Effect of Different ‌Bonding Methods of Fiber Post on the Push-Out Bond Strength of Fiber Posts to Intra Radicular Dentin

Abstract

Background and Objectives:Various methods were introduced to reinforceoverflared root canals. This study aimed to investigate the effect of different reinforcement techniques ofoverflared root canals on the push-out bond strength of fiber poststo root canal. Methods:Crowns of 48 single-rooted teeth were cut, and root canal treatment was performed. After 72 hours, the roots were prepared for receiving fiber posts and overflared. Then,they were randomly divided into four groups. Group 1 (control group): luting with self-adhesive resin cement (SARC); Group 2: luting with dual-cure core build-upresin composite(DCC); Group 3: relining root canal walls with bulk-fill resin composite thenlutingfiber post using self-adhesive resin cement (CRR); Group 4: relining fiber post with bulk-fill resin composite and light-curing it outside the root canal thenlutingthe set with self-adhesive cement (DAP). Then roots were cut in a manner thatthree samples were achieved from each root, which were named cervical, middle, and apicalbased on root regions.The push-out test was performed using a Universal Testing Machine at a cross-head speed of 0.5 mm/min. Kruskal-Wallis and a post-hoc Dunn-Bonferroni tests were used for statistical analysis (P<0.05). Results:In the cervical region, there was a statistically significant difference between the bond strength of SARC group with CRR (P=0.009) and DAPgroups(P=0.007).In the middle region, there was a statistically significant difference between the bond strength of SARC group with DCC (P=0.044), CRR (P=0.021), and DAP groups (P<0.001).However, there was no statistically significant difference in the apical region. The lowest bond strength was related to the apical region, and the highest was related to the cervical region. Conclusion: Almost all reinforcement techniques increased the bond strength in the middle and cervical regions.