Effect of 10‐Methacryloyloxydecyl Dihydrogen Phosphate Concentrations in Primers on Bonding Resin Cements to Zirconia
Keiichi Yoshida
Abstract
PURPOSE: To investigate the effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) concentration in primers on bonding of resin cements to zirconia. MATERIALS AND METHODS: Highly translucent partially stabilized zirconia plates were bonded to stainless steel rods using one of 3 commercially available resin cements without adhesive functional monomers and without air-abrasion. Ten specimens of each resin cement group were pretreated with one of the primers containing 0.5, 1.0, 2.0, 3.0, 4.0, or 5.0 wt% of MDP dissolved in ethanol, or one of 3 commercial ceramic primers containing MDP and silane coupling agents. Untreated specimens were used as controls. The tensile bond strength was measured after 24 hours (TC0) and after thermal cycling at 4 to 60°C (TC3,500). Data were statistically analyzed using 1- or 2-way ANOVA and Tukey-Kramer post-hoc tests (α = 0.05). RESULTS: The mean tensile bond strength in the unpretreated group was significantly lower compared to that in the pretreated groups with MDP-containing primers regardless of the resin cement used (p < 0.0001). The tensile bond strengths increased with an increase in MDP concentration from 0.5 wt% to 3.0 wt% or 4.0 wt%. Pretreated groups with 4.0-wt% MDP-containing primer showed significantly higher tensile bond strengths than pretreated groups with commercial ceramic primers regardless of the resin cement used and thermal cycling (p < 0.0001). CONCLUSION: Primers containing 4.0-wt% MDP achieved higher bond strengths of resin cements to zirconia compared to commercial ceramic primers containing MDP and silane coupling agent.