Effects of surface treatments on the shear bond strenght of luting cements to zirconia

Appropriate cementation protocole is still investigated subject for managing stable bond between resin cement and zirconia restorations. The aim of this in-vitro study was to evaluate the effect of surface treatments on the shear bond strength of resin cements to zirconia. Sintered zirconia specimens (n=192) were divided into different surface treatment groups: Control, sandblasting, glaze and hydrofluoric acid application and hot acid etching application (n=48). Twelve specimens were randomly selected from each group and measured for surface roughness. Then each groups were divided into 4 subgroups (n=12), the 3 different resin cements were adhered onto the zirconia surfaces. Shear bond strenght of each sample was evaluated after 5000 thermal cycles and the zirconia specimens were examined with a stereomicroscope to assess the failure types. two specimens for the scanning electron microscope analysis were prepared. Shear bond strenght values were analyzed through two-way analysis of variance and Tukey LSD tests. One-way analysis of variance and Tukey LSD tests were used for analysis of the surface roughness values. For the all resin cements, the sandblasting surface treatment increased the shear bond strength (p<0.05). The glaze and hydrofluoric acid application increased the shear bond strenght values, except the D-SRXU group (p<0.05). The surface roughness values of the sandblasted specimens were similar with the control and hot etching solution specimens (p>0.05). Although the glaze and hydrofluoric acid group served the highest surface roughness value, this surface treatment was not achieved high shear bond strenght values for all groups (p<0.05). The data of shear bond strenght were supported by the scanning electrone microscopic images. As a result of this study, it can be recommended to use the appropriate combination of the adhesive/silane coupling agent and surface treatment for achieving durable zirconia-resin bonding.