 mL of 65% nitric acid for five hours. The absorbance was determined spectrophotometrically at 590 nm. Dye uptake was expressed in microgram dye/specimen. The data were analyzed by two-way ANOVA and Tukey-Kramer tests. All surface protectors tested were effective. For Fuji II LC and Vitremer no differences were observed among tested protections. For Photac-Fil, nail varnish showed better performance than the proprietary glaze. PMID:11504441

Cefaly, D F; Seabra, B G; Tapety, C M; Taga, E M; Valera, F; Navarro, M F

2001-01-01

116

Tensile bond strength of a resinous cement to a nickel-chromium alloy modified with five surface treatments.  

PubMed

A problem associated with resin-bonded fixed partial dentures is inadvertent dislodgment at the metal/cement interface. It has been suggested that Panavia Ex resinous cement requires only air abrasion of the alloy with 50 microns aluminum oxide particles to record reliable bond strength values. The purpose of this study was to discuss the consequences of changes in the type of air abrasion and surface oxidation of the alloy. Fifty pairs of disks of a Ni-Cr alloy were treated by five methods: (1) air abrasion with 50 microns aluminum oxide (control), (2) air abrasion with 50 microns glass beads, (3) air abrasion with a mixture of aluminum oxide and glass beads (ratio 1:1), (4) air abrasion with aluminum oxide and immersion in acid solution of potassium permanganate, and (5) air abrasion with aluminum oxide and immersion in aqueous solution of potassium permanganate. The disks were cemented to each other with Panavia Ex composite resinous cement and tensile tests were conducted at a crosshead speed of 0.5 mm/ minute. No statistically significant differences were recorded among the treatments for the alloys used in this study except air abrasion with glass beads, which exhibited the lowest bond strength values. PMID:8887795

Coelho, C M; Rubo, J H; Pegoraro, L F

1996-09-01

117

Development of a ceramic primer with higher bond durability for resin cement.  

PubMed

To increase the bond durability of resin to the CAD/CAM ceramic surface, two types of two-bottle type ceramic primers, consisting of Primer A1 or A2 and Primer B, were designed. Primer A1 was prepared by dissolving 25, 50, or 100 mg of gamma-methacryloxypropyltrimethoxysilane in 1 mL of ethanol. Primer A2 was prepared by dissolving 50 mg of mixed silanes, consisting of 1,2-bis(trimethoxysilyl)ethane to gamma-methacryloxypropyltrimethoxysilane, in 1 mL of ethanol. Mole fractions of 1,2-bis(trimethoxysilyl)ethane to gamma-methacryloxypropyltrimethoxysilane were 0, 10, 20, 30, 40 and 50 mol%. Primer B was prepared after dissolving 0.01, 0.05 or 0.1 mol L(-1) hydrochloric acid in ethanol by 50 vol%. Ceramic surface was silanated with a mixture of Primers A1 and B or Primers A2 and B for 1 min, and then air-dried. Commercial GC ceramic primer and Porcelain Liner M were utilized. Thereafter, dual-curing type resin cement was bonded to silanated ceramic surface through visible-light irradiation. Shear bond strength of resin to the ceramic surface was measured, before and after thermo-cycling. Addition of 0.01 or 0.05 mol L(-1) hydrochloric acid to the gamma-methacryloxypropyltrimethoxysilane allowed for significant increases in the bond strength. However, thermo-cycling resulted in significant decreases of approximately 5 MPa in the bond strength. Conversely, when the mixed silane, where 30 mol% of 1,2-bis(trimethoxysilyl)ethane dissolved in gamma-methacryloxypropyltrimethoxysilane, was utilized with 0.05 mol L(-1) hydrochloric acid, the reduction in the bond strength decreased to approximately 2 MPa. The designed ceramic primers exhibited higher ceramic bond durability than commercial ceramic primers. PMID:20136699

Li, Rui

2010-07-01

118

Long-term degradation of resin-based cements in substances present in the oral environment: influence of activation mode  

PubMed Central

Indirect restorations in contact with free gingival margins or principally within the gingival sulcus, where the presence of organic acids produced by oral biofilm is higher, may present faster degradation of the resin-based cement pellicle. Objectives: To investigate the degradation of four resin-based cements: Rely X ARC (R), Variolink II (V), enforce (E) and All Cem (A), after immersion in distilled water (DW), lactic acid (LA) and artificial saliva (AS) and to analyze the influence of the activation mode on this response. Material and Methods: Two activation modes were evaluated: chemical (Ch) and dual (D). In the dual activation, a two-millimeter thick ceramic disk (IPS empress System) was interposed between the specimen and light-curing unit tip. Specimens were desiccated, immersed in distilled water, artificial saliva and lactic acid 0.1 M at 37ºC for 180 days, weighed daily for the first 7 days, and after 14, 21, 28, 90 and 180 days and were desiccated again. Sorption and solubility (µg/mm3) were calculated based on ISO 4049. The data were submitted to multifactor analysis of variance (MANOVA) and Tukey's HSD test for media comparisons (?=0.05). Results: Sorption was higher after immersion in LA (p<0.05) and increased significantly with time (p<0.05). Sorption was influenced by the activation mode: Ch>D (p<0.05). The lowest solubility was presented by R (p<0.05). Conclusions: Lactic acid increased the degradation of resin-based cements. Moreover, the physical component of activation, i.e., light-activation, contributed to a low degradation of resin-based cements.

da SILVA, Eduardo Moreira; NORONHA-FILHO, Jaime Dutra; AMARAL, Cristiane Mariote; POSKUS, Laiza Tatiana; GUIMARAES, Jose Guilherme Antunes

2013-01-01

119

Influence of Surface Nano-roughness of Dental Alumina Ceramic on Bond Strength to Dual-Cure Resin Cements  

Microsoft Academic Search

The goal of this research is to evaluate the effect of sandblasting and silica coating on the nano-roughness and on the microtensile bond strength (MTBS) of glass-infiltrated alumina bonded to different resin cements. Six slabs of In-Ceram Alumina (Vita) were randomly treated according to the following groups: (1) no treatment; (2) sandblasting (125 ?m Al2O3-particles); and (3) tribochemical silica-coating (50

Raquel C. Oyagüe; Estrella Osorio; Manuel Toledano; Raquel Osorio

2011-01-01

120

Cytotoxicity Evaluation of Self Adhesive Composite Resin Cements by Dentin Barrier Test on 3D Pulp Cells  

PubMed Central

Objectives: The aim of this study was to evaluate the effects of five self-etch dental composite resin cements on the cell viability of bovine dental papilla-derived cells. Methods: The cytotoxicity of composite resin cements (Rely X Unicem Clicker, 3M ESPE; MaxCem; KERR, Panavia F 2.0; Kuraray, BisCem; Bisco and Bistite II DC; Tokuyama) was analyzed in a dentin barrier test device using three-dimensional (3D) pulp cell cultures. A commercially available cell culture perfusion chamber was separated into two compartments by 500 ?m dentin disc. The three dimensional cultures placed on a dentin disk held in place by a special biocompatible stainless-steel holder. Test materials were introduced into the upper compartment in direct contact with the cavity side of the dentin disks according to the manufacturer’s instructions. Subsequently, the pulpal part of the perfusion chamber containing the cell cultures was perfused with medium (2 ml/h). After an exposure period of 24 h, the cell survival was determined by the MTT assay. Statistical analyses were performed using the Mann–Whitney U-test. Results: In dentin barrier test, cell survival was similar with Maxcem and negative control group (P>.05), and all other tested materials were cytotoxic for the three dimensional cell cultures (P>.05). Conclusions: The significance of composite resin cements is being more important in dentistry. The cytotoxic potencies demonstrated by these materials might be of clinical relevance. Some composite resin cements include biologically active ingredients and may modify pulp cell metabolism when the materials are used in deep cavities or directly contact pulp tissue.

Ulker, Hayriye Esra; Sengun, Abdulkadir

2009-01-01

121

Ceramic primer heat-treatment effect on resin cement/Y-TZP bond strength.  

PubMed

The purpose of this study was to evaluate the effect of different heat-treatment strategies for a ceramic primer on the shear bond strength of a 10-methacryloyloxydecyl-dihydrogen-phosphate (MDP)-based resin cement to a yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic. Specimens measuring 4.5 × 3.5 × 4.5 mm(3) were produced from Y-TZP presintered cubes and embedded in polymethyl methacrylate (PMMA). Following finishing, the specimens were cleaned using an ultrasound device and distilled water and randomly divided into 10 experimental groups (n=14) according to the heat treatment of the ceramic primer and aging condition. The strategies used for the experimental groups were: GC (control), without primer; G20, primer application at ambient temperature (20°C); G45, primer application + heat treatment at 45°C; G79, primer application + heat treatment at 79°C; and G100, primer application + heat treatment at 100°C. The specimens from the aging groups were submitted to thermal cycling (6000 cycles, 5°C/55°C, 30 seconds per bath) after 24 hours. A cylinder of MDP-based resin cement (2.4 mm in diameter) was constructed on the ceramic surface of the specimens of each experimental group and stored for 24 hours at 37°C. The specimens were submitted to a shear bond strength test (n=14). Thermal gravimetric analysis was performed on the ceramic primer. The data obtained were statistically analyzed by two-way analysis of variance and the Tukey test (?=0.05). The experimental group G79 without aging (7.23 ± 2.87 MPa) presented a significantly higher mean than the other experimental groups without aging (GC: 2.81 ± 1.5 MPa; G20: 3.38 ± 2.21 MPa; G100: 3.96 ± 1.57 MPa), showing no difference from G45 only (G45: 6 ± 3.63 MPa). All specimens of the aging groups debonded during thermocycling and were considered to present zero bond strength for the statistical analyses. In conclusion, heat treatment of the metal/zirconia primer improved bond strength under the initial condition but did not promote stable bonding under the aging condition. PMID:22621166

Silva, L H; Costa, A K F; Queiroz, J R C; Bottino, M A; Valandro, L F

2012-01-01

122

Effect of eugenol-based root canal sealers on retention of prefabricated metal posts luted with resin cement  

PubMed Central

Objective This study evaluated the effect of two different eugenol-based root canal sealers on the retention of prefabricated metal posts luted with adhesive resin cement. Materials and methods Thirty prefabricated ParaPosts randomly divided among three groups of 10 each were luted into extracted single-rooted teeth with adhesive resin cement. Two of the groups had been obturated with Gutta–Percha and one of two eugenol-based root canal sealers (Endofil and Tubli-Seal), respectively. The third group was not obturated and served as the control. The forces required for dislodgment of posts from their prepared post spaces were recorded using a universal testing machine. Data were statistically analyzed using one-way ANOVA and Tukey’s multiple range test was used to determine the mean differences. Results Endofil and Tubli-Seal groups demonstrated significantly reduced retention compared to the unobturated (control) group (P < 0.05). Conclusion Eugenol-based sealers significantly reduced the retention of prefabricated posts luted with adhesive resin cement.

Al-Ali, Khalil

2009-01-01

123

Evaluation of the sealing ability of resin cement used as a root canal sealer: An in vitro study  

PubMed Central

Aim: This study was designed to evaluate the apical seal of root canals obturated with resin cement as a root canal sealer and compare with that of the glass ionomer and zinc oxide eugenol sealers using a cold lateral condensation gutta-percha technique. Background: Successful root canal treatment requires three-dimensional obturation of the root canal system with nonirritating biomaterials. None of the available materials are capable of providing a fluid tight seal. Materials and Methods: The prepared teeth were randomly divided into three groups of 15 each to be obturated using three different sealers. Group I: zinc oxide eugenol (Tubliseal), Group II: Glass ionomer (Ketac Endo), and Group III: resin cement (C & B Superbond). All the specimens were stored in 100% relative humidity at 37° for 24 h. The specimens were placed in 2% methylene blue dye for 48 h and sectioned. The dye penetration was evaluated under a stereomicroscope. Results: The “Kruskal” Wallis test was carried out to test the equality of mean. All the specimens showed dye leakage, and there was a statistically significant difference (P < 0.0001) among the groups. The specimens in Group III showed a minimal leakage and the specimens in Group I showed a maximum leakage. Conclusion: Resin cement sealed the root canals significantly better when compared with zinc oxide eugenol and glass ionomer sealers.

Kumar, R Vinod; Shruthi, CS

2012-01-01

124

A prospective clinical study of a multipurpose adhesive used for the cementation of resin-bonded bridges.  

PubMed

A clinical trial was conducted to assess comparatively the clinical performance of anterior resin-bonded bridges (RBBs) cemented with Panavia 21 Opaque (PO) or Scotchbond Multi-Purpose Plus (SBMP) used in conjunction with Scotchbond Resin Cement (SRC). Thirty-three bridges were cemented with PO and 31 bridges with SRC. The bridges were assessed six months after placement via a postal questionnaire. Two bridges (one in each group) failed at that stage. Clinical assessments at one year revealed that one PO bridge and five SRC bridges had failed. Chi-squared analysis, however, showed no significant difference (p > 0.05) in the retention rate of the two groups. At the end of two years, eight bridges had failed (three PO and five SRC). Chi-squared analysis again revealed no significant difference in the retention rate provided by the two adhesives. Greyness of the abutment teeth of bridges cemented with SRC was a drawback in using this material. Many operators who participated in the trial felt the use of SRC/SBMP was time-consuming and rather complicated. PMID:11699175

Aboush, Y E; Estetah, N

2001-01-01

125

Effect of different adhesives combined with two resin composite cements on shear bond strength to polymeric CAD/CAM materials.  

PubMed

This study tested the impact of different adhesives and resin composite cements on shear bond strength (SBS) to polymethyl methacrylate (PMMA)- and composite-based CAD/CAM materials. SBS specimens were fabricated and divided into five main groups (n=30/group) subject to conditioning: 1. Monobond Plus/Heliobond (MH), 2. Visio.link (VL), 3. Ambarino P60 (AM), 4. exp. VP connect (VP), and 5. no conditioning-control group (CG). All cemented specimens using a. Clearfil SA Cement and b. Variolink II were stored in distilled water for 24 h at 37 °C. Additionally, one half of the specimens were thermocycled for 5,000 cycles (5 °C/55 °C, dwell time 20 s). SBS was measured; data were analyzed using descriptive statistics, four- and one-way ANOVA, unpaired two-sample t-test and Chi(2)-test. CAD/CAM materials without additional adhesives showed no bond to resin composite cements. Highest SBS showed VL with Variolink II on composite-based material, before and after thermocycling. PMID:23719013

Bähr, Nora; Keul, Christine; Edelhoff, Daniel; Eichberger, Marlis; Roos, Malgorzata; Gernet, Wolfgang; Stawarczyk, Bogna

2013-01-01

126

Modelling of the interaction between chemical and mechanical behaviour of ion exchange resins incorporated into a cement-based matrix  

NASA Astrophysics Data System (ADS)

In this paper, we present a predictive model, based on experimental data, to determine the macroscopic mechanical behavior of a material made up of ion exchange resins solidified into a CEM III cement paste. Some observations have shown that in some cases, a significant macroscopic expansion of this composite material may be expected, due to internal pressures generated in the resin. To build the model, we made the choice to break down the problem in two scale's studies. The first deals with the mechanical behavior of the different heterogeneities of the composite, i.e. the resin and the cement paste. The second upscales the information from the heterogeneities to the Representative Elementary Volume (REV) of the composite. The heterogeneities effects are taken into account in the REV by applying a homogenization method derived from the Eshelby theory combined with an interaction coefficient drawn from the poroelasticity theory. At the first scale, from the second thermodynamic law, a formulation is developed to estimate the resin microscopic swelling. The model response is illustrated on a simple example showing the impact of the calculated internal pressure, on the macroscopic strain.

Neji, M.; Bary, B.; Burlion, N.; Le Bescop, P.

2013-07-01

127

In vivo biocompatibility versus degree of conversion of resin-reinforced cements in different time periods.  

PubMed

This study focused on test the null hypothesis that there is no difference between the degree of conversion and biocompatibility of different resin reinforced glass ionomer cements (RRGICs). Forty-eight male Wistar rats were used, distributed into four groups (n?=?12), as follows: Group C (Control, polyethylene), Group FOB (Fuji Ortho Band), Group UBL (Ultra band Lok), and Group MCG (Multicure Glass), in subcutaneous tissue. The events of edema, necrosis, granulation tissue, multinuclear giant cells, young fibroblasts, and collagen formation were analyzed at 7, 15, and 30 days. The degree of conversion was evaluated by the Fourier method. Biocompatibility and degree of conversion were assessed using the Kruskal-Wallis and Dunn tests, and ANOVA and Tukey's test, respectively (P?

Lacerda-Santos, Rogério; De Farias, Maria Isabel Serpa Simões; De Carvalho, Fabiola Galbiatti; Pithon, Matheus Melo; Alves, Pollianna Muniz; Tanaka, Orlando Motohiro; Guênes, Gymenna Maria Tenório

2014-05-01

128

Internal coating of zirconia restoration with silica-based ceramic improves bonding of resin cement to dental zirconia ceramic.  

PubMed

Resin bonding to zirconia ceramic cannot be established by standard methods that are utilized for conventional silica-based dental ceramics. This study was aimed to examine the tensile bond strength of resin cement to zirconia ceramic using a new laboratory technique. Sixty-four zirconia ceramic specimens were air-abraded using Al2O3 particles and divided into two groups; the control group with no pretreatment (Control), and the group pretreated using the internal coating technique (INT), in which the surface of the zirconia specimens were thinly coated by fusing silica-based ceramic and air-abraded in the same manner. The specimens in each group were further divided into two subgroups according to the silane coupling agents applied; a mixture of dentin primer/silane coupling agent (Clearfil SE Bond Primer/Porcelain Bond Activator) or a newly developed single-component silane coupling agent (Clearfil Ceramic Primer). After bonding with dual-cured resin cement (Panavia F 2.0), they were stored in water for 24 h and half of them were additionally subjected to thermal cycling. The tensile bond strengths were tested using a universal testing machine. ANOVAs revealed significant influence of ceramic surface pretreatment (p<0.001), silane coupling agent (p<0.001) and thermal cycling (p<0.001); the INT coating technique significantly increased the bond strengths of resin cement to zirconia ceramic, whereas thermal cycling significantly decreased the bond strengths. The use of a single-component silane coupling agent demonstrated significantly higher bond strengths than that of a mixture of dentin primer/silane coupling agent. The internal coating of zirconia dental restorations with silica-based ceramic followed by silanization may be indicated in order to achieve better bonding for the clinical success. PMID:20592445

Kitayama, Shuzo; Nikaido, Toru; Ikeda, Masaomi; Alireza, Sadr; Miura, Hiroyuki; Tagami, Junji

2010-01-01

129

Pre-heated dual-cured resin cements: analysis of the degree of conversion and ultimate tensile strength.  

PubMed

This study evaluated the degree of conversion (DC) and ultimate tensile strength (UTS) of dual-cured resin cements heated to 50º C prior to and during polymerization. Disc- and hourglass-shaped specimens of Rely X ARC (RX) and Variolink II (VII) were obtained using addition silicon molds. The products were manipulated at 25º C or 50º C and were subjected to 3 curing conditions: light-activation through a glass slide or through a pre-cured 2-mm thick resin composite disc, or they were allowed to self-cure (SC). All specimens were dark-stored dry for 15 days. For DC analysis, the resin cements were placed into the mold located on the center of a horizontal diamond on the attenuated total reflectance element in the optical bench of a Fourier Transformed Infrared spectrometer. Infrared spectra (n = 6) were collected between 1680 and 1500 cm-1, and DC was calculated by standard methods using changes in ratios of aliphatic-to-aromatic C=C absorption peaks from uncured and cured states. For UTS test, specimens (n = 10) were tested in tension in a universal testing machine (crosshead speed of 1 mm/min) until failure. DC and UTS data were submitted to 2-way ANOVA, followed by Tukey's test (?= 5%). Both products showed higher DC at 50º C than at 25º C in all curing conditions. No significant difference in UTS was noted between most light-activated groups at 25º C and those at 50º C. VII SC groups showed higher UTS at 50º C than at 25º C (p < 0.05). Increased temperature led to higher DC, but its effects on resin cement UTS depended on the curing condition. PMID:21537644

França, Flávio Álvares; Oliveira, Michele de; Rodrigues, José Augusto; Arrais, César Augusto Galvão

2011-01-01

130

Metal-ceramic crowns cemented with two luting agents: short-term results of a prospective clinical study.  

PubMed

A prospective, randomized, controlled, split-mouth trial was performed to evaluate the cementation modes for metal-ceramic crowns. A total of 40 fully veneered metal-ceramic crowns were delivered in the posterior jaw segments of 20 patients using either a self-adhesive resin cement (RelyX Unicem Aplicap, 3M ESPE; n = 20) or a zinc oxide phosphate cement (Hoffmann's Cement, Hoffmann; n = 20). Thirteen parameters related to the abutment teeth and their periodontal status were evaluated. A visual analog scale was used to assess the sensitivity of the abutment teeth by patient-based outcomes. Data were statistically analyzed by a single-classification ANOVA (? = 0.05) and logistic regression analysis. The results presented were obtained after a mean observation period of 1.8 years. The dropout rate was 0%. None of the abutment teeth exhibited secondary caries at the restoration margins. No significant differences were demonstrated between the luting agents based on visual analog scale (p > 0.05), hypersensitivity (OR = 1.31), abutment mobility (p > 0.05), or probing depths (p > 0.05). Based on the sulcus fluid flow rates, a significantly greater mean difference was obtained with zinc oxide phosphate cement than with self-adhesive resin cement (9.2 units; p = 0.0006). Significant differences between the baseline examination and the follow-up examinations for sulcus bleeding index (p = 0.0013) and plaque index (p < 0.0001) were observed regardless of the luting agent used. The two cement types showed scarcely any differences between the parameters investigated. The outcomes of cementing fully veneered metal-ceramic crowns were equally good with self-adhesive resin cement as with the clinically proven zinc oxide phosphate cement. PMID:21681387

Piwowarczyk, Andree; Schick, Karina; Lauer, Hans-Christoph

2012-06-01

131

Do blood contamination and haemostatic agents affect microtensile bond strength of dual cured resin cement to dentin?  

PubMed Central

Objective: The purpose of this study was to evaluate the effects of blood contamination and haemostatic agents such as Ankaferd Blood Stopper (ABS) and hydrogen peroxide (H2O2) on the microtensile bond strength between dual cured resin cement-dentin interface. Material and Methods: Twelve pressed lithium disilicate glass ceramics were luted to flat occlusal dentin surfaces with Panavia F under the following conditions: Control Group: no contamination, Group Blood: blood contamination, Group ABS: ABS contamination Group H2O2: H2O2 contamination. The specimens were sectioned to the beams and microtensile testing was carried out. Failure modes were classified under stereomicroscope. Two specimens were randomly selected from each group, and SEM analyses were performed. Results: There were significant differences in microtensile bond strengths (µTBS) between the control and blood-contaminated groups (p<0.05), whereas there were no significant differences found between the control and the other groups (p>0.05). Conclusions: Contamination by blood of dentin surface prior to bonding reduced the bond strength between resin cement and the dentin. Ankaferd Blood Stoper and H2O2 could be used safely as blood stopping agents during cementation of all-ceramics to dentin to prevent bond failure due to blood contamination.

KILIC, Kerem; ARSLAN, Soley; DEMETOGLU, Goknil Alkan; ZARARSIZ, Gokmen; KESIM, Bulent

2013-01-01

132

Degree of conversion of two dual-cured resin cements light-irradiated through zirconia ceramic disks  

PubMed Central

PURPOSE The aim of this Fourier transform infrared (FTIR) spectroscopic study was to measure the degree of conversion (DC) of dual-cured resin cements light-irradiated through zirconia ceramic disks with different thicknesses using various light-curing methods. MATERIALS AND METHODS Zirconia ceramic disks (KT12) with three different thicknesses (1.0, 2.0, and 4.0 mm) were prepared. The light transmittance of the disks was measured using ultraviolet visible near-infrared spectroscopy. Four different light-curing protocols were used by combining two curing light modes (Elipar TriLight (standard mode) and bluephase G2 (high power mode)) with light-exposure times of 40 and 120 seconds. The DCs of the two dual-cured resin cements (Duo-Link and Panavia F2.0) light-irradiated through the disks was analyzed at three time intervals (3, 7, and 10 minutes) by FTIR spectroscopy. The data was analyzed using repeated measures ANOVA (?=.05).Two-way ANOVA and Tukey post hoc test were used to analyze the 10 minute DC results. RESULTS The 1.0 mm thick disk exhibited low light transmittance (<25%), and the transmittance decreased considerably with increasing disk thickness. All groups exhibited significantly higher 10 minute DC values than the 3 or 7 minute values (P<.05), but some exceptions were observed in Duo-Link. Two-way ANOVA revealed that the influence of the zirconia disk thickness on the 10 minute DC was dependent on the light-curing methods (P<.001). This finding was still valid even at 4.0 mm thickness, where substantial light attenuation took place. CONCLUSION The curing of the dual-cured resin cements was affected significantly by the light-curing technique, even though the additional chemical polymerization mechanism worked effectively.

Kim, Min-Jeong; Kim, Kyo-Han; Kim, Young-Kyung

2013-01-01

133

Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation.  

PubMed

This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1?±?0.2 µm) or submicron-sized (180?±?30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n?=?20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Microsc. Res. Tech. 77:363-367, 2014. © 2014 Wiley Periodicals, Inc. PMID:24610793

Valentini, Fernanda; Moraes, Rafael R; Pereira-Cenci, Tatiana; Boscato, Noéli

2014-05-01

134

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

PubMed

Abstract Objective: The purpose of this study was to investigate the shear bond strength (SBS) of two different adhesive resin cements used to lute ceramics on laser-etched dentin. Background data: Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation has been claimed to improve the adhesive properties of dentin, but results to date have been controversial, and its compatibility with existing adhesive resin cements has not been conclusively determined. Materials and methods: Two adhesive cements, one "etch-and-rinse" [Variolink II (V)] and one "self-etch" [Clearfil Esthetic Cement (C)] luting cement, were used to lute ceramic blocks (Vita Celay Blanks, Vita) onto dentin surfaces. In total, 80 dentin specimens were distributed randomly into eight experimental groups according to the dentin surface-etching technique used Er,Cr:YSGG laser and Er:YAG laser: (1) 37% orthophosphoric acid+V (control group), (2) Er,Cr:YSGG laser+V, (3) Er,Cr:YSGG laser+acid+V, (4) Er:YAG laser+V, (5) Er:YAG laser+acid+V, (6) C, (7) Er,Cr:YSGG laser+C, and (8) Er:YAG laser+C. Following these applications, the ceramic discs were bonded to prepared surfaces and were shear loaded in a universal testing machine until fracture. SBS was recorded for each group in MPa. Shear test values were evaluated statistically using the Mann-Whitney U test. Results: No statistically significant differences were evident between the control group and the other groups (p>0.05). The Er,Cr:YSGG laser+A+V group demonstrated significantly higher SBS than did the Er,Cr:YSGG laser+V group (p=0.034). The Er,Cr:YSGG laser+C and Er:YAG laser+C groups demonstrated significantly lower SBS than did the C group (p<0.05). Conclusions: Dentin surfaces prepared with lasers may provide comparable ceramic bond strengths, depending upon the adhesive cement used. PMID:24992276

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

2014-07-01

135

Leach studies on cement-solidified ion exchange resins from decontamination processes at operating nuclear power stations  

SciTech Connect

The effects of varying pH and leachant compositions on the physical stability and leachability of radionuclides and chelating agents were determined for cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small scale waste-form specimens were collected during waste solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station. The collected specimens were leach tested, and their compressive strength was measured in accordance with the Nuclear Regulatory Commission's Technical Position on Waste Form'' (Revision 1), from the Low-Level Waste Management Branch. Leachates from these studies were analyzed for radionuclides, selected transition metals, and chelating agents to assess the leachability of these waste form constituents. Leachants used for the study were deionized water, simulated seawater, and groundwater compositions similar to those found at Barnwell, South Carolina and Hanford, Washington. Results of this study indicate that initial leachant pH does not affect leachate pH or releases from cement-solidified decontamination ion-exchange resin waste forms. However, differences in leachant composition and the presence of chelating agents may affect the releases of radionuclides and chelating agents. In addition, results from this study indicate that the cumulative releases of radionuclides and chelating agents observed for forms that disintegrated were similar to those for forms that maintained their general physical integrity.

McIsaac, C.V.; Akers, D.W.; McConnell, J.W.; Morcos, N.

1992-01-01

136

Leach studies on cement-solidified ion exchange resins from decontamination processes at operating nuclear power stations  

SciTech Connect

The effects of varying pH and leachant compositions on the physical stability and leachability of radionuclides and chelating agents were determined for cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small scale waste-form specimens were collected during waste solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station. The collected specimens were leach tested, and their compressive strength was measured in accordance with the Nuclear Regulatory Commission`s ``Technical Position on Waste Form`` (Revision 1), from the Low-Level Waste Management Branch. Leachates from these studies were analyzed for radionuclides, selected transition metals, and chelating agents to assess the leachability of these waste form constituents. Leachants used for the study were deionized water, simulated seawater, and groundwater compositions similar to those found at Barnwell, South Carolina and Hanford, Washington. Results of this study indicate that initial leachant pH does not affect leachate pH or releases from cement-solidified decontamination ion-exchange resin waste forms. However, differences in leachant composition and the presence of chelating agents may affect the releases of radionuclides and chelating agents. In addition, results from this study indicate that the cumulative releases of radionuclides and chelating agents observed for forms that disintegrated were similar to those for forms that maintained their general physical integrity.

McIsaac, C.V.; Akers, D.W.; McConnell, J.W.; Morcos, N.

1992-08-01

137

Effect of surface treatment on the initial bond strength of different luting cements to zirconium oxide ceramic  

Microsoft Academic Search

The objective of this study was to compare the shear bond strength to zirconium oxide ceramic of adhesive-phosphate-monomer-containing\\u000a (APM) and non-APM-containing (nAPM) luting cements after different surface treatments. nAPM cements: Bifix QM, Dual Cement,\\u000a Duo Cement Plus, Multilink Automix, ParaCem Universal DC, PermaCem Smartmix, RelyX ARC, Variolink Ultra, and Variolink II;\\u000a APM cements: Panavia EX, Panavia F2.0, and RelyX UniCem.

F. P. Nothdurft; P. J. Motter; P. R. Pospiech

2009-01-01

138

Genotoxic and cytotoxic effects of different types of dental cement on normal cultured human lymphocytes.  

