Effect of Zirconia Surface Treatments on the Shear Strength of Zirconia/Veneering Ceramic Composites

TLDR

The study aimed to evaluate how various surface treatments affect the bond strength between veneering ceramics and zirconia. Shear tests were performed on zirconia surfaces treated with polishing, sandblasting, silica coating, liner application, and regeneration firing, using five veneering ceramics and one-way ANOVA with Scheffé post hoc analysis to assess bond strength. Bond strength exceeded the cohesive strength of the veneering ceramic, with shear strengths ranging 23.5–33.0 MPa; regeneration firing reduced strength, while sandblasting did not improve bonding, suggesting chemical bonding dominates and regeneration firing is not recommended.

Abstract

Aim of the investigation was to assess the effect of different surface treatments on the bond strength of veneering ceramics to zirconia. In a shear test, the influences of polishing, sandblasting, and silica-coating of the zirconia surface on bonding were assessed with five different veneering ceramics. In addition the effect of liner application was examined. With one veneering ceramic, the impact of regeneration firing of zirconia was also evaluated. Statistical analysis was performed with one-way ANOVA and post hoc Scheffé's test. Failure in every case occurred in the veneering ceramic adjacent to the interface with a thin layer of ceramic remaining on the zirconia surface, indicating that bond strength was higher than the cohesive strength of the veneering ceramic. Shear strength ranged from 23.5 +/- 3.4 MPa to 33.0 +/- 6.8 MPa without explicit correlation to the respective surface treatment. Regeneration firing significantly decreased the shear strength of both polished and sandblasted surfaces. Findings of this study revealed that bonding between veneering ceramics and zirconia might be based on chemical bonds. On this note, sandblasting was not a necessary surface pretreatment to enhance bond strength and that regeneration firing was not recommended.