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

• So far, neither the ProTaper Next system nor the Twisted File Adaptive system was assessed regarding dentin microcrack formation through nondestructive imaging technology.
• A micro–computed tomographic experimental model was used in the present study to evaluate the presence of dentin defects before and after root canal preparation with multiple-file nickel-titanium rotary systems, precluding the need for cutting the specimens.
• Root canal preparation with ProTaper Next and Twisted File Adaptive systems did not induce the formation of new dentinal microcracks.
• There is no similar peer-reviewed evidence on that topic thus far.

IntroductionThe 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.MethodsTwenty 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.ResultsDentinal 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.ConclusionsRoot canal preparation with PTN and TFA systems did not induce the formation of new dentinal microcracks.