cbct evaluation of gutta-percha removal using protaper and mtwo retreatment files, wave one, and hedstrom files: an ex vivo study

objectives: this study aimed to evaluate the efficacy of protaper, mtwo, and waveone retreatment files and hedstrom files for removal of gutta-percha from the straight root canals using cone-beam computed tomography (cbct). materials and methods: forty freshly extracted single-rooted and single-canal teeth were selected for this study. the teeth were decoronated, and biomechanical preparation was performed up to #30 k-file. the root canals were obturated using lateral compaction technique with gutta-percha and resilon sealer. the teeth were then randomly divided into 4 groups, and cbct images were obtained. all the canals were then retreated with either protaper retreatment files, mtwo retreatment files, waveone files, or hedstrom files. the surface area of the remaining filling material after the retreatment procedure was quantified by cbct. statistical analysis was performed via one-way anova and the tukey-kramer multiple comparisons test. results: none of the file systems could completely remove the filling material from the canals. data analysis revealed significant differences between the groups in the apical and middle thirds (p 0.05). conclusion: all the file systems left some filling material in the canals. mtwo retreatment files had maximum efficacy for removal of filling materials in comparison with other files. waveone files can also be used for root canal retreatment.