PubMed

In this study we have investigated the genotoxic and cytotoxic effects of eluates derived from different types of commercially available dental cements, including glass ionomer cements (GICs) (Ketac Cem/3M ESPE and GC Fuji I/GC Corp), resin-modified glass ionomer cements (RM-GICs) (RelyX Luting/3M ESPE and Vitrebond/3M ESPE) and dual-cure resin cements (RCs) (Variolink II/ Ivoclar-Vivadent and Panavia F 2.0/Kuraray) on normal cultured human lymphocytes. Lymphocyte primary cultures obtained from blood samples of three healthy donors were exposed to serial dilutions of eluates derived from specimens of each material tested. Metaphases were induced with phytohaemagglutinin, collected after 72h treatment by use of colchicine and stained according to the fluorescence plus giemsa (FPG) procedure. Preparations were scored for sister chromatid exchange (SCE) and chromosomal aberrations (CAs), while the proliferation rate index (PRI) was also calculated. Our results show that eluates derived from the RM-GICs and RCs caused severe genotoxic effects by significantly increasing the frequencies of SCEs and CAs in cultures of peripheral blood lymphocytes and by decreasing the relevant PRI values in a dose-dependent manner, whereas the two GICs caused only minor cytogenetic effects. Eluates of the two RM-GICs (Vitrebond and RelyX) were also very cytotoxic, as the first serial dilutions of both materials caused a complete mitotic arrest in lymphocyte cultures. Overall, the degree of genotoxicity and cytotoxicity caused by dental cements decreased as follows: Viterbond>Rely X>Panavia F 2.0>Variolink II>Ketac Cem=GC Fuji I. These results indicate that different types of dental cement differ extensively in their genotoxic and cytotoxic potential and their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. Although these results cannot be directly extrapolated to the clinical situation, the potential occurrence of adverse effects caused by the RM-GICs and RCs tested in this study should be considered when making a clinical decision about dental cements. PMID:19028600

Bakopoulou, A; Mourelatos, D; Tsiftsoglou, A S; Giassin, N P; Mioglou, E; Garefis, P

2009-01-31

139

Effect of time on the diametral tensile strength of resin-modified restorative glass ionomer cements and compomer.  

PubMed

The aim of this study was to analyze the diametral tensile strengths of three resin-modified restorative glass ionomer cements--Vitremer, Fuji II LC and Photac Fil and one compomer--Dyract. They were tested at 1 hour, 1 day and 1 week. Kratos testing machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed by two-way ANOVA and Tukey's test that showed statistically significant differences among the materials. The tested materials presented an increase in strength from 1 hour to 1 week and were as follows for each material respectively: Vitremer (19.22-27.29), Fuji II LC (23.91-28.67), Photac Fil (19.35-22.86), Dyract (28.83-46.95). Dyract presented the highest strengths. PMID:11696919

Cefaly, D F; Valarelli, F P; Seabra, B G; Mondelli, R F; Navarro, M F

2001-01-01

140

Evaluation of push-out bond strength of two fiber-reinforced composite posts systems using two luting cements in vitro  

PubMed Central

Introduction: The concept of using a “post” for the restoration of teeth has been practiced to restore the endodontically treated tooth. Metallic posts have been commonly used, but their delirious effects have led to the development of fiber-reinforced materials that have overcome the limitations of metallic posts. The use of glass and quartz fibers was proposed as an alternative to the dark color of carbon fiber posts as far as esthetics was concerned. “Debonding” is the most common failure in fiber-reinforced composite type of posts. This study was aimed to compare the push-out bond strength of a self-adhesive dual-cured luting agent (RelyX U100) with a total etch resin luting agent (Variolink II) used to cement two different FRC posts. Materials and Methods: Eighty human maxillary anterior single-rooted teeth were decoronated, endodontically treated, post space prepared and divided into four groups (n = 20); Group I: D.T. light post (RTD) and Variolink II (Ivoclare vivadent), Group II: D.T. light post (RTD) and RelyX U100 (3M ESPE), Group III: Glassix post (Nordin) and Variolink II (Ivoclare vivadent) and Group IV: Glassix post (Nordin) and RelyX U100 (3M ESPE). Each root was sectioned to get slices of 2 ± 0.05-mm thickness. Push-out tests were performed using a triaxial loading frame. To express bond strength in megapascals (Mpa), load value recorded in Newton (N) was divided by the area of the bonded interface. After testing the push-out strengths, the samples were analyzed under a stereomicroscope. Results: The mean values of the push-out bond strength show that Group I and Group III had significantly higher values than Group II and Group IV. The most common mode of failure observed was adhesive between dentin and luting material and between post and luting material. Conclusions: The mean push-out bond strengths were higher for Groups I and III where Variolink II resin cement was used for luting the fiber post, which is based on the total etch adhesive approach. In most of the samples, failure was observed between cement–dentine interface, followed by post–cement interface, which shows difficulty in bonding between post–cement–dentine interface.

Kadam, Ajay; Pujar, Madhu; Patil, Chetan

2013-01-01

141

Synthesis, formulation and evaluation of novel zinc-calcium phosphate-based adhesive resin composite cement  

Microsoft Academic Search

Three novel adhesive oligomers having carboxylic acid and methacrylate groups were synthesized, characterized and used to formulate composite bone cements with newly synthesized zinc-calcium-silicate phosphate. The optimal formulation was determined based on types of oligomer, oligomer\\/diluent ratio, initiator concentration, and filler level using compressive strength (CS) and curing time (CT) as screening tools. Shrinkage, exotherm and aging of the formed

Dong Xie; IL-Doo Chung; Guigui Wang; Dingsong Feng; Jimmy Mays

2004-01-01

142

In vitro investigation of aluminum and fluoride release from compomers, conventional and resin-modified glass-ionomer cements: a standardized approach.  

PubMed

The amount of fluoride release from dental cements necessary for an anticariogenic effect is not established: moreover, the possible toxic effects due to high fluoride and aluminum release are not well known and the results are still controversial. The aim of our study was to evaluate fluoride (F) and aluminum (Al) release from dental cements using a 'standardized approach' according to the end-use of the materials, i.e. biocompatibility testing. Two polyacid-modified resin composites of recent application, commonly called compomers (Dyract and Dyract Cem), were compared with two conventional acid-based (Fuji I, Ketac-Cem) and two resin-modified (Vitremer, Vitrebond) glass-ionomer cements (GICs). All types of cement are used in dentistry and are commercially available. Extracts of the cements into minimum essential medium, after setting over a 1-h (group A) and 1-week (group B) period, were performed. The extraction conditions were rigorously standardized. Mean values +/- standard deviation of F- and Al-levels in such extracts were measured and were expressed as microg g(-1) (micrograms of ions per gram of cement). A great difference in the amount of ion release, both F and Al, was shown among the tested materials. The GICs, as well as Ketac-Cem, released more F and Al than the compomers. All of the materials released the greatest proportion of ions when the extraction was performed in the first hour after mixing (group A). Al- and F-values showed a highly significant positive correlation, independently from the curing time. We conclude that the biological assessment of dental cements can be performed only if a pre-evaluation of the leachables is obtained by applying a standardized protocol which allows a useful comparison between the different materials. PMID:10841280

Savarino, L; Cervellati, M; Stea, S; Cavedagna, D; Donati, M E; Pizzoferrato, A; Visentin, M

2000-01-01

143

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

PubMed Central

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

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

2012-01-01

144

STUDY OF THE EFFECT OF TWO BPO\\/AMINE INITIATION SYSTEMS ON THE FREE-RADICAL POLYMERIZATION OF MMA USED IN DENTAL RESINS AND BONE CEMENTS  

Microsoft Academic Search

The kinetics of the free radical bulk polymerization of methyl methacrylate (MMA) was studied by DSC, using the benzoyl peroxide (BPO)\\/amine initiation system. N,N dimethyl-4-aminophenethyl alcohol (DMPOH), which is a newly synthesized and used amine in the preparation of acrylic dental resins and bone cements was examined, and the results compared to the most commonly used in these applications amine,

Dimitris S. Achilias; Irini Sideridou

2002-01-01

145

Comparison of conventional and resin-modified glass-ionomer luting cements in the retention of post-crowns by fatigue loading.  

PubMed

Fatigue testing may be used for in vitro evaluation of luting cements, allowing comparison of materials under controlled conditions. It is recognized that glass-ionomer cements are materials which are susceptible to microcracking, even during curing prior to load application, and their failure can be related to crack propagation. The aim of this study was to compare the retention of post-crowns cemented with conventional and resin-modified glass-ionomer cements, the latter having significantly greater fracture toughness, under cyclic loads which are representative of physiological service. A custom-designed fatigue machine was used for three tests each comprising 18 specimens in a modified randomized complete block programme. Correlation of load amplitude to endurance was low, as expected from static test experience, but cement comparison was made through Kaplan-Meier survival and cumulative hazard functions. Differences in the performance of the cements were indicated, but were not statistically significant in this study, although analysis by Cox's proportional hazards model indicated that significance may be gained by a larger study. PMID:9687122

Mitchell, C A; Orr, J F

1998-06-01

146

Shear bond strength of resin-modified glass ionomer cements to Er:YAG laser-treated tooth structure.  

PubMed

This study evaluated the effect of Er:YAG laser irradiation of enamel and dentin on the shear bond strength of resin-modified glass ionomer cements (RMGIC). Twenty molars were selected and the roots removed. The crowns were bisected, embedded in polyester resin and ground to plane the enamel or expose the dentin. The bonding site was delimited, and samples were randomly assigned according to the cavity preparation device: I--Er.YAG laser (350mJ/2Hz); II--Carbide bur (control group). They were subdivided according to the restorative material employed: A) Fuji II LC (GC); B) Vitremer (3M). Samples were then fixed to a metallic device where ionomer cylinders were prepared. Sequentially, the molars were stored for 24 hours and subjected to a shear bond strength test (50Kgf at 0.5 mm/minute). Means in MPa were: Enamel--IA) 4.77 (+/- 1.12); IB) 4.36 (+/- 1.50); IIA) 7.70 (+/- 1.53); IIB) 7.34 (+/- 1.52) and Dentin--IA) 3.13 (+/- 1.15); IB) 2.67 (+/- 0.74); IIA) 6.38 (+/- 1.44); IIB) 5.58 (+/-2.09). Data were submitted to statistical analysis by ANOVA. Adhesion for enamel was more efficient than for dentin (p < 0.01). The cavities prepared with a conventional bur (control group) presented higher bond strength values than those recorded for Er:YAG laser (p < 0.01). No significant differences were observed between the restorative materials. Based on these results, it was concluded that Er:YAG laser adversely affected the shear bond strength of RMGIC for both enamel and dentin. PMID:16827024

de Souza-Gabriel, Aline Evangelista; do Amaral, Flávia Lucisano Botelho; Pécora, Jesus Djalma; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

2006-01-01

147

Effects of metal primers on bonding of adhesive resin cement to noble alloys for porcelain fusing.  

PubMed

This study evaluated the effects of metal primers on the bonding of adhesive resin to four pure metals (Au, Pd, Ag, Cu) and two noble alloys for porcelain fusing (high-gold and high-palladium content alloys). Bonding surface was polished with 600-grit silicon carbide paper and primed with one of the three metal primers (V-Primer, Metaltite, and M.L. Primer). Bonded specimens were fabricated by applying adhesive resin (Super-Bond C&B) on the primed surface. Shear bond strength (SBS) was determined both before and after thermocycling (4-60 degrees C for 2,000 cycles). The highest SBS values to each pure metal after thermocycling were 33.5 MPa for Au by M.L. Primer, 35.0 MPa for Ag by V-Primer, and 34.4 MPa for Cu by Metaltite. SBS to high-gold content alloy after thermocycling was 33.3 MPa by M.L. Primer. None of the primers was effective for pure Pd and high-palladium content alloy after thermocycling. PMID:20379028

Okuya, Nobuhiro; Minami, Hiroyuki; Kurashige, Hisanori; Murahara, Sadaaki; Suzuki, Shiro; Tanaka, Takuo

2010-03-01

148

Influence of air-particle deposition protocols on the surface topography and adhesion of resin cement to zirconia.  

PubMed

Abstract Objectives. This study evaluated the influence of air-particle abrasion protocols on the surface roughness (SR) of zirconia and the shear bond strength (SBS) of dual-polymerized resin cement to this ceramic. Materials and methods. Sintered zirconia blocks (n = 115) (Lava, 3M ESPE) were embedded in acrylic resin and polished. The specimens were divided according to the 'particle type' (Al: 110 µm Al2O3; Si: 110 µm SiO2) and 'pressure' factors (2.5 or 3.5 bar) (n = 3 per group): (a) Control (no air-abrasion); (b) Al2.5; (c) Si2.5; (d) Al3.5; (e) Si3.5. SR (Ra) was measured 3-times from each specimen after 20 s of air-abrasion (distance: 10 mm) using a digital optical profilometer. Surface topography was evaluated under SEM analyses. For the SBS test, 'particle type', 'pressure' and 'thermocycling' (TC) factors were considered (n = 10; n = 10 per group): Control (no air-abrasion); Al2.5; Si2.5; Al3.5; Si3.5; ControlTC; Al2.5TC; Si2.5TC; Al3.5TC; Si3.5TC. After silane application, resin cement (Panavia F2.0) was bonded and polymerized. Specimens were thermocycled (6.000 cycles, 5-55°C) and subjected to SBS (1 mm/min). Data were analyzed using ANOVA, Tukey's and Dunnett tests (5%). Results. 'Particle' (p = 0.0001) and 'pressure' (p = 0.0001) factors significantly affected the SR. All protocols significantly increased the SR (Al2.5: 0.45 ± 0.02; Si2.5: 0.39 ± 0.01; Al3.5: 0.80 ± 0.01; Si3.5: 0.64 ± 0.01 µm) compared to the control group (0.16 ± 0.01 µm). For SBS, only 'particle' factor significantly affected the results (p = 0.015). The SiO2 groups presented significantly higher SBS results than Al2O3 (Al2.5: 4.78 ± 1.86; Si2.5: 7.17 ± 2.62; Al3.5: 4.97 ± 3.74; Si3.5: 9.14 ± 4.09 MPa) and the control group (3.67 ± 3.0 MPa). All TC specimens presented spontaneous debondings. SEM analysis showed that Al2O3 created damage in zirconia in the form of grooves, different from those observed with SiO2 groups. Conclusions. Air-abrasion with 110 µm Al2O3 resulted in higher roughness, but air-abrasion protocols with SiO2 promoted better adhesion. PMID:24175663

Sarmento, Hugo R; Campos, Fernanda; Sousa, Rafael S; Machado, Joao P B; Souza, Rodrigo O A; Bottino, Marco A; Ozcan, Mutlu

2014-07-01

149

Effect of pH on the release of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resins collected from operating nuclear power stations  

SciTech Connect

Data are presented on the physical stability and leachability of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small-scale waste--form specimens collected during solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station were leach-tested and subjected to compressive strength testing in accordance with the Nuclear Regulatory Commission's Technical Position on Waste Form'' (Revision 1). Samples of untreated resin waste collected from each solidification vessel before the solidification process were analyzed for concentrations of radionuclides, selected transition metals, and chelating agents to determine the quantities of these chemicals in the waste-form specimens. The chelating agents included oxalic, citric, and picolinic acids. In order to determine the effect of leachant chemical composition and pH on the stability and leachability of the waste forms, waste-form specimens were leached in various leachants. Results of this study indicate that differences in pH do not affect releases from cement-solidified decontamination ion-exchange resin waste forms, but that differences in leachant chemistry and the presence of chelating agents may affect the releases of radionuclides and chelating agents. Also, this study indicates that the cumulative releases of radionuclides and chelating agents are similar for waste- form specimens that decomposed and those that retained their general physical form. 36 refs., 60 figs., 28 tabs.

McIsaac, C.V.; Akers, D.W.; McConnell, J.W. (EG and G Idaho, Inc., Idaho Falls, ID (USA))

1991-06-01

150

Effect of novel chitosan-fluoroaluminosilicate resin modified glass ionomer cement supplemented with translationally controlled tumor protein on pulp cells.  

PubMed

Dental materials that can promote cell proliferation and function is required for regenerative pulp therapy. Resin modified glass ionomer cement (RMGIC), a broadly used liner or restorative material, can cause apoptosis to pulp cells mainly due to HEMA (2-hydroxyethyl methacrylate), the released residual monomer. Recent studies found that chitosan and albumin could promote release of protein in GIC while translationally controlled tumor protein (TCTP) has an anti-apoptotic activity against HEMA. The aim of this study was to examine the effect of chitosan and albumin modified RMGIC (Exp-RMGIC) supplemented with TCTP on pulp cell viability and mineralization. Exp-RMGIC+TCTP was composed of RMGIC powder incorporated with 15 % of chitosan, 5 % albumin and supplemented with TCTP mixed with the same liquid components of RMGIC. The effect of each specimen on pulp cells was examined using the Transwell plate. From the MTT assay, Exp-RMGIC+TCTP had the highest percentages of viable cells (P < 0.05) at both 24 and 74 h. Flow cytometry revealed that, after 24 h, Exp-RMGIC+TCTP gave the lowest percentages of apoptotic cells compared to other groups. There was no difference in alkaline phosphatase (ALP) activity among different formula of the specimens, while cells cultured in media with TCTP had higher ALP activity. Von Kossa staining revealed that RMGIC+TCTP, and Exp-RMGIC+TCTP had higher percentages of calcium deposit area compared to those without TCTP. It was concluded that Exp-RMGIC supplemented with TCTP had less cytotoxicity than RMGIC and can protect cells from apoptosis better than RMGIC supplemented with TCTP. PMID:24398913

Wanachottrakul, Nattaporn; Chotigeat, Wilaiwan; Kedjarune-Leggat, Ureporn

2014-04-01

151

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

PubMed Central

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 (? = 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.

Kachuei, Marzieh

2014-01-01

152

Bond Strength of Two Resin Cements to Dentin After Disinfection Pretreatment: Effects of Er,Cr:YSGG Laser Compared with Chemical Antibacterial Agent  

PubMed Central

Abstract Objective: This study compared the effects of two disinfection procedures (2% chlorhexidine [CHX] solution versus Er,Cr:YSGG laser irradiation) on the shear bond strength of ED primer II/Panavia F2.0 (ED/P) and Excite DSC/Variolink N (Ex/V). Background data: Different methods are used for cavity disinfection prior to adhesive cementation, which may influence the bonding ability of resin cements. Methods: Flat dentin surfaces were prepared on 100 extracted premolars and randomly divided into 10 groups. In the eight experimental groups, indirect composite samples were cemented with either ED/P or Ex/V under three disinfecting conditions on the dentin surface as follows: (1) CHX application before ED primer II/ after etching, (2) wet laser irradiation (Er,Cr:YSGG laser, 20?Hz, 0.75?W, 15% water +15% air), (3) dry laser irradiation with no water and air cooling. The control groups had no disinfectant application. After 24?h water storage, bond strength test was performed. The data (MPa) were analyzed using two way ANOVA and Tukey tests. Results: The lowest and highest bond strengths were obtained by dry laser and wet laser (10.18±2.67 and 17.36±2.94 for ED/P, 9.64±2.66 and 20.07±3.36 for Ex/V, respectively). For each cement, two-by-two comparisons of four groups revealed significant differences only for dry laser with others (p<0.001). Conclusions: The use of CHX and Er,Cr:YSGG laser at the low fluences with water/air cooling as the antibacterial agents does not adversely influence the bonding ability of the etch-and-rinse and the self-etch cements.

Shafiei, Fereshteh; Fekrazad, Reza; Shafiei, Ehsan

2013-01-01

153

Effect of light-activation with different light-curing units and time intervals on resin cement bond strength to intraradicular dentin.  

PubMed

The aim of this study was to assess the bond strength of a resin cement to intraradicular dentin varying the light-curing unit and the moment at which the light was applied. Post spaces of endodontically treated canines were prepared. The roots were distributed into 6 groups (n=10) according to the light-curing unit and the moment of light exposure: I) Quartz tungsten halogen-600 mW/cm² (QTH) + immediate light activation (t0); II) QTH + light activation after 10 min (t10); III) Light-emitting diodes (LED)-800 mW/cm² (LED-800)+ t0; IV) LED-800 + t10; V) LED-1,500 mW/cm² (LED-1500)+ t0; VI) LED-1500 + t10. After post cementation, slices from coronal, middle and apical post/root regions were submitted to the push-out test and failure evaluation. It was verified that LED-800 (4.40 ± 3.00 MPa) and LED-1500 (4.67 ± 3.04 MPa) provided bond strength statistically superior to QTH (3.13 ± 1.76 MPa) (p<0.05), and did not differ from each other (p>0.05). There was no significant difference between t0 and t10 (p>0.05). Coronal post/root region (4.75 ± 3.10 MPa) presented significantly higher bond strength than the apical (3.32 ± 2.30 MPa) (p<0.05) and middle regions (4.14 ± 2.99 MPa) showed intermediate values. Adhesive failures were predominant when using QTH. Adhesive and mixed failures occurred more frequently in the apical region. Higher adhesion of the resin cement to intraradicular dentin was observed in the coronal region with LED light-activation, regardless of the moment of light exposure. PMID:23207850

Miguel-Almeida, Maria Eleonora; Azevedo, Mario Lucio da Costa; Rached-Júnior, Fuad Abi; Oliveira, Camila Favero; Silva, Ricardo Gariba; Messias, Danielle Cristine

2012-01-01

154

Effect of loading weight on bond durability of composite-type resin cement under cyclic impact test (part 2). Loading with light weight of 100-120 g.  

PubMed

The bond durability of composite-type resin cement was evaluated by means of cyclic impact tests using three different loads. In terms of experimental setup, a casting alloy, 12% Au-Pd-Ag, was used as the adherend and bonded to a cast block using a composite-type cement (Bistite II). A shear load--using plungers of three different weights at 100, 110, and 120 g--was dropped from a 3-mm height onto a small piece of the casting alloy until debonding. The cycle numbers that caused debonding were 1756 +/- 680 x 10(4) times for 100 g, 1403 +/- 515 x 10(4) times for 110 g, and 420 +/- 200 x 10(4) times for 120 g, respectively. Therefore, the group loaded with 120 g showed a significantly lower value as compared to the other two groups. On the fracture mode of the cement, it was a bulk fracture regardless of the loading weight employed in this study--the same result obtained in a previous study where heavier weights were employed. PMID:19496399

Ohsawa, Masahiro; Fujiwara, Mamoru; Hayashi, Yoshihiko

2009-03-01

155

The measurement of 129I for the cement and the paraffin solidified low and intermediate level wastes (LILWs), spent resin or evaporated bottom from the pressurized water reactor (PWR) nuclear power plants  

Microsoft Academic Search

In this paper a relatively simple and low cost analysis procedure to apply to a routine analysis of 129I in low and intermediate level radioactive wastes (LILWs), cement and paraffin solidified evaporated bottom and spent resin, which are produced from nuclear power plants (NPPs), pressurized water reactors (PWR), is presented. The 129I is separated from other nuclides in LILWs using

S. D. Park; J. S. Kim; S. H. Han; Y. K. Ha; K. S. Song; K. Y. Jee

2009-01-01

156

Solidification of ion exchange resin wastes  

SciTech Connect

Solidification media investigated included portland type I, portland type III and high alumina cements, a proprietary gypsum-based polymer modified cement, and a vinyl ester-styrene thermosetting plastic. Samples formulated with hydraulic cement were analyzed to investigate the effects of resin type, resin loading, waste-to-cement ratio, and water-to-cement ratio. The solidification of cation resin wastes with portland cement was characterized by excessive swelling and cracking of waste forms, both after curing and during immersion testing. Mixed bed resin waste formulations were limited by their cation component. Additives to improve the mechanical properties of portland cement-ion exchange resin waste forms were evaluated. High alumina cement formulations dislayed a resistance to deterioration of mechanical integrity during immersion testing, thus providing a significant advantage over portland cements for the solidification of resin wastes. Properties of cement-ion exchange resin waste forms were examined. An experiment was conducted to study the leachability of /sup 137/Cs, /sup 85/Sr, and /sup 60/Co from resins modified in portland type III and high alumina cements. The cumulative /sup 137/Cs fraction release was at least an order of magnitude greater than that of either /sup 85/Sr or /sup 60/Co. Release rates of /sup 137/Cs in high alumina cement were greater than those in portland III cement by a factor of two.Compressive strength and leach testing were conducted for resin wastes solidified with polymer-modified gypsum based cement. /sup 137/Cs, /sup 85/Sr, and /sup 60/Co fraction releases were about one, two and three orders of magnitude higher, respectively, than in equivalent portland type III cement formulations. As much as 28.6 wt % dry ion exchange resin was successfully solidified using vinyl ester-styrene compared with a maximum of 25 wt % in both portland and gypsum-based cement.

Not Available

1982-08-01

157

A comparative evaluation of the retention of metallic brackets bonded with resin-modified glass ionomer cement under different enamel preparations: A pilot study  

PubMed Central

Introduction: For orthodontists, the ideal bonding material should be less moisture-sensitive and should release fluoride, thereby reducing unfavorable iatrogenic decalcification. Resin-Modified Glass Ionomer Cements (RMGICs), due to their ability to bond in the presence of saliva and blood can be a very good bonding agent for orthodontic attachments especially in the areas of mouth, which are difficult to access. Moreover, their fluoride releasing property makes them an ideal bonding agent for patients with poor oral hygiene. However, their immediate bond strength is said to be too low to immediately ligate the initial wire, which could increase the total number of appointments. The effect of sandblasting and the use of sodium hypochlorite (NaOCL) on the immediate bond failure of RMGIC clinically have not been reported in the literature until the date. This investigation intended to assess the effect of sandblasting (of the bracket base and enamel) and NaOCL on the rate of bond failure (with immediate ligation at 30 min) of Fuji Ortho LC and its comparison with that of conventional light cured composite resin over a period of 1 year. Materials and Methods: 400 sample teeth were further divided into 4 groups of 100 each and bonded as follows: (1) Group 1: Normal metallic brackets bonded with Fuji Ortho LC. (2) Group 2: Sandblasted bracket base and enamel surface, brackets bonded with Fuji Ortho LC. (3) Group 3: Deproteinized enamel surface using sodium hypochlorite and brackets bonded with Fuji Ortho LC. (4) Group 4: Normal metallic bracket bonded with Transbond XT after etching enamel with 37% phosphoric acid. This group served as control group. Results and Conclusion: Results showed that sandblasting the bracket base and enamel, can significantly reduce the bond failure rate of RMGIC.

Sharma, Padmaja; Valiathan, Ashima; Arora, Ankit; Agarwal, Sachin

2013-01-01

158

Bond and Durability of Concrete and Resinous Overlays.  

National Technical Information Service (NTIS)

Tests were made on portland cement and resinous concrete overlays to determine their suitability as overlays for deteriorated concrete bridge decks. Direct shear strengths of overlays bonded with epoxy, portland cement grout, and latex modified cement gro...

H. L. Furr L. L. Ingram

1971-01-01

159

Effect of Water Storage on the Flexural Strength of Four Self-etching Adhesive Resin Cements and on the Dentin-titanium Shear Bond Strength Mediated by Them.  

PubMed

SUMMARY Aim : The aim of this study was to evaluate the effect of water storage on the flexural strength (?f) of four self-etching adhesive resin cements (SEARC) and on the dentin-titanium shear bond strength (SBS) mediated by them. Materials and Methods : The selected SEARC were Rely X Unicem, G-Cem, Maxcem, and SmartCem2. For each material, 50 bars (2×2×25 mm) were made and stored in water at 37°C for 1 hour, 1 day, 7 days, 30 days, and 60 days before ?f was determined via a three-point bend test. Titanium cylinders were bonded to freshly exposed human dentin surfaces using the selected cements. Fifty samples were obtained for each SEARC and were stored in water at 37°C for 1 hour, 1 day, 7 days, 30 days, and 60 days before SBS was determined. The results were statistically analyzed using two-way analysis of variance followed by Scheffé multiple means comparisons (?=0.05). Pearson's correlation coefficient between ?f and SBS was determined. Results : Significantly different ?f and SBS values were obtained for the four cements. With regards to the effect of water storage, the ?f of all materials increased during the first 7 days, was not significantly different between materials by 30 days, and then remained relatively constant or decreased for SmartCem2; SBS was not affected by water storage, with the exception of Maxcem, where a significant drop in SBS was detected after 1 day and no deterioration thereafter. No correlation was found between ?f and SBS. Conclusions : Under the experimental conditions of this study, 60 days of water storage negatively affected the ?f of SmartCem2 but did not negatively affect the SEARC-mediated dentin-titanium SBS (Maxcem showed a significant drop in SBS after 1 day but no deterioration thereafter). The dentin-titanium adherence afforded by Rely X and G-Cem was significantly higher than that of Maxcem and SmartCem2. PMID:24720264

Schittly, E; Le Goff, S; Besnault, C; Sadoun, M; Ruse, Nd

2014-01-01

160

Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro.  

PubMed

One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I), 30 days (phase II), 90 days (phase III), and 180 days (Phase IV). At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the root canals with a sealer. The specimens were further equally divided into four groups. Unrestored Group I served as control and the root canals of teeth in the other three group specimens were reinforced with resin modified glassionomer cement (RMGIC) (Group II), Flowable Compomer (Group III), and Flowable Composite (Group IV), respectively, using a translucent curing post. All specimens were subjected to compressive force using an Instron Testing machine, until fracture occurred. All the materials evaluated substantially reinforced the root specimens compared to the control. At the end of 180 days, Flowable composites showed maximum reinforcement compared to the other groups; however, no significant differences were found between the reinforcement capabilities of Flowable Compomer and RMGIC. PMID:22114449

Prathibha, Rani S

2011-01-01

161

Radiographic appearance of commonly used cements in implant dentistry.  

PubMed

Cement-retained restorations allow for a conventional fixed partial denture approach to restoring dental implants. However, inadequate removal of excess cement at the time of cementation may introduce a severe complication: cement-induced peri-implantitis. Radiopaque cements are more easily detected on radiographs and should improve the recognition of extravasated cement at the time of insertion. The purpose of this study was to evaluate the radiopacity of commercially available cements in vitro. Eighteen different cements commonly used for luting restorations to implants were tested at both 0.5- and 1.0-mm thicknesses. The cements examined were zinc oxide eugenol, zinc oxide, zinc polycarboxylate, zinc phosphate, resin-reinforced glass ionomer, urethane resin, resin, and composite resin. Two samples of each cement thickness underwent standardized radiography next to an aluminum step wedge as a reference. The mean grayscale value of each of the nine 1-mm steps in the step wedge were used as reference values and compared to each of the cement samples. Temp Bond Clear (resin), IMProv (urethane resin), Premier Implant Cement (resin), and Temrex NE (resin) were not radiographically detectable at either sample thickness. Cements containing zinc were the most detectable upon radiographic analysis. There are significant differences in the radiopacity of many commonly used cements. Since cementinduced peri-implantitis can lead to late implant failure, cements that can be visualized radiographically may reduce the incidence of this problem. PMID:23342348

Pette, Gregory A; Ganeles, Jeffrey; Norkin, Frederic J

2013-01-01

162

Bond strength evaluation of three self-adhesive luting systems used for cementing composite and porcelain.  

