Influence of heat-treated retreatment files on the canal transportation and centering ability during retreatment: An in vitro cone beam computed tomography study

Aim: To assess the canal transportation and centering ability of different retreatment rotary files with the help of cone beam computed tomography (CBCT). Materials and Methods: Forty single-rooted human mandibular premolars with mean curvature of less than 20° apically were selected. Root canal preparation was done until size F2 (ProTaper Universal, Dentsply Sirona, Swiss), obturated using AH Plus resin-based sealer, and randomly divided into two groups. Hyflex Remover files and Solite RS3 retreatment files (Solite Dental, Chennai, Tamil Nadu, India) were used to remove root canal fillings, and CBCT scan was done to analyze the canal centering and transportation ratio. The data obtained were tabulated and evaluated using the Statistical Package for the Social Sciences (SPSS) software program, version 23.0 (IBM, Chicago, Illinois). Results: Between the two groups, a statistically significant difference was seen in the mesiodistal and buccolingual direction in relation to canal centering ability (P < 0.05, significant). Moreover, no significant difference was evident for canal transportation. Conclusion: It was noticed that both retreatment systems produced some deviation from the root canal curvature in mandibular premolars with regard to canal transportation capabilities. However, SoliteRS3 heat-treated retreatment group had clinically acceptable canal centering ratio values after the root canal filling material has been removed.