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Nishi-Tokyo-shi, Japan

Hosaka K.,Cariology and Operative Dentistry | Nakajima M.,Cariology and Operative Dentistry | Takahashi M.,Cariology and Operative Dentistry | Itoh S.,Cariology and Operative Dentistry | And 4 more authors.
Dental Materials | Year: 2010

Objectives: The purpose of this study was to evaluate the relationship between changes in the modulus of elasticity and ultimate tensile strength of one-step self-etch adhesives, and their degree of water sorption. Methods: Five one-step self-etch adhesives, Xeno IV (Dentsply Caulk), G Bond (GC Corp.), Clearfil S3 Bond (Kuraray Medical Inc.), Bond Force (Tokuyama Dental Corp.), and One-Up Bond F Plus (Tokuyama Dental Corp.) were used. Ten dumbelled-shaped polymers of each adhesive were used to obtain the modulus of elasticity by the three-point flexural bending test and the ultimate tensile strength by microtensile testing. The modulus of elasticity and the ultimate tensile strength were measured in both dry and wet conditions before/after immersion in water for 24 h. Water sorption was measured, using a modification of the ISO-4049 standard. Each result of the modulus of elasticity and ultimate tensile strength was statistically analyzed using a two-way ANOVA and the result of water sorption was statistically analyzed using a one-way ANOVA. Regression analyses were used to determine the correlations between the modulus of elasticity and the ultimate tensile strength in dry or wet states, and also the percent decrease in these properties before/after immersion of water vs. water sorption. Results: In the dry state, the moduli of elasticity of the five adhesive polymers varied from 948 to 1530 MPa, while the ultimate tensile strengths varied from 24.4 to 61.5 MPa. The wet specimens gave much lower moduli of elasticity (from 584 to 1073 MPa) and ultimate tensile strengths (from 16.5 to 35.0 MPa). Water sorption varied from 32.1 to 105.8 g mm-3. Significance: The moduli of elasticity and ultimate tensile strengths of the adhesives fell significantly after water-storage. Water sorption depended on the constituents of the adhesive systems. The percent decreases in the ultimate tensile strengths of the adhesives were related to water sorption, while the percent reductions in the moduli of elasticity of the adhesives were not related to water sorption. © 2009 Academy of Dental Materials. Source

Kitayama S.,Cariology and Operative Dentistry | Kitayama S.,Global Center | Nikaido T.,Cariology and Operative Dentistry | Takahashi R.,Cariology and Operative Dentistry | And 6 more authors.
Dental Materials | Year: 2010

Objectives: To evaluate and compare bond strengths of different primers and resin cements to silica-based and zirconia ceramics. Methods: Silica-based and zirconia ceramic specimens were ground flat with #600-grit SiC paper. The ceramic surfaces were airborne-particle abraded and then divided into 11 groups of seven each: untreated (control); and conditioned with one of the six primers in combination with a resin cement from the same manufacturer as follows: Bistite II/Tokuso Ceramic Primer, Linkmax/GC Ceramic Primer, RelyX ARC/RelyX Ceramic Primer, Panavia F 2.0/Clearfil Ceramic Primer, and Resicem/Shofu Porcelain Primer and Resicem/AZ Primer. Stainless steel rods were bonded to the ceramic surfaces using one of the five resin cements. After 24-h water storage, the tensile bond strengths were tested using a universal testing machine and failure modes were examined. Results: Conditioning with primers containing a silane coupling agent (all the primers except AZ Primer) significantly enhanced bond strengths of resin cements to silica-based ceramic. For zirconia ceramic, Resicem/AZ Primer exhibited significantly higher bond strength than the other groups except Panavia F 2.0/Clearfil Ceramic Primer. The predominant failure mode of the groups conditioned with primers containing a phosphonic acid monomer (AZ Primer) or a phosphate ester monomer (Clearfil Ceramic Primer and Tokuso Ceramic Primer) was cohesive failure in cements whereas that with the other primers was adhesive failure at the zirconia surfaces. Significance: The use of primers containing a silane coupling agent improved resin bonding to silica-based ceramic. On the other hand, the use of primers containing a phosphonic acid monomer or a phosphate ester monomer improved resin bonding to zirconia ceramic. © 2010 Academy of Dental Materials. Source

Shimada Y.,Cariology and Operative Dentistry | Sadr A.,Global Center | Burrow M.F.,University of Melbourne | Tagami J.,Cariology and Operative Dentistry | And 3 more authors.
Journal of Dentistry | Year: 2010

Objectives: In this laboratory study, we examined the use of a swept-source optical coherence tomography (SS-OCT) as a diagnostic tool for occlusal caries. Methods: One-hundred and eleven investigation sites of occlusal fissures were selected from 62 extracted teeth and examined visually using conventional dental equipment without any magnification. SS-OCT observations were carried out on the same locations as where the conventional examination had been performed. The teeth were then sectioned using a diamond saw and directly viewed under a confocal laser scanning microscope (CLSM). Presence and extent of caries was scored in each observation and the obtained results from SS-OCT and conventional visual inspection were compared with the CLSM. The reproducibility and indices of sensitivity and specificity of SS-OCT were calculated and compared with those of the visual inspection. The results were statistically analyzed using receiver operating characteristic (ROC) curve and Spearman rank correlation test. Results: SS-OCT could clearly detect the presence of enamel demineralization lesion in a tomography image synthesized based on the backscatter signal (sensitivity = 0.98). Although the sensitivity for dentine caries of SS-OCT was over that of the visual inspection, the detection level was decreased to 0.60. When the methods were compared to the CLSM, the diagnostic accuracy of SS-OCT was better than that of the conventional visual inspection (Az values of visual inspection and SS-OCT, 0.74 versus 0.86 for enamel demineralization, 0.68 versus 0.80 for dentine caries; Spearman's correlation coefficients to CLSM; visual inspection: 0.665, SS-OCT: 0.824). Conclusions: The carious demineralization, especially in enamel, can be clearly discriminated as a highlighted area due to scattering of light matches the location of demineralized area at the base of the fissure and the results correlated well with the CLSM. © 2010 Elsevier Ltd. All rights reserved. Source

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