Evaluation of canal centering ability of novel rotary files used in conventional sequence and as a single file system using CBCT-an in vitro study

ABSTRACT Aim: This study aims to evaluate the canal centering ability (CCA) of novel rotary files used in conventional sequence and as a single file system, in curved canals of extracted molars using cone-beam computed tomography (CBCT) Methods: Mesial canals of mandibular molars, with closed apices and within the curvature limits of 15°–45° were selected. After access opening and working length determination, pre-instrumentation measurements from the outer root surface to the root canal periphery were done using CBCT. Teeth were randomly grouped as: Group 1 – NT Rainbow S (NTRBS) conventional sequence, Group 2 – NTRBS single file, Group 3 – Jizai conventional sequence, and Group 4 – Jizai, single file. Pre- and postinstrumentation CBCT measurements were used to calculate CCA. Results: The mixed-design repeated-measures analysis of variance demonstrated no statistically significant main effect of group for the buccolingual direction of the mesiobuccal canal ( P = 0.057) and mesiodistal direction of the mesiolingual canal ( P = 0.955) across indicating canal transportation across all levels. Group 2 NTRBS single file showed the least canal transportation compared to the other groups, and the most canal transportation was observed with Group 3 – Jizai conventional sequence, though differences were statistically non-significant Conclusion: Both the rotary systems exhibited canal transportation when used in conventional sequence and as a single-file system across all levels. NTRBS as a single-file system exhibited the least canal transportation. However, the potential benefits of rotary files, when used as a single file system, should be evaluated.