RESUMEN
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. 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: groupA- 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 groupswere obturated by laterally condensed gutta-percha withAH26 sealer. The positive control group was obturated without sealer. The teethwere stored in 100%humidity and 37°C for 48 hours. In the experimental groups and positive control group, the root surfaces except for the apical 2mmwere covered with nail polish and stickywax. In the negative control group, the roots were completely covered. The samples were then immersed in 2% methylene blue dye for 72 hours at 37°C.After that the roots were sectioned longitudinally and the dye penetrationwasmeasured. The resultswere statistically analyzed by One-way Variance and Post Hoc Tukey tests. Statistically significant difference was found between groups [P<0.05]. Group C showed the least [1.072mm] and groupAshowed themost [2.072mm] amount of dye penetration. 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 EDTAto remove the smear layer and to improve the apical seal