Effect of zirconia surface modification using dopamine polymerisation on the shear bond strength of resin cement

This study evaluated the influence of polydopamine treatment on the surface properties and bond strength of yttria-stabilised tetragonal zirconia polycrystal (Y-TZP). Sixty-three zirconia blocks (10 × 10 × 2 mm) were randomly divided into three groups defined by surface treatment: (i) control group (C), (ii) grit-blasted with 110 μm alumina particles (GB), and (iii) polydopamine (PDA) coating. The surfaces of specimens subjected to different treatments were investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and water contact angle measurements. After the surface treatments, the specimens were cemented to resin composite cylinders. After bonding, the shear bond strength of the ceramic to the resin was measured, and the failure mode of each specimen was analysed using a stereomicroscope. The results indicated that the shear bond strength is highest for the GB treatment and lowest for the controls. However, the difference between groups GB and PDA was not statistically significant. In the control group, adhesive failure was predominant, whereas in the treatment groups, mixed mode failure was predominant. The pre-treatment of Y-TZP ceramic with the polydopamine coating might improve the bond strength of the resin cement to the zirconia ceramic.