Surface wettability and nano roughness at different grit blasting operational pressures and their effects on resin cement to zirconia adhesion.

This study analyzed the effect of grit blasting pressures on resin cement to zirconia (ZrO) adhesion using enclosed mold shear bond test (EM-SBS). ZrO blanks were pre-treated with Rocatec Soft as follows: group 1: control, group 2: specimens treated at 80 kPa, group 3: at 180 kPa, group 4: at 280 kPa, and group 5: at 380 kPa. Monobond N and Multilink Speed were used as the silane and resin cement, respectively. Next, the blanks were assigned into three sub-groups (n=8, N=108) according to storage conditions. A non-linear relation was observed between EM-SBS and contact angle versus grit blasting pressure (r=-0.542, p=0.01). According to ANOVA (p<0.05), the EM-SBS values with both 180 kPa (17.4±6.7 MPa) and 280 kPa (19.4±4.8 MPa) were statistically higher after 12,000 thermo-cycles. Relatively equal thermo-cycled bond strength might also be achieved with intermediate (180 kPa) grit blasting pressure instead of the recommended 280 kPa.