Bond Strength of new Self-Adhesive Resin Cements to Zirconia

Objectives: This in vitro study measured and compared shear bond strength of new self-adhesive resin cements to zirconia.
Methods: Seventy-two KATANA Zirconia STML (n=12) specimens were sectioned and sintered in an induction furnace (CEREC SpeedFire, Dentsply Sirona, Germany). Specimen surfaces were ground finished with 800 grit silicon carbide abrasive with cooling water and cleaned with ultrasonication in alcohol. Specimens were air-particle abraded with 50 μm aluminum oxide at 2.8 bar pressure. Cylindrical composite resin specimens (2.1 mm in diameter, 3 mm in height) were bonded to the zirconia samples with self-adhesive resin cements Panavia SA Universal (PSA), TheraCem (TEC), SpeedCem 2.0 (SPC), RelyX Unicem 2 (RUC), PermaCem 2.0 (PMC) and dual-cure multi-step composite resin cement Panavia V5 after application of a special zirconia primer (control, PV5) following manufacturers’ instructions. A load of 1000 g was applied to the composite cylinders during bonding in an alignment apparatus, then light cured for 80 s. Samples were stored in distilled water at 37° C for 24 h, then subjected to 10,000 thermal cycles. Shear bond strength was determined using a universal testing machine at a crosshead speed of 0.5 mm/min expressed in MPa. The fractured surfaces of specimens were inspected with a stereo microscope and classified as adhesive, cohesive, or mixed failures. One-way ANOVA was applied for statistical analysis.
Results: Shear bond strength values [MPa] were for PSA 8.64 (1.78 SD), TEC 9.05 (2.64 SD), SPC 8.54 (1.92 SD), RUC 7.60 (1.26 SD), PMC 7.59 (1.10 SD) and PV5 9.59 (1.55 SD). The bond strength values of PV5 control group were slightly higher than the other study groups, however, there were no statistically significant differences in shear bond strength between the resin cements tested (p>0.05).
Conclusions: The five self-adhesive cements and dual-cure multi-step composite resin cement showed the same bonding performance to zirconia surfaces.