Surface Roughness and Bond Strength of Zirconia Posts to a Resin Cement After Various Surface Pretreatments

Objective: The purpose of this study was to investigate the influence of post surface conditioning methods on the surface roughness and microtensile bond strength (mu TBS) of zirconia posts to a resin cement. Background data: Debonding at the post-adhesive interface is a major problem for zirconia posts. Methods: 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 mu TBS. After sticks were stored in distilled water at 37 degrees C for 24 h, mu TBS 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 (alpha=0.05) were performed on all data. Results: All surface treatment groups demonstrated significant higher mu TBS 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. Conclusions: All surface treatments were found to be effective methods to achieve a durable bond between zirconia posts to resin cement.