An in vitro comparative evaluation of efficiency of three rotary nickel–titanium file systems in terms of remaining dentin thickness using cone-beam computed tomography

Abstract

The objective of the present research was to assess and compare the residual dentin thickness after biomechanical preparation of teeth using three distinct rotary nickel–titanium (Ni-Ti) file systems. In the current experimental study, a total of 45 single-rooted teeth were selected for the analysis. The cementoenamel junction of each tooth was decoronated using a diamond disc. The teeth were randomly allocated to three groups, with each group representing a different rotary file system: Group 1: Hero GOLD (Micro Mega), Group 2: One Curve (Micro Mega), and Group 3: HyFlex electro-discharge machining (EDM) (Coltene-Whaledent, Altstatten, Switzerland). To evaluate the initial condition of the teeth, cone-beam computed tomography (CBCT) scans were conducted before the biomechanical preparation. The teeth were positioned on a modeling wax sheet, and the CBCT scans provided baseline measurements. The biomechanical preparation of the root canals followed the manufacturer’s recommended guidelines for each file system. After the completion of the canal preparation, follow-up CBCT scans were conducted. The postprocedure CBCT scans were then compared with the initial scans to assess any changes in the residual thickness of dentin in the teeth. Post hoc Tukey analysis of variance tests was utilized to examine differences between the groups. A statistically significant result was defined as P = 0.05 or less for every test. The comparison of preinstrumentation and postinstrumentation CBCT images showed that the HyFlex EDM group removed less dentin clinically compared to the other two groups, i.e., Hero GOLD and One Curve. No significant statistical difference was found between Hero GOLD versus One Curve, One Curve versus HyFlex EDM, and Hero GOLD versus HyFlex EDM. Based on the results of this study, the HyFlex EDM file system exhibited superior cutting efficiency at various levels. Nonetheless, additional investigations are required to comprehensively assess the influence of Ni-Ti rotary file systems on the remaining dentin thickness.