Enhancing Bond Strength of Zirconia Prosthesis by Using Liners and Primers

Objectives: Due to low bonding strength with cement, various clinical complications were reported about zirconia prostheses. Several surface treatments have been suggested to improve this problem, but there are limitations. The purpose of this study was to evaluate the effect of silica-containing glass-ceramic liners on tensile bond strength between zirconia and resin cement and comparing the effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) containing primers.
Methods: Titanium abutments and zirconia crowns (n=60) were fabricated and the adhesive surface of specimens was treated by airborne-particle abrasion. The specimens were divided into 5 groups by surface treatment; Control group, 2 primer groups (MP: Monobond Plus, ZP: Z Prime™ Plus), 2 liner groups (ACL1: Amber Ceram Liner 1, ACL2: Amber Ceram Liner 2). All specimens were cemented with self-adhesive resin cement. After 24 hours water storage and aging (5000 thermal cycles), tensile bond strength was measured using universial testing machine. Failure mode analysis and elemental analysis of the bonding interface were performed. The data was analyzed using One-way ANOVA, Tukey HSD test and Fisher’s exact test.
Results: The liner groups and primer groups showed significantly higher tensile bond strength than control group (P<.05). ACL2 showed significantly higher tensile bond strength than primer groups (P<.05). The percentage of adhesive failure was higher in control group and the percentage of mixed failure was higher in primer groups (P<.001). In liner groups, all specimens showed mixed failure (P<.001).
Conclusions: The application of liner significantly increased tensile bond strength between zirconia and resin cement. ACL2 was more effective than MDP-containing primers in improving the tensile bond strength between zirconia and resin cement.