Effect of Calcium Hypochlorite and Sodium Hypochlorite as Root Canal Irrigants on Push-Out Bond Strength of Fiber Post Cemented with Etch-and-Rinse Resin Cement: An In Vitro Study

Objectives: Calcium hypochlorite (CH) has been recently used as a root canal irrigant. The aim of the present study was to compare the effect of CH and sodium hypochlorite (SH), as root canal irrigants, on the push-out bond strength of fiber posts cemented with an etch-and-rinse resin cement.  Materials and Methods: In this experimental in-vitro study, 40 human anterior teeth with similar root lengths were randomly divided into five groups (N=8) according to the protocol of root canal irrigation as follows: group 1: saline (control); group 2: 2.5% SH; group 3: 5.25% SH; group 4: 2.5% CH; group 5: 5% CH. Before post placement, the post space was irrigated using the same irrigation protocol, and after that, they were irrigated by distilled water. Fiber posts were cemented with All-Bond 3 bonding and Dou-Link Universal cement. After thermocycling (1000 cycles, 5- 55°C), a push-out test was performed, and data were analyzed using one-way analysis of variance and Tukey's post-hoc test with SPSS version 23 (α=0.05). Results: The highest and lowest mean bond strengths were detected in groups 2 and 5, respectively. There was no significant difference between group 1 and the SH groups (P>0.05), but the difference between group 1 and the CH groups was significant (P<0.001). There was a significant difference between SH groups and CH groups (P<0.001). Conclusion: Compared to SH, as a root canal irrigant, CH decreased the push-out bond strength of fiber posts cemented with an etch-and-rinse resin cement.