Long-term tensile bond durability of two different 4-META containing resin cements to dentin

Objectives: This study was conducted to evaluate the tensile bond durability of two different types of 4-META containing resin cements over a period of 3 years. Methods: Ten bovine dentin specimens were tested for tensile bond strengths with each of the following materials: Super Bond C&B: unfilled methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) resin cement, MASA Bond (experimental material): filled dimethacrylate resin cement at 1 day, 6 months, 1 and 3 years. The mean bond strengths were compared statistically by two-way ANOVA and Fisherʹs PLSD test (P<0.05). The mode of failure was classified by SEM observation. Results for the mode of fracture were analyzed using the Mann–Whitney U test. Results: Although there was no statistical difference in mean bond strength between Super Bond C&B and MASA Bond (P>0.05) during the experimental periods, the 1-day bond strengths were significantly greater than those at the other experimental periods except for 6 months (P<0.05). Regarding the fracture modes, at 6 months and 1 year, statistical differences were observed between Super Bond C&B and MASA Bond (P<0.05). Significance: The bond strengths of both resin cements to dentin significantly decreased after 6 months, and the long-term failure patterns of the 4-META/TBB resin cements showed a marked change.