DOI: 10.36347/sjds.2019.v06i09.013

Pages: 447-450

The aim of this study was to investigate the incidence of dentinal cracks after root canal preparation with ProTaper Universal (Dentsply Maillefer), ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex (ColteneWhaledent, Switzerland), and Mtwo(VDW, Munich, Germany) rotary instruments. Methods: One-hundred mandibular premolars were selected and divided into 4 experimental groups of 25 specimen each. The experimental groups were instrumented with ProTaper Universal, ProTaper Next, Hyflex and Mtwo systems. After root canal preparation, roots were sectioned perpendicular to their long axis at 2, 4 and 6mm from the apex, and the sections were then observed under a stereomicroscope. The presence of cracks was recorded, and the data was analyzed with a chi-square test. The significance level was set at P = .05. Results: Vertical root fractures were not observed in any of the groups. The ProTaper Next, HyFlex and Mtwo instruments caused fewer cracks than the ProTaper Universal instrument (P < .05). However, there were no significant differences in crack formation between the ProTaper Next, HyFlex and Mtwo groups (P > .05). Conclusions: Within the limitations of this in vitro study, all of the instrumentation systems resulted in cracks in the root dentin. The ProTaper Next, HyFlex and Mtwo instruments tended to cause fewer dentinal cracks compared with the ProTaper Universal instrument.