THE EFFECT OF EDTA IRRIGATION TIME ON THE MICROTENSILE BOND STRENGTH OF RESIN SEALERS AND ROOT CANAL DENTIN

Abstract

Introduction: Several studies have recommended the use of EDTA as a final flush before root canal obturation, but the optimal irrigating time remains unverified. The aim of the study was to determine how the duration of EDTA irrigation affects microtensile bond strength. Materials and methods: The 160 extracted human premolars were decoronated and embedded in resin block. Root canals were prepared by using the rotary files (Protaper Universal) and distilled water irrigation, and irrigated with 5% NaOCl. In Group 1, this was followed by irrigation with distilled water, while in Groups 2–5, this was followed by irrigation with 17% EDTA for 1, 3, 5, and 10 min, followed by distilled water. Two specimens of each group were used for scanning electron microscopic (SEM) observation. The remaining specimens were divided into 2 groups—AH Plus and MetaSEAL (n = 15 each). The specimens were prepared for microtensile tests. The failure mode was identified, and the bond strength value was analyzed using one-way ANOVA and Tukey’s HSD post-hoc test. Results: The 10-min EDTA-treated specimens (Group 5) showed greater microtensile bond strength than non-EDTA-treated specimens (Group 1) (p < 0.001) in MetaSEAL group. Mixed failure accounted for the majority of failures in all groups. In SEM, the NaOCl group showed a smear layer covering the dentin surface, but the EDTA groups showed an absence of smear layer and various depths of demineralized dentin and exposed collagen. Conclusions: The duration of EDTA irrigation affected on the microtensile bond strength of the methacrylate resin sealer and root dentin.