Effect of differtent surface treatments on bond strength of zirconia

Objectives: The purpose of this study was to evaluate different methods of zirconia ceramic surface treatments to obtain the best bond strength results.

Methods: 105 zirconia discs, 4 mm X 3 mm, (Cercon, Dentsply) were prepared following the manufacturer's instructions for 7 groups that consisted of 15 specimens each. All specimens were assigned randomly to one of the surface treatments: (1) Airborne particle abrasion with 50 µm Al₂O₃ particles (AP 50), (2) Airborne particle abrasion with 110 µm Al₂O₃ particles (AP 110), (3) Airborne particle abrasion with 50 µm Al₂O₃ particles + silan application (APS 50), (4) Airborne particle abrasion with 110 µm Al₂O₃ particles + silan application (APS 110), (5) Silica coating with 30 µm SiO_x (CoJet, 3M ESPE) + silan application (CS), (6) Only silan application (S), and (7) Control group (Control). All specimens were cemented using a phosphate monomer resin cement. Shear bond strength tests were performed in a universal testing machine. The mean bond strengths of the specimens of each group were statistically analyzed using 1-way analysis of varience (ANOVA) and Post Hoc tests to assess the significance of differences in shear bond strength between groups. Debonded surfaces were examined with a scanning electron microscope to asses the mode of failure.

Results: The bond strengths (mean ± SD; MPa) in the groups were as follows: APS 50 (31,44 ± 5,188 MPa), APS 110 (32,67 ± 3,83 MPa) and CS (27,66 ± 5,30 MPa) gave higher shear bond strength results than AP 50 (15,81 ± 2,82 MPa), AP 110 (18,39 ± 4,39 MPa), S (24,83 ± 2,82 MPa) and control group (11,71 ± 1,50 MPa).

Conclusion: Highest bond strengths between zirconia ceramic and dentin were obtained using airborne particle abrasion + silanization. Tribochemical silica coating also gave results close to airborne particle abrasion + silan application groups.