shaping ability of single-file systems with different movements: a micro-computed tomographic study

introduction: this study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (mb) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (waveone with reciprocating motion and oneshape with rotary movement), using micro-computed tomography (micro-ct). methods and materials: ten mb roots with single canals were included, uniformly distributed into two groups ( n =5). the samples were prepared with a waveone or oneshape files. the shaping ability and amount of canal transportation were assessed by a comparison of the pre- and post-instrumentation micro-ct scans. the kolmogorov-smirnov and t-tests were used for statistical analysis. the level of significance was set at 0.05. results: instrumentation of canals increased their surface area and volume. canal transportation occurred in coronal, middle and apical thirds and no statistical difference was observed between the two systems ( p >0.05). in apical third, significant differences were found between groups in canal roundness (in 3 mm level) and perimeter (in 3 and 4 mm levels) ( p <0.05). conclusion: the waveone and one shape single-file systems were able to shape curved root canals, producing minor changes in the canal curvature.