RESUMO
PURPOSE: To evaluate the effect of composite cement components and thermocycling on the bond strength of monolithic lithium-disilicate (LS2) glass-ceramic implant-supported restorations bonded to titanium (Ti) abutments. MATERIALS AND METHODS: Eighty LS2 blocks were treated with five types of composite cement and primer, then divided accordingly into groups: M (Multilink hybrid abutment), G (G-CEM LinkAce), GP (G-CEM LinkAce with G-Multi PRIMER), P (Panavia F2.0), and U (RelyX U200). Half of the 16 specimens from each group were subjected to thermocycling (groups T-M, T-G, T-GP, T-P, and T-U). The tensile bond strength (TBS) of all specimens was measured using a pull-off test. The cross section of the LS2 block from which the Ti abutment was removed was examined for mode of failure. Two-way ANOVA and Tukey's HSD test (significance level = 0.05) were used to determine the effect of composite cement composition and thermocycling on TBS. RESULTS: There was no difference in TBS between the five groups before thermocycling (p = 0.16). However, groups M (p < 0.001) and G (p = 0.014) showed significantly lower TBS than the corresponding thermocycled groups. Groups T-GP, T-P, and T-U did not show significant changes in TBS after thermocycling (p > 0.05). All failures occurred at the interface between the composite cement and Ti abutment and not between the cement and the LS2 block. CONCLUSION: Thermocycling can reduce the bond strength between the composite cements and Ti abutment. The composite cements containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) or methacrylate phosphate ester monomers stabilize bonding.
