Surface Topography and Pushout Bond Strength of Glass Fiber Posts with Different Surface Treatments to Root Dentin Following Cementation by Precuring and Co-Curing Methods : Short title: Surface Topography and Pushout Bond Strength of Glass Fiber Posts to Root Dentin Following Cementation.

Background: This study assessed the surface topography and pushout bond strength (PBS) of glass fiber posts (GFPs) with different surface treatments to root dentin following cementation by precuring and co-curing methods. Materials and Methods: In this in vitro study, 80 extracted single-rooted premolars were decoronated and randomly assigned to 4 groups (n=20) for surface treatment of GFPs with 20% H2O2, Er,Cr:YSGG laser (2780 nm, 90 mJ, 4.5 W, 50 Hz, 60 seconds) and sandblasting (50 µm aluminum oxide particles, 2.8 bar pressure, 10 mm distance, 20 seconds). No surface treatment was performed in group 4. Each group was randomly divided into two subgroups (n=10) for cementation of GFPs with precuring and co-curing methods. The PBS was measured, the mode of failure was determined, and the surface topography of the posts was assessed under a scanning electron microscope (SEM). Data were analyzed by ANOVA, Tukey, and Dunnett tests (alpha=0.05). Results: The mean PBS of H2O2-treated GFPs was significantly higher in co-curing than precuring method (P=0.04). No significant difference was found between the precuring and co-curing in PBS of GFPs with other surface treatments (P0.05). The mean PBS of sandblasted, laser-treated, and H2O2-treated GFPs was not significantly different in precuring method. In co-curing cementation, sandblasting significantly decreased the PBS (P=0.04) while laser and H2O2 surface treatments had no significant effect on PBS (P0.05). Conclusion: The co-curing cementation method yielded a significantly higher PBS than the precuring method in H2O2-treated GFPs. Sandblasting significantly decreased the PBS of GFPs cemented by the co-curing method.