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

Purpose: 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).

Materials and methods: 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.

Results: 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.

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