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.