PubMed

Self-adhesive resin cements were recently introduced with the purpose of simplifying the cementation technique, as they combine the use of adhesive and cement in a single application, eliminating the need for pretreatment of the tooth. In the present study a microtensile bond strength test (?-TBS) was used to compare three self-adhesives, an etch-and-rinse and a self-etch luting system, in the cementation of resin-based composite (RBC) and ceramic disks to dentin. Freshly extracted molars were transversally sectioned to expose flat, deep dentin surfaces. Cylindrical specimens (5 mm in diameter and 10 mm in height), consisting of RBC disks and leucite-based glass ceramic disks, were produced. The RBC disks were sandblasted with 50-?m Al2O3. The ceramic disks were conditioned with 9.5% hydrofluoric acid gel and silane application. All of the disks were then bonded to dentin surfaces employing five different luting agents: iCEM Self Adhesive (Heraeus Kulzer), MaxCem (Kerr Corporation), RelyX UniCem (3M ESPE), EnaCem HF (Micerium), and Panavia F2.0 (Kuraray-Dental). The products were applied according to the manufacturers' instructions. The specimens were sectioned perpendicular to the adhesive interface to produce multiple beams measuring approximately 1 mm2 in cross section. For each experimental group 12 beams were tested. The preterm failures were also taken into account. All of the specimen preparations were performed by the same operator. The beams were tested under tension at a crosshead speed of 0.5 mm/min until failure. Mean ?-TBS values were calculated for each group. Data were analyzed by a two-way analysis of variance, and multiple comparisons were performed using a Tukey test (?=0.05). The UniCem group showed the lowest number of preterm failures among the tested self-adhesive systems. When premature debondings were included in the mean value calculation, bond strength values for the UniCem group were statistically equal to or even higher than those achieved with the other self-adhesives, although these values were still statistically worse than those obtained using traditional multi-step luting agents. PMID:21864126

De Angelis, F; Minnoni, A; Vitalone, L M; Carluccio, F; Vadini, M; Paolantonio, M; D'Arcangelo, C

2011-01-01

163

Effect of Ascorbic Acid on Shear Bond Strength of Orthodontic Brackets Bonded with Resin-modified Glass-ionomer Cement to Bleached Teeth  

PubMed Central

Background and aims Bleaching can considerably reduce shear bond strength (SBS) of orthodontic brackets bonded with composite adhesives. Application of antioxidants is a method to reverse the negative effect of bleaching on composite-to-enamel bond. However, the efficacy of antioxidants in increasing the SBS of brackets bonded using resin-modified glass-ionomer cement (RMGIC) has not been studied, which was the aim of this study. Materials and methods Fifty freshly extracted human maxillary first premolars were bleached with 35% hydrogen peroxide (Pola Office Bleaching, SDI). Sodium ascorbate 10% was applied to the experimental specimens (n=25). All the specimens were etched with 37% phosphoric acid (Ivoclar/Vivadent) and bonded using RMGIC (Fuji Ortho LC, GC). The specimens were subjected to incubation (37°C, 24h) and thermocycling (1000 cycles, 5-55°C, dwell time = 1 min). The SBS was measured at 0.5 mm/min debonding crosshead speed. The adhesive remnant index (ARI) was scored under ×10 magni-fication. Data were analyzed using Mann-Whitney U test, one- and independent-samples t-test, and Fisher’sexact test (?=0.05). Results The mean SBS of experimental and control groups were 11.97 ± 4.49 and 7.7 ± 3.19 MPa, respectively. The dif-ference was statistically significant (P=0.000 by t-test). SBS of both control (P=0.014) and experimental (P=0.000) groups were significantly higher than the minimum acceptable SBS of 6 MPa, according to one-sample t-test. Conclusion Application of ascorbic acid can guarantee a strong bond when RMGIC is to be used. However, RMGIC might tolerate the negative effect of bleaching with minimum SA treatments (or perhaps without treatments), which de-serves further studies.

Khosravanifard, Behnam; Rakhshan, Vahid; Araghi, Solmaz; Parhiz, Hadi

2012-01-01

164

[Effects of different surface conditioning agents on the bond strength of resin-opaque porcelain composite].  

PubMed

The objective of this research is to evaluate the effects of different silane coupling agents on the bond strength between Ceramco3 opaque porcelain and indirect composite resin. Five groups of Co-Cr metal alloy substrates were fabricated according to manufacturer's instruction. The surface of metal alloy with a layer of dental opaque porcelain was heated by fire. After the surface of opaque porcelain was etched, five different surface treatments, i.e. RelyX Ceramic Primer (RCP), Porcelain Bond Activator and SE Bond Primer (mixed with a proportion of 1:1) (PBA), Shofu Porcelain Primer (SPP), SE bond primer (SEP), and no primer treatment (as a control group), were used to combine P60 and opaque porcelain along with resin cement. Shear bond strength of specimens was tested in a universal testing machine. The failure modes of specimens in all groups were observed and classified into four types. Selected specimens were subjected to scanning electron microscope and energy disperse spectroscopy to reveal the relief of the fracture surface and to confirm the failure mode of different types. The experimental results showed that the values of the tested items in all the tested groups were higher than that in the control group. Group PBA exhibited the highest value [(37.52 +/- 2.14) MPa] and this suggested a fact that all of the specimens in group PBA revealed combined failures (failure occurred in metal-porcelain combined surface and within opaque porcelain). Group SPP and RCP showed higher values than SEP (P < 0.05) and most specimens of SPP and RCP performed combined failures (failure occurred in bond surface and within opaque porcelain or composite resin) while all the specimens in group SEP and control group revealed adhesive failures. Conclusions could be drawn that silane coupling agents could reinforce the bond strength of dental composite resin to metal-opaque porcelain substrate. The bond strength between dental composite resin and dental opaque porcelain could meet the clinical requirements. PMID:25039143

Liu, Wenjia; Fu, Jing; Liao, Shuang; Su, Naichuan; Wang, Hang; Liao, Yunmao

2014-04-01

165

21 CFR 177.1500 - Nylon resins.  

Code of Federal Regulations, 2010 CFR

...5 0.5 5.1 Nylon 11 resins for use in articles intended...25 .3 5.2 Nylon 11 resins for use only: 1.04...with food b. In side-seam cements for articles intended for...this chapter 6.1 Nylon 6 resins 1.15±.015...

2009-04-01

166

21 CFR 177.1500 - Nylon resins.  

Code of Federal Regulations, 2010 CFR

...5 0.5 5.1 Nylon 11 resins for use in articles intended...25 .3 5.2 Nylon 11 resins for use only: 1.04...with food b. In side-seam cements for articles intended for...this chapter 6.1 Nylon 6 resins 1.15±.015...

2010-01-01

167

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Bracket adhesive resin and tooth conditioner. 872...872.3750 Bracket adhesive resin and tooth conditioner. ...Identification. A bracket adhesive resin and tooth conditioner is a...polymethylmethacrylate, intended to cement an orthodontic bracket to...

2010-04-01

168

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Bracket adhesive resin and tooth conditioner. 872...872.3750 Bracket adhesive resin and tooth conditioner. ...Identification. A bracket adhesive resin and tooth conditioner is a...polymethylmethacrylate, intended to cement an orthodontic bracket to...

2009-04-01

169

Influence of the temperature on the cement disintegration in cement-retained implant restorations.  

PubMed

The aim of this study was to estimate the average disintegration temperature of three dental cements used for the cementation of the implant-supported prostheses. One hundred and twenty metal frameworks were fabricated and cemented on the prosthetic abutments with different dental cements. After heat treatment in the dental furnace, the samples were set for the separation to test the integration of the cement. Results have shown that resin-modified glass-ionomer cement (RGIC) exhibited the lowest disintegration temperature (p<0.05), but there was no difference between zinc phosphate cement (ZPC) and dual cure resin cement (RC) (p>0.05). Average separation temperatures: RGIC - 306 ± 23 °C, RC - 363 ± 71 °C, it could not be calculated for the ZPC due to the eight unseparated specimens. Within the limitations of the study, it could be concluded that RGIC cement disintegrates at the lowest temperature and ZPC is not prone to break down after exposure to temperature. PMID:23455980

Linkevicius, Tomas; Vindasiute, Egle; Puisys, Algirdas; Linkeviciene, Laura; Svediene, Olga

2012-01-01

170

A bioactive bone cement containing Bis-GMA resin and A-W glass-ceramic as an augmentation graft material on mandibular bone.  

PubMed

The potential of a bioactive bone cement (BABC) as an onlay graft material for the mandible with and without the periosteum was investigated in rabbits. Its matrix consists of bisphenol-alpha-glycidyl methacrylate (Bis-GMA) and triethylene-glycol dimetacrylate (TEGDMA) and its filler is silane-treated CaO-SiO2-P2O5-MgO-CaF2 glass (A-W glass-ceramic) powder. The BABC was pasted onto the mandible under the periosteum in Group 1, and onto the mandible with the periosteum removed in Group 2 and allowed to set in situ. In both groups, the cement-bone interface was filled by new bone at 4, 12 and 48 weeks, and bone grew from adjacent bone tissue into the cement-soft tissue interface at 12 and 48 weeks. There were no differences in the rate of bone formation between the groups. The shearing strength increased progressively from 0.25+/-0.10 MPa (mean+/-SD) at week 1 to 7.98+/-0.62 MPa at week 48. The results suggest that the BABC has good handling properties, a high bonding strength and good biocompatibility, and that it has potential for clinical application as a substitute material for autogenous bone transplantation. PMID:12969371

Fujimura, Kazuma; Bessho, Kazuhisa; Okubo, Yasunori; Segami, Natsuki; Iizuka, Tadahiko

2003-10-01

171

Cement paste–epoxy adhesive interactions  

Microsoft Academic Search

In the field of civil engineering, the durability of concrete assemblies using adhesives is widely conditioned by the properties of the interface between the resin and the mineral support (concrete). In this context we studied first the molecular interactions at the interface between an epoxy resin and cement pastes by several approaches based on XPS and IR spectroscopies, DSC, and

Fatma Djouani; Carole Connan; Michel Delamar; Mohamed M. Chehimi; Karim Benzarti

2011-01-01

172

Micromechanical properties of veneer luting resins after curing through ceramics.  

PubMed

The aim of this study was to assess the performance of light-cured luting resin after curing under the ceramic restoration in comparison to dual-cured luting resin, by evaluating the micromechanical properties. Two hundred seventy thin luting composite films of ca. 170 ?m in thickness were prepared by using two light-cured luting resins (Variolink Veneer, Ivoclar Vivadent; RelyX Veneer, 3M ESPE) and a dual-cured luting resin (Variolink II, Ivoclar Vivadent). The composites were cured by using a LED-unit (Bluephase®, Ivoclar Vivadent) with three different curing times (10, 20, and 30 s) under two ceramics (IPS e.max Press, Ivoclar Vivadent; IPS Empress® CAD, Ivoclar Vivadent) of different thicknesses (0, 0.75, and 2 mm). Forty-five groups were included, each containing six thin films. The samples were stored after curing for 24 h at 37°C by maintaining moisture conditions with distilled water. Micromechanical properties of the composites were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). For each sample, ten indentations were made, thus totalizing 60 measurements per group. Micromechanical properties of the luting resins were statistically analyzed (SPSS 17.0). Significant differences were observed between the micromechanical properties of the luting resins (p < 0.05). Variolink II showed the highest values in modulus of elasticity (E = 11 ± 0.5)* and Vickers hardness (HV = 48.2 ± 3.2)* and the lowest values in creep (Cr = 4.3 ± 0.1)* and elastic-plastic deformation (We/Wtot = 38.6 ± 0.7)* followed by RelyX Veneer (E = 6.9 ± 0.3, HV = 33 ± 2.5, Cr = 4.6 ± 0.2, We/Wtot = 41.8 ± 1.0)* and Variolink Veneer (E = 4.4 ± 0.4, HV = 20.1 ± 2.6, Cr = 5 ± 0.2, We/Wtot = 43.7 ± 1.3)*. Dual-cured luting resin expressed higher values in the micro-mechanical properties compared to the light-cured luting resins. The effect of luting resin type on the micromechanical properties of the luting resins was higher than the effect of curing time, ceramic type and ceramic thickness respectively (*The values of reference without ceramics for 30 s curing time). PMID:21057833

Oztürk, Elif; Hickel, Reinhard; Bolay, Sükran; Ilie, Nicoleta

2012-02-01

173

Effect of surface treatment on the initial bond strength of different luting cements to zirconium oxide ceramic.  

PubMed

The objective of this study was to compare the shear bond strength to zirconium oxide ceramic of adhesive-phosphate-monomer-containing (APM) and non-APM-containing (nAPM) luting cements after different surface treatments. nAPM cements: Bifix QM, Dual Cement, Duo Cement Plus, Multilink Automix, ParaCem Universal DC, PermaCem Smartmix, RelyX ARC, Variolink Ultra, and Variolink II; APM cements: Panavia EX, Panavia F2.0, and RelyX UniCem. Groups of ten test specimens were each prepared by layering luting cement, using cylindrical Teflon molds, onto differently treated zirconium dioxide discs. The surface treatments were airborne-particle abrasion with 110 mum alumina particles, silica coating (SC) using 30 mum alumina particles modified by silica (Rocatec System) or SC and silanization. Bifix QM and Multilink Automix were used in combination with an additional bonding/priming agent recommended by the manufacturers. After 48 h of water storage, each specimen was subjected to a shear test. Combinations involving APM-containing cements (14.41-23.88 MPa) generally exhibited higher shear bond strength than those without APM (4.29-17.34 MPa). Exceptions were Bifix QM (14.20-25.11 MPa) and Multilink Automix (19.14-23.09 MPa) in combination with system-specific silane or priming agent, which were on the upper end of shear bond strength values. With the use of the Rocatec system, a partially significant increase in shear bond strength could be achieved in nAPM cement. Modified surface treatment modalities increased the bond strength to zirconium oxide, although the most important factor in achieving a strong bond was the selection of a suitable cement. System-specific priming or bonding agents lead to further improvement. PMID:18758827

Nothdurft, F P; Motter, P J; Pospiech, P R

2009-06-01

174

Zirconia: cementation of prosthetic restorations. Literature review  

PubMed Central

SUMMARY Aim of the work Aim of the work was to execute a review of the international literature about the cementation of zirconia restorations, analyzing the properties of the cements most commonly used in clinical activities. Materials and methods It was performed, through PubMed, a bibliographic search on the international literature of the last 10 years using the following limits: studies in English, in vitro studies, randomized clinical trial, reviews, meta-analysis, guide-lines. Were excluded from the search: descriptive studies, case reports, discussion articles, opinion’s leader. Results From studies results that common surface treatments (silanization, acid etching) are ineffective on zirconia because it has an inert surface without glassy component (on which this surface treatments act primarily), instead the sandblasting at 1atm with aluminium oxide (Al2O3) results significantly effective for the resulting roughening that increase the surface energy and the wettability of the material. Furthermore it has been shown that zinc phosphate-based cements, Bis-GMA-based and glass-ionomer cements can’t guarantee a stable long-term adhesion, instead resin cements containing phosphate monomer 10-methacryloyloxyidecyl-dihyidrogenphosphate (MDP) have shown higher adhesion and stability values than the other cements. In particular, it has seen that bond strength of zirconia copings on dentin, using MDP-based cement, is about 6,9MPa; this value is comparable to that obtained with gold copings cementation. Conclusions Analyzed studies have led to the following conclusions: sandblasting with aluminium oxide (Al2O3) is the best surface treatment to improve adhesion between resin cements and zirconia; resin cements containing phosphate ester monomers 10-methacryloyloxyidecyl-dihyidrogenphosphate (MDP) have shown in the studies an higher bond strength and stability after ageing treatment; the best procedure for cementing zirconia restorations results the combination of sandblasting with aluminium oxide (Al2O3) at 50?m and MDP-based cements.

GARGARI, M.; GLORIA, F.; NAPOLI, E.; PUJIA, A.M.

2011-01-01

175

Shear bond strength evaluation of resin composite bonded to glass-ionomer cement using self-etching bonding agents with different pH: In vitro study  

PubMed Central

Aim: To evaluate the bonding ability of composite to unset glass-ionomer cement (GIC) using different self-etching bonding systems. Materials and Methods: One hundred samples of composite bonded to unset GIC were prepared and were divided into four groups. In Group A, composite was bonded to unset GIC employing a strong (pH 1) self-etch primer was used. In Group B, intermediary strong (pH 1.4) self-etch primer was employed. In Group C and D, mild (pH 2) and (pH 2.2) self-etch primer was employed. Shear bond strength analysis was performed at a cross-head speed of 0.5 mm/min. Results: Statistical analysis performed with one way analysis of variance and Tukey's test showed that the bond strength of composite to unset GIC was significantly higher for the mild self-etch primer group. In addition, energy dispersive x-ray (EDX) analysis was used to determine the composition of various structural phases identified by FE-SEM along the GIC-bonding agent interfaces. Conclusion: Hence this present study concludes that clinically the use of mild self-etching bonding agent over unset GIC has improved bond strength compared to the use of strong and intermediate self-etching bonding agent.

Kandaswamy, Deivanayagam; Rajan, Karunamoorthy Jeyavel; Venkateshbabu, Nagendrababu; Porkodi, Ilango

2012-01-01

176

Asphalt cement  

MedlinePLUS

... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. This is ... Road paving materials Roofing materials Tile cements Note: This list may not include all uses of asphalt.

177

Practical clinical considerations of luting cements: A review  

PubMed Central

The longevity of fixed partial denture depends on the type of luting cement used with tooth preparation. The clinician’s understating of various cements, their advantages and disadvantages is of utmost importance. In recent years, many luting agents cements have been introduced claiming clinically better performance than existing materials due to improved characteristics. Both conventional and contemporary dental luting cements are discussed here. The various agents discussed are: Zinc phosphate, Zinc polycarboxylate, Zinc oxide-eugenol, Glass-ionomer, Resin modified GIC, Compomers and Resin cement. The purpose of this article is to provide a discussion that provides a clinical perspective of luting cements currently available to help the general practitioner make smarter and appropriate choices. How to cite the article: Lad PP, Kamath M, Tarale K, Kusugal PB. Practical clinical considerations of luting cements: A review. J Int Oral Health 2014;6(1):116-20.

Lad, Pritam P; Kamath, Maya; Tarale, Kavita; Kusugal, Preethi B

2014-01-01

178

Practical clinical considerations of luting cements: A review.  

PubMed

The longevity of fixed partial denture depends on the type of luting cement used with tooth preparation. The clinician's understating of various cements, their advantages and disadvantages is of utmost importance. In recent years, many luting agents cements have been introduced claiming clinically better performance than existing materials due to improved characteristics. Both conventional and contemporary dental luting cements are discussed here. The various agents discussed are: Zinc phosphate, Zinc polycarboxylate, Zinc oxide-eugenol, Glass-ionomer, Resin modified GIC, Compomers and Resin cement. The purpose of this article is to provide a discussion that provides a clinical perspective of luting cements currently available to help the general practitioner make smarter and appropriate choices. How to cite the article: Lad PP, Kamath M, Tarale K, Kusugal PB. Practical clinical considerations of luting cements: A review. J Int Oral Health 2014;6(1):116-20. PMID:24653615

Lad, Pritam P; Kamath, Maya; Tarale, Kavita; Kusugal, Preethi B

2014-02-01

179

Cement disease.  

PubMed

Does "cement disease" exist? The bony environment surrounding a loosened cemented prosthesis is an abnormal pathologic condition which, if left unattended, will progress to a total failure of the joint including an inhibition of function and immobilizing pain. That biomaterial properties of the cement used for fixation also contribute to the pathologic state separates this disease from other modes of loosening. This leads inevitably to the conclusion that "cement disease" does exist. Methyl methacrylate has revolutionized the treatment of severe joint dysfunction. There can be no doubt that improving surgical technique, cement handling, and the cement itself will continue to improve the results and reduce the incidence of failure due to loosening. Cement is undoubtedly satisfactory for elderly patients with low activity levels and relatively short life expectancies. However, because of the inherent biologic and biomechanical properties of methyl methacrylate, it is unlikely that it can be rendered satisfactory in the long run for the young, the active, or the overweight patient, for whom alternatives are currently being sought. In such cases, the elimination of "cement disease" can only occur with the elimination of cement. Alternatives include the search for other grouting materials and the development of prostheses with satisfactory surfaces for either press-fit or biologic ingrowth. PMID:3315375

Jones, L C; Hungerford, D S

1987-12-01

180

Decomposition of ion exchange resins by pyrolysis  

SciTech Connect

Pyrolysis of spent ion exchange resins is one of the most effective methods for reducing radioactive waster volume and for making the final waste form more stable. Fundamental experiments were performed to clarify the pyrolysis characteristics of anion and cation exchange resins. Residual elemental analyses and off-gas analyses showed that the decomposition ratio of cation resins was only 50 wt% at 600/sup 0/C, while that of anion resins was 90 wt% at 400/sup 0/C. Infrared spectroscopy for cation resins attributed its low decomposition ratio to formation of a highly heat-resistant polymer (sulfur bridged) during pyrolysis. Measurements of residual hygroscopicity and cement package strength indicated that the optimum pyrolysis temperatures for preventing resins swelling and package expansion were between 300 and 500/sup 0/C.

Matsuda, M.; Funabashi, K.; Nishi, T.; Yusa, H.; Kikuchi, M.

1986-11-01

181

Amino acid containing glass-ionomer cement for orthopedic applications  

NASA Astrophysics Data System (ADS)

Amino acid containing glass-ionomer cements were synthesized, formulated, and evaluated for orthopedic application. The formulation of different amino acid containing glass-ionomer bone cements was optimized, and conventional and resin-modified glass-ionomer bone cements were compared. Properties of interest included handling characteristics, physical and chemical properties, and mechanical strength of the bone cement. The study was based on the synthesis of different vinyl containing amino acids, different polyelectrolytes containing these amino acid residues, and different resin-modified polyelectrolytes, as well as formulation and evaluation of conventional and resin-modified glass-ionomer bone cements using these polyelectrolytes. Systematic preparation of polyelectrolytes and formulation of glass-ionomer bone cements were essential features of this work, since we anticipated that the mechanical properties of the glass-ionomer bone cements could be strongly affected by the nature of the polyelectrolytes and formulation. Mechanical properties were evaluated in a screw driven mechanical testing machine, and structure-property relationships were determined by scanning electron microscopic (SEM) observation of the fracture surface of the specimens. How the structure of polyelectrolytes, such as different amino acid residues, molecular weight, different modifying resin, and formulation of glass-ionomer bone cement, affected the mechanical properties was also studied.

Wu, Wei

182

Clinical applications of preheated hybrid resin composite.  

PubMed

This clinical article describes and discusses the use of preheated nanohybrid resin composite for the placement of direct restorations and luting of porcelain laminate veneers. Two clinical cases are presented. Preheating hybrid composite decreases its viscosity and film thickness offering the clinician improved handling. Preheating also facilitates the use of nanohybrid composite as a veneer luting material with relatively low polymerisation shrinkage and coefficient of thermal expansion compared to currently available resin luting cements. PMID:21779058

Rickman, L J; Padipatvuthikul, P; Chee, B

2011-07-01

183

21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...devices intended for use with bone cement (§ 888.3027). The patellar component...Metallic Surfaces Apposing Bone or Bone Cement,â (iv) âGuidance Document...Implants for SurgeryâAcrylic Resin Cements,â (v) ISO 5834-2:1998...

2010-04-01

184

21 CFR 888.3150 - Elbow joint metal/polymer constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...prostheses intended for use with bone cement (§ 888.3027). (b) Classification...Metallic Surfaces Apposing Bone or Bone Cement,â (iv) âGuidance Document...Implants for SurgeryâAcrylic Resin Cements,â (v) ISO 5834-2:1998...

2009-04-01

185

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...prostheses intended for use with bone cement (§ 888.3027). (b) Classification...Metallic Surfaces Apposing Bone or Bone Cement,â (iv) âGuidance Document...Implants for SurgeryâAcrylic Resin Cements,â (v) ISO 5834-2:1998...

2010-04-01

186

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...prostheses intended for use with bone cement (§ 888.3027). (b) Classification...Metallic Surfaces Apposing Bone or Bone Cement,â (iv) âGuidance Document...Implants for SurgeryâAcrylic Resin Cements,â (v) ISO 5834-2:1998...

2009-04-01

187

21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...devices intended for use with bone cement (§ 888.3027). The patellar component...Metallic Surfaces Apposing Bone or Bone Cement,â (iv) âGuidance Document...Implants for SurgeryâAcrylic Resin Cements,â (v) ISO 5834-2:1998...

2009-04-01

188

21 CFR 888.3150 - Elbow joint metal/polymer constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...prostheses intended for use with bone cement (§ 888.3027). (b) Classification...Metallic Surfaces Apposing Bone or Bone Cement,â (iv) âGuidance Document...Implants for SurgeryâAcrylic Resin Cements,â (v) ISO 5834-2:1998...

2010-04-01

189

Evaluation of resin adhesion to zirconia ceramic using some organosilanes  

Microsoft Academic Search

ObjectivesThis study evaluated and compared the effect of three trialkoxysilane coupling agents on the bond strength of a Bis-GMA-based unfilled resin and a dimethacrylate-based resin composite luting cement to a zirconia ceramics (Procera® AllZircon, Nobel Biocare, Göteborg, Sweden).

Jukka P. Matinlinna; Timo Heikkinen; Mutlu Özcan; Lippo V. J. Lassila; Pekka K. Vallittu

2006-01-01

190

Cementing apparatus  

SciTech Connect

For use in cementing a casing string within a well bore, an assembly is described comprising: a float collar including an outer body connectable as part of the casing string and an inner body having a bore there through having upper and lower ends and a valve member in the bore to permit flow downwardly and prevent flow upwardly there through, a cement plug including a body having a bore there through and upper and lower ends with a frangible diaphragm there across and lips there about flexibly engagable with the casing string to permit the plug to be prepared downwardly onto the float collar, the upper end of the bore of the float collar having threads thereon and the lower end of the body of the cement plug having threads there about for limited make-up with the threads in the bore of the float collar in response to rotation of the cement plug in one direction, and a wiper plug comprising a body having lips there about flexibly engagable with the casing string to permit the wiper plug to be pumped downwardly onto the cement plug, the upper end of the bore of the cement plug having threads thereon and the lower end of the bore of the body of the wiper plug having threads there about for limited make-up with the threads in the bore of the cement plug in response to rotation of the wiper plug in said one direction, and the inner body of the float collar and the bodies of the cement and wiper plugs being of a drillable material.

Coone, M.G.; Cole, F.

1993-08-10

191

Cement invasion  

SciTech Connect

Damage from cement and cement filtrate has been a much discussed subject since set-through-and-perforate completions were first used. Historically, much of the discussion was similar to that for rotary drilling and drilling mud - it would be nice to prevent all damage, but in the real world, some damage must be tolerated to allow the operator to reap the benefits of cementing. The principal perceived formation damage due to cement invasion is seen by the operator as reducing production. The pure idealist requires full potential production under all alternatives, and would to complete all oil and gas wells free of any formation damage. The more practical idealist holds that damage would result in lower production with the completion method he prefers should be prevented. The pragmatic operator compares the cost of preventing damage to the cost of correcting the damage. Even an extremely high damage ratio is academic if the planned stimulation treatment eliminates the influence the cement invasion might have on production. Formations with permeability high enough to yield economical production without some sort of stimulation or cleanup treatment are unlikely to be subject to significant cement filtrate damage.

Sutton, D.L.

1988-09-01

192

Luting of ceramic crowns with a self-adhesive cement: Effect of contamination on marginal adaptation and fracture strength  

PubMed Central

Objectives: This study evaluated the percentages of continuous margins (%CM) and fracture strength (FS) of crowns made out from blocs of leucite-reinforced ceramic (IPS Empress CAD) and luted with a representative self-adhesive cement (RelyX Unicem) under four contaminating agents: saliva, water, blood, a haemostatic solution containing aluminium chloride (pH= 0.8) and a control group with no contamination. Study Design: %CM at both tooth-cement (TC) and cement-crown (CC) interfaces were determined before and after a fatigue test consisting of 600’000 chewing loads and 1’500 temperature cycles changing from 5º C to 50º C. Load to fracture was recorded on fatigued specimens. Kruskal-Wallis test was used to compare %CM and FS between the five groups with a level of confidence of 95%. Results: At the TC interface, no significant differences in marginal adaptation before loading could be detected between groups. After loading, a significant marginal degradation was observed in the group contaminated with aluminium chloride (52 ± 22 %CM) in respect to the other groups. No significant differences in %CM could be detected between the groups contaminated with saliva, water, blood and the control. At the CC interface, no significant differences in marginal adaptation were observed between the groups. The FS on loaded specimens was around 1637N, with no significant differences between groups as well. Conclusions: An adverse interaction of the highly acidic haemostatic agent with either dentin or the self-adhesive cement could explain the specimens’ marginal degradation. The self-adhesive cement tested in this study was no sensitive to moisture contamination either with saliva, water or blood. Key words:Marginal adaptation, RelyX Unicem, contamination, all-ceramic crowns.

Slavcheva, Slavena; Krejci, Ivo

2013-01-01

193

Lunar cement  

NASA Technical Reports Server (NTRS)

With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

Agosto, William N.

1992-01-01

194

Lunar cement  

NASA Astrophysics Data System (ADS)

With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

Agosto, William N.

195

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.  

...Materials—Part 12: Wrought Cobalt-chromium-molybdenum alloy,” (iv) ISO 5833:1992 “Implants for Surgery—Acrylic Resin Cements,” (v) ISO 5834-2:1998 “Implants for Surgery—Ultra-high Molecular Weight Polyethylene—Part 2:...

2014-04-01

196

21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.  

...Materials—Part 12: Wrought Cobalt-Chromium-Molybdenum Alloy,” (iv) ISO 5833:1992 “Implants for Surgery—Acrylic Resin Cements,” (v) ISO 5834-2:1998 “Implants for Surgery—Ultra-high Molecular Weight Polyethylene—Part 2:...

2014-04-01

197

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.  

...Materials—Part 12: Wrought Cobalt-Chromium-Molybdenum Alloy,” (iv) ISO 5833:1992 “Implants for Surgery—Acrylic Resin Cements,” (v) ISO 5834-2:1998 “Implants for Surgery—Ultra-high Molecular Weight Polyethylene—Part 2:...

2014-04-01

198

Sculpting with Cement.  

ERIC Educational Resources Information Center

Cement offers many creative possibilities for school art programs. Instructions are given for sculpting with fiber-cement and sand-cement, as well as for finishing processes and the addition of color. Safety is stressed. (IS)

Olson, Lynn

1983-01-01

199

Adhesive properties of modified glass-ionomer cements.  

