Canal transportation and centering ability of rotary and reciprocal files in mandibular molar root canals using micro computed tomography: an ex-vivo study

Abstract

Abstract Background It is important to use proper endodontic rotary files during treatment. Because of the canal curvature and the desire of the endodontic files to return to their original form during root canal preparation, errors such as canal transportation and deviation from the root canal center might occur. This study aimed to assess the canal transportation and centering ability of 2Shape, Neoniti, and EdgeFile X1 in extracted human mandibular molar root canals with 20-40-degree curvature by using micro computed tomography (micro-CT). Methods Out of two hundred and fifty extracted human mandibular molars, thirty with mesiobuccal canals with 20-40-degree curvature were selected. They were then randomly assigned to three groups (n = 10). The crowns of the teeth and the distal roots were cut off, and the mesial roots were standardized to have 12 ± 1 mm length. The roots were mounted in acrylic blocks, and the primary micro-CT images were obtained. Root canal instrumentation was then performed, and secondary micro-CT images were taken. RadiAnt software was used to compare before- and after-instrumentation images at 1, 3, 5, and 7 mm from the apex and make the measurements. Results Root canal instrumentation with all three systems caused apical transportation and deviation from the original central path of the canal. No significant difference was found in apical transportation (P > 0.05) or centering ability (P > 0.05) among the three file systems at the aforementioned four levels from the apex. Conclusions All three file systems showed some degrees of apical transportation and deviation from the original central canal path with no statistically significant difference among them in this respect.