Bond Strength Durability of Self-etching Adhesives and Resin Cements to Dentin

OBJECTIVES To evaluate the microtensile bond strength (microTBS) of one- (Xeno III, Dentsply) and two-step (Tyrian-One Step Plus, Bisco) self-etching adhesive systems bonded to dentin and cemented to chemically cured (C&B Metabond) or light-cured paste of a dual-cure resin cement (Variolink II, Ivoclar) within a short (24 h) and long period of evaluation (90 days). MATERIAL AND METHODS Forty recently extracted human molars had their roots removed and their occlusal dentin exposed and ground wet with 600-grit SiC paper. After application of one of the adhesives, the resin cement was applied to the bonded surface and a composite resin block was incrementally built up to a height of 5 mm (n=10). The restored teeth were stored in distilled water at 37 degrees C for 7 days. The teeth were then cut along two axes (x and y), producing beam-shaped specimens with 0.8 mm(2) cross-sectional area, which were subjected to microTBS testing at a crosshead speed of 0.05 mm/min and stressed to failure after 24 h or 90 days of storage in water. The microTBS data in MPa were subjected to three-way analysis of variance and Tukey's test (alpha= 0.05). RESULTS The interaction effect for all three factors was statistically significant (three-way ANOVA, p<0.001). All eight experimental means (MPa) were compared by the Tukey's test (p<0.05) and the following results were obtained: Tyrian-One Step Plus /C&B/24 h (22.4+/-7.3); Tyrian-One Step Plus /Variolink II/24 h (39.4+/-11.6); Xeno III/C&B/24 h (40.3+/-12.9); Xeno III/Variolink II/24 h (25.8+/-10.5); Tyrian-One Step Plus /C&B/90 d (22.1+/-12.8) Tyrian-One Step Plus/VariolinkII/90 d (24.2+/-14.2); Xeno III/C&B/90 d (27.0+/-13.5); Xeno III/Variolink II/90 d (33.0+/-8.9). CONCLUSIONS Xeno III/Variolink II was the luting agent/adhesive combination that provided the most promising bond strength after 90 days of storage in water.