Bond Strength of Fiber Posts to Composite Core: Effect of Surface Treatment With Er,Cr:YSGG Laser and Thermocycling

Introduction: This study aimed to determine the bond strength of fiber post to composite core following surface treatment with Er,Cr:YSGG laser at different powers and sandblasting with and without thermocycling. Methods: In this experimental study, 30 fiber posts (Glassix, Nordin, Switzerland) were randomly divided into 5 groups of sandblasting, no treatment and laser irradiation at 1, 1.5 and 2 W powers. Following composite filling and mounting, 1-mm thick sections were made for push-out bond strength testing. Half of the samples in each group were subjected to thermocycling (n=15). Two-way analysis of variance (ANOVA) was used to analyze the bond strength values. Pairwise comparisons were made using Tukey test (P < 0.05). Results: Effect of treatment method on push-out bond strength of fiber post to composite core was significant (P = 0.017), while thermocycling had no significant effect on bond strength (P = 0.964). Pairwise comparison of surface treatment methods revealed no significant difference in groups with and without thermocycling (P > 0.05), but Er,Cr:YSGG laser irradiation with 1 W power yielded significantly higher bond strength than the control group (P =0.01). Conclusion: Irradiation of Er,Cr:YSGG laser at 1 W power increased the bond strength of fiber post to composite core. Thermocycling slightly decreased the bond strength at the fiber post-core interface.