Effects of Different Bonding Agents on the Shear Bond Strength Between Monolithic Zirconia and Indirect Composite

To investigate the effects of different bonding agents and application of glaze on the shear bond strength (SBS) between monolithic zirconia (MZ) and indirect composite (IC).

Five different bonding agents (G-Premio Bond [GP]; Tokuyama Universal Bond [TU]; Signum Zirconia bond [SZ]; Clearfil Ceramic Primer Plus [CCP]; Z-Prime Plus [ZP]) were applied to a total of 200 MZ disk-shaped specimens (n = 100 glazed and 100 nonglazed). Half of the specimens then underwent thermocycling and the other half no thermocycling (n = 10 specimens each subgroup). The experimental setup was prepared as two pieces according to the ISO TR 11405 standards. Specimens embedded in acrylic resin were placed into the experimental setup and a universal testing machine at a crosshead speed of 0.5 mm/minute. Mann-Whitney U test and Kruskal-Wallis test were used for statistical analyses. Bonferroni correction was then performed, and test results with P < .05 were accepted as statistically significant.

The application of glaze significantly enhanced SBS when ZP or CCP was used; however, it did not have any significant effect when GP, TU, or SZ were used. Thermocycling significantly decreased the SBS in all bonding agent groups except GP specimens with glaze (P = .16). The highest SBS in all conditions was noted when GP and TU were used.

These findings suggest that the bonding agents GP and TU may be recommended for better bonding between MZ and IC.