PubMed

The incorporation of water-soluble polymers and/or vinyl monomers into glass-ionomer cements can yield toughened "hybrid cement-composites". This study compared a commercial water-hardening glass-ionomer cement and seven experimental hybrids in their bonding to both dentin and Silar composite. The cements were sanded and phosphoric-acid-etched or left with an unaltered matrix-formed surface when adhesion to composite was tested. The seven hybrids included: 15% 2-hydroxyethyl methacrylate (HEMA) with appropriate initiators/activators, 29% HEMA, 27% HEMA + 0.5% polyacrylic acid (PAA), 0.5% PAA, 1.5% PAA, 2.5% polyvinyl alcohol, and 2.5% gelatin. Acceptable bond strengths to applied composite and to dentin were observed for most of the modified hybrid cements. There were higher bond strengths with composite when the hybrids were left unetched. Bonding of some unetched, HEMA-containing cements achieved bond strengths (29% HEMA, 10.09 MPa) significantly higher than those of the unmodified cement (4.92 MPa). Resin-modified cements may promote better bonding by improved interaction and compatibility with the resin component of the composite. PMID:1387853

Rusz, J E; Antonucci, J M; Eichmiller, F; Anderson, M H

1992-01-01

200

Influence of Luting Material Filler Content on Post Cementation  

Microsoft Academic Search

Luting of fiber posts to intra-radicular dentin represents the worst-case scenario in terms of control of polymerization shrinkage. This study tested the hypothesis that filler content of resin cements does not influence luting of fiber posts to intra-radicular dentin, by assaying polymerization stress, push-out bond strength, and nanoleakage expression. The polymerization stress of experimental cements containing 10%, 30%, 50%, or

M. Ferrari; C. A. Carvalho; C. Goracci; F. Antoniolli; A. Mazzoni; G. Mazzotti; M. Cadenaro; L. Breschi

2009-01-01

201

The influence of luting systems on the microtensile bond strength of dentin to indirect resin-based composite and ceramic restorations.  

PubMed

Microtensile bond strength (microTBS) evaluation and fractographic analysis were used to compare four luting systems in the cementation of resin-based composite (RBC) and ceramic disks to dentin. Forty freshly-extracted molars were transversally sectioned to expose flat, deep dentin surfaces. Forty cylindrical specimens (5-mm diameter and 10-mm height), consisting of 20 RBC disks and 20 leucite-based glass ceramic disks, were produced. The RBC disks were sandblasted with 50-microm Al2O3. The ceramic disks were conditioned with 9.5% hydrofluoric acid gel and silane application. All the disks were then bonded to dentin surfaces according to the luting cements to be used: two etch-and-rinse luting agents (XP bond/CoreXFlow; Dentsply [XP]) (Enabond/EnaCem HF; Micerium [ENA]), a self-etch luting system (ED Primer II A+B/Panavia F2.0; Kuraray-Dental [PAN]) and a self-adhesive luting agent (RelyX Unicem; 3M ESPE [UNI]). The adhesive/luting cement systems were applied according to the manufacturers' instructions. The specimens were sectioned perpendicular to the adhesive interface to produce multiple beams, approximately 1 mm2 in area. All the specimen preparations were performed by the same operator. The beams were tested under tension at a crosshead speed of 0.5 mm/minute until failure. The microTBS data were analyzed by two different one-way-ANOVA and multiple comparison Tukey tests (alpha = 0.05). All the fractured beams were observed using a Scanning Electron Microscope (SEM) at 200x magnification for fracture mode determination. The mean bond strength in MPa (SD) for the RBC (Co) and ceramic (Ce) groups were: XP-Co = 31.39 (13.51), ENA-Co = 30.93 (10.17), PAN-Co = 18.29 (10.02), UNI-Co = 19.33 (7.91); XP-Ce = 4.83 (1.86), ENA-Ce = 5.15 (1.66), PAN-Ce = 4.36 (1.80), UNI-Ce = 7.16 (2.52). Statistical analysis showed that the bond strengths were significantly affected by the luting agent employed for both the RBC and ceramic groups (p<0.001). In particular, the XP-Co group and the ENA-Co group did not differ from each other (p > 0.05) and showed significantly higher bond strengths than the PAN-Co and UNI-Co groups (p < 0.05). On the contrary, the UNI-Ce group showed the highest bond strengths compared to the other ceramic experimental groups (p < 0.05). Regarding failure mode, differences were found between the RBC groups: for the etch-and-rinse luting systems (XP-Co and ENA-Co groups), most failures occurred cohesively in the luting agent, while the self-etch luting system (PAN-Co group) and self-adhesive luting system (UNI-Co group) failed predominantly adhesively at the luting agent-dentin interface. Little differences were found between the ceramic groups, where failure type was primarily adhesive between cement and ceramic. PMID:19544823

D'Arcangelo, Camillo; De Angelis, Francesco; D'Amario, Maurizio; Zazzeroni, Simone; Ciampoli, Christian; Caputi, Sergio

2009-01-01

202

Clinical aspects of resin-bonded bridges.  

PubMed

Resin-bonded bridges have emerged as an attractive, minimally invasive prosthodontic option for the restoration of edentulous spaces. Although success rates, determined by retrospective studies, vary greatly, resin-bonded bridges now have success rates approaching those of their cemented counterparts; success is dependent, however, upon appropriate design and careful technique. The metal framework must be rigid and of sufficient surface area to afford secure adhesion to the underlying teeth. Tooth preparation should be restricted to enhancing the bonding area, and it is important that prostheses are designed to maintain axial loading, and guidance upon metal. PMID:12642953

Stokes, Alastair

2002-12-01

203

Long-term monitoring of microleakage of dental cements by radiochemical diffusion  

SciTech Connect

Radioactive /sup 14/C sucrose was found to be an ideal marker for microleakage because it did not penetrate tooth tissue, dental cement, or mounting resin. The main finding is that the adhesive cements--the glass-ionomer and polycarboxylate--are significantly more effective at preventing microleakage than are the traditional phosphate cements--silicate and zinc phosphate. The differences can be as high as two orders of magnitude. The adhesive cements provide almost perfect and reliable seals. By contrast, the nonadhesive cements are erratic sealants with most of the restorations leaking.

Powis, D.R.; Prosser, H.J.; Wilson, A.D.

1988-06-01

204

Leachability of decontamination reagents from cement waste forms  

SciTech Connect

Brookhaven National Laboratory, in order to provide technical information needed by the US Nuclear Regulatory Commission to evaluate the adequacy of near-surface disposal of decontamination wstes, has begun to study the leachability of organic reagents from solidified simulated decontamination wastes. Laboratory-scale cement waste forms containing EDTA, picolinic acid or simulated LOMI decontamination reagent were leach tested. Samples containing an organic reagent on either mixed bed ion-exchange resins or anion exchange resins were tested. A fixed interval leach procedure was used, as well as the standard procedure ANS 16.1. The leachability indices measured for the release of the acid from resin/cement composites are: 10.1 for EDTA on mixed bed resins; 9.1 for picolinic acid on mixed bed resins; 9.2 for picolinic acid on anion exchange resins; 8.8 for picolinic acid in forms containing simulated low oxidation metallic ion (LOMI) reagent on mixed bed resins and 8.7 for picolinic acid in forms containing simulated LOMI reagent on anion exchange resins. The leachability indices measured varied with leach time and the data indicate that the release mechanism may not be simply diffusion controlled. 5 references, 2 tables.

Piciulo, P.L.; Davis, M.S.; Adams, J.W.

1984-11-26

205

Brushing abrasion of luting cements under neutral and acidic conditions.  

PubMed

Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion. PMID:11203860

Buchalla, W; Attin, T; Hellwig, E

2000-01-01

206

Synthesis of new phosphonate ester resins for adsorption of gold from alkaline cyanide solution  

Microsoft Academic Search

Resin ion-exchange technology is a possible alternative to well-established gold recovery processes of carbon adsorption and\\u000a zinc-dust cementation. The search for a suitable resin for gold recovery from alkaline cyanide solution continues at several\\u000a research centers. Recent discoveries involving alkyl phosphorus esters for selective gold solvent extraction from alkaline\\u000a cyanide solution suggest that similar chemistry on a resin substrate might

M. Akser; R. Y. Wan; J. D. Miller; D. R. Quillen; S. D. Alexandratos

1987-01-01

207

Clinical evaluation of a new resin composite crown system to eliminate postoperative sensitivity.  

PubMed

This study evaluated the long-term clinical performance of a new resin composite restorative system with a 4-META dentin-bonding agent to seal complete crown preparations prior to temporization and after permanent luting with a companion resin cement. Complete-coverage crown preparations were completed on 33 vital teeth and 5 nonvital teeth (control). The new restorative material demonstrated satisfactory clinical performance for the 3-year test period. The dentin-bonding agent and its companion resin cement successfully eliminated postoperative hypersensitivity in 100% of the prepared vital teeth over the 3-year term, suggesting excellent seal of dentinal tubules exposed by the complete-crown preparations. PMID:11203587

Suzuki, S

2000-10-01

208

Fabrication Process of Blocks of Radioactive Wastes Encapsulated in Cement and Resistant to Leaching and Salt Solutions.  

National Technical Information Service (NTIS)

Waterproof additives are claimed to decrease water penetration through the cement such as silicone resins, latex emulsions or organic aluminium salts, avoiding leaching of radioactive wastes. (ERA citation 14:021761)

H. Holtz

1987-01-01

209

Thermocycling Effects on Resin Bond to Silicatized and Silanized Zirconia  

Microsoft Academic Search

Various techniques have been introduced to create a durable resin composite bond to sintered zirconia (Y-TZP). Shear bond strength values achieved through tribochemical treatment have been investigated in numerous studies, but less is reported about long-term durability. The objective here was to evaluate the effects of thermocycling and silane on shear bond strength of a composite luting cement to silicatized

Timo T. Heikkinen; Lippo V. J. Lassila; Jukka P. Matinlinna; Pekka K. Vallittu

2009-01-01

210

A comparison of retentive strength of implant cement depending on various methods of removing provisional cement from implant abutment  

PubMed Central

PURPOSE This study evaluated the effectiveness of various methods for removing provisional cement from implant abutments, and what effect these methods have on the retention of prosthesis during the definitive cementation. MATERIALS AND METHODS Forty implant fixture analogues and abutments were embedded in resin blocks. Forty cast crowns were fabricated and divided into 4 groups each containing 10 implants. Group A was cemented directly with the definitive cement (Cem-Implant). The remainder were cemented with provisional cement (Temp-Bond NE), and classified according to the method for cleaning the abutments. Group B used a plastic curette and wet gauze, Group C used a rubber cup and pumice, and Group D used an airborne particle abrasion technique. The abutments were observed using a stereomicroscope after removing the provisional cement. The tensile bond strength was measured after the definitive cementation. Statistical analysis was performed using one-way analysis of variance test (?=.05). RESULTS Group B clearly showed provisional cement remaining, whereas the other groups showed almost no cement. Groups A and B showed a relatively smooth surface. More roughness was observed in Group C, and apparent roughness was noted in Group D. The tensile bond strength tests revealed Group D to have significantly the highest tensile bond strength followed in order by Groups C, A and B. CONCLUSION A plastic curette and wet gauze alone cannot effectively remove the residual provisional cement on the abutment. The definitive retention increased when the abutments were treated with rubber cup/pumice or airborne particle abraded to remove the provisional cement.

Keum, Eun-Cheol

2013-01-01

211

The effect of various primers on shear bond strength of zirconia ceramic and resin composite  

PubMed Central

Aims: To determine the in vitro shear bond strengths (SBS) of zirconia ceramic to resin composite after various primer treatments. Materials and Methods: Forty zirconia ceramic (Zeno, Wieland Dental) specimens (10 mm in diameter and 2 mm thick) were prepared, sandblasted with 50 ?m alumina, and divided into four groups (n = 10). Three experimental groups were surface treated with three primers; CP (RelyX Ceramic Primer, 3M ESPE), AP (Alloy Primer, Kuraray Medical), and MP (Monobond Plus, Ivoclar Vivadent AG). One group was not treated and served as the control. All specimens were bonded to a resin composite (Filtek Supreme XT, 3M ESPE) cylinder with an adhesive system (Adper Scotchbond Multi-Purpose Plus Adhesive, 3M ESPE) and then stored in 100% humidity at 37°C for 24 h before SBS testing in a universal testing machine. Mean SBS (MPa) were analyzed with one-way analysis of variance (ANOVA) and the Tukey's Honestly Significant Difference (HSD) test (? = 0.05). Results: Group AP yielded the highest mean and standard deviation (SD) value of SBS (16.8 ± 2.5 MPa) and Group C presented the lowest mean and SD value (15.4 ± 1.6 MPa). The SBS did not differ significantly among the groups (P = 0.079). Conclusions: Within the limitations of this study, the SBS values between zirconia ceramic to resin composite using various primers and untreated surface were not significantly different.

Sanohkan, Sasiwimol; Kukiattrakoon, Boonlert; Larpboonphol, Narongrit; Sae-Yib, Taewalit; Jampa, Thibet; Manoppan, Satawat

2013-01-01

212

The Biocompatibility of Porous vs Non-Porous Bone Cements: A New Methodological Approach  

PubMed Central

Composite cements have been shown to be biocompatible, bioactive, with good mechanical properties and capability to bind to the bone. Despite these interesting characteristic, in vivo studies on animal models are still incomplete and ultrastructural data are lacking. The acquisition of new ultrastructural data is hampered by uncertainties in the methods of preparation of histological samples due to the use of resins that melt methacrylate present in bone cement composition. A new porous acrylic cement composed of polymethyl-metacrylate (PMMA) and ?-tricalcium-phosphate (p-TCP) was developed and tested on an animal model. The cement was implanted in femurs of 8 New Zealand White rabbits, which were observed for 8 weeks before their sacrifice. Histological samples were prepared with an infiltration process of LR white resin and then the specimens were studied by X-rays, histology and scanning electron microscopy (SEM). As a control, an acrylic standard cement, commonly used in clinical procedures, was chosen. Radiographic ultrastructural and histological exams have allowed finding an excellent biocompatibility of the new porous cement. The high degree of osteointegration was demonstrated by growth of neo-created bone tissue inside the cement sample. Local or systemic toxicity signs were not detected. The present work shows that the proposed procedure for the evaluation of biocompatibility, based on the use of LR white resin allows to make a thorough and objective assessment of the biocompatibility of porous and non-porous bone cements.

Dall'Oca, C.; Maluta, T.; Cavani, F.; Morbioli, G.P.; Bernardi, P.; Sbarbati, A.; Degl'Innocenti, D.; Magnan, B.

2014-01-01

213

The biocompatibility of porous vs non-porous bone cements: a new methodological approach.  

PubMed

Composite cements have been shown to be biocompatible, bioactive, with good mechanical properties and capability to bind to the bone. Despite these interesting characteristic, in vivo studies on animal models are still incomplete and ultrastructural data are lacking. The acquisition of new ultrastructural data is hampered by uncertainties in the methods of preparation of histological samples due to the use of resins that melt methacrylate present in bone cement composition. A new porous acrylic cement composed of polymethylmetacrylate (PMMA) and ?-tricalciumphosphate (?-TCP) was developed and tested on an animal model. The cement was implanted in femurs of 8 New Zealand White rabbits, which were observed for 8 weeks before their sacrifice. Histological samples were prepared with an infiltration process of LR white resin and then the specimens were studied by X-rays, histology and scanning electron microscopy (SEM). As a control, an acrylic standard cement, commonly used in clinical procedures, was chosen. Radiographic ultrastructural and histological exams have allowed finding an excellent biocompatibility of the new porous cement. The high degree of osteointegration was demonstrated by growth of neo-created bone tissue inside the cement sample. Local or systemic toxicity signs were not detected. The present work shows that the proposed procedure for the evaluation of biocompatibility, based on the use of LR white resin allows to make a thorough and objective assessment of the biocompatibility of porous and non-porous bone cements. PMID:24998920

Dall'Oca, C; Maluta, T; Cavani, F; Morbioli, G P; Bernardi, P; Sbarbati, A; Degl'Innocenti, D; Magnan, B

2014-01-01

214

Downhole cementing tool assembly  

SciTech Connect

A cementing apparatus for use in cementing a casing string in a well bore is described comprising: (a) a float collar incorporated in the casing string, the float collar including a passage extending therethrough; (b) a cementing plug having a cylindrical body including an axial passage extending therethrough, the cementing plug body further including closure means extending across the axial passage; (c) a wiper plug having a cylindrical body including wiper means extending about the wiper plug body for wiping the casing as the wiper plug is advanced through the casing; (d) cooperative interlocking means located on the float collar, the cementing plug and the wiper plug for locking the cementing plug and the wiper plug to the float collar in a nonrotatable position; and (e) wherein the cementing plug and the wiper plug including frangible internal cutters embedded in the cementing plug and the wiper plug.

Wardlaw, L.J.; Young, J.A.

1987-12-08

215

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra- lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2003-10-31

216

Do cement nanotubes exist?  

PubMed

Using atomistic simulations, this work indicates that cement nanotubes can exist. The chemically compatible nanotubes are constructed from the two main minerals in ordinary Portland cement pastes, namely calcium hydroxide and a calcium silicate hydrate called tobermorite. These results show that such nanotubes are stable and have outstanding mechanical properties, unique characteristics that make them ideally suitable for nanoscale reinforcements of cements. PMID:22589176

Manzano, H; Enyashin, A N; Dolado, J S; Ayuela, A; Frenzel, J; Seifert, G

2012-06-26

217

Westinghouse Modular Grinding Process - Enhancement of Volume Reduction for Hot Resin Supercompaction - 13491  

SciTech Connect

In nuclear power plants (NPP) ion exchange (IX) resins are used in several systems for water treatment. Spent resins can contain a significant amount of contaminates which makes treatment for disposal of spent resins mandatory. Several treatment processes are available such as direct immobilization with technologies like cementation, bitumisation, polymer solidification or usage of a high integrity container (HIC). These technologies usually come with a significant increase in final waste volume. The Hot Resin Supercompaction (HRSC) is a thermal treatment process which reduces the resin waste volume significantly. For a mixture of powdered and bead resins the HRSC process has demonstrated a volume reduction of up to 75 % [1]. For bead resins only the HRSC process is challenging because the bead resins compaction properties are unfavorable. The bead resin material does not form a solid block after compaction and shows a high spring back effect. The volume reduction of bead resins is not as good as for the mixture described in [1]. The compaction properties of bead resin waste can be significantly improved by grinding the beads to powder. The grinding also eliminates the need for a powder additive.Westinghouse has developed a modular grinding process to grind the bead resin to powder. The developed process requires no circulation of resins and enables a selective adjustment of particle size and distribution to achieve optimal results in the HRSC or in any other following process. A special grinding tool setup is use to minimize maintenance and radiation exposure to personnel. (authors)

Fehrmann, Henning [Westinghouse Electric Germany GmbH, Dudenstr. 44, D-68167 Mannheim (Germany)] [Westinghouse Electric Germany GmbH, Dudenstr. 44, D-68167 Mannheim (Germany); Aign, Joerg [Westinghouse Electric Germany GmbH, Global D and D and Waste Management, Tarpenring 6, D-22419 Hamburg (Germany)] [Westinghouse Electric Germany GmbH, Global D and D and Waste Management, Tarpenring 6, D-22419 Hamburg (Germany)

2013-07-01

218

Comparative study of nanomechanical properties of cements used in teeth restoration  

NASA Astrophysics Data System (ADS)

The discipline of dental science includes the diagnosis of disease in the mouth and teeth, its manifestations and the procedures involved in the restoration of their integrity and function. Restoration of lost tooth structure with suitable materials plays an integral part in the successful rehabilitation of oral tissues. Several factors influence the performance of dental restorations. These factors include the type of cement used to bond crown restoration to prepared teeth. The nanoindentation method was used to explore the mechanical properties of different types of resin cement polymerized using different techniques. A Nano Indenter XP (from MTS Nano Instruments, USA) was used for the experimental tests. A sample of 40 extracted human teeth were restored using two different resin cements: Variolink II (Ivoclar Vivadent, Liechtenstein) and Venus A2 (Heraeus Kulzer, Germany). Both resin cements are light-cured and one of them is self-cured so that the degree of polymerization would be higher. The data obtained for nanohardness and the Young's modulus were analysed using ANOVA to evaluate the influence of different factors (the resin cement and polymerization technique used, the position on the tooth-restoration interface) and to determine the best performance for restoration. The results obtained could give a useful indication of the choice of cementation technique and of the materials used for the restoration of lost tooth structure in different clinical cases.

Peluccio, M. S.; Bignardi, C.; Lombardo, S.; Montevecchi, F. M.; Carossa, S.

2007-10-01

219

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, and shear bond. Testing to determine the effect of temperature cycling on the shear bond properties of the cement systems was also conducted. In addition, the stress-strain behavior of the cement types was studied. This report discusses a software program that is being developed to help design ULHS cements and foamed cements.

Fred Sabins

2002-04-29

220

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that will be performed for analyzing the alkali-silica reactivity of ULHS in cement slurries, as well as the results of Field Tests 1 and 2.

Fred Sabins

2002-10-31

221

Development of PBBI Laminating Resin.  

National Technical Information Service (NTIS)

PBBI resin formulary studies were performed in order to increase resin toughness and to decrease resin shrinkage while maintaining improved moisture resistance over state of the art, 177 C (350 F) service epoxy resins. The most promising approach was iden...

R. W. Vaughan R. A. Buyny

1979-01-01

222

Evaluation of adhesive and compressive strength of glass ionomer cements.  

PubMed

The aim of the study was to assess, compare and evaluate the adhesive strength and compressive strength of different brands of glass ionomer cements to a ceramometal alloy. (A) Glass ionomer cements: GC Fuji II (GC Corporation, Tokyo), Chem Flex (Dentsply DeTrey, Germany), Glass ionomer FX (Shofu-11, Japan), MR dental (MR dental suppliers Pvt Ltd, England). (B) Ceramometal alloy (Ni-Cr: Wiron 99; Bego, Bremen, Germany). (C) Cold cure acrylic resin. (E) Temperature cum humidity control chamber. (F) Instron Universal Testing Machine. Four different types of Glass ionomer cements were used in the study. From each type of the Glass ionomer cements, 15 specimens for each were made to evaluate the compressive strength and adhesive strength, respectively. The 15 specimens were further divided into three subgroups of five specimens. For compressive strength, specimens were tested at 2, 4 and 12 h by using Instron Universal Testing Machine. To evaluate the adhesive strength, specimens were surface treated with diamond bur, silicone carbide bur and sandblasting and tested under Instron Universal Testing Machine. It was concluded from the study that the compressive strength as well as the adhesive bond strength of MR dental glass ionomer cement with a ceramometal alloy was found to be maximum compare to other glass ionomer cements. Sandblasting surface treatment of ceramometal alloy was found to be comparatively more effective for adhesive bond strength between alloy and glass ionomer cement. PMID:23204729

Ramashanker; Singh, Raghuwar D; Chand, Pooran; Jurel, Sunit Km; Tripathi, Shuchi

2011-12-01

223

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project.

Fred Sabins

2001-01-15

224

Repair of porcelain/metal restoration with resin bonded overcasting.  

PubMed

Porcelain occasionally fractures from ceramometal fixed partial dentures following final cementation. Repair of these porcelain fractures can be a challenging task. When the problem occurs on anterior teeth, it is especially difficult because the repair must not only be durable, but esthetically pleasing as well. Although composite resins can be used for some repairs, it is often difficult to match the color and texture to the surrounding intact porcelain. In addition, the bonding between the resin and porcelain is susceptible to margin leakage, which may ultimately cause an esthetic failure. Techniques involving a cemented porcelain-fused-to-metal overcasting have often been successful in restoring the fixed partial denture to form and function. Although the esthetic result of a porcelain/metal overcasting can be quite successful, retention of the overcasting is sometimes poor. The compromised retention and resistance form is due to lack of interproximal walls on the underlying fractured unit. To improve the retention of the overcasting, the following technique of tin plating the overcasting and fractured unit prior to cementing with a composite resin cement is presented. PMID:1389357

Wood, M; Litkowski, L J; Thompson, V P; Church, T

1992-01-01

225

Biological Ion Exchanger Resins  

PubMed Central

The cell is presented as a biological ion exchanger resin. The similarities between ion accumulating cells and ion exchanger resins are correlated. The kinetic characteristics of biological ion exchange are shown to be amenable to analysis by a model commonly used for ion exchanger resins. The theories of ion exchange equilibria currently in use with ion exchanger resins are reviewed with their suitability for adaptation to biological ion exchange in mind. ImagesFIGURE 1

Damadian, Raymond

1971-01-01

226

Resin-Powder Dispenser  

NASA Technical Reports Server (NTRS)

Resin-powder dispenser used at NASA's Langley Research Center for processing of composite-material prepregs. Dispenser evenly distributes powder (resin polymer and other matrix materials in powder form) onto wet uncured prepregs. Provides versatility in distribution of solid resin in prepreg operation. Used wherever there is requirement for even, continuous distribution of small amount of powder.

Standfield, Clarence E.

1994-01-01

227

Downhole cementing tool assembly  

SciTech Connect

This patent describes a cementing apparatus for use in cementing a casing string in a well bore. It comprises a float collar incorporated in the casing string, the float collar including a passage extending therethrough; a cementing plug having a cylindrical body including an axial passage extending therethrough, the cementing plug body further including closure means extending across the axial passage; a wiper plug having a cylindrical body including wiper means extending about the wiper plug body for wiping the casing as the wiper plug is advanced through the casing; and cooperative interlocking means located on the float collar, the cementing plug and the wiper plug for locking the cementing plug and the wiper plug to the float collar in a nonrotatable position.

Wardlaw, L.J.; Young, J.A.

1991-08-06

228

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

Fred Sabins

2003-01-31

229

The Dycal try-in technique for Resin-bonded bridges.  

PubMed

The resin-bonded bridge (RBB) is a predictable technique that has a useful place in modern day dentistry. Practitioners' main concerns, regarding this technique, are a lower survival rate when compared with conventional prostheses, and unpredictable aesthetics. Unfortunately, the minimal preparation and adhesive concepts used with RBBs complicates provisional cementation. Ideally, the RBB should be assessed as if it were the definitively bonded prosthesis. It is possible to achieve a good final aesthetic result as the grey shine-through of the metal wing can be eliminated by the use of opaque resin cements such as Panavia 21 OP. Ideally, the restoration should be assessed with an identical opaque try-in paste but, unfortunately, such a proprietary paste is not available. This paper describes the use of Dycal as a try-in paste for provisionally cementing a resin-bonded bridge and the benefits this offers. PMID:15485120

Poyser, Neil J; Briggs, Peter F A

2004-09-01

230

Method of adhering bone to a rigid substrate using a graphite fiber reinforced bone cement  

NASA Technical Reports Server (NTRS)

A method is described for adhering bone to the surface of a rigid substrate such as a metal or resin prosthesis using an improved surgical bone cement. The bone cement has mechanical properties more nearly matched to those of animal bone and thermal curing characteristics which result in less traumatization of body tissues and comprises a dispersion of short high modulus graphite fibers within a bonder composition including polymer dissolved in reactive monomer such as polymethylmethacrylate dissolved in methylmethacrylate monomer.

Knoell, A. C.; Maxwell, H. G. (inventors)

1977-01-01

231

In vivo response of bioactive PMMA-based bone cement modified with alkoxysilane and calcium acetate.  

PubMed

The use of polymethylmethacrylate (PMMA)-based bone cement is popular in orthopedics for the fixation of artificial joints with bone. However, it has a major problem with prostheses loosening because of coverage by fibrous tissue after long-term implantation. Recently, a bioactive bone cement has been developed that shows direct bonding to living bone through modification of PMMA resin with gamma-methacryloxypropyltrimethoxysilane (MPS) and calcium acetate. The cement is designed to exhibit bioactivity, through incorporation of silanol groups and calcium ions. Thus, it has the potential to form a layer of bone-like hydroxyapatite, which is essential for achieving direct bonding to living bone. This type of modification allows the cement to show spontaneous hydroxyapatite formation on its surface in a simulated body fluid after one day, and there is evidence of osteoconduction of the cement in rabbit tibia for periods of more than three weeks. However, the influence of the dissolved ions from the modified cement has not yet been clarified. Thus, the authors focused on the dissolution of the modified PMMA-based bone cement and its tissue response in muscle and bone by comparison with the behavior of non-modified PMMA-based bone cement. One week after implantation in the latissimus dorsi of a rabbit, the modified PMMA-based bone cement showed more inflammatory width than the commercial cement. However, four weeks after implantation, the inflammatory width of both cements was essentially the same. The osteoconductivity around the modified cement was higher than that for the conventional cement after four weeks implantation. These results indicate that the initial dissolution of calcium acetate from the modified cement to form the hydroxyapatite induced the acute inflammation around tissue, but also developed the osteoconductivity. It is suggested that the initial inflammation can be effective for inducing osteoconduction through a bone healing reaction when the material provides an environment that promotes bone formation. PMID:18632771

Sugino, Atsushi; Ohtsuki, Chikara; Miyazaki, Toshiki

2008-11-01

232

The preparation (by an epoxy-resin method) and physical properties of artificial sandstones  

NASA Astrophysics Data System (ADS)

A new method is described for the preparation of artificial sandstones by cementing either glass beads or quartz grains. The particles are initially wetted with an epoxy-resin mixture and then subjected to a vacuum so that the small quantity of epoxy-resin left acts only as a cement. Using this method with glass beads one can predetermine both porosity and permeability in the artificial sandstones thus created. We present both measured and expected poroperm data and test the validity of Carman-Kozeny's equation.

Klimentos, Theodoros; Parker, Andrew

1988-10-01

233

High Aspect Ratio Fatty Acid Functionalized Strontium Hydroxyapatite Nanorod and PMMA Bone Cement Filler  

Microsoft Academic Search

High aspect ratio strontium hydroxyapatite nanorod significant enhances the mechanical strength of bioactive bone cement,\\u000a due to its fiber like nature. However, incompatibility between resin matrix and strontium hydroxyapatite (Sr-HA) reduce the\\u000a maximum filler loading and excessive strontium release leads to cytotoxicity problem. The aim of this study is to design a\\u000a high aspect ratio hydroxyapatite nanorod with good resin

W. M. Lam; C. T. Wong; T. Wang; Z. Y. Li; H. B. Pan; W. K. Chan; C. Yang; K. D. K. Luk; M. K. Fong; W. W. Lu

234

Strength of cemented grains  

NASA Astrophysics Data System (ADS)

We conducted compaction tests (isotropic drained loading) on randomly packed glass beads that were a) uncemented and b) cemented by epoxy at their contacts. In the latter case, the volume of the epoxy accounted for 10 percent of the pore space. Intensive crushing of grains was observed in the first case at about 50 MPa. In the second case, the cemented grains stayed intact, the failure being localized within the epoxy. Therefore, even small amounts of cement at contacts prevent the failure of grains. Theoretically, this effect follows from our theory of cemented granular materials: stress concentration is high at the contacts of uncemented grains, whereas even small amounts of relatively soft cement result in a more uniform stress distribution over a larger contact area.

