Methods: Forty extracted teeth with moderately curved mesiobuccal canals were selected for the study. Conventional access was performed and the samples were divided into two experimental groups of 20 teeth each. Group A and group B were prepared by using WaveOne and HyFlex CM respectively. Canal transportation and canal centering ability at coronal, middle and apical third were assessed using computed tomography (CT).The two groups were statisticallyanalysed using One way analysis of variance (ANOVA) technique adjusted for multiple comparisons using Tukey’s method in each group, followed by unpaired t test to evaluate inter-group comparison. The significance was set at P<0.05.

Results: Less canal transportation and better centering ability occurred with the Hyflex CM file system (P>0.05). The WaveOne file system remained centered but showed significant canal transportation in the coronal and middle third of the canal (P<0.05). In the inter-group comparison Hyflex CM group caused significantly less canal transportation at the middle third and superior canal centering ability at the middle and apical thirds (P>0.05).

Conclusion: The ‘HyFlex-CM’ rotary system demonstrated the best results for all the variables measured in this study.