Effects of different surface treatments on bond strength between resin cements and zirconia ceramics

This study compares the bond strength of resin cement and yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic with different surface conditioning methods. Two hundred presintered Y-TZP ceramic specimens were prepared, sintered (4 × 4 × 4 mm), and randomly assigned to four equal groups as control (C, no conditioning); airborne particle abraded (APA, air abrasion with 11 μm Al2O3); tribochemical silica coating/silane coupling system (TSC, Rocatec, air abrasion with 110 μm Al2O3, 30 μm silica-coated Al2O3 and silane); and laser (L, Er:YAG laser irradiation treated at a power setting of 200 mJ). After specimen preparation, composite resin cylinders were prepared and cemented with resin cements (Clearfil Esthetic, Panavia F 2.0, Rely X-U100, Super Bond C&B, and Multilink Automix) on the ceramic surfaces and kept in an incubator at 37°C for 60 days. All specimens were tested for shear bond strength with a universal testing machine, and fractured surfaces were evaluated by environmental scanning electron microscopy. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U-tests (α=0.05). The bond strengths for C and L groups were not significantly different according to adhesive resin cement. APA and TSC resulted in increased bond strength for Panavia F 2.0 and Rely X-U100 resin cements. Additionally, TSC presented higher bond strength with Multilink Automix. Adhesive fracture between the ceramic and resin cement was the most common failure. Complete cohesive fracture at the ceramic or composite cylinders was not observed. Regardless of the adhesive resin cement used, laser treatment did not improve resin bond strength.