Resin bond strength of surface-treated zirconia implant material

Objectives: The dental application of zirconia has recently been expanded to the implant field. The aim of this investigation was to evaluate the effect of surface treatment on the shear bond strength of resin cement to zirconia implant material.

Methods: Zirconia specimens were manufactured to dimensions of 30 x 5 x 1 mm using the thermo-gel molding method. Evaluated surface treatment groups were: no treatment (AS), alumina sand-blasting treatment (SB), hydrofluoric acid immersion treatment (HF), alumina sand-blasting and hydrofluoric acid immersion treatment (SH). The treated specimens were placed in Teflon molds for making simple shear or lap shear bond test specimens. All surfaces were treated with a primer (AZ primer, Shofu) and resin cement (ResiCem, Shofu) and cured with a LED curing unit for 30 seconds. Specimens were stored in 100% humidity at 37 °C for 1 week. Simple shear and lap bond strengths were measured using a universal testing machine, at a crosshead speed of 1 mm/min. Five specimens were used in each group. Statistical analysis was performed using the one-way ANOVA and Tukey’s tests for each method (p<0.01).

Results: Both bond strength tests showed the same trend. Simple shear bond strength resulted in SB (13.8MPa) = SH (13.6MPa) = HF (9.0MPa) > AS (6.0MPa). Lap shear bond strength resulted in SH (15.4MPa) = SB (15.2MPa) = HF (12.7MPa) > AS (7.3MPa).

Conclusions: The shear and lap resin bond strength is affected by surface treatment of zirconia. Therefore, it is suggested that surface treatments be completed to enhance adhesion of between zirconia implant abutments and suprastructures.