The effects of canal preparation by different NiTi rotary instruments and reciprocating WaveOne file on the incidence of dentinal defects

The purpose of this study was to compare dentinal defect formation while usinghand files (HFs), two brands of nickel-titanium (NiTi) rotary files and the WaveOnefile. Eighty mandibular first molars were selected and divided into 4 groups. Hand file(HFs), WaveOne reciprocating file (WO), EndoSequence file (ES), ProTaper file(PT), were used to prepare the 2 mesial canals. Roots were then sectioned 3, 6, and 9mm from the apex, and the cut surface was observed under a microscope and checkedfor the presence of dentinal defects. HF group showed the lowest percentages ofdentinal defects (5%). In roots prepared with the WO, ES, and PT, dentinal defectswere observed in 25%, 10%, and 50% of teeth, respectively. There was a significantdifference between HFs group and both of WO group and PT group (P