Ceramic repair: influence of chemical and mechanical surface conditioning on adhesion to zirconia.

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.