Yin, Hezhu; Dvorkin, Jack

1994-05-01

235

Cement-based electronics  

NASA Astrophysics Data System (ADS)

The term Intelligent Highway is usually intended to mean external systems that are added to pre-existing highways. However, the ability to construct basic passive electronic elements is demonstrated employing electrically dissimilar Portland cement pastes. These electronic elements include resistors, rectifying pn-junctions, piezoelectric and piezoresistive sensors, and thermocouple junctions. It may therefore be possible to build intelligence into the highway itself utilizing cement-based electronic devices. As compared to semiconductor-based electronic components, those derived from cement have minimal materials and processing costs, do not require clean rooms, and are mechanically more rugged. Results and characterizations are presented for resistive elements and rectifying pn-junctions derived from admixtures of stainless steel fiber (n-type) and carbon fiber (p-type) in Portland cement. These elements are then combined to produce a monolithic cement-based digital logic 2-input AND gate.

Konesky, Gregory A.

236

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

Fred Sabins

2002-01-23

237

Effect of Provisional Cements on Shear Bond Strength of Porcelain Laminate Veneers  

PubMed Central

Objectives: The purpose of this study was to evaluate the effect of three provisional cements and two cleaning techniques on the final bond strength of porcelain laminate veneers. Methods: The occlusal third of the crowns of forty molar teeth were sectioned and embedded in autopolymerizing acrylic resin. Dentin surfaces were polished and specimens were randomly divided into four groups (n=10). Provisional restorations were fabricated and two provisional restorations were cemented onto each tooth. Restorations were fixed with one of three different provisional cements: eugenol-free provisional cement (Cavex), calcium hydroxide (Dycal), and light-cured provisional cement (Tempond Clear). Provisional restorations were removed with either a dental explorer and air-water spray, or a cleaning bur (Opticlean). In the control group, provisional restorations were not used on the surfaces of specimens. IPS Empress 2 ceramic discs were luted with a dual-cured resin cement (Panavia F). Shear bond strength was measured using a universal testing machine. Data were statistically analyzed by ANOVA, Tukey’s HSD and Dunnett tests. Surfaces were examined by scanning electronic microscopy. Results: Significant differences were found between the control group and both the light-cured provisional cement groups and the eugenol-free provisional cement-cleaning bur group (P<.05). Groups that had received light-cured provisional cement showed the lowest bond strength values. Conclusions: Selection of the provisional cement is an important factor in the ultimate bond strength of the final restoration. Calcium hydroxide provisional cement and cleaning with a dental explorer are advisable.

Altintas, Subutay Han; Tak, Onjen; Secilmis, Asli; Usumez, Aslihan

2011-01-01

238

Large strains in cemented granular aggregates: Elastic-plastic cement  

Microsoft Academic Search

We describe large-strain behavior of cemented geomaterials by modeling the deformation of a random pack of identical cemented spheres. In this model we assume that the grains are elastic but that the intergranular cement becomes partly plastic as local stresses meet a plasticity condition. This plasticity condition for a thin elastic-plastic cement layer is derived based on the von Mises

Jack Dvorkin

1996-01-01

239

Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation  

SciTech Connect

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive alternative option. This paper reports the development of photochemical mineralization process for organic ion-exchange resins of poly (styrene-divinyl benzene) type with sulfonic acid and quaternary ammonium functional groups. It is a two-step process consisting of dissolution (conversion of solid resin into water-soluble reaction products) and photo-Fenton mineralization of the dissolved resin. Cation and anion resin dissolution was effected by reaction of the resin with H2O2 at 50-60 C in the presence of ferrous/copper sulphate catalyst. Direct dissolution of mixed resin was not efficient. However, the cation resin portion in the mixed resin could be selectively dissolved without affecting the anion portion. The solid anion resin after separation from the cation resin solution could be dissolved. About 0.5 liters of 50% H2O2 was required for dissolution of one kg of wet resin. The reaction time was 4-5 hours. Dissolution experiments were conducted on up to 8 liters of wet resin. The second step, viz., photo-Fenton mineralization of the dissolved resin was effected at ambient temperature(25-35 C). Kinetic results of laboratory scale experiments in immersion type photo-reactor and pilot scale experiments in tubular flow photo-reactor were presented. These results clearly demonstrated the photo-Fenton mineralization of dissolved resin at ambient temperature with stoichiometric quantity of H2O2 as against 70-200% excess H2O2 requirement in chemical mineralization experiments under Fenton oxidation conditions at 90-95 C. Based on these studies, a treatment scheme was developed and presented in this paper.

Srinivas, C.; Sugilal, S.; Wattal, P. K.

2003-02-26

240

In vivo Dentin Microhardness beneath a Calcium-Phosphate Cement  

PubMed Central

A minimally invasive caries-removal technique preserves potentially repairable, caries-affected dentin. Mineral-releasing cements may promote remineralization of soft residual dentin. This study evaluated the in vivo remineralization capacity of resin-based calcium-phosphate cement (Ca-PO4) used for indirect pulp-capping. Permanent carious and sound teeth indicated for extraction were excavated and restored either with or without the Ca-PO4 base (control), followed by adhesive restoration. Study teeth were extracted after 3 months, followed by sectioning and in vitro microhardness analysis of the cavity floor to 115-µm depth. Caries-affected dentin that received acid conditioning prior to Ca-PO4 basing showed significantly increased Knoop hardness near the cavity floor. The non-etched group presented results similar to those of the non-treated group. Acid etching prior to cement application increased microhardness of residual dentin near the interface after 3 months in situ.

Bresciani, E.; Wagner, W.C.; Navarro, M.F.L.; Dickens, S.H.; Peters, M.C.

2010-01-01

241

Phosphate based oil well cements  

Microsoft Academic Search

The main application of the cement in an oil well is to stabilize the steel casing in the borehole and protect it from corrosion. The cement is pumped through the borehole and is pushed upwards through the annulus between the casing and the formation. The cement will be exposed to temperature and pressure gradients of the borehole. Modified Portland cement

Ramkumar Natarajan

2005-01-01

242

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. Laboratory testing during the eleventh quarter focused on evaluation of the alkali-silica reaction of eight different cement compositions, four of which contain ULHS. This report provides a progress summary of ASR testing. The original laboratory procedure for measuring set cement expansion resulted in unacceptable erosion of the test specimens. In subsequent tests, a different expansion procedure was implemented and an alternate curing method for cements formulated with TXI Lightweight cement was employed to prevent sample failure caused by thermal shock. The results obtained with the modified procedure showed improvement over data obtained with the original procedure, but data for some compositions were still questionable. Additional modification of test procedures for compositions containing TXI Lightweight cement were implemented and testing is ongoing.

Fred Sabins

2003-07-31

243

Bioactive glass-ionomer cement with potential therapeutic function to dentin capping mineralization.  

PubMed

We have developed a novel bioactive resin-modified glass-ionomer cement system with therapeutic function to dentin capping mineralization. In the system, the newly synthesized star-shape poly(acrylic acid) was formulated with water, Fuji II LC filler, and bioactive glass S53P4 to form resin-modified glass-ionomer cement. Compressive strength (CS) was used as a screening tool for evaluation. The commercial glass-ionomer cement Fuji II LC was used as a control. All the specimens were conditioned in simulated body fluid (SBF) at 37 degrees C prior to testing. The effect of aging in SBF on CS and microhardness of the cements was investigated. Scanning electron microscopy was used to examine the in vitro dentin surface changes caused by the incorporation of bioactive glass. The results show that the system not only provided strengths comparable to original commercial Fuji II LC cement but also allowed the cement to help mineralize the dentin in the presence of SBF. It appears that this bioactive glass-ionomer cement system has direct therapeutic impact on dental restorations that require root surface fillings. PMID:18821992

Xie, Dong; Zhao, Jun; Weng, Yiming; Park, Jong-Gu; Jiang, Hui; Platt, Jeffrey A

2008-10-01

244

Interfacial interactions of structural adhesive components with cement pastes - Studies by inverse gas chromatography (IGC)  

NASA Astrophysics Data System (ADS)

The surface energy of hardened cement pastes, before and after treatment by organic coating, and two individual cement paste components (CSH and ettringite) have been characterized by inverse gas chromatography (IGC) at 35 °C, using n-alkanes, 1-alkenes, benzene, chloroform and CCl 4 molecular probes. The cement pastes were prepared by mixing an ordinary Portland cement (OPC) with water at a water/cement ratio (W/C) equal to 0.3 and 0.5. They were further coated with an epoxy resin (R) and triethylenetetramine hardener (H), separately, at a mass loading of 1 and 10 wt.%, respectively. Changes in the dispersive contribution to the surface energy ( ?sd) and Lewis acid-base interaction energies were found to be significantly dependent on the W/C parameter on the one hand, and the adsorption of H and R, on the other hand.

Baeta Neves, Inês; Chabut, Maud; Perruchot, Christian; Chehimi, Mohamed M.; Benzarti, Karim

2004-11-01

245

Cement composite delivery system.  

PubMed

Several new and innovative techniques have recently been introduced that purport to increase the strength of polymethyl methacrylate bone cement. One of these concepts is the use of carbon and polymer fibers to form a cement composite. Bone cement composites usually 1% fiber, are very difficult to use clinically. The composite is very sticky and viscous, which precludes effective hand packing or the use of conventional delivery systems. A new delivery system for very viscous materials is presented and examples of in vitro application are shown. PMID:3453485

Convery, F R; Devine, S D; Hollis, J M; Woo, S L

1986-09-01

246

Cement and concrete  

NASA Astrophysics Data System (ADS)

To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

Corley, Gene; Haskin, Larry A.

247

Cement and concrete  

NASA Technical Reports Server (NTRS)

To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

Corley, Gene; Haskin, Larry A.

1992-01-01

248

Advanced Thermoplastic Resins, Phase 1.  

National Technical Information Service (NTIS)

Eight thermoplastic polyimide resin systems were evaluated as composite matrix materials. Two resins were selected for more extensive mechanical testing and both were versions of LaRC-TPI (Langley Research Center - Thermoplastic Polyimide). One resin was ...

C. L. Hendricks S. G. Hill A. Falcone N. T. Gerken

1991-01-01

249

Soil-Cement Study.  

National Technical Information Service (NTIS)

This study consisted of an examination of the compressive strengths of soil-cement mixtures on 15 construction projects from the standpoint of design and actual achievement. The laboratory design test was examined closely along with the present field meth...

J. L. Melancon S. C. Shah

1973-01-01

250

[Allergy towards bone cement].  

PubMed

Bone cements based on polymethylmethacrylate are typically used for fixation of artificial joints. Intolerance reactions to endoprostheses not explained by infection or mechanical failure may lead to allergological diagnostics, which mostly focuses on metal allergy. However, also bone cement components may provoke hypersensitivity reactions leading to eczema, implant loosening, or fistula formation. Elicitors of such reactions encompass acrylates and additives such as benzoyl peroxide, N,N-dimethyl-p-toluidine, hydroquinone, or antibiotics (particularly gentamicin). Upon repeated contact with bone cement components, e.g., acrylate monomers, also in medical personnel occasionally hand eczema or even asthma may develop. Therefore, in the case of suspected hypersensitivity reactions to arthroplasty, the allergological diagnostics should include bone cement components. PMID:16865384

Thomas, P; Schuh, A; Summer, B; Mazoochian, F; Thomsen, M

2006-09-01

251

Biomimetic Remineralization of Resin-bonded Acid-etched Dentin  

PubMed Central

Degradation of denuded collagen within adhesive resin-infiltrated dentin is a pertinent problem in dentin bonding. A biomimetic remineralization scheme that incorporates non-classic crystallization pathways of fluidic amorphous nanoprecursors and mesoscopic transformation has been successful in remineralizing resin-free, acid-etched dentin, with evidence of intrafibrillar and interfibrillar remineralization. This study tested the hypothesis that biomimetic remineralization provides a means for remineralizing incompletely infiltrated resin-dentin interfaces created by etch-and-rinse adhesives. The remineralization medium consists of a Portland cement/simulated body fluid that includes polyacrylic acid and polyvinylphosphonic acid biomimetic analogs for amorphous calcium phosphate dimension regulation and collagen targeting. Both interfibrillar and intrafibrillar apatites became readily discernible within the hybrid layers after 2-4 months. In addition, intra-resin apatite clusters were deposited within the porosities of the adhesive resin matrices. The biomimetic remineralization scheme provides a proof-of-concept for the adoption of nanotechnology as an alternative strategy to extend the longevity of resin-dentin bonds.

Tay, F.R.; Pashley, D.H.

2009-01-01

252

IRRADIATED PETROLEUM RESINS  

Microsoft Academic Search

A method for improving the properties of polymeric material produced by ; the Friedel-Crafts polymerization of light, cracked petroleum fractions is ; presented. The petroleum resins are mixed with a divinyl aromatic and irradiated ; at a dose rate of at least 0.1 equivalent Mr\\/hr until at least 1\\/2 equivalent Mr ; is absorbed. Resinous solids are obtained that have

J. E. Shewmaker; J. F. Nelson

1963-01-01

253

Incombustible resin composition  

NASA Technical Reports Server (NTRS)

Incombustible resin compositions composed of aromatic compounds were obtained through (1) combustion polymer material and (2) bisphenol A or halogenated bisphenol A and bisphenol A diglycidl ether or halogenated bisphenol A diglycidyl ether. The aromatic compound is an adduct of bifunctional phenols and bifunctional epoxy resins.

Akima, T.

1982-01-01

254

Delayed cure bismaleimide resins  

DOEpatents

Prior art polybismaleimides begin to polymerize at or just above the melting point of the monomer. This patent describes new bismaleimide resins which have an increased pot life and provide longer time periods in which the monomer remains fluid. The resins can be polymerized into molded articles with a high uniformity of properties. (DLC)

Not Available

1982-08-12

255

Development of a new temporary luting agent consisting of PEMA and eugenol--residue ratio and bond strength of luting cements for abutment materials.  

PubMed

PEMA- and eugenol-based trial agents (PE 1.0, PE 1.6) possessed the requisite dental engineering properties that satisfied the requirements for temporary luting agents. To assess their clinical applicability, this study examined the following properties after the trial agents were removed: their residue ratios on the abutment surface and the bond strengths of resin-modified glass ionomer cement and resin cement for the abutment materials. The residue ratio of PE 1.0 on the abutment material after temporary restoration removal was lower than those of comparable temporary luting agents (polycarboxylate cement type, zinc oxide-eugenol cement type), and no residue was recognized for PE 1.6. On bond strength, those of the resin-modified glass ionomer cement and resin cement for the resin core and bovine dentin surface after the removal of trial agents tended to be the same or increase in comparison to commercial temporary luting agents. In conclusion, results of this study suggested that the trial agents were suitable for clinical use. PMID:19662723

Okada, Hidetoshi; Ishida, Yoshinori; Noguchi, Hiroshi; Ryukata, Ichiro; Nagayama, Katsuya

2009-05-01

256

21 CFR 888.3150 - Elbow joint metal/polymer constrained cemented prosthesis.  

...Materials—Part 12: Wrought Cobalt-Chromium-Molybdenum Alloy,” (iv) ISO 5833:1992 “Implants for Surgery—Acrylic Resin Cements,” (v) ISO 5834-2:1998 “Implants for Surgery—Ultra High Molecular Weight Polyethylene—Part 2: Moulded...

2014-04-01

257

Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial  

Microsoft Academic Search

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth.Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass

A. B. S. Moretti; T. M. Oliveira; A. P. C. Fornetti; C. F. Santos; M. A. A. M. Machado; R. C. C. Abdo; V. T. Sakai

2009-01-01

258

Summary of: Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial  

Microsoft Academic Search

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth.Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass

M. Duggal

2009-01-01

259

Marginal ridge strength of tunnel-prepared teeth restored with various adhesive filling materials 1 1 This paper was originally submitted to Advanced Cement Based Materials on 2 February 1998. The paper was received at the Editorial Office of Cement and Concrete Research on 2 November 1998 and accepted in final form on 22 December 1998  

Microsoft Academic Search

This study evaluated the load required to fracture the marginal ridge of tunnel-filled teeth restored with various adhesive filling materials. Five test groups, each consisting of 20 extracted maxillary premolars, were filled with either composite resin or a conventional, a cermet, or two brands of resin-modified glass ionomer (polyalkenoat) cements. The tunnels were prepared with the occlusal access placed in

Gunhild Vesterhus Strand; Anne Bjørg Tveit; Nils Roar Gjerdet

1999-01-01

260

Development of resins for composites by resin transfer molding  

NASA Technical Reports Server (NTRS)

Designed to cover a wide range of resin technology and to meet the near-term and long-term needs of the aircraft industry, this research has three objectives: to produce resin transfer molding (RES) resins with improved processability, to produce prepreg systems with high toughness and service temperature, and to produce new resin systems. Progress on reaching the objectives is reported.

Woo, Edmund P.; Puckett, Paul M.; Maynard, Shawn J.

1991-01-01

261

Field Testing of Waste Forms Containing EPICOR-II Ion Exchange Resins Using Lysimeters.  

National Technical Information Service (NTIS)

A field study was designed to monitor the release (if any) of beta- and gamma-producing radionuclides from solidifed EPICOR-II ion exchange resins. Both Portland Type I-II cement and Dow vinyl ester-styrene waste forms are being tested in lysimeter arrays...

R. D. Rogers J. W. McConnell E. C. Davis M. W. Findley

1986-01-01

262

Biocidal quaternary ammonium resin  

NASA Technical Reports Server (NTRS)

Activated carbon (charcoal) and polymeric resin sorbents are widely used in the filtration and treatment of drinking water, mainly to remove dissolved organic and inorganic impurities and to improve the taste. Earlier hopes that activated carbon might "disinfect' water proved to be unfounded. The feasibility of protecting against microbial infestation in charcoal and resin beds such as those to be incorporated into total water reuse systems in spacecraft was investigated. The biocidal effect of IPCD (insoluable polymeric contact disinfectants) in combination with a representative charcoal was assessed. The ion exchange resins (IPCD) were shown to adequately protect charcoal and ion exchange beds.

Janauer, G. E.

1983-01-01

263

Foamed cement: A second generation. [Foamed cement slurries  

Microsoft Academic Search

Advanced technology in design and implementation of stable foamed cement systems now offers new solutions to critical oil-field cementing problems well beyond the original utility of lightweight slurries in reducing hydrostatic pressure across fracture-sensitive zones. Implications of new high-performance foamed cement capabilities are discussed for specialized applications such as thermal recovery, deep cementing in a narrow annular gap, lost-circulation control

Loeffler

1984-01-01

264

Evaluation and comparison of the effect of different surface preparations on bond strength of glass ionomer cement with nickel-chrome metal-ceramic alloy: a laboratory study.  

PubMed

Retention of fixed partial dentures is mostly dependent upon the bond between metal and cement as well as cement and tooth structure. However, most of the time clinical failure of bond has been observed at metal and cement interface. The treatment of metal surface, prior to luting, plays a crucial role in bonding cement with the metal. This study is conducted to evaluate and compare the effect of different surface preparations on the bond strength of resin-modified glass ionomer cement with nickel-chromium metal ceramic alloy. Fifty caries-free extracted molar teeth were made flat until the dentin of the occlusal surface was exposed. After fabrication of the wax patterns and subsequent castings, the castings were subjected to porcelain firing cycles. The nickel-chromium metal ceramic alloy discs were also divided into five groups and subjected to various surface treatments: (1) Unsandblasted (U), (2) sandblasted (S), (3) sandblasted and treated with 10% aqueous solution of KMnO4 (SK), (4) unsandblasted and roughened with diamond abrasive points (UD) and (5) unsandblasted and roughened with diamond abrasive points and treated with 10% aqueous solution of KMnO(4) (UDK). After surface treatments, the castings were cemented using Fuji PLUS encapsulated resin-modified glass ionomer cement. The obtained values of all the groups were subjected to statistical analysis for Tensile and Shear bond strength. Different surface treatments of the metal affects the bond strength values of resin-modified glass ionomer cement when used as luting agent. PMID:22379300

Hasti, Kalpana; Jagadeesh, H G; Patil, Narendra P

2011-03-01

265

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

Fred Sabins

2001-10-23

266

Early erosion of dental cements.  

PubMed

The disintegration in water of various unset glass ionomer cements, a polycarboxylate and a zinc phosphate cement was measured gravimetrically after exposure of the cements to a constant water jet. The test gave reproducible results with significant variations between the various types and brands of cements. For zinc phosphate and polycarboxylate cements, no weight loss was observed in the period from 4 to 8 min after commencement of mixing. All the glass ionomer cements showed a significant loss of weight at 4 min and a somewhat reduced weight loss at 6 min after start of mixing. Two cements, a filling and a luting material, showed reduced weight when exposed to a water jet even 8 min after start of mixing. The early erosion as recorded in the present study conforms with the setting of the glass ionomer cements. PMID:6597538

Oilo, G

1984-12-01

267

Expansive Cements and Their Use.  

National Technical Information Service (NTIS)

The primary purpose of shrinkage-compensating expansive cement concrete is to minimize cracking in concrete pavements and structures caused by drying shrinkage. The paper reviews the various types of expansive cements and their properties. The expansive m...

G. C. Hoff

1972-01-01

268

Dilatometry on Thermoset Resins.  

National Technical Information Service (NTIS)

A simple capillary and bulb mercury dilatometer designed for making specific volume measurements on thermoset resin systems during the curing reaction and as a function of temperature is described. The design, calibration, operation, data treatment and er...

A. W. Snow J. P. Armistead

1991-01-01

269

Thermally stable laminating resins  

NASA Technical Reports Server (NTRS)

Improved thermally stable laminating resins were developed based on the addition-type pyrolytic polymerization. Detailed monomer and polymer synthesis and characterization studies identified formulations which facilitate press molding processing and autoclave fabrication of glass and graphite fiber reinforced composites. A specific resin formulation, termed P10P was utilized to prepare a Courtaulds HMS reinforced simulated airfoil demonstration part by an autoclave molding process.

Jones, R. J.; Vaughan, R. W.; Burns, E. A.

1972-01-01

270

Reducing cement's CO2 footprint  

USGS Publications Warehouse

The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

van Oss, Hendrik G.

2011-01-01

271

High temperature lightweight foamed cements  

DOEpatents

Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed.

Sugama, Toshifumi (Mastic Beach, NY)

1989-01-01

272

High temperature lightweight foamed cements  

DOEpatents

Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. 3 figs.

Sugama, Toshifumi.

1989-10-03

273

Bond strength of composite resin to pulp capping biomaterials after application of three different bonding systems.  

PubMed

Background and aims. Bonding of composite resin filling materials to pulp protecting agents produces an adhesive joint which is important for the quality of filling as well as success of restoration. We aimed to assess the bond strength of composite resin to three pulp capping biomaterials: Pro Root mineral trioxide aggregate (PMTA), Root MTA (RMTA) and calcium enriched mixture (CEM) cement, using three bonding systems [a total-etch (Single Bond) and two self-etch systems (Protect bond and SE Bond)]. Materials and methods. Ninety acrylic molds, each containing a 6×2-mm hole, were divided into 3 groups and filled with PMTA, RMTA and CEM cements. The samples in each experimental group were then randomly divided into 3 sub-groups; Single Bond, Protect Bond and SE Bond bonding systems were applied to the tested materials. Cylindrical forms of composite resin (Z100, 2×2 mm) were placed onto the samples and cured. Shear bond strength values were measured for 9 subgroups using a universal testing machine. Data were analyzed using two-way ANOVA. Results. The average shear bond strengths of Z100 composite resin after application of Single Bond, Protect Bond and SE Bond systems were as follows; PMTA: 5.1±2.42, 4.56±1.96 and 4.52±1.7; RMTA: 4.71±1.77, 4.31±0.56 and 4.79±1.88; and CEM cement: 4.75±1.1, 4.54±1.59 and 4.64±1.78 MPa, respectively. The type of pulp capping material, bonding system and their interacting effects did not have a significant effect on the bond strengths of composite resin to pulp capping biomaterials. Conclusion. Within the limitations of this in vitrostudy, bond strength of composite resin to two types of MTA as well as CEM cement were similar following application of the total-etch or self-etch bonding systems. PMID:24082986

Jaberi-Ansari, Zahra; Mahdilou, Maryam; Ahmadyar, Maryam; Asgary, Saeed

2013-01-01

274

Bond Strength of Composite Resin to Pulp Capping Biomaterials after Application of Three Different Bonding Systems  

PubMed Central

Background and aims. Bonding of composite resin filling materials to pulp protecting agents produces an adhesive joint which is important for the quality of filling as well as success of restoration. We aimed to assess the bond strength of composite resin to three pulp capping biomaterials: Pro Root mineral trioxide aggregate (PMTA), Root MTA (RMTA) and calcium enriched mixture (CEM) cement, using three bonding systems [a total-etch (Single Bond) and two self-etch systems (Protect bond and SE Bond)]. Materials and methods. Ninety acrylic molds, each containing a 6×2-mm hole, were divided into 3 groups and filled with PMTA, RMTA and CEM cements. The samples in each experimental group were then randomly divided into 3 sub-groups; Single Bond, Protect Bond and SE Bond bonding systems were applied to the tested materials. Cylindrical forms of composite resin (Z100, 2×2 mm) were placed onto the samples and cured. Shear bond strength values were measured for 9 subgroups using a universal testing machine. Data were analyzed using two-way ANOVA. Results. The average shear bond strengths of Z100 composite resin after application of Single Bond, Protect Bond and SE Bond systems were as follows; PMTA: 5.1±2.42, 4.56±1.96 and 4.52±1.7; RMTA: 4.71±1.77, 4.31±0.56 and 4.79±1.88; and CEM cement: 4.75±1.1, 4.54±1.59 and 4.64±1.78 MPa, respectively. The type of pulp capping material, bonding system and their interacting effects did not have a significant effect on the bond strengths of composite resin to pulp capping biomaterials. Conclusion. Within the limitations of this in vitrostudy, bond strength of composite resin to two types of MTA as well as CEM cement were similar following application of the total-etch or self-etch bonding systems.

Jaberi-Ansari, Zahra; Mahdilou, Maryam; Ahmadyar, Maryam; Asgary, Saeed

2013-01-01

275

Evaluation of Resin Dissolution Using an Advanced Oxidation Process - 13241  

SciTech Connect

The ion-exchange resin is widely used in nuclear reactors, in cooling water purification and removing radioactive elements. Because of the long periods of time inside the reactor system, the resin becomes radioactive. When the useful life of them is over, its re-utilization becomes inappropriate, and for this reason, the resin is considered radioactive waste. The most common method of treatment is the immobilization of spent ion exchange resin in cement in order to form a solid monolithic matrix, which reduces the radionuclides release into the environment. However, the characteristic of contraction and expansion of the resin limits its incorporation in 10%, resulting in high cost in its direct immobilization. Therefore, it is recommended the utilization of a pre-treatment, capable of reducing the volume and degrading the resin, which would increase the load capacity in the immobilization. This work aims to develop a method of degradation of ion spent resins from the nuclear research reactor of Nuclear and Energy Research Institute (IPEN/CNEN-SP), Brazil, using the Advanced Oxidative Process (AOP) with Fenton's reagent (hydrogen peroxide and ferrous sulphate as catalyst). The resin evaluated was a mixture of cationic (IR 120P) and anionic (IRA 410) resins. The reactions were conducted by varying the concentration of the catalyst (25, 50, 100 e 150 mM) and the volume of the hydrogen peroxide, at three different temperatures, 50, 60 and 70 deg. C. The time of reaction was three hours. Total organic carbon content was determined periodically in order to evaluate the degradation as a function of time. The concentration of 50 mM of catalyst was the most effective in degrading approximately 99%, using up to 330 mL of hydrogen peroxide. The most effective temperature was about 60 deg. C, because of the decomposition of hydrogen peroxide in higher temperatures. TOC content was influenced by the concentration of the catalyst, interfering in the beginning of the degradation process. It was possible to correlate it with the final amount of non-degraded resins. These results show that these conditions were favorable to destroy the resins, indicating to be the AOP an effective technique to reduce the volume of the waste. (authors)

Goulart de Araujo, Leandro; Vicente de Padua Ferreira, Rafael; Takehiro Marumo, Julio [Nuclear and Energy Research Institute, Av. Lineu Prestes, 2242., Sao Paulo, SP. (Brazil)] [Nuclear and Energy Research Institute, Av. Lineu Prestes, 2242., Sao Paulo, SP. (Brazil); Passos Piveli, Roque; Campos, Fabio [The Polytechnic School of the University of Sao Paulo, Av. Prof. Almeida Prado, 83, trav.2. Sao Paulo, SP (Brazil)] [The Polytechnic School of the University of Sao Paulo, Av. Prof. Almeida Prado, 83, trav.2. Sao Paulo, SP (Brazil)

2013-07-01

276

40 CFR 414.50 - Applicability; description of the thermosetting resins subcategory.  

Code of Federal Regulations, 2013 CFR

...Ketone-Formaldehyde Resins *Melamine Resins *Phenolic Resins *Polyacetal Resins Polyacrylamide *Polyurethane Prepolymers *Polyurethane Resins *Urea Formaldehyde Resins *Urea Resins [52 FR 42568, Nov. 5, 1987, as amended...

2013-07-01

277

Immobilization of organic pollutants in cement pastes admixed with organophilic materials.  

PubMed

The results of 2-chloroaniline (2-CA) immobilization experiments in cement matrices, using an organophilic clay modified with phenolic resins as pre-sorbent, are shown. The 2-CA suspended in water was kept in contact with the organoclay for 24 h, and the slurry obtained was then admixed with ordinary Portland cement (OPC) without additional water, to obtain a firm solid waste. Six cement-clay pastes were prepared with the same water-to-cement ratio (0.50 wt/wt), but with different slurry composition (water-to-organoclay ratio equal to 10 and 5 wt/wt, respectively) and different amounts of 2-CA suspended in water, namely 5000, 15 000, and 25 000 ppmw (weight). Dynamic leach tests were performed on solidified monoliths in order to assess the successful immobilization of the 2-CA. Moreover, X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy analyses were carried out. PMID:19039067

Dotelli, Giovanni; Stampino, Paolo Gallo; Zampori, Luca; Sora, Isabella Natali; Pelosato, Renato

2008-12-01

278

Performance testing of grout-based waste forms for the solidification of anion exchange resins  

SciTech Connect

The solidification of spent ion exchanges resins in a grout matrix as a means of disposing of spent organic resins produced in the nuclear fuel cycle has many advantages in terms of process simplicity and economy, but associated with the process is the potential for water/cement/resins to interact and degrade the integrity of the waste form solidified. Described in this paper is one possible solution to preserving the integrity of these solidified waste forms: the encapsulation of beaded anion exchange resins in grout formulations containing ground granulated blast furnace slag, Type I-II (mixed) portland cement, and additives (clays, amorphous silica, silica fume, and fly ash). The results of the study reported herein show the cured waste form tested has a low leach rate for nitrate ion from the resin (and a low leach rate is inferred for Tc-99) and acceptable durability as assessed by the water immersion and freezing/thawing test protocols. The results also suggest a tested surrogate waste form prepared in vinyl ester styrene binder performs satisfactorily against the wetting/drying criterion, and it should offer additional insight into future work on the solidification of spent organic resins. 26 refs., 4 figs., 5 tabs.

