evaluation of residual sealer in dentinal tubules after retreatment of canals obturated with two types of sealers

Objective: this study compared the retrievability of an epoxy resin-based sealer (ah26) and an mta-based sealer (endoseal mta) following root canal retreatment.methods: twenty-six extracted single-rooted human maxillary central incisors were prepared up to size f3 using the denco super files iii rotary system. the teeth were randomly assigned to two groups and obturated with either ah26 or endoseal mta sealers, employing a single-cone technique for all samples. after one week of storage in distilled water, the filling materials were removed by denco super files iii rotary system. the residual sealer was evaluated using scanning electron microscopy (sem) at x800 and x2000 magnifications. the statistical analysis was done by two-way anova, and a p-value less than 0.05 was considered significant.results: under the two magnifications, both the type of utilized sealer and the root section assessed had a significant effect on the percentage of remaining sealer (p<0.05), but the interaction was not significant (p>0.05). the overall percentage of residual sealer was significantly lower in the endoseal mta group compared to the ah26 groups as assessed under x800 (p=0.08) and x2000 (p=0.012) magnifications. in each group, the percentage of residual sealer was significantly greater in the apical than in the coronal third.conclusions: the residual sealer in the ah26 group was greater than that in the endoseal mta in all three root sections. the apical third section showed more sealer than the coronal section, irrespective of the sealer type used.