Micro-computed Tomographic Assessment on the Effect of ProTaper Next and Twisted File Adaptive Systems on Dentinal Cracks

Introduction: The aim of the present study was to evaluate the frequency of dentinal microcracks observed after root canal preparation with ProTaper Next (PIN; Dentsply Maillefer, Ballaigues, Switzerland) and Twisted File Adaptive (TFA; SybronEndo, Orange, CA) systems through micro computed tomographic analysis. Methods: Twenty moderately curved mesial roots of mandibular molars presenting a type II Vertucci canal configuration were randomly assigned to 2 experimental groups (n = 10) according to the system used for the root canal preparation: PIN or TFA systems. The specimens were scanned through high-resolution micro computed tomographic imaging before and after root canal preparation. Afterward, pre- and postoperative cross-sectional images of the mesial roots (N = 25,820) were screened to identify the presence of dentinal defects. Results: Dentinal microcracks were observed in 38.72% (n = 5150) and 30.27% (n = 3790) of the cross-sectional images in the PIN and TFA groups, respectively. All dentinal defects identified in the postoperative scans were already present in the corresponding preoperative images. Conclusions: Root canal preparation with PIN and TFA systems did not induce the formation of new dentinal microcracks.