cbct assessment of root dentine removal by gates-glidden drills and two engine-driven root preparation systems

introduction: the aim of this study was to compare the dentine removing efficacy of gates-glidden drills with hand files, protaper and oneshape single-instrument system using cone-beam computed tomography (cbct). methods and materials: a total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups ( n =13) and were prepared using either gates-glidden drills and hand instruments, protaper and oneshape systems. pre- and post-instrumentation cbct images were obtained. the dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. data were analyzed using one-way anova test. tukey’s post hoc tests were used for two-by-two comparisons. results: gates-glidden drills with hand files removed significantly more ( p <0.001) dentine than the engine-driven systems in all canal walls (buccal, palatal, mesial and distal). there were no significant differences between oneshape and protaper rotary systems ( p >0.05). conclusion: the total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to gates-glidden drills. there were no significant differences between residual dentine thicknesses left between the various canal walls.