retreatability of root canals obturated using gutta-percha with bioceramic, mta and resin-based sealers

introduction: the aim of this study was to evaluate the retreatability of root canals obturated with gutta-percha (gp) and three different endodontic sealers [iroot sp (bioceramic sealer), mta fillapex (mta-based sealer) and ah-26 (epoxy resin-based sealer)] using the protaper universal retreatment (ptr) system. methods and materials: forty extracted single-rooted human teeth were prepared with universal protaper files up to f4 (40/0.06). specimens were randomly divided into four groups according to obturation technique/material: single-cone gp/ah-26, lateral compaction of gp/ah-26, single-cone gp/iroot sp, and single-cone gp/mta fillapex. root fillings were removed with ptr. the time taken to reach the working-length (twl) was recorded. roots were longitudinally sectioned and each half was evaluated using a stereomicroscope. three observers scored each third of all specimen. obtained data were analyzed using the kruskal-wallis, mann-whitney u, welch and games-howell tests. the level of significance was set at 0.05. results: in single-cone gp/mta fillapex group the twl was significantly shorter. the remnant of filling material in the apical and middle thirds of groups was similar and higher than the coronal thirds. conclusion: none of the tested sealers were completely removed from the root canal system