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 (PTN; 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: PTN 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 PTN 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 PTN and TFA systems did not induce the formation of new dentinal microcracks.