Aims: To evaluate the influence of mechanical surface treatment and chemical primer application on the composite shear bond strength to zirconia.
Methods: Eighty blocks of Lava Frame Zirconia were randomly assigned to the experimental groups, according to the several possible combinations between mechanical (untreated/aluminum oxide sandblast) and chemical treatment (no primer/Monobond Plus/Experimental Zirkon-Primer/Z-Prime Plus) (n=10). Adhesive system and composite resin were then applied, and samples were thermal cycled (5°C-55°C, 500 cycles). Shear bond strength tests and failure mode analysis were performed. SBS data were analyzed by two-way ANOVA, followed by Student-Newman-Keuls post-hoc tests, and failure mode by Kruskal-Wallis and Mann-Whitney tests (p<0.05).
Results: Shear bond strength mean values ranged from 6.9 to 23.2 MPa. Surface treatment with aluminum oxide sandblasting allowed a statistically significant increase (p<0.05) in bond strength values. The group treated with Z-Prime Plus achieved (p<0.05) higher bond strength results than the other chemical treatments.
Conclusions: The surface mechanical treatment almost doubled the bond strength values. Z-Primer Plus have enhanced bond strength values of composite to zirconia.