Effect of Intracanal Dentin Conditioning with Xylene, Phosphoric Acid and Chlorhexidine on Bond Strength to Glass Fiber Post with Self-Adhesive Cement

Background and Aim: Debonding is the most commonly encountered failure in teeth restored with fiber posts that mainly occurs at the weakest interface (dentin-cement interface). Thus, reinforcement of this interface is mandatory. The aim of this study was to evaluate the effect of different root dentin surface treatments after post space preparation on bond strength of fiber posts cemented with a self-adhesive resin cement. Materials and Methods: Forty extracted sound single-rooted teeth underwent root canal therapy. After post space preparation, the teeth were assigned to four group of 10 teeth according to the type of dentin surface treatment: Group 1: 2% chlorhexidine rinse, group 2: 37% phosphoric acid etching and then irrigating with saline, group 3: rinse with xylene and then irrigation with saline, group 4: rinse with saline (control group). Then, fiber posts were cemented with Total cem cement and the teeth were sectioned horizontally. Specimens were observed under a stereomicroscope at X10 magnification and failure modes of each group were determined. Results were analyzed by one-way ANOVA. Results: There was no significant difference between the mean bond strength of the four groups (P=0.174). The highest mean bond strength value was found in phosphoric acid group (8.18±3.19 MPa) and the lowest belonged to the control group (6.21±1.81 MPa). Conclusion: Our results showed that dentin surface treatment with phosphoric acid before cementation of fiber posts with a self-adhesive cement improves the bond strength.