Adhesion behavior of conventional and high-translucent zirconia: Effect of surface conditioning methods and aging using an experimental methodology.

OBJECTIVE: Evaluate the adhesive behavior of conventional and high-translucent zirconia after surface conditioning and hydrothermal aging. MATERIALS AND METHODS: Conventional (ZrC) and high-translucent zirconia (ZrT) specimens were divided into six groups: without surface treatment (ZrC and ZrT), air-borne particle abrasion with 50-mum Al(2) O(3) sized particles (ZrC-AO and ZrT-AO), and tribochemical treatment with 30-mum silica modified Al(2) O(3) sized particles (ZrC-T and ZrT-T). Zirconia specimens were treated using an MDP-containing universal adhesive and bonded to two resins blocks with an adhesive luting cement. Microbar specimens with cross-sectioned areas of 1 mm(2) were achieved. Half of the microbars were subjected to hydrothermal aging. Bond strength was evaluated by microtensile bond strength test and statistically evaluated by the Weibull analysis. RESULTS: Roughness of the ZrC-AO and ZrT-AO groups were statistically higher. Bond strength analysis revealed higher bond strength for ZrC-AO and ZrC-T groups compared to ZrT-AO and ZrT-T, respectively. Mixed failure was the most frequent for the mechanically treated groups, while no cohesive failures were obtained. CONCLUSION: Lower values of bond strength were obtained for the mechanically treated high-translucent zirconia groups when compared to their conventional zirconia counterparts. Mechanical surface treatment significantly improved the bond strength to conventional and high-translucent zirconia. CLINICAL SIGNIFICANCE: Mechanical surface treatment (air-borne particle abrasion or tribochemical treatment) associated with the use of universal adhesives containing MDP could provide a durable bonding to conventional and high-translucent zirconia.