In Vitro Evaluation of Shear Bond Strength of Three Primer/Resin Cement Systems to Monolithic Zirconia

Purpose: To investigate the shear bond strength (SBS) of various primer/resin cement systems to monolithic zirconia under different levels of storage. Materials and Methods: Disk- shaped specimens of monolithic zirconia (10 x 3 mm, n = 72) were polished with silicon carbide paper, and the bonding surfaces were sandblasted with aluminum oxide (Al2O3). The samples were divided into three groups (n = 24) according to primer/cement system: Z-PRIME Plus/DUO- LINK (Bisco); Clearfil Ceramic Primer Plus/PANAVIA SA (Kuraray); and Single Bond Universal Adhesive/RelyX Ultimate (3M ESPE). After bonding was completed, each group was divided into two subgroups (n = 12) under different levels of 24-hour storage and thermocycling. The specimens were embedded in acrylic molds, and SBS tests were conducted. Modes of failure were also evaluated. The data were analyzed using one- and two-way analysis of variance (ANOVA) and Tukey Honest Significant Difference test. Significance was set at P <.05. Results: The highest and lowest SBS values were observed in the Kuraray (12.52 +/- 1.34 MPa) and Bisco (5.32 +/- 0.54 MPa) systems, respectively, in the thermocycled groups (P <.05). Similarly, in short-term storage groups, Kuraray had the highest (16.47 +/- 1.5 MPa) and Bisco the lowest (7.43 +/- 1.06 MPa) SBS values (P <.05). Regardless of adhesive system used, thermocycling significantly decreased the SBS of all cement groups (P <.05). Of the failures, 49% were adhesive, 45% were mixed, and 6% were cohesive. Conclusion: A methacryloyloxydecyl dihydrogen phosphate-containing resin cement is recommended to provide a durable bond for monolithic zirconia.