Morgan, I.L.; Bostick, W.D.

1990-10-01

279

Reliability of fiber post bonding to root canal dentin after simulated clinical function in vitro.  

PubMed

The aim of this study was to investigate the effect of thermomechanical loading (TML) on the bond strength of fiber posts luted with three different resin cements. Sixty-six extracted human anterior teeth were endodontically treated and restored with fiber posts (RelyX Fiber Posts, 3M ESPE) using three commercially available resin cements and three corresponding core build-up materials (n=22 each): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), and RelyX Unicem/Filtek Z250 (3M ESPE). Twelve specimens of each group received all-ceramic crowns and were subjected to TML. The other 10 specimens were stored in saline solution for 24 hours. The roots were sectioned and bond strength was measured using a push-out test. Adhesive interfaces of two specimens of each group subjected to TML were analyzed using field emission scanning electron microscopy (FESEM). Bond strengths of fiber posts were significantly affected by the type of resin cement (p<0.0005) and TML (p<0.0005; two-way analysis of variance). TML significantly reduced bond strengths for all materials ((6.0 (6.2) MPa)) compared with initial bond strengths ((14.9 (10.4) MPa)). RelyX Unicem resulted in significantly higher bond strengths before ((18.3 (10.3) MPa)) and after TML ((9.8 (7.5) MPa)) compared with the other materials (p<0.0005; Tukey HSD). Using FESEM, Variolink II and Panavia F demonstrated a hybrid layer partly detached from the underlying resin cement, whereas no hybrid layer was observed for RelyX Unicem. The decrease in bond strength after TML suggests that retention of fiber posts may be reduced after clinical function. Therefore, endodontically treated teeth that are restored using fiber posts may benefit from additional reinforcement via coronal restorations using adequate ferrules and/or adhesive techniques. PMID:22339386

Bitter, K; Perdigão, J; Exner, M; Neumann, K; Kielbassa, Am; Sterzenbach, G

2012-01-01

280

External sleeve cementing tool  

SciTech Connect

This patent describes a cementing tool apparatus. It comprises a tubular housing having an inner passage defined longitudinally therethrough and having a radially outer surface, the housing also having a cementing port and a longitudinal slot both disposed through a wall thereof; an outer closure sleeve slidably received about the outer surface of the housing and movable relative to the housing between an open position wherein the cementing port is uncovered by the closure sleeve and a closed position wherein the cementing port is closed by the closure sleeve; an inner operating sleeve slidably received in the housing and slidable between first and second positions relative to the housing; and mechanical interlocking means, extending through the slot and operably associated with both the operating sleeve and the closure sleeve, for mechanically transferring a closing force from the operating sleeve to the closure sleeve and thereby moving the closure sleeve to its closed position as the operating sleeve moves from its first position to its second position.

Giroux, R.L.; Brandell, J.T.

1991-08-13

281

Phenoxy Resins Containing Pendent Ethynyl Groups and Cured Resins Therefrom.  

National Technical Information Service (NTIS)

Phenoxy resins containing pendent ethynyl groups, the process for preparing the same, and the cured resin products obtained therefrom, are discussed. Upon the application of heat, the ethynyl groups react to provide branching and crosslinking. The cure te...

P. M. Hergenrother

1984-01-01

282

A comparative evaluation of dental luting cements by fracture toughness tests and fractography.  

PubMed

In recent years there has been a shift from traditional methods of investigating dental materials to a fracture mechanics approach. Fracture toughness (KIC) is an intrinsic material property which can be considered to be a measure of a material's resistance to crack propagation. Glass-ionomer cements are biocompatible and bioactive dental restorative materials, but they suffer from poor fracture toughness and are extremely susceptible to dehydration. The main objective of this study was to evaluate the fracture toughness of three types of commercially available dental cements (polyacid-modified composite resin, resin-modified and conventional glass ionomer) using a short-rod chevron-notch test and to investigate and interpret the results by means of fractography using scanning electron microscopy. Ten specimens of each cement were fabricated according to manufacturers' instructions, coated in varnish, and stored at ambient laboratory humidity, 100 per cent relative humidity, or in water at 37 degrees C for 7 days prior to preparation for testing. Results indicated that significant differences existed between each group of materials and that the fracture toughness ranged from 0.27 to 0.72 MN/m3/2. It was concluded that the resin-modified glass-ionomer cement demonstrated the highest resistance to crack propagation. Fractographs clearly showed areas of stable and unstable crack growth along the fractured surfaces for the three materials examined. PMID:11323987

Ryan, A K; Orr, J F; Mitchell, C A

2001-01-01

283

High-performance bismaleimide resin for resin film infusion  

Microsoft Academic Search

A novel high-performance resin system, suitable for resin film infusion (RFI) process, has been developed. It was prepared from N,N?-diphenylbismaleimide, o,o?-diallylbisphenol A, and polyethylsulfone. The resin and its composite, reinforced by a glass fiber cloth, were prepared and characterized in detail. The results showed that the prepared resin film is stable at room temperature, the infusion temperature is 120°C, and

Guozheng Liang; Dong Wang

2002-01-01

284

Method for regenerating ion exchange resin.  

National Technical Information Service (NTIS)

This invention is comprised of a method for regenerating ion exchange resin consisting of a mixed resin containing granular cation exchange resin and anion exchange resin contaminated during condensation treatment in steam power generating plants, charact...

M. Ogihara, K. Ichikawa, T. Idemizu

1991-01-01

285

Adhesion of composite luting cement to Er:YAG-laser-treated dentin.  

PubMed

Although some studies claim to the increase of composite resin adhesion to Er:YAG-laser-treated dentin, there are still no reports on the adhesion of composite resin cements to the irradiated surface. This in vitro study evaluated the tensile bond strength (TBS) of a composite resin cement to dentin treated with the Er:YAG laser. Sixty human dentin samples were divided into four groups (n = 15): G1 (Control)-no treatment; G2-Er:YAG laser 60 mJ, 2 Hz, with water cooling, non-contact (19 J/cm(2)); G3-Er:YAG laser 60 mJ, 10 Hz, 50/10 fiber, contact, without water cooling (40 J/cm(2)); G4-Er:YAG laser 60 mJ, 10 Hz, 50/10 fiber, contact, with water cooling (40 J/cm(2)). After the surface treatment, each sample was submitted to bonding procedures. The analysis of variance (ANOVA) and Tukey tests revealed no statistical significant difference on TBS values for groups G1 (13.73 +/- 3.05 MPa), G2 (12.60 +/- 2.09 MPa) and G4 (11.17 +/- 4.04 MPa). G4 was not statistically different from G3 (8.64 +/- 2.06 MPa). Er:YAG laser irradiation with different settings can constitute an alternative tool to the use of composite resin-luting cements. PMID:17235450

Carrieri, Teresa C D; de Freitas, Patricia M; Navarro, Ricardo S; Eduardo, Carlos de P; Mori, Matsuyoshi

2007-09-01

286

Waiting time for coronal preparation and the influence of different cements on tensile strength of metal posts.  

PubMed

This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16?mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP) cement or resin cement (RC), the specimens were divided into 3 groups (n = 10) according to the waiting time for core preparation: no preparation (control), 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5?mm/min) until failure. Two-way ANOVA (time versus cement) and the Tukey tests (P < 0.05) showed significantly higher (P < 0.05) tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation. PMID:22291705

Oliveira, Ilione Kruschewsky Costa Sousa; Arsati, Ynara Bosco de Oliveira Lima; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes

2012-01-01

287

Waiting Time for Coronal Preparation and the Influence of Different Cements on Tensile Strength of Metal Posts  

PubMed Central

This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16?mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP) cement or resin cement (RC), the specimens were divided into 3 groups (n = 10) according to the waiting time for core preparation: no preparation (control), 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5?mm/min) until failure. Two-way ANOVA (time versus cement) and the Tukey tests (P < 0.05) showed significantly higher (P < 0.05) tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation.

Oliveira, Ilione Kruschewsky Costa Sousa; Arsati, Ynara Bosco de Oliveira Lima; Basting, Roberta Tarkany; Franca, Fabiana Mantovani Gomes

2012-01-01

288

Westinghouse Cementation Facility of Solid Waste Treatment System - 13503  

SciTech Connect

During NPP operation, several waste streams are generated, caused by different technical and physical processes. Besides others, liquid waste represents one of the major types of waste. Depending on national regulation for storage and disposal of radioactive waste, solidification can be one specific requirement. To accommodate the global request for waste treatment systems Westinghouse developed several specific treatment processes for the different types of waste. In the period of 2006 to 2008 Westinghouse awarded several contracts for the design and delivery of waste treatment systems related to the latest CPR-1000 nuclear power plants. One of these contracts contains the delivery of four Cementation Facilities for waste treatment, s.c. 'Follow on Cementations' dedicated to three locations, HongYanHe, NingDe and YangJiang, of new CPR-1000 nuclear power stations in the People's Republic of China. Previously, Westinghouse delivered a similar cementation facility to the CPR-1000 plant LingAo II, in Daya Bay, PR China. This plant already passed the hot functioning tests successfully in June 2012 and is now ready and released for regular operation. The 'Follow on plants' are designed to package three 'typical' kind of radioactive waste: evaporator concentrates, spent resins and filter cartridges. The purpose of this paper is to provide an overview on the Westinghouse experience to design and execution of cementation facilities. (authors)

Jacobs, Torsten; Aign, Joerg [Westinghouse Electric Germany GmbH, Global Waste Management, Tarpenring 6, D- 22419 Hamburg (Germany)] [Westinghouse Electric Germany GmbH, Global Waste Management, Tarpenring 6, D- 22419 Hamburg (Germany)

2013-07-01

289

Quality improvement of photopolimerizable-cement root canal obturation  

NASA Astrophysics Data System (ADS)

The sealing cements commonly used for endodontic applications are of the type cured through chemical reactions. During the polymerization process, mechanical contractions are not uncommon, leading to a non-perfect sealing. Photopolymerizable cements usually presents superior performance as compared to those chemically activated. However, difficulties in carrying the light to difficult-to-reach regions like the dental apex preclude those material of being accepted in the dental office routine. This work reports on a novel technique which allow the light curing of photopolymerizable cements in endodontic applications. A special light guide had been developed to allow the curing light to reach and polymerize the sealing cement in the apex region. The technique was tested by using single-root human teeth with normal canal morphology. The Ultradent EndoREZ root canal sealer and a resin-based photopolymerizable filler specially developed for the current application had been used. The cone-shaped light guide was introduced into treated canals filled with the photopolymerizable material, up to the apical region. Light from an argon laser was launched onto the light guide for polymerization. All test samples were immersed in methylene-blue solution for microleakage testing. All samples treated with the self-polymerizable material presented dye penetration to some extent. No sample within the group which had the filling material polymerized by using the light guide presented dye penetration through the canal wall.

Lupato Conrado, Luis A.; Frois, Iris M.; Amaro Zangaro, Renato; Munin, Egberto; Kuranaga, Carlos; Dias da Silva, Marcos; do Carmo de Andrade Nono, Maria; Cerquiera Rezende, Mirabel

2003-06-01

290

Method for removing contaminants from plastic resin  

DOEpatents

A resin recycling method that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The method includes receiving the resin in container form. The containers are then ground into resin particles. The particles are exposed to a solvent, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. After separating the particles and the resin, a solvent removing agent is used to remove any residual solvent remaining on the resin particles after separation.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2008-12-09

291

Phosphonic acid based exchange resins  

DOEpatents

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1995-01-01

292

Phosphonic acid based exchange resins  

DOEpatents

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1995-09-12

293

Graphite Fiber Reinforced Thermoplastic Resins.  

National Technical Information Service (NTIS)

Mechanical properties of neat resin samples and graphite fiber reinforced samples of thermoplastic resins were characterized with particular emphasis directed to the effects of environmental exposure (humidity, temperature and ultraviolet radiation). Tens...

R. C. Novak

1975-01-01

294

Mineral resource of the month: hydraulic cement  

USGS Publications Warehouse

Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

van Oss, Hendrik G.

2012-01-01

295

Bond Strength of Adhesive Luting Agents to Caries-affected Dentin.  

PubMed

SUMMARY Introduction: The aim of this study was to evaluate the bond strength of adhesive luting agents to caries-affected dentin (CAD). Methods: Forty human molars were sectioned to create dental slices presenting exposed occlusal dentin. Half of the samples were submitted to eight caries-induction demineralizing/mineralizing cycles. The pH-cycling model consisted of three hours in a demineralizing solution followed by 45 hours of immersion in a mineralizing solution. Dentin hardness was measured before and after the pH cycling. Resin cement cylinders were built up over the dentin surface using RelyX Unicem or RelyX ARC/Scotchbond Multipurpose Plus. The cement cylinders were submitted to shear load, and the data were analyzed using two-way analysis of variance (ANOVA) and Tukey test (p<0.05). Hardness data were also submitted to two-way ANOVA and Tukey test (p<0.05). The relationship of hardness vs bond strength was assessed via nonlinear regression analysis. Results: Sound dentin (tested and used in caries induction) showed similar values of hardness and were superior to CAD. Both resin cements showed higher bond strength to sound dentin than to CAD. Independent of substrate, RelyX ARC showed the highest values of bond strength. A positive linear relationship between dentin hardness and bond strength was observed for both cements evaluated. Conclusions: The adhesive luting agents evaluated showed lower bond strength to CAD. PMID:24147744

Rocha, Ct; Faria-E-Silva, Al; Peixoto, Ac

2014-01-01

296

Thermal Shock-resistant Cement  

SciTech Connect

We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved cement, causing its volume to expand.

Sugama T.; Pyatina, T.; Gill, S.

2012-02-01

297

Production of petroleum polymer resins  

Microsoft Academic Search

In other countries, petroleum polymer resins are being used successfully in large volumes. In the U.S. in 1982, for example, 128,000 tonnes of petroleum polymer resins were produced [2], much of which was used in the paint and varnish industry. In commercial production in the USSR are a dark-colored styrene-lndene resin and light-colored petroleum polymer resins of two types --

Yu. V. Dumskii; M. E. Belyakov; A. K. Suroto; G. F. Cherednikova; L. B. Grin'ko

1988-01-01

298

Development of Volume-Reduction System for Ion Exchange Resin Using Inductively Coupled Plasma  

NASA Astrophysics Data System (ADS)

The spent ion exchange resin generated as radioactive waste in water purifying system at nuclear power stations or related facilities of nuclear power has been stored in the site, and its volume has been increasing year by year. We had developed a full-scale system of IC plasma volume-reduction system for the spent resin, and have performed basic performance test using some samples imitating the spent resin. As the results, the imitation of the resin can be reduced in volume by more than 90% so that the processing performance in actual scale was proved to be effective. In addition, it was clarified that the residuum after volume-reduction process is easy to mix with cement, and solidity containing 30wt% residuum provides high strength of 68MPa. Therefore, we evaluate the application of this process to stabilization of the disposal to be very effective.

Fujisawa, Morio; Katagiri, Genichi

299

Dental composite resins: measuring the polymerization shrinkage using optical fiber Bragg grating sensors  

NASA Astrophysics Data System (ADS)

Polymerization shrinkage of dental composite materials is recognized as one of the main reasons for the development of marginal leakage between a tooth and filling material. As an alternative to conventional measurement methods, we propose optical fiber Bragg grating (FBG) based sensors to perform real-time strain and shrinkage measurements during the curing process of dental resin cements. We introduce a fully automated set-up to measure the Bragg wavelength shift of the FBG strain sensors and to accurately monitor the linear strain and shrinkage of dental resins during curing. Three different dental resin materials were studied in this work: matrix-filled BisGMA-based resins, glass ionomers and organic modified ceramics.

Ottevaere, H.; Tabak, M.; Chah, K.; Mégret, P.; Thienpont, H.

2012-05-01

300

Cement evaluation tool: a new approach to cement evaluation  

SciTech Connect

Cement bond logging achieves its greatest utility when it provides the production engineer with precise indications of cement strength and distribution around the casing. Zone isolation is of critical importance in production. Previous logging systems have yielded measures of cement bond that were circumferential averages of cement quality. These were difficult to interpret. Additionally, they were sensitive to the degree of shear coupling between pipe, cement, and formation and thus were affected by microannulus. The cement evaluation tool (CET) described here overcomes these difficulties. It provides a measurement of cement presence and strength, which is largely insensitive to microannulus. Its log output is interpreted easily. Tool design allows examination of the casing circumferentially at each depth. Impedance behind casing is measured. Laboratory calibration measurements allow this to be presented in terms of cement compressive strength. Cement channels are distinguished easily, and a zone isolation indicator can be presented. Additionally, casing internal diameter and distortion are displayed. European and North American field tests have been completed, and performance for a variety of well conditions is discussed. The ability of the tool to identify channels is confirmed. Sequential runs with and without excess pressure demonstrate immunity to microannulus in cases where CBL is affected but where microannulus is small enough to prohibit hydraulic communication. Geometrical measurements have been good indicators of casing deformation and have identified casing corrosion and wear.

Froelich, B.; Dumont, A.; Pittman, D.; Seeman, B.

1982-08-01

301

Resin impregnation process for producing a resin-fiber composite  

NASA Technical Reports Server (NTRS)

Process for vacuum impregnation of a dry fiber reinforcement with a curable resin to produce a resin-fiber composite, by drawing a vacuum to permit flow of curable liquid resin into and through a fiber reinforcement to impregnate same and curing the resin-impregnated fiber reinforcement at a sufficient temperature and pressure to effect final curing. Both vacuum and positive pressure, e.g. autoclave pressure, are applied to the dry fiber reinforcement prior to application of heat and prior to any resin flow to compact the dry fiber reinforcement, and produce a resin-fiber composite of reduced weight, thickness and resin content, and improved mechanical properties. Preferably both a vacuum and positive pressure, e.g. autoclave pressure, are also applied during final curing.

Palmer, Raymond J. (Inventor); Moore, William E. (Inventor)

1994-01-01

302

Diametral tensile strength and water sorption of glass-ionomer cements used in Atraumatic Restorative Treatment.  

PubMed

The purposes of this study were to evaluate the diametral tensile strength and the water sorption of restorative (Fuji IX and Ketac Molar) and resin-modified glass-ionomer luting cements (ProTec Cem, Fuji Plus and Vitremer) mixed at both manufacturer and increased powder: liquid ratio, for their use in the Atraumatic Restorative Treatment. A conventional restorative glass-ionomer (Ketac Fil) was used as control. Specimens (6.0 mm in diameter x 3.0 mm in height) were prepared and stored (1 hour, 1 day and 1 week) for a diametral tensile strength test. Data were subjected to two-way ANOVA and Tukey tests (p<0.05). For the water sorption test, specimens of 15.0 mm in diameter x 0.5 mm in height were prepared and transfered to desiccators until a constant mass was obtained. Then the specimens were immersed in deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Data were subjected to one-way ANOVA and Tukey tests (p<0.05). Five specimens of each studied material and consistency were prepared for each test. The resin-modified glass-ionomer cements showed significantly higher strength than the conventional materials. Except for ProTec Cem, the diametral tensile strength of the resin-modified materials significantly increased from luting to restorative consistency. Except for ProTec Cem, the water sorption of the resin-modified glass ionomers was higher than the others. The water sorption of resin-modified materials at restorative consistency was significantly lower than at luting consistency. Resin-modified glass-ionomer luting cements mixed at increased powder: liquid ratio showed better properties than at luting consistency. PMID:21409320

Cefaly, Daniela Francisca Gigo; Franco, Eduardo Batista; Mondelli, Rafael Francisco Lia; Francisconi, Paulo Afonso Silveira; Navarro, Maria Fidela de Lima

2003-06-01

303

Development of Polyimide Resins.  

National Technical Information Service (NTIS)

Polyimides are well-known to be attractive matrix resins for fiber-reinforced composites due to their superior thermal stability. However, their poor fabricability and high cost have been preventing them from being widely used. This paper reports three ap...

Y. Aito

1984-01-01

304

Cement penetration after patella venting.  

PubMed

There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

2009-01-01

305

Natural cement and monumental restoration  

Microsoft Academic Search

Natural cement, called “Roman” cement, was invented at the end of the 19th century and played an important role in the development\\u000a of civil engineering works until the 1860s. More surprisingly, it was also used to restore historic buildings, such as gothic\\u000a cathedrals. This paper deals with the mineralogy and the durability of natural cement in the particular case of

C. Gosselin; V. Verges-Belmin; A. Royer; G. Martinet

2009-01-01

306

Abrasive wear of cemented carbides  

SciTech Connect

Cemented carbides are used for a wide variety of applications where wear is a problem. Usually the wear of the cemented carbides is a combination of metal-to-metal and abrasion. Wear can occur at room or elevated temperatures. This research summarizes initial research to understand the abrasive wear of various cemented carbides (various grain sizes, carbide types, carbide grain sizes and binder compositions) in terms of absolute material removal rates and material removal mechanisms.

Hawk, Jeffrey A.; Wilson, Rick D.

2003-10-01

307

Nontoxic Resins Advance Aerospace Manufacturing  

NASA Technical Reports Server (NTRS)

The 2008 NASA Commercial Invention of the Year, PETI-330, is a polyimide matrix resin that performs well at high temperatures and is easily processed into composites in a simple, short curing cycle. Invented by scientists at Langley Research Center, PETI-330 is now licensed to Ube Industries, based in Japan with its American headquarters in New York. In addition to being durable and lightweight, the resin is also nontoxic, which makes it safe for workers to handle. PETI-330 was created specifically for heat-resistant composites formed with resin transfer molding and resin infusion, which formerly could only be used with low temperature resin systems.

2009-01-01

308

[Allergy to bone cement components].  

PubMed

Intolerance reactions to endoprostheses may lead to allergological diagnostics, which focus mainly on metal allergy. However, bone cement may also contain potential allergens, e.g. acrylates and additives such as benzoyl peroxide (BPO), N,N-dimethyl-p-toluidine, hydroquinone, and antibiotics (particularly gentamicin). In the Munich implant allergy clinic, we found that 28 of 113 patients (24.8%) with cemented prostheses had contact allergies to bone cement components, mostly to gentamicin (16.8%) and BPO (8.0%). The clinical significance of test results cannot always be shown, but we still recommend including bone cement components in the allergological diagnostics of suspected hypersensitivity reactions to arthroplasty. PMID:18227996

Thomas, P; Schuh, A; Eben, R; Thomsen, M

2008-02-01

309

High elastic modulus nanopowder reinforced resin composites for dental applications  

NASA Astrophysics Data System (ADS)

Dental restorations account for more than $3 billion dollars a year on the market. Among them, all-ceramic dental crowns draw more and more attention and their popularity has risen because of their superior aesthetics and biocompatibility. However, their relatively high failure rate and labor-intensive fabrication procedure still limit their application. In this thesis, a new family of high elastic modulus nanopowder reinforced resin composites and their mechanical properties are studied. Materials with higher elastic modulus, such as alumina and diamond, are used to replace the routine filler material, silica, in dental resin composites to achieve the desired properties. This class of composites is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Most of the work focuses on nano-sized Al2O3 (average particle size 47 nm) reinforcement in a polymeric matrix with 50:50 Bisphenol A glycidyl methacrylate (Bis-GMA): triethylene glycol dimethacrylate (TEGDMA) monomers. Surfactants, silanizing agents and primers are examined to obtain higher filler levels and enhance the bonding between filler and matrix. Silane agents work best. The elastic modulus of a 57.5 vol% alumina/resin composite is 31.5 GPa compared to current commercial resin composites with elastic modulus <15 GPa. Chemical additives can also effectively raise the hardness to as much as 1.34 GPa. Besides>alumina, diamond/resin composites are studied. An elastic modulus of about 45 GPa is obtained for a 57 vol% diamond/resin composite. Our results indicate that with a generally monodispersed nano-sized high modulus filler, relatively high elastic modulus resin-based composite cements are possible. Time-dependent behavior of our resin composites is also investigated. This is valuable for understanding the behavior of our material and possible fatigue testing in the future. Our results indicate that with effective coupling agents and higher filler loading, viscous flow can be greatly decreased due to the attenuation of mobility of polymer chains. Complementary studies indicate that our resin composites are promising for the proposed applications as a stiff support to all-ceramic crowns.

Wang, Yijun

310

The effect of different adhesive system applications on push-out bond strengths of glass fiber posts  

PubMed Central

PURPOSE Over the past years, the adhesion of fiber posts luted with simplified adhesive systems has been a matter of great interest. The aim of this study was to assess the post retentive potential of a self-adhesive resin cement using different adhesive systems to compare the push-out bond strengths of fiber posts. MATERIALS AND METHODS The post spaces of 56 mandibular premolar roots were prepared and divided into 4 experimental groups and further divided into 2 subgroups according to testing time (n=7). The fiber posts (Rely X Fiber Post) were luted with a self-adhesive resin cement (RelyX Unicem) and one of the following adhesive systems: no adhesive, a total-etch adhesive resin (Single Bond), a two-step self-etch adhesive resin (Clearfil SE Bond) and a one-step self-etch adhesive resin (Clearfil S3 Bond). Each root was cut horizontally, and 1.5 mm thick six root segments were prepared. Push-out tests were performed after one week or three months (0.5 mm/min). Statistical analysis were performed with three-way ANOVA (?=.05). RESULTS Cervical root segments showed higher bond strength values than middle segments. Adhesive application increased the bond strength. For one week group, the total-etch adhesive resin Single Bond showed higher bond strength than the self-adhesive resin cement RelyX Unicem applied without adhesive resin at middle region. For 3 months group, the two-step self-etch adhesive resin Clearfil SE Bond showed the highest bond strength for both regions. Regarding the time considered, Clearfil SE Bond 3 months group showed higher bond strength values than one week group. CONCLUSION Using the adhesive resins in combination with the self-adhesive resin cement improves the bond strengths. The bond strength values of two-step self-etch adhesive resin Clearfil SE Bond improved as time passes.

Deniz Ar?su, Hacer; Uctasl?, Mine Betul; Okay, Tufan Can

2013-01-01

311

Phosphate based oil well cements  

NASA Astrophysics Data System (ADS)

The main application of the cement in an oil well is to stabilize the steel casing in the borehole and protect it from corrosion. The cement is pumped through the borehole and is pushed upwards through the annulus between the casing and the formation. The cement will be exposed to temperature and pressure gradients of the borehole. Modified Portland cement that is being used presently has several shortcomings for borehole sealant. The setting of the Portland cement in permafrost regions is poor because the water in it will freeze even before the cement sets and because of high porosity and calcium oxide, a major ingredient it gets easily affected by the down hole gases such as carbon dioxide. The concept of phosphate bonded cements was born out of considerable work at Argonne National Laboratory (ANL) on their use in stabilization of radioactive and hazardous wastes. Novel cements were synthesized by an acid base reaction between a metal oxide and acid phosphate solution. The major objective of this research is to develop phosphate based oil well cements. We have used thermodynamics along with solution chemistry principles to select calcined magnesium oxide as candidate metal oxide for temperatures up to 200°F (93.3°C) and alumina for temperatures greater than 200°F (93.3°C). Solution chemistry helped us in selecting mono potassium phosphate as the acid component for temperatures less than 200°F (93.3°C) and phosphoric acid solution greater than 200°F (93.3°C). These phosphate cements have performance superior to common Portland well cements in providing suitable thickening time, better mechanical and physical properties.

Natarajan, Ramkumar

312

Effect of Hygroscopic Expansion on the Push-Out Resistance of Glass Ionomer-Based Cements Used for the Luting of Glass Fiber Posts  

Microsoft Academic Search

This study examined the contribution of hygroscopic expansion of glass-ionomer (GIC) and resin modified glass-ionomer (RMGIC) luting cements to the push-out resistance of fiber posts. Glass fiber posts were luted to post spaces using different cements. Experimental specimens were stored in water, while control specimens were desiccated and stored in mineral oil to eliminate water from intraradicular dentinal tubules and\\/or

Álvaro H. Cury; Cecilia Goracci; Maria Fidela de Lima Navarro; Ricardo M. Carvalho; Fernanda T. Sadek; Franklin R. Tay; Marco Ferrari

2006-01-01

313

Solidification of Ion Exchange Resin Wastes.  

National Technical Information Service (NTIS)

Solidification media investigated included portland type I, portland type III and high alumina cements, a proprietary gypsum-based polymer modified cement, and a vinyl ester-styrene thermosetting plastic. Samples formulated with hydraulic cement were anal...

1982-01-01

314

Flame Retardant Epoxy Resins  

NASA Technical Reports Server (NTRS)

As part of a program to develop fire resistant exterior composite structures for future subsonic commercial aircraft, flame retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured epoxies were characterized by thermogravimetric analysis, propane torch test, elemental analysis and microscale combustion calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness of plaques of several cured formulations was determined on single-edge notched bend specimens. The chemistry and properties of these new epoxy formulations are discussed.

Thompson, C. M.; Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.; Lyon, R. E.

2004-01-01

315

Resin composite restorative materials.  

PubMed

This paper surveys the most important developments in resin-based dental composites and focuses on the deficits (e.g. polymerization shrinkage) and strengths of the materials and their clinical implications. Moreover, differences between composite categories, such as hybrid, nanohybrid, microfilled, packable, ormocer-based, silorane-based, polyacid-modified composites (compomers) and flowable composites are highlighted, especially in view of their mechanical behaviour. In addition to the classical dimethacrylate-based composites, special attention is given to alternative monomers, such as siloranes, ormocers or high-molecular-weight dimethacrylate monomers (e.g. dimer acid-based dimethacrylates and tricyclodecane (TCD)-urethane), analysing their advantages, behaviour and abilities. Finally, the paper attempts to establish the needs and wishes of clinicians for further development of resin-based composites. PMID:21564116

Ilie, N; Hickel, R

2011-06-01

316

Accelerating set of retarded cement  

SciTech Connect

This patent describes improvement in a method of setting a volume of cement in a well completed in a subterranean formation in which a cement is or may become retarded and is pumped into the well and allowed to set to form a hard cementitious material there within. The improvement comprises contacting the cement with a solution of a compatible organic accelerator comprising a material that will produce formate ions in the cement slurry and selected from the group consisting of the first four carbon esters of formic acid, the esters including methyl formate, ethyl formate, normal-propyl formate, iso-propyl formate, normal-butyl formate, iso-butyl formate, and t-butyl formate. The patent also describes improvement in a method of setting a volume of cement in a well completed in subterranean formation, in which a cement is or may become retarded and is pumped into the well and allowed to set to form hard cementitious material therewithin at liner tops and in wellbore plugs. The improvement comprises contacting downhole the cement with a solution of a compatible organic accelerator comprising a material that will produce formate ions in the cement slurry and selected from the group consisting of formamide, and esters of formic acid, the esters including methyl formate, ethyl formate, normal propyl formate, isopropyl formate, normal butyl formate, iso-butyl formate and t-butyl formate.

