cone-beam computed tomography for evaluation of apical transportation in root canals prepared by two rotary systems

introduction: due to the importance of apical transportation during root canal preparation, the aim of the current study was to use cone-beam computed tomography (cbct) to assess the extent of apical transportation caused by protaper and mtwo files. methods and materials: forty extracted maxillary first molars with 19-22 mm length and 20-40 degrees of curvature were selected. the mesiobuccal canals were prepared using either mtwo or protaper rotary files ( n =20). cbct images were obtained before and after canal preparation to compare the apical transportation in different cross-sections of mesial and distal surfaces. the apical transportation values were analyzed using the spss software. the results were compared with student’s t-test and mann-whitney u test. results: there was no significant difference in the extent of apical transportation between mtwo and protaper systems in different canal cross-sections. the apical transportation value was less than 0.1 mm in most of the specimens, which was clinically acceptable. conclusion: considering the insignificant difference between the two systems, it can be concluded that both system have low rates of apical transportation and can be assuredly used in clinical settings.