The Effect of Three Different Root Canal Irrigant Protocols for Removing Smear Layer on the Apical Microleakage of AH26 Sealer

INTRODUCTION The purpose of this in vitro study was to assess the apical microleakage of AH26 sealer when three different root canal irrigant regimens were used. MATERIALS AND METHODS Eighty single-rooted human teeth were randomly divided into three experimental (n=20) and two control groups (n=10). NaOCl was used as irrigant during instrumentation, and apical patency was ensured in all teeth. Final irrigation was implemented as follow: group A- 17% EDTA + 5.25% NaOCl, Group B- 7% citric acid + 5.25% NaOCl, and group C- 20% citric acid + 5.25% NaOCl. The experimental and negative control groups were obturated by laterally condensed gutta-percha with AH26 sealer. The positive control group was obturated without sealer. The teeth were stored in 100% humidity and 37ºC for 48 hours. In the experimental groups and positive control group, the root surfaces except for the apical 2 mm were covered with nail polish and sticky wax. In the negative control group, the roots were completely covered. The samples were then immersed in 2% methylene blue dye for 72 hours at 37ºC. After that the roots were sectioned longitudinally and the dye penetration was measured. The results were statistically analyzed by One-way Variance and Post Hoc Tukey tests. RESULTS Statistically significant difference was found between groups (P<0.05). Group C showed the least (1.072 mm) and group A showed the most (2.072 mm) amount of dye penetration. CONCLUSION When a resin-based sealer is used for the obturation of the root canal system, it is better to use a citric acid irrigant instead of EDTA to remove the smear layer and to improve the apical seal.