Bloys, J.B.; Carpenter, R.B.; Wilson, W.N.

1991-04-09

317

Microtensile bond strength of composite resin to glass-infiltrated alumina composite conditioned with Er,Cr:YSGG laser.  

PubMed

Tribochemical silica-coating is the recommended conditioning method for improving glass-infiltrated alumina composite adhesion to resin cement. High-intensity lasers have been considered as an alternative for this purpose. This study evaluated the morphological effects of Er,Cr:YSGG laser irradiation on aluminous ceramic, and verified the microtensile bond strength of composite resin to ceramic following silica coating or laser irradiation. In-Ceram Alumina ceramic blocks were polished, submitted to airborne particle abrasion (110 ?m Al(2)O(3)), and conditioned with: (CG) tribochemical silica coating (110 ?m SiO(2)) + silanization (control group); (L1-L10) Er,Cr:YSGG laser (2.78 ?m, 20 Hz, 0.5 to 5.0 W) + silanization. Composite resin blocks were cemented to the ceramic blocks with resin cement. These sets were stored in 37°C distilled water (24 h), embedded in acrylic resin, and sectioned to produce bar specimens that were submitted to microtensile testing. Bond strength values (MPa) were statistically analyzed (? ?0.05), and failure modes were determined. Additional ceramic blocks were conditioned for qualitative analysis of the topography under SEM. There were no significant differences among silicatization and laser treatments (p > 0.05). Microtensile bond strength ranged from 19.2 to 27.9 MPa, and coefficients of variation ranged from 30 to 55%. Mixed failure of adhesive interface was predominant in all groups (75-96%). No chromatic alteration, cracks or melting were observed after laser irradiation with all parameters tested. Surface conditioning of glass-infiltrated alumina composite with Er,Cr:YSGG laser should be considered an innovative alternative for promoting adhesion of ceramics to resin cement, since it resulted in similar bond strength values compared to the tribochemical treatment. PMID:20737182

Eduardo, Carlos de Paula; Bello-Silva, Marina Stella; Moretto, Simone Gonçalves; Cesar, Paulo Francisco; de Freitas, Patricia Moreira

2012-01-01

318

Dual setting ?-tricalcium phosphate cements.  

PubMed

An extension of the application of calcium phosphate cements (CPC) to load-bearing defects, e.g. in vertebroplasty, would require less brittle cements with an increased fracture toughness. Here we report the modification of CPC made of alpha-tricalcium phosphate (?-TCP) with 2-hydroxyethylmethacrylate (HEMA), which is polymerised during setting to obtain a mechanically stable polymer-ceramic composite with interpenetrating organic and inorganic networks. The cement liquid was modified by the addition of 30-70 % HEMA and ammoniumpersulfate/tetramethylethylendiamine as initiator. Modification of ?-TCP cement paste with HEMA decreased the setting time from 14 min to 3-8 min depending on the initiator concentration. The 4-point bending strength was increased from 9 MPa to more than 14 MPa when using 50 % HEMA, while the bending modulus decreased from 18 GPa to approx. 4 GPa. The addition of ?50 % HEMA reduced the brittle fracture behaviour of the cements and resulted in an increase of the work of fracture by more than an order of magnitude. X-ray diffraction analyses revealed that the degree of transformation of ?-TCP to calcium deficient hydroxyapatite was lower for polymer modified cements (82 % for polymer free cement and 55 % for 70 % HEMA) after 24 h setting, while the polymerisation of HEMA in the cement liquid was quantitative according to FT-IR spectroscopy. This work demonstrated the feasibility of producing fracture resistant dual-setting calcium phosphate cements by adding water soluble polymerisable monomers to the liquid cement phase, which may be suitable for an application in load-bearing bone defects. PMID:23239262

Christel, T; Kuhlmann, M; Vorndran, E; Groll, J; Gbureck, U

2013-03-01

319

System for removing contaminants from plastic resin  

DOEpatents

A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2010-11-23

320

Advanced thermoplastic resins, phase 1  

NASA Technical Reports Server (NTRS)

Eight thermoplastic polyimide resin systems were evaluated as composite matrix materials. Two resins were selected for more extensive mechanical testing and both were versions of LaRC-TPI (Langley Research Center - Thermoplastic Polyimide). One resin was made with LaRC-TPI and contained 2 weight percent of a di(amic acid) dopant as a melt flow aid. The second system was a 1:1 slurry of semicrystalline LaRC-TPI powder in a polyimidesulfone resin diglyme solution. The LaRC-TPI powder melts during processing and increases the melt flow of the resin. Testing included dynamic mechanical analysis, tension and compression testing, and compression-after-impact testing. The test results demonstrated that the LaRC-TPI resins have very good properties compared to other thermoplastics, and that they are promising matrix materials for advanced composite structures.

Hendricks, C. L.; Hill, S. G.; Falcone, A.; Gerken, N. T.

1991-01-01

321

Corrosion susceptibility of steel drums containing cemented intermediate level nuclear wastes  

NASA Astrophysics Data System (ADS)

Cementation processes are used as immobilization techniques for low or intermediate level radioactive waste for economical and safety reasons and for being a simple operation. In particular, ion-exchange resins commonly used for purification of radioactive liquid waste from nuclear reactors are immobilized before being stored to improve the leach resistance of the waste matrix and to maintain mechanical stability. Combustible solid radioactive waste can be incinerated and the resulting ashes can also be immobilized before storage. The immobilized resins and ashes are then contained in steel drums that may undergo corrosion depending on the presence of certain contaminants. The work described in this paper was aimed at evaluating the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins and incineration ashes containing different concentrations of aggressive species (mostly chloride and sulphate ions). A special type of specimen was designed to simulate the cemented waste in the drum. The evolution of the corrosion potential and the corrosion current density of the steel, as well as the electrical resistivity of the matrix were monitored over a time period of 1 year. The results show the deleterious effect of chloride on the expected lifespan of the waste containers.

Duffó, Gustavo S.; Farina, Silvia B.; Schulz, Fátima M.; Marotta, Francesca

2010-10-01

322

Immediate resin-bonded bridgework: results of a medium-term clinical follow-up study.  

PubMed

A total of 21 immediate resin-bonded bridges were inserted under controlled and standardized clinical conditions and evaluated over a period of 35 months. During the evaluation period, two bridges debonded (9.5%). The debonded bridges were re-cemented successfully. This low incidence of debonding indicates that this simple alternative procedure for the immediate replacement of a single unsaveable tooth was satisfactory. The subjects included in this study expressed their satisfaction with this form of treatment. PMID:15125604

Al-Wahadni, A M; Al-Omari, W M

2004-01-01

323

Dry PMR-15 Resin Powders  

NASA Technical Reports Server (NTRS)

Shelf lives of PMR-15 polymides lengthened. Procedure involves quenching of monomer reactions by vacuum drying of PRM-15 resin solutions at 70 to 90 degree F immediately after preparation of solutions. Absence of solvent eliminates formation of higher esters and reduces formation of imides to negligible level. Provides fully-formulated dry PMR-15 resin powder readily dissolvable in solvent at room temperature immediately before use. Resins used in variety of aerospace, aeronautical, and commercial applications.

Vannucci, Raymond D.; Roberts, Gary D.

1988-01-01

324

Vitrification of ion exchange resins  

DOEpatents

The present invention relates to vitrification of ion exchange resins that have become loaded with hazardous or radioactive wastes, in a way that produces a homogenous and durable waste form and reduces the disposal volume of the resin. The methods of the present invention involve directly adding borosilicate glass formers and an oxidizer to the ion exchange resin and heating the mixture at sufficient temperature to produce homogeneous glass.

Cicero-Herman, Connie A. (Aiken, SC); Workman, Rhonda Jackson (North Augusta, SC)

2001-01-01

325

Natural cement as the precursor of Portland cement: Methodology for its identification  

Microsoft Academic Search

When cements appeared in the 19th century, they took the place of traditional binding materials (lime, gypsum, and hydraulic lime) which had been used until that time. Early cements can be divided into two groups, natural and artificial (Portland) cements. Natural cements were introduced first, but their widespread usage was short-lived as they were quickly replaced by artificial cements (Portland),

M. J.. Varas; M. Alvarez de Buergo; R. Fort

2005-01-01

326

A three-year clinical trial using a glass ionomer cement for the bonding of orthodontic brackets.  

PubMed

Recent clinical studies measuring orthodontic bracket failure, when using glass ionomer cement as an adhesive, have reported a wide range of percentages of bracket failure. The present study recorded bracket failure over a 3-year period, longer than had been previously measured. Seventeen participants were randomly assigned to one of two treatment groups, either using glass ionomer cement or composite resin for bonding. In each group, brackets were bonded to incisors, canines, and premolars. Bracket failure was measured over the duration of comprehensive orthodontic treatment for all participants. Brackets bonded with the glass ionomer cement were more likely to fail (log-rank test; P < or = 0.022). This difference was clinically significant. At the present time, the disadvantage of extra bracket failures appears to outweigh potential advantages when considering glass ionomer cement for the routine bonding of orthodontic brackets. PMID:8863967

Miller, J R; Mancl, L; Arbuckle, G; Baldwin, J; Phillips, R W

1996-01-01

327

Infrared study of the interaction of acrylic bone cement with bone structure in vitro  

NASA Astrophysics Data System (ADS)

Infrared Spectroscopy was used for the characterization of some commercial bone cements and investigation of their inter-action with compact bone in vitro. The IR spectra of the cements and their mixtures with bone powder were recorded at various periods ranging from day one to 8 weeks. The quantitative analysis of the IR spectra of the mixtures provided a strong evidence that a certain reaction takes place between the acrylic resin and bone powder. It was found that the rate of reaction depends on the concentration of the bone powder and time. In any event, the rate of reaction showed a maximum value at 45-days for all concentrations. It was concluded that, a bond is formed between the cement and the bone powder, and this bond is not perfect.

Moharram, M. A.; Khalil, Safaa

1992-08-01

328

Phosphorus-containing bisimide resins  

NASA Technical Reports Server (NTRS)

The production of fire-resistant resins particularly useful for making laminates with inorganic fibers such as graphite fibers is discussed. The resins are by (1) condensation of an ethylenically unsaturated cyclic anhydride with a bis(diaminophenyl) phosphine oxide, and (2) by addition polymerization of the bisimide so obtained. Up to about 50%, on a molar basis, of benzophenonetetracarboxylic acid anhydride can be substituted for some of the cyclic anhydride to alter the properties of the products. Graphite cloth laminates made with these resins show 800 C char yields greater than 70% by weight in nitrogen. Limiting oxygen indexes of more than 100% are determined for these resins.

Varma, I. K.; Fohlen, G. M.; Parker, J. A. (inventors)

1981-01-01

329

Wear and microhardness of glass-ionomer cements.  

PubMed

Pin-and-disc wear and Knoop Hardness measurements were made on three commercial glass-ionomer cements having slightly different compositions. The specific objective was to determine whether these cements have potential for use in posterior teeth, and, if not, what modifications in composition and structure would be appropriate to enhance their performance. The specimens were pre-conditioned in air, water, or lactic acid at 37 degrees C for one week prior to being wear-tested. Although differences among the samples were noted, some common trends were observed. From changes in hardness, before and after storage, two opposing trends were observed. One trend involved continued cross-linking and possible dehydration, resulting in a substantial increase in hardness. The other trend involved softening from penetrant liquid absorption and a concomitant decrease in hardness. The wear resistances compared favorably with those for resin-based composites except for the lactic-acid-stored specimens, for which changes in microstructure were revealed by SEM. All specimens were very brittle, and catastrophic failure during wear was frequent. Although our conclusion is that glass-ionomer cements with composition similar to those evaluated here are not acceptable for posterior occlusal application, some compositional changes may enhance their performance in stress-bearing applications. PMID:3476584

McKinney, J E; Antonucci, J M; Rupp, N W

1987-06-01

330

New Cement Composite of Carbon Fiber,  

National Technical Information Service (NTIS)

Continuous carbon fiber cement composites are developed to have high fire resistance and high strength by using PAN type carbon fiber and fine cement as matrix. To improve the bond strength between carbon fiber and cement matrix, fine cement is used to fi...

K. Suzuki T. Nishigaki T. Matsuhashi H. Sasaki

1987-01-01

331

Correlation between margin fit and microleakage in complete crowns cemented with three luting agents.  

PubMed

Microleakage can be related to margin misfit. Also, traditional microleakage techniques are time-consuming. This study evaluated the existence of correlation between in vitro margin fit and a new microleakage technique for complete crowns cemented with 3 different luting agents. Thirty human premolars were prepared for full-coverage crowns with a convergence angle of 6 degrees, chamfer margin of 1.2 mm circumferentially, and occlusal reduction of 1.5 mm. Ni-Cr cast crowns were cemented with either zinc phosphate (ZP) (S.S. White), resin-modified glass-ionomer (RMGI) (Rely X Luting Cement) or a resin-based luting agent (RC) (Enforce). Margin fit (seating discrepancy and margin gap) was evaluated according to criteria in the literature under microscope with 0.001 mm accuracy. After thermal cycling, crowns were longitudinally sectioned and microleakage scores at tooth-cement interface were obtained and recorded at x100 magnification. Margin fit parameters were compared with the one-way ANOVA test and microleakage scores with Kruskal-Wallis and Dunn's tests (alpha=0.05). Correlation between margin fit and microleakage was analyzed with the Spearman's test (alpha=0.05). Seating discrepancy and marginal gap values ranged from 81.82 microm to 137.22 microm (p=0.117), and from 75.42 microm to 78.49 microm (p=0.940), respectively. Marginal microleakage scores were ZP=3.02, RMGI=0.35 and RC=0.12 (p<0.001), with no differences between RMGI and RC scores. The correlation coefficient values ranged from -0.27 to 0.30 (p>0.05). Conclusion: Margin fit parameters and microleakage showed no strong correlations; cast crowns cemented with RMGI and RC had lower microleakage scores than ZP cement. PMID:19089292

Rossetti, Paulo Henrique Orlato; do Valle, Accacio Lins; de Carvalho, Ricardo Marins; De Goes, Mario Fernando; Pegoraro, Luiz Fernando

2008-01-01

332

21 CFR 177.1380 - Fluorocarbon resins.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Fluorocarbon resins. 177.1380 Section 177.1380 Food and Drugs...Food Contact Surfaces § 177.1380 Fluorocarbon resins. Fluorocarbon resins may be safely used as articles or components...

2011-04-01

333

21 CFR 177.1595 - Polyetherimide resin.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Polyetherimide resin. 177.1595 Section 177.1595 Food and Drugs...Contact Surfaces § 177.1595 Polyetherimide resin. The polyetherimide resin identified in this section may be safely...

2012-04-01

334

21 CFR 177.1595 - Polyetherimide resin.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Polyetherimide resin. 177.1595 Section 177.1595 Food and Drugs...Contact Surfaces § 177.1595 Polyetherimide resin. The polyetherimide resin identified in this section may be safely...

2011-04-01

335

21 CFR 178.3930 - Terpene resins.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Terpene resins. 178.3930 Section 178.3930 Food and Drugs...Adjuvants and Production Aids § 178.3930 Terpene resins. The terpene resins identified in paragraph (a) of this...

2011-04-01

336

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Polyestercarbonate resins. 177.1585 Section 177.1585 Food and...Contact Surfaces § 177.1585 Polyestercarbonate resins. Polyestercarbonate resins may be safely used as articles or...

2010-01-01

337

21 CFR 178.3930 - Terpene resins.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Terpene resins. 178.3930 Section 178.3930 Food and Drugs...Adjuvants and Production Aids § 178.3930 Terpene resins. The terpene resins identified in paragraph (a) of this...

2012-04-01

338

21 CFR 177.1680 - Polyurethane resins.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Polyurethane resins. 177.1680 Section 177.1680 Food and...Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane resins identified in paragraph (a) of this...

2011-04-01

339

40 CFR 721.9495 - Acrylosilane resins.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Acrylosilane resins. 721.9495 Section 721.9495 ...Substances § 721.9495 Acrylosilane resins. (a) Chemical substance and significant...chemical substances identified as acrylosilane resins (PMNs P-95-1024/1040) are...

2012-07-01

340

21 CFR 872.3140 - Resin applicator.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 2012-04-01 false Resin applicator. 872.3140 Section 872.3140...DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device intended...

2012-04-01

341

21 CFR 872.3140 - Resin applicator.  

... 2014-04-01 2014-04-01 false Resin applicator. 872.3140 Section 872.3140...DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device intended...

2014-04-01

342

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Polyestercarbonate resins. 177.1585 Section 177.1585 Food and...Contact Surfaces § 177.1585 Polyestercarbonate resins. Polyestercarbonate resins may be safely used as articles or...

2011-04-01

343

21 CFR 872.3140 - Resin applicator.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 2011-04-01 false Resin applicator. 872.3140 Section 872.3140...DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device intended...

2011-04-01

344

40 CFR 721.9495 - Acrylosilane resins.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Acrylosilane resins. 721.9495 Section 721.9495 ...Substances § 721.9495 Acrylosilane resins. (a) Chemical substance and significant...chemical substances identified as acrylosilane resins (PMNs P-95-1024/1040) are...

2010-07-01

345

21 CFR 177.1560 - Polyarylsulfone resins.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Polyarylsulfone resins. 177.1560 Section 177.1560 Food and Drugs...Contact Surfaces § 177.1560 Polyarylsulfone resins. Polyarylsulfone resins (CAS Reg. No. 79293-56-4) may be...

2010-01-01

346

21 CFR 177.1380 - Fluorocarbon resins.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Fluorocarbon resins. 177.1380 Section 177.1380 Food and Drugs...Food Contact Surfaces § 177.1380 Fluorocarbon resins. Fluorocarbon resins may be safely used as articles or components...

2010-01-01

347

21 CFR 177.1680 - Polyurethane resins.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Polyurethane resins. 177.1680 Section 177.1680 Food and...Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane resins identified in paragraph (a) of this...

2012-04-01

348

21 CFR 177.1560 - Polyarylsulfone resins.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Polyarylsulfone resins. 177.1560 Section 177.1560 Food and Drugs...Contact Surfaces § 177.1560 Polyarylsulfone resins. Polyarylsulfone resins (CAS Reg. No. 79293-56-4) may be...

2011-04-01

349

21 CFR 872.3140 - Resin applicator.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Resin applicator. 872.3140 Section 872.3140...DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device intended...

2010-04-01

350

40 CFR 721.9495 - Acrylosilane resins.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Acrylosilane resins. 721.9495 Section 721.9495 ...Substances § 721.9495 Acrylosilane resins. (a) Chemical substance and significant...chemical substances identified as acrylosilane resins (PMNs P-95-1024/1040) are...

2011-07-01

351

40 CFR 721.9495 - Acrylosilane resins.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Acrylosilane resins. 721.9495 Section 721.9495 ...Substances § 721.9495 Acrylosilane resins. (a) Chemical substance and significant...chemical substances identified as acrylosilane resins (PMNs P-95-1024/1040) are...

2013-07-01

352

21 CFR 177.2440 - Polyethersulfone resins.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Polyethersulfone resins. 177.2440 Section 177.2440 Food and...Repeated Use § 177.2440 Polyethersulfone resins. Polyethersulfone resins identified in paragraph (a) of this...

2011-04-01

353

21 CFR 177.1560 - Polyarylsulfone resins.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Polyarylsulfone resins. 177.1560 Section 177.1560 Food and Drugs...Contact Surfaces § 177.1560 Polyarylsulfone resins. Polyarylsulfone resins (CAS Reg. No. 79293-56-4) may be...

2012-04-01

354

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Polyestercarbonate resins. 177.1585 Section 177.1585 Food and...Contact Surfaces § 177.1585 Polyestercarbonate resins. Polyestercarbonate resins may be safely used as articles or...

2012-04-01

355

21 CFR 177.1595 - Polyetherimide resin.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Polyetherimide resin. 177.1595 Section 177.1595 Food and Drugs...Contact Surfaces § 177.1595 Polyetherimide resin. The polyetherimide resin identified in this section may be safely...

2010-01-01

356

21 CFR 177.2440 - Polyethersulfone resins.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Polyethersulfone resins. 177.2440 Section 177.2440 Food and...Repeated Use § 177.2440 Polyethersulfone resins. Polyethersulfone resins identified in paragraph (a) of this...

2012-04-01

357

21 CFR 177.1380 - Fluorocarbon resins.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Fluorocarbon resins. 177.1380 Section 177.1380 Food and Drugs...Food Contact Surfaces § 177.1380 Fluorocarbon resins. Fluorocarbon resins may be safely used as articles or components...

2012-04-01

358

Novel silica-based ion exchange resin.  

National Technical Information Service (NTIS)

Eichrom's highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchang...

1997-01-01

359

Curing efficiency of various resin-based materials polymerized through different ceramic thicknesses and curing time  

PubMed Central

PURPOSE The aim of this in vitro study was to examine the curing efficiency of various resin-based materials polymerized through ceramic restorations with 3 different thicknesses. Curing efficiency was evaluated by determining the surface microhardness (VHN) of the resin specimens. MATERIALS AND METHODS Four kinds of resin materials were used. Z350 (3M ESPE Filtek™ Z350: A2 Shade), Z250 (3M ESPE Filtek™ Z250: A2 Shade) and Variolink® II (VL: Ivoclar vivadent, base: transparent) either with or without a self-curing catalyst (VLC: Ivoclar vivadent, catalyst: low viscosity/transparent) were filled into the silicone mold (10 mm diameter, 1 mm thick). They were cured through ceramic discs (IPS e.max Press MO-0 ingot ivoclar vivadent, 10 mm diameter, 0.5, 1 and 2 mm thicknesses) by LED light-curing units for 20 and 40 seconds. Vicker's microhardness numbers (VHNs) were measured on the bottom surfaces by a microhardness tester. Data were analyzed using a 3- way analysis of variance (ANOVA) at a significance level of 0.05. RESULTS The thickness of ceramic disc increased, the VHNs of all four resin types were decreased (P<.05). The mean VHN values of the resins light cured for 40 seconds were significantly higher than that of LED for 20 seconds in all four resin materials (P<.05). VLC showed significantly higher VHN values than VL regardless of other conditions (P<.05). Z350 and Z250 showed higher values than VL or VLC (P<.01). CONCLUSION Thinner ceramic disc with increased curing time resulted higher VHN values of all resin materials. The use of a catalyst produced a greater hardness with all polymerization methods. Restorative resin materials (Z350, Z250) showed higher VHN values than resin cement materials (VL, VLC).

Lee, Jung-Won; Cha, Hyun-Suk

2011-01-01

360

Well cementing valve  

SciTech Connect

A well cementing valve is described for a well tubing string, comprising: a tubular mandrel having at least one mandrel port communicating the interior of the mandrel with the exterior thereof, the mandrel being adapted to be made-up in the well tubing string; an axially movable sleeve valve initially covering the mandrel port on the mandrel exterior, the sleeve valve having a pressure responsive seal area subject to fluid pressure in the mandrel for moving the sleeve valve; an axially slidable protective sleeve initially surrounding the mandrel and the sleeve valve; and shear means connecting the protective sleeve to the sleeve valve to restrain the sleeve valve against axial displacement, the pressure responsive seal area on the sleeve valve being operable to apply a shearing load on the shear means, permitting an axial displacement of the protective sleeve and an opposite axial displacement of the sleeve valve to open the port.

VanWormer, R.A.; Baugh, J.L.

1986-07-29

361

Indirect resin composites  

PubMed Central

Aesthetic dentistry continues to evolve through innovations in bonding agents, restorative materials, and conservative preparation techniques. The use of direct composite restoration in posterior teeth is limited to relatively small cavities due to polymerization stresses. Indirect composites offer an esthetic alternative to ceramics for posterior teeth. This review article focuses on the material aspect of the newer generation of composites. This review was based on a PubMed database search which we limited to peer-reviewed articles in English that were published between 1990 and 2010 in dental journals. The key words used were ‘indirect resin composites,’ composite inlays,’ and ‘fiber-reinforced composites.’

Nandini, Suresh

2010-01-01

362

Intramedullary plugs in cemented hip arthroplasty.  

PubMed

The use of intramedullary plugs in cemented total joint arthroplasty is currently considered standard practice by most surgeons. In this in vitro study, the authors evaluated the holding power, migration, and leakage of four commonly used plug types--bone, acrylic bone cement, and two polymeric plugs from different manufacturers. Only acrylic bone cement plugs prevented distal leakage of cement and did not migrate under the influences of pressurized cement injection. PMID:2746246

Beim, G M; Lavernia, C; Convery, F R

1989-01-01

363

Holocene cemented beach deposits in Belize  

Microsoft Academic Search

Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented mainly by vadose low-magnesium-calcite cements. Besides differences in position relative to present sea level and resulting early diagenesic features, beachrock and cayrock can

Eberhard Gischler; Anthony J. Lomando

1997-01-01

364

Imide Modified Epoxy Matrix Resins.  

National Technical Information Service (NTIS)

Results of a program designed to develop tough imide modified epoxy (IME) resins cured by bisimide amine (BIA) hardeners are presented. State of the art epoxy resin, MY720, was used. Three aromatic bisimide amines and one aromatic aliphatic BIA were evalu...

D. A. Scola

1982-01-01

365

Imide modified epoxy matrix resins  

NASA Technical Reports Server (NTRS)

High char yield epoxy using novel bisimide amines (BIA's) as curing agents with a state of the art epoxy resin was developed. Stoichiometric quantities of the epoxy resin and the BIA's were studied to determine the cure cycle required for preparation of resin specimens. The bisimide cured epoxies were designated IME's (imide modified epoxy). The physical, thermal and mechanical properties of these novel resins were determined. The levels of moisture absorption exhibited by the bisimide amine cured expoxies (IME's) were considerably lower than the state of the art epoxies. The strain-to-failure of the control resin system was improved 25% by replacement of DDS with 6F-DDS. Each BIA containing resin exhibited twice the char yield of the control resin MY 720/DDS. Graphite fiber reinforced control (C) and IME resins were fabricated and characterized. Two of the composite systems showed superior properties compared to the other Celion 6000/IME composite systems and state of the art graphite epoxy systems. The two systems exhibited excellent wet shear and flexural strengths and moduli at 300 and 350 F.

Scola, D. A.; Pater, R. H.

1981-01-01

366

Graphite-reinforced bone cement  

NASA Technical Reports Server (NTRS)

Chopped graphite fibers added to surgical bone cement form bonding agent with mechanical properties closely matched to those of bone. Curing reaction produces less heat, resulting in reduced traumatization of body tissues. Stiffness is increased without affecting flexural strength.

Knoell, A. C.

1976-01-01

367

Synthesis and characterization of hydroxyapatite cement  

NASA Astrophysics Data System (ADS)

This study deals with synthesizing hydroxyapatite bone cement as a bone substitute for clinical applications. The powder part of the cement is using ?-tricalcium phosphate, calcium carbonate, dicalcium phosphate and the liquid part contains NaH 2PO 4·2H 2O solution with different concentrations. The effects of liquid concentration on the setting times of the cement have been investigated. XRD analysis and FT-IR spectroscopy were used to study the phase composition of calcium phosphate cement. Morphology and chemical analysis of the synthesized cement was performed using a scanning electron microscope equipped with an energy dispersive X-ray analyser. In addition, the effect of soaking time of synthesized bone cement in simulated body fluid (SBF) on the final phase and strength has been studied. Soaking prepared cement in SBF solution for appropriate time resulted in transformation of the composition of the cement into hydroxyapatite and hence the strength of the cement has been increased.

Rabiee, S. M.; Moztarzadeh, F.; Solati-Hashjin, M.

2010-04-01

368

Marginal Integrity of CAD/CAM Fixed Partial Dentures  

PubMed Central

Objectives Computer-aided design (CAD) and manufacturing (CAM) allows the milling of high strength zirconia fixed partial dentures (FPD), however bonding to an inert ZrO2 ceramic surface may effect the marginal integrity of the FPDs. The aim of this investigation was to evaluate the marginal adaptation of zirconia FPDs at the interfaces between zirconia, cement, and tooth. Methods 32 3-unit FPDs were fabricated of the CAD/CAM Y-TZP zirconia (Lava, 3M Espe, Germany) according to the manufacturers’ instructions. Resin cements with corresponding primer and bonding systems were used to lute the FPDs: Compolute/EBS multi (3M Espe, Germany), Panavia F/ED (Kuraray, Japan), Variolink 2/Syntac classic (Ivoclar-Vivadent, FL) and RelyX Unicem/without treatment (3M Espe, Germany). Aualloy FPDs (BioPontostar, Bego, Germany) were cemented with RelyX Unicem and Harvard (Harvard, Germany) as the control. Marginal adaptation was evaluated with scanning electron microscopy using replica specimen before and after artificial aging. After aging, microleakage tests were performed with fuchsine solution. The interfaces between cement-tooth and cement-FPD were examined. Results At the interfaces (cement-tooth and cement-FPD), the systems showed a 95% or higher perfect margin before and after aging. Only Variolink2/Syntac had a marginal adaptation, lower than a 70% perfect margin. Generally, the fuchsine penetration was below 20%, only BioPontstar/Harvard andLava/Variolink2 showed penetration results between 80% and 100%. Conclusion The success of the adhesive cementation of zirconia FPDs depends on the cement system. Under the conditions of this study, zirconia FPDs showed good to sufficient marginal integrity in combination with Panavia/ED, Compolute/EBS and RelyX Unicem.

Rosentritt, Martin; Behr, Michael; Kolbeck, Carola; Handel, Gerhard

2007-01-01

369

Chromatography resin support  

DOEpatents

An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

Dobos, James G. (North Augusta, SC)

2002-01-01

370

Stage cementing valve  

SciTech Connect

This patent describes a method for stage cementing a string of pipe in a well bore. The string of pipe includes a stage valve having a tubular valve collar intermediate of its length and has a tubular sleeve valve member slidably received in the stage collar for movement between first and second longitudinal positions relative to the stage collar and where the sleeve valve member has a flange in engagement with an engagement surface on the valve collar in the first longitudinal position. The sleeve valve member has a piston portion located in an annular chamber between the sleeve valve member and the valve collar and where the sleeve valve member has a sleeve valve port with access to one surface of the piston portion in the annular chamber for placing the one surface in fluid communication with the bore of the sleeve valve member. The valve collar has a valve collar port with access to the other surface of the of the piston portion in the annular chamber for placing the other surface in fluid communication with the exterior of the valve collar. The piston portion separates the sleeve valve port from the valve collar in a the first longitudinal position and permits the ports to be in fluid communication with one another in an the second longitudinal position.

Lindsey, H.E.; Adams, R.W.

1989-11-14

371

Evaluation of shear bond strength of composite resin bonded to alloy treated with sandblasting and electrolytic etching.  

PubMed

Conservation of natural tooth structure precipitated the emergence of resin-retained fixed partial dentures. The weakest link in this modality is the bond between resin cement and alloy of the retainer. Various alloy surface treatment have been recommended to improve alloy-resin bond. This in vitro study was carried out to observe changes in the Nickel-Chromium alloy (Wiron 99, Bego) surface following sandblasting or electrolytic etching treatment by scanning electron microscope (SEM) and to evaluate the shear bond strength of a resin luting cement bonded to the surface treated alloy. 80 alloy blocks were cast and divided into four groups of 20 each. In groups-A & B, the test surfaces were treated by sandblasting with 50 and 250 ?m sized aluminium oxide particles respectively. In groups-C & D, the test surfaces were first treated by sandblasting with 50 and 250 ?m sized aluminium oxide particles respectively followed by electrolytic etching. Test surfaces were observed under SEM at 1,000× magnification. Two alloy blocks of each group were luted together by a resin luting cement (Rely X, 3M) and their shear bond strength was tested. The mean shear bond strength in MPa of groups-A to D were 6.44 (±0.74), 8.18 (±0.51), 14.45 (±0.59) and 17.43 (±1.20) respectively. Group-D showed bond strength that is more than clinically acceptable bond strength. It is recommended that before luting resin-retained fixed partial dentures, the fitting surface of the retainer should be electrolytically etched to achieve adequate micromechanical retention. PMID:24605005

Goswami, M M; Gupta, S H; Sandhu, H S

2014-03-01

372

Flammability screening tests of resins  

NASA Technical Reports Server (NTRS)

Selected flammability characteristics of glass cloth laminates of thermosetting resins are evaluated. A protocol for the evaluation of the flammability hazards presented by glass cloth laminates of thermosetting resins and the usefulness of that protocol with two laminates are presented. The glass laminates of an epoxy resin, M-751 are evaluated for: (1) determination of smoke generation from the laminates; (2) analysis of products of oxidative degradation of the laminates; (3) determination of minimum oxygen necessary to maintain flaming oxidation; (4) evaluation of toxicological hazards.

Arhart, R. W.; Farrar, D. G.; Hughes, B. M.

1979-01-01

373

Resin/graphite fiber composites  

NASA Technical Reports Server (NTRS)

High temperature resin matrices suitable for use in advanced graphite fiber composites for jet engine applications were evaluated. A series of planned, sequential screening experiments with resin systems in composite form were performed to reduce the number of candidates to a single A-type polyimide resin that repetitively produced void-free, high strength and modulus composites acceptable for use in the 550 F range for 1000 hours. An optimized processing procedure was established for this system. Extensive mechanical property studies characterized this single system, at room temperature, 500 F, 550 F and 600 F, for various exposure times.

Cavano, P. J.; Jones, R. J.; Vaughan, R. W.

1972-01-01

374

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange-resin are also disclosed.

Trochimcznk, Andrzej W. (Knoxville, TN); Gatrone, Ralph C. (Plymouth, PA); Alexandratos, Spiro (Knoxville, TN); Horwitz, E. Philip (Naperville, IL)

1998-01-27

375

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorus. The pendent groups have the formula as shown in the patent wherein R is hydrogen, a cation or mixtures thereof; and R{sup 1} is hydrogen or an C{sub 1}-C{sub 2} alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Trochimcznk, A.W.; Gatrone, R.C.; Alexandratos, S.; Horwitz, E.P.

1997-04-08

376

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Trochimcznk, Andrzej W. (Knoxbille, TN); Gatrone, Ralph C. (Plymouth, PA); Alexandratos, Spiro (Knoxville, TN); Horwitz, E. Philip (Naperville, IL)

1997-01-01

377

Oilwell/gaswell cement-sheath evaluation  

SciTech Connect

Cement is placed in the casing/openhole annulus for two primary purposes: to isolate producible formation horizons and to support the casing. When one evaluates a cement in an oilwell/gaswell annulus, all one really needs to know is whether cement exists in the annulus (regardless of its strength) and whether the cement occupies 100% of the annulus. If 10-psi cement exists in 100% of the annulus, no portion of it can be removed for replacement by a 1,000-psi cement. If the annulus is packed with settled barite (from the drilling mud) or formation particles, no portion of the particulate matter can be removed and replaced by cement. Only liquids can be removed from the annulus for replacement by squeeze cementing. Acceptance of this basic premise can both simplify evaluation of a cement sheath in a casing/openhole annulus significantly and complicate measurement methods significantly. This leaves one with trying to identify solids or liquids behind the casing, not the difference between 250- and 5,000-psi cement. The paper discusses cement-sheath complications, cement-bond logs, annular segmentation for analysis, cement-evaluation recommendations, and interpretation guidelines.

Goodwin, K.J. [Mobil Technology Co., Dallas, TX (United States). Producing Technical Center

1997-12-01

378

Development of strong and bioactive calcium phosphate cement as a light-cure organic-inorganic hybrid.  

PubMed

In this research, light cured calcium phosphate cements (LCCPCs) were developed by mixing a powder phase (P) consisting of tetracalcium phosphate and dicalcium phosphate and a photo-curable resin phase (L), mixture of hydroxyethylmethacrylate (HEMA)/poly acrylic-maleic acid at various P/L ratios of 2.0, 2.4 and 2.8 g/mL. Mechanical strength, phase composition, chemical groups and microstructure of the cured cements were evaluated at pre-set times, i.e. before and after soaking in simulated body fluid (SBF). The proliferation of Rat-derived osteoblastic cells onto the LCCPCs as well as cytotoxicity of cement extracts were determined by cell counting and 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazolium bromide assay after different culture times. It was estimated from Fourier transforming infrared spectra of cured cements that the setting process is ruled by polymerization of HEMA monomers as well as formation of calcium poly-carboxylate salts. Microstructure of the cured cements consisted of calcium phosphate particles surrounded by polymerized resin phase. Formation of nano-sized needlelike calcium phosphate phase on surfaces of cements with P/L ratios of 2.4 and 2.8 g/mL was confirmed by scanning electron microscope images and X-ray diffractometry (XRD) of the cured specimen soaked in SBF for 21 days. Also, XRD patterns revealed that the formed calcium phosphate layer was apatite phase in a poor crystalline form. Biodegradation of the cements was confirmed by weight loss, change in molecular weight of polymer and morphology of the samples after different soaking periods. The maximum compressive strength of LCCPCs governed by resin polymerization and calcium polycarboxylate salts formation was about 80 MPa for cement with P/L ratio of 2.8 g/mL, after incubation for 24 h. The strength of all cements decreased by decreasing P/L ratio as well as increasing soaking time. The preliminary cell studies revealed that LCCPCs could support proliferation of osteoblasts cultured on their surfaces and no cytotoxic effect was observed for the extracts of them. PMID:22528071

Barounian, M; Hesaraki, S; Kazemzadeh, A

2012-07-01

379

A MODIFIED PMMA CEMENT (SUB-CEMENT) FOR ACCELERATED FATIGUE TESTING OF CEMENTED IMPLANT CONSTRUCTS USING CADAVERIC BONE  

PubMed Central

Pre-clinical screening of cemented implant systems could be improved by modeling the longer-term response of the implant/cement/bone construct to cyclic loading. We formulated bone cement with degraded fatigue fracture properties (Sub-cement) such that long-term fatigue could be simulated in short-term cadaver tests. Sub-cement was made by adding a chain-transfer agent to standard polymethylmethacrylate (PMMA) cement. This reduced the molecular weight of the inter-bead matrix without changing reaction-rate or handling characteristics. Static mechanical properties were approximately equivalent to normal cement. Over a physiologically reasonable range of stress intensity factor, fatigue crack propagation rates for sub-cement were higher by a factor of 25 ± 19. When tested in a simplified 2 1/2D physical model of a stem-cement-bone system, crack growth from the stem was accelerated by a factor of 100. Sub-cement accelerated both crack initiation and growth rate. Sub-cement is now being evaluated in full stem/cement/femur models.

Race, Amos; Miller, Mark A.; Mann, Kenneth A.

2008-01-01

380

Epoxy hydantoins as matrix resins  

NASA Technical Reports Server (NTRS)

Tensile strength and fracture toughness of castings of the hydantoin resins cured with methylenedianiline are significantly higher than MY 720 control castings. Water absorption of an ethyl, amyl hydantoin formulation is 2.1 percent at equilibrium and Tg's are about 160 C, approximately 15 deg below the final cure temperature. Two series of urethane and ester-extended hydantoin epoxy resins were synthesized to determine the effect of crosslink density and functional groups on properties. Castings cured with methylenedianiline or with hexahydrophthalic anhydride were made from these compounds and evaluated. The glass transition temperatures, tensile strengths and moduli, and fracture toughness values were all much lower than that of the simple hydantoin epoxy resins. Using a methylene bishydantoin epoxy with a more rigid structure gave brittle, low-energy fractures, while a more flexible, ethoxy-extended hydantoin epoxy resin gave a very low Tg.

Weiss, J.

1983-01-01

381

Regenerating Water-Sterilizing Resins  

NASA Technical Reports Server (NTRS)

Iodine-dispensing resin can be regenerated after iodine content has been depleted, without being removed from water system. Resin is used to make water potable by killing bacteria, fungi, and viruses. Regeneration technique may be come basis of water purifier for very long space missions. Enough crystalline iodine for multiple regenerations during mission can be stored in one small cartridge. Cartridge could be inserted in waterline as necessary on signal from iodine monitor or timer.

Colombo, G. V.; Putnam, D. F.

1982-01-01

382

Resin glycosides from Porana duclouxii.  

PubMed

A new intact resin glycoside (3) and two glycosidic acids (1 and 2), all having a common trisaccharide moiety and (11S)-hydroxytetradecanoic acid or (3S,11S)-dihydroxytetradecanoic acid as the aglycone, were obtained from the roots of Porana duclouxii. Their structures were elucidated by spectroscopic analyses and chemical correlations. These compounds represent the first examples of resin glycosides from the genus Porana. PMID:24320876

Ding, Wen-Bing; Zhang, Dai-Gui; Liu, Chun-Jie; Li, Guan-Hua; Li, You-Zhi

2014-01-01

383

Immobilization of chromium in cement matrices  

Microsoft Academic Search

Portland cement and blended cements containing blast furnace slag afford both physical and chemical immobilization of chromium. To separate physical and chemical effects, the pore fluid contained in set, hydrated cements has been expressed and analyzed. In Portland cement spiked with 5,000 ppm Cr(III), pore fluid levels are 0.1--1 ppm, whereas in well-cured slag blends, they decrease to <0.01 ppm.

A. Kindness; A. Macias; F. P. Glasser

1994-01-01

384

Cementing oil and gas wells  

SciTech Connect

This patent describes a cement composition for cementing in a well penetrating subterranean formations and having an aqueous drilling fluid containing at least one cement retarder. It comprises a major proportion of the drilling fluid from the well as it was drilled the fluid having a density in the range of about 9.0 - 18.0 ppg; water; a lesser proportion of dry cementitious material; about 0.5 to about 10.0 ppb of a dispersant selected from the group consisting of sulfonated styrene maleic anhydride, sulfonated styrene imide, and sulfonate styrene itaconic acid; and a compatible accelerator selected from the group consisting of acetic acid; the first 4 carbon esters thereof; acetamide; monoethanolamine; and diethanolamine.

Bloys, J.B.; Wilson, W.N.; Bradshaw, R.D.

1991-12-31

385

Blended cement using volcanic ash and pumice  

Microsoft Academic Search

This paper reports the results of investigation to assess the suitability of volcanic ash (VA) and pumice powder (VPP) for blended cement production. Tests were conducted on cement where Portland cement (PC) was replaced by VA and VPP within the range of 0 to 50%. The physical and chemical properties of VA and VPP were critically reviewed to evaluate the

Khandaker M. Anwar Hossain

2003-01-01

386

Plastic compaction of cemented granular materials  

Microsoft Academic Search

We analytically relate hydrostatic stress to strain in a random dense pack of identical spheres cemented at their contacts. The spheres are elastic and the cement is perfectly plastic. This solution for the sphere pack is based on a solution for the normal interaction of two cemented spheres. Initially, the two spheres touch each other at a point. We show

J. Dvorkin; D. Yale

1997-01-01

387

Behavior of cemented sands - I. Testing  

Microsoft Academic Search

This paper is accompanied by a study on constitutive modelling issues of cemented sands. The concentration here is on experimental issues related to the triaxial testing of cemented sands. A preliminary investigation is performed aiming to identify potential effects of specimen size and slenderness on the stress-strain-strength characteristics of cemented sands. A comprehensive experimental study follows where clean sand specimens,

Ali A. Abdulla; Panos D. Kiousis

1997-01-01

388

Elastic moduli of cemented sphere packs  

Microsoft Academic Search

We present a method for estimating the effective elastic moduli of a dense random pack of identical elastic spheres with elastic binder (cement). The cement concentration in the pore space varies from a few percent (where it fills the space at grain contacts) to 100%. To construct the solution we start at a small cement concentration value where the effective

Jack Dvorkin; Jim Berryman; Amos Nur

1999-01-01

389

Skin ulceration due to cement.  

PubMed

Despite legislation that requires manufacturers to inform the public about the dangers of contact with cement, severe ulceration from cement contact still occurs. We present a retrospective study of seven patients presenting to this department over a 2-year period. All were male and employed in the building trade, their injuries being sustained whilst at work. The injuries were to the lower limb, often multiple and required a median of seven visits before healing was complete. One required hospital admission and skin grafting. PMID:1449582

Robinson, S M; Tachakra, S S

1992-09-01

390

Properties of cement waste composites  

SciTech Connect

Many nominally inert waste materials can be activated by alkaline substances, including Ca(OH){sub 2} and Portland cement, to form valuable supplementary cementitious materials. Waste materials are inherently more variable in composition than well specified, manufactured materials. Nevertheless, sufficient characterization techniques are available to permit the specification of materials such as fly ash and blast furnace slags with confidence. Applications for other processed waste materials, e.g. metakaolin, are being developed. Properly applied, these wastes can actually improve the performance of cement materials. The leach testing of products containing potentially hazardous waste materials, suited only for disposal, is described.

Glasser, F.P. [Univ. of Aberdeen (United Kingdom). Dept. of Chemistry] [Univ. of Aberdeen (United Kingdom). Dept. of Chemistry

1996-12-31

391

Molecular Self-Assembled Microcapsules Prepared by In Situ Polymerization Technology for Self-Healing Cement Materials  

Microsoft Academic Search

Monodisperse core–shell microcapsules have been widely used as self-healing cement materials and paid more attentions. A new\\u000a series of self-assembled microcapsules containing poly(styrene-divinylbenzene) as shell material were prepared by in situ\\u000a polymerization technology. The microencapsulating process of core material using mixture of epoxy resins and benzyl alcohol\\u000a was monitored using optical microscopy (OM). Morphology and shell wall thickness of microcapsule

Shenguang Ge; Fuwei Wan; Juanjuan Lu; Jinghua Yu

392

Effect of three radicular dentine treatments and two luting cements on the regional bond strength of quartz fibre posts  

Microsoft Academic Search

The purpose was to investigate by push-out tests and scanning electron microscopy (SEM)\\/energy-dispersive spectroscopy (EDS)\\u000a the effect, after first acid etching the post space walls, of three radicular dentine treatments on the regional bond strength\\u000a of quartz fibre posts placed using two heavily filled resin luting cements. The crowns of 39 extracted maxillary central incisors\\u000a were sectioned transversely 2 mm coronal

Haiyan Mao; Yaming Chen; Kevin H. K. Yip; Roger J. Smales

393

Different surface preparation techniques of porcelain repaired with composite resin and fracture resistance  

PubMed Central

Background: Porcelain from prosthesis such as crown or bridge can be fractured if exposed to trauma; and, can be repaired at chairside using composite resin. Aim: To investigate the fracture resistance of few techniques of surface preparation in repairing fractured porcelain using composite resin. Materials and Methods: Eighty samples of porcelain blocks were divided into 4 groups for different surface preparations, such as, Cimara repairing kit; porcelain etch kit containing hydrofluoric acid; Panavia F resin cement; and, sandblasting using aluminium oxide, before composite resin (Filtek Z250, 3M ESPE) was bonded to the prepared porcelain blocks. Twenty others samples in the control group comprised of pure porcelain blocks. The fracture resistance of each sample was tested using Instron machine (UK). Results: With the exception of the group repaired using hydrofluoric acid (3.04±1.04 Mpa), all the other groups showed significant difference in the fracture resistance values when compared to the control group (3.05 ± 1.42 MPa) at P<0.05. Conclusions: Etching of the porcelain blocks with hydrofluoric acid holds promise in the repair of fractured porcelain with composite resin at chairside.

Abd Wahab, Mohd Helmy Khalid; Bakar, Wan Zaripah Wan; Husein, Adam

2011-01-01

394

DEVELOPMENT OF WET-OXIDATION TREATMENT SYSTEM FOR FILTER BACKWASH SLUDGE AND ION EXCHANGE RESINS  

SciTech Connect

Decomposition of organic compounds contained in filter backwash sludge and spent ion exchange resins is considered effective in reducing the waste volume. A system using the wet-oxidation process has been studied for the treatment of the sludge and resins stored at Tsuruga Power Station Unit 1, 357MWe BWR, owned by The Japan Atomic Power Company. Compared with various processes for treating sludge and resin, the wet-oxidation system is rather simple and the process conditions are mild. Waste samples collected from storage tanks were processed by wet-oxidation and appropriate decomposition of the organic compounds was verified. After the decomposition the residue can be solidified with cement or bitumen for final disposal. When compared with direct solidification without decomposition, the number of waste packages can be reduced by a factor of a few dozens for the sludge and three for the resin. Additional measures for conditioning secondary waste products have also been studied, and their applicability to the Tsuruga Power Station was verified. Some of the conditions studied were specific to the Tsuruga Power Station, but it is expected that the system will provide an effective solution for sludge and resin treatment at other NPPs.

Miyamoto, T.; Motoyama, M.; Shibuya, M.; Wada, H.; Yamazaki, K.

2003-02-27

395

Synthesis of new phosphonate ester resins for adsorption of gold from alkaline cyanide solution  

NASA Astrophysics Data System (ADS)

Resin ion-exchange technology is a possible alternative to well-established gold recovery processes of carbon adsorption and zinc-dust cementation. The search for a suitable resin for gold recovery from alkaline cyanide solution continues at several research centers. Recent discoveries involving alkyl phosphorus esters for selective gold solvent extraction from alkaline cyanide solution suggest that similar chemistry on a resin substrate might likewise be effective. In this regard, polystyrene-supported phosphonate ester-based resins were synthesized from the poly(styrene/divinylbenzene) copolymers. Gold adsorption/desorption characteristics were established for these resins with respect to functional group chemistry, pH, ionic strength, and temperature. Gold loading was found to be promoted at increased ionic strength with fair selectivity over various cyanoanions. Stripping was possible at higher temperatures and/or low ionic strength of the strip solution. Solvation extraction of an alkali cation/aurocyanide anion ion pair seems to explain the adsorption/desorption phenomena which are discussed in terms of the variables studied.

Akser, M.; Wan, R. Y.; Miller, J. D.; Quillen, D. R.; Alexandratos, S. D.

1987-12-01

396

On the three-point flexural tests of dental polymeric resins.  

PubMed

Currently acrylic resins are commonly employed in many medical applications, especially for the fabrication of long span provisional restorations in dentistry and bone cement in orthopedics. On of the major problems associated with the conventional type of acrylic resins is their unsatisfactory mechanical properties. Among many attempts to strengthen acrylic resins, it has been demonstrated that they can be strengthened through the addition of reinforcement(s) as structural components of different size, shape and chemical composition, dispersed in the acrylic matrix, thus forming a composite structure. In the course of studies to strengthen dental polymeric resins by admixing various metallic oxide particles, PMMA-, PEMA-, and PIMA-based resins were reinforced by 2 vol.% added alumina, magnesia, zirconia, and silica powders. It was found that PMMA admixed with 2 vol.% zirconia exhibited the best improvement of mechanical properties (breaking strength, modulus of elasticity, offset yield strength, and fracture toughness as well). All tests were conducted under three-point bending. It was also found that the breaking strength based on the original sample dimension was, at most 20% less than those based on the final sample dimension. Moreover, this discrepancy was independent of the type of tested material, but dependent on the sample's modulus of elasticity. PMID:9262824

Oshida, Y; Zuccari, A G

1997-01-01

397

21 CFR 178.3610 - ?-Methylstyrene-vinyltoluene resins, hydrogenated.  

Code of Federal Regulations, 2010 CFR

... α-Methylstyrene-vinyltoluene resins, hydrogenated. 178.3610 Section... ?-Methylstyrene-vinyltoluene resins, hydrogenated. Hydrogenated ?-methylstyrene-vinyltoluene copolymer resins having a molar ratio of 1...

2010-01-01

398

21 CFR 178.3610 - ?-Methylstyrene-vinyltoluene resins, hydrogenated.  

Code of Federal Regulations, 2012 CFR

... α-Methylstyrene-vinyltoluene resins, hydrogenated. 178.3610 Section... ?-Methylstyrene-vinyltoluene resins, hydrogenated. Hydrogenated ?-methylstyrene-vinyltoluene copolymer resins having a molar ratio of 1...

2012-04-01

399

21 CFR 178.3610 - ?-Methylstyrene-vinyltoluene resins, hydrogenated.  

Code of Federal Regulations, 2011 CFR

... α-Methylstyrene-vinyltoluene resins, hydrogenated. 178.3610 Section... ?-Methylstyrene-vinyltoluene resins, hydrogenated. Hydrogenated ?-methylstyrene-vinyltoluene copolymer resins having a molar ratio of 1...

2011-04-01

400

The bond of two adhesive resins to alumina blasted and heat-treated gold alloy surfaces.  

PubMed

The purpose of this study was to test in shear mode the bond strengths of two BIS-GMA resin cements bonded to alumina blasted and heat-treated gold alloy surfaces. This was carried out in order to investigate the manufacturer's claim of the superiority of Panavia 21 over Panavia Ex. Alumina blasted gold alloy surfaces were cemented in pairs with either Panavia Ex or Panavia 21 resin cements. Heat-treated gold alloy surfaces were similarly paired. The luted pairs were stored in water at 37 degrees C for 48 h before bond was tested with shearing forces. Although the differences were not statistically significant, it was found that Panavia 21 formed stronger bonds on the alumina blasted surfaces than Panavia Ex. However, Panavia Ex exhibited higher mean strength values than Panavia 21 on the heat-treated surfaces. Not only was this difference statistically significant, but the bond strength values obtained for Panavia Ex on this surface were the highest in the data set. On the basis of bond testing in shear, it would appear that Panavia 21 is inferior to Panavia Ex on heat-treated gold alloy surfaces. PMID:10887913

Ogunyinka, A

2000-05-01

401

Radioactive spent resins conditioning by the hot super-compaction process  

SciTech Connect

Spent ion exchanger media are considered to be problematic waste that, in many cases, requires special approaches and precautions during its immobilization to meet the acceptance criteria for disposal. The waste acceptance criteria define, among others, the quality of waste forms for disposal, and therefore will sometimes define appropriate treatment options. The selection of treatment options for spent ion exchange materials must consider their physical and chemical characteristics. Basically, the main methods for the treatment of spent organic ion exchange materials, following to pretreatment methods are: - Direct immobilization, producing a stable end product by using Cement, Bitumen, Polymer or High Integrity Containers, - The destruction of the organic compounds by using Thermochemical processes or Oxidation to produce an inorganic intermediate product that may or may not be further conditioned for storage and/or disposal, - The complete removal of the resin inner structural water by a thermal process. After a thorough technical economical analysis, Tractebel Engineering selected the Resin Hot Compaction Process to be installed at Tihange Nuclear Power Plant. The Resin Hot Compaction Process is used to make dense homogenous organic blocks from a wide range of particulate waste. In this process spent resins are first dewatered and dried to remove the inner structural water content. The drying takes place in a drying vessel that holds the contents of two 200 L drums (Figure). In the oil heated drying and mixing unit, the resins are heated to the necessary process temperature for the hot pressing step and then placed into special metal drums, which are automatically lidded and immediately transferred to a high force compactor. After high force compaction the pellets are transferred to a measuring unit, where the dose rate, height and weight are automatically measured and recorded. A volume reduction factor of approximately up to four (depending on the type of resins) is achievable using hot compaction techniques. This paper will describe the application of the Resin Hot Compaction Process,at Tihange NPP. (authors)

Roth, Andreas [Hansa Projekt Anlagentechnik GmbH (Germany); Centner, Baudouin [Tractebel Engineering (Belgium); Lemmens, Alain [Electrabel, Rhodestraat 125 B-1630 - Linkebeek (Belgium)

2007-07-01

402

Dentin-cement Interfacial Interaction  

PubMed Central

The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline caustic effect of the calcium silicate cement’s hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca2+, OH-, and CO32- ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, “the mineral infiltration zone”, is suggested for these calcium-silicate-based cements.

Atmeh, A.R.; Chong, E.Z.; Richard, G.; Festy, F.; Watson, T.F.

2012-01-01

403

The effect of alumina and aluminium nitride coating by reactive magnetron sputtering on the resin bond strength to zirconia core  

PubMed Central

PURPOSE Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 µm aluminum oxide particles (Al2O3), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 µm Al2O3 + Al coating and air particle abrasion with 50 µm Al2O3 + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (?=.05). RESULTS The highest bond strengths were obtained by air abrasion with 50 µm Al2O3, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.

Kulunk, Safak; Baba, Seniha; Ozturk, Ozgur; Danisman, Sengul; Savas, Soner

2013-01-01

404

Low Melt Viscosity Resins for Resin Transfer Molding  

NASA Technical Reports Server (NTRS)

In recent years, resin transfer molding (RTM) has become one of the methods of choice for high performance composites. Its cost effectiveness and ease of fabrication are major advantages of RTM. RTM process usually requires resins with very low melt viscosity (less than 10 Poise). The optimum RTM resins also need to display high thennal-oxidative stability, high glass transition temperature (T(sub g)), and good toughness. The traditional PMR-type polyimides (e.g. PMR-15) do not fit this requirement, because the viscosities are too high and the nadic endcap cures too fast. High T(sub g), low-melt viscosity resins are highly desirable for aerospace applications and NASA s Reusable Launch Vehicle (RLV) program. The objective of this work is to prepare low-melt viscosity polyimide resins for RTM or resin film infusion (RFI) processes. The approach involves the synthesis of phenylethynyl-terminated imide oligomers. These materials have been designed to minimize their melt viscosity so that they can be readily processed. During the cure, the oligomers undergo both chain extension and crosslinking via the thermal polymerization of the phenylethynyl groups. The Phenylethynyl endcap is preferred over the nadic group due to its high curing temperature, which provides broader processing windows. This work involved the synthesis and polymerization of oligomers containing zig-zag backbones and twisted biphenyl structures. Some A-B type precursors which possessed both nitro and anhydride functionality, or both nitro and amine functionality, were also synthesized in order to obtain the well defined oligomers. The resulting zig-zag structured oligomers were then end-capped with 4-phenylethynylphthalic anhydride (PEPA) for further cure. The properties of these novel imide oligomers are evaluated.

Harris, Frank W.

2002-01-01

405

Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance  

NASA Astrophysics Data System (ADS)

Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate-belite cement that contained medium C4A3 S¯ and C2S contents showed good dimensional stability, sulfate resistance, and compressive strength development and was considered the optimum phase composition for calcium sulfoaluminate-belite cement in terms of comparable performance characteristics to portland cement. Furthermore, two calcium sulfoaluminate-belite cement clinkers were successfully synthesized from natural and waste materials such as limestone, bauxite, flue gas desulfurization sludge, Class C fly ash, and fluidized bed ash proportioned to the optimum calcium sulfoaluminate-belite cement synthesized from reagent-grade chemicals. Waste materials composed 30% and 41% of the raw ingredients. The two calcium sulfoaluminate-belite cements synthesized from natural and waste materials showed good dimensional stability, sulfate resistance, and compressive strength development, comparable to commercial portland cement.

Chen, Irvin Allen

406

Waste form development/test. [Low-density polyethylene and modified sulfur cement as solidification agents  

SciTech Connect

The main objective of this study is to investigate new solidification agents relative to their potential application to wastes generated by advanced high volume reduction technologies, e.g., incinerator ash, dry solids, and ion exchange resins. Candidate materials selected for the solidification of these wastes include a modified sulfur cement and low-density polyethylene, neither of which are currently employed commerically for the solidification of low-level waste (LLW). As both the modified sulfur cement and the polyethylene are thermoplastic materials, a heated screw type extruder is utilized in the production of waste form samples for testing and evaluation. In this regard, work is being conducted to determine the range of conditions under which these solidification agents can be satisfactorily applied to the specific LLW streams and to provide information relevant to operating parameters and process control.

Kalb, P.D.; Colombo, P.

1983-01-01

407

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

PubMed Central

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

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

2014-01-01

408

Characterization of PMR Polyimide Resin and Prepreg.  

National Technical Information Service (NTIS)

Procedures for the chemical characterization of PMR-15 resin solutions and graphite-reinforced prepregs were developed, and a chemical data base was established. In addition, a basic understanding of PMR-15 resin chemistry was gained; this was translated ...

C. H. Sheppard P. H. Lindenmeyer

1984-01-01

409

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2013 CFR

...following specifications: (i) The solution intrinsic viscosity of the polyestercarbonate resins shall be a minimum of 0...per gram, as determined by a method entitled âIntrinsic Viscosity (IV) of Lexan ® Polyestercarbonate Resin by...

2013-04-01

410

Microparticle and Fiber Reinforcement of Epoxy Resins.  

National Technical Information Service (NTIS)

Microparticle and fiber materials have been investigated as reinforcing agents for a diglycidyl ether of bisphenol a type of epoxy resin. These materials were limited to low concentrations in order to insure retention of the resin binder properties, such ...

A. G. Sands E. J. Kohn R. C. Clark

1966-01-01

411

Phosphonic acid based ion exchange resins  

DOEpatents

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 9 figures.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1994-01-25