Comparison of the effect of QMix and conventional root canal irrigants on push-out bond strength of fiber post to root dentin

Objectives This study aimed to assess the effect of application of QMix and common root canal irrigating solutions on the bond strength of fiber post to root dentin. Material and Methods In this in-vitro study, 60 extracted incisor teeth were decoronated such that 15 mm of root length remained. The canals were prepared with ProTaper rotary system to F5 and filled with gutta-percha and AH26 sealer. Prior to post placement, the teeth were divided into four groups based on the type of final irrigating solution namely saline, 5.25% NaOCl, 2% chlorhexidine, and QMix. The fiber posts were then cemented with Panavia F2 resin cement. The roots were sectioned perpendicular to their longitudinal axis, and four sections with 1 mm thickness were made at the middle and coronal thirds of the roots. The push-out bond strength of fiber posts was measured by a universal testing machine in megapascals. Data were analyzed by two-way ANOVA and Tukey's test. Results The maximum and minimum bond strength values were noted in QMix and NaOCl groups in both the middle and coronal third of the root, respectively. But, there was no significant difference between the push-out bond strength in the middle or coronal third of the root (p = 0.054). Adhesive failure was the most common mode of failure in all groups. Conclusion Use of QMix for post space irrigation does not compromise the bond strength of fiber post to root dentin, and can be used for final rinsing of the post space.