Bond strength of resin cements to a zirconia ceramic with different surface treatments

This study evaluated the influence of surface treatments and metal primers on the bond strength of resin cements to a yttrium-stabilized tetragonal zirconia (Y-TZP) ceramic. Two-hundred and forty plates of Y-TZP ceramic were randomly assigned to 24 groups (n = 10) according to the combination of surface treatment (none, air abrasion with Al2O3 particles, Er:YAG laser irradiation), metal primer (none, Alloy Primer, Metal Primer II or Metaltite) and resin cement (Calibra [Bis-GMA-based] or Panavia F2.0 [MDP-based]). Fragments of dentin with a cylindrical edge (0.8 mm in diameter) were fixed to ceramic surfaces with the resin cements. The micro-shear bond test was carried out at a 1 mm/minute speed until failure, and the ceramic surfaces were examined after debonding. Bond strengths were analyzed through three-way ANOVA/Tukey test with a 5% significance level. Changes in topography after surface treatments were evaluated with scanning electron microscopy. Surface treatments significantly modified the topography of the Y-TZP ceramic. Air abrasion resulted in increased bond strength for both resin cements. However, air abraded and laser irradiated specimens presented higher bond strength with the Bis-GMA-based resin cement than with the MDP-based cement. Both cements presented similar behavior on untreated surfaces. The three metal primers yielded a significant increase in bond strength, regardless of the surface treatment and resin cement. Adhesive failures were the most prevalent. Air abrasion with Al2O3 particles and the application of metal primers increased bond strength to Y-TZP surfaces for both resin cements.