Comparative evaluation of remaining dentin thickness using single file, two file, and multiple rotary file system – An in vitro CBCT study

Abstract

Context: Endodontic success hinges on a multifactorial interplay, with meticulous canal shaping, proper disinfection, and three-dimensional obturation being paramount. Among these factors, the amount of dentin remaining after instrumentation directly influences the biomechanical resilience and longevity of the tooth. Aims: This study aims to evaluate the impact of various rotary instrumentation systems, including single-file, two-file, and multiple-file configurations, on the remaining dentin thickness (RDT) following canal preparation. Settings and Design: