Canal transportation caused by one single-file and two multiple-file rotary systems: A comparative study using cone-beam computed tomography

Aim: This ex-vivo study aimed to compare canal transportation in mesio-buccal canal of mandibular first molars prepared with Mtwo and Revo-S multi-file and Neoniti single-file nickel[18TD$DIF]—titanium (Ni—Ti) rotary systems using cone-beam computed tomography (CBCT). Methodology: CBCTscans were obtained from 60 extracted mandibular first molars and the teeth were randomly divided into three groups. Mesio-buccal canal of mesial root was prepared with Revo-S, Neoniti or Mtwo rotary systems according to the instructions of the manufacturers. Postoperative CBCT scans were also obtained. A single operator performed canal preparations while another operator blinded to the group allocation of teeth did the measurements. Data were analyzed using SPSS 20. The mean and standard deviation (SD) of the amount of canal transportation were calculated and compared between the groups using the Friedman test ([19TD$DIF]P 0.05). Results: No significant difference was noted in canal transportation among the groups in the middle and apical third ([20TD$DIF]P > 0.05). The rotary single-file instrument caused significantly greater canal transportation in the coronal third. Conclusion: No significant difference exists among different rotary systems in the amount of canal transportation caused in the middle and apical third of the mesio-buccal canal in mandibular first molars. Although all rotary files caused some degrees of canal transportation, the rotary single-file instrument caused significantly greater canal transportation than the multiple-file sequences in the coronal third.