Surface roughness and bond strength of zirconia posts to a resin cement after various surface pretreatments

The purpose of this study was to investigate the influence of post surface conditioning methods on the surface roughness and microtensile bond strength (μTBS) of zirconia posts to a resin cement.

Debonding at the post-adhesive interface is a major problem for zirconia posts.

A total of 25 zirconia posts (n=5) were prepared as follows: untreated (control, group C), airborne-particle abraded (group AA), silica coated (group SC), Nd:YAG laser irradiated (group N), and Er:YAG laser irradiated (group E). Prior to application of a dual-cured resin cement on the posts, roughness values of the post surfaces were detected with a profilometer. Specimens were then sectioned to obtain rectangular sticks for μTBS. After sticks were stored in distilled water at 37°C for 24 h, μTBS values were determined in a universal testing machine at a crosshead speed of 1 mm/min until failure. Furthermore, scanning electron microscopic (SEM) analysis was performed for one specimen of each group to evaluate the post surface morphology. One-way ANOVA and post-hoc comparison tests (α=0.05) were performed on all data.

All surface treatment groups demonstrated significant higher μTBS values than the control group (p<0.001). The highest mean force value was observed in group SC. In addition, similar bond strength results were detected between group SC and group E (p=0.669). None of treatment groups resulted in significant improvement in roughness values of the post (p<0.05), except group N.

All surface treatments were found to be effective methods to achieve a durable bond between zirconia posts to resin cement.