Evaluation of Root Dentin Cracks Caused by Three Single File Systems Versus Pro Taper System – An In Vitro Study

Introduction: Biomechanical preparation of root canals is one of the main steps in achieving endodontic success due to enabling bacterial elimination, removal of debris, and facilitating obturation. The aim of this study was to compare the incidence of dentinal cracks observed in the canal wall after canal instrumentation with 3 single-file systems and the ProTaper system (Dentsply Maillefer, Switzerland). Material and Methods: Eighty mandibular premolars with single root canal were selected. Teeth were decoronated and mounted in resin blocks with simulated periodontal ligaments. They were divided into 4 experimental groups (n = 20); then instrumented to the full working length with the ProTaper, OneShape (MicroMega, Besancon, France), Reciproc (VDW, Munich, Germany), and WaveOne Gold (Dentsply Malliefer) was performed. The roots were sectioned perpendicular to the long axis at 3, 6, and 9 mm from the apex and were observed under a stereomicroscope. The presence of cracks was noted. The chi-square test was performed to compare the appearance of cracked roots between the experimental groups. Results: Cracks found after canal instrumentation with the ProTaper, OneShape, and Reciproc and WaveOne Gold files, were 46.6%, 23.3%, 13.6%, 11.6% respectively. The difference between the experimental groups was statistically significant (P < .001). Conclusion: Nickel-titanium instruments cause cracks in root surface or in the canal wall; Reciproc and WaveOne Gold files caused less cracks than the ProTaper and OneShape files.