Effect of Opaque on Resin Bonding to Calcium Phosphate Crystalline Ceramic

The purpose of this study was to examine the effect of opaque on resin bonding to calcium phosphate crystalline ceramics (CPCC). Disk-shaped specimens were made from the calcium phosphate crystalline ceramics (Crys-Cera). All specimens were ground with 800-grit abrasive paper, cleaned and finally air-dried. Control group (CT group) didn't undergo any treatment. Coating of one layer opaque treatment (OP1) and two layer opaque treatment (OP2) was performed. Sandblasting (SB group) was done with alumina powders. After that resin cements (Duo-Link, Panavia F 2.0, Maxcem) were applied to the surface using a bonding clamp and light-cured. All the specimens were stored in distilled water at 37oC. After 24 h storage in water, each specimen was fixed to a jig and loaded at a crosshead speed of 1 mm/min until failure in a universal testing machine. Surface morphology of the treated specimens was observed and surface roughness values (Ra) were measured. The data were analyzed using a one-way ANOVA with Tukey’s post hoc test at a significance level of 0.05. Coating of the opaque on CPCC surface substantially increased surface roughness of CPCC surface. Two layer coating of the opaque group substantially increased surface roughness, when compared to one layer coating of the opaque group. Mechanical roughening using alumina particle increased surface roughness similar to one layer coating of the opaque group. In shear bond strength tests with specimens bonded with Duolink and Panavia F 2.0, OP2 group showed the highest shear bond strength. In test using Maxcem, SB group showed the highest shear bond strength. In failure pattern, CT and SB groups showed all adhesive failure, and OP1 and OP2 groups showed adhesive failure and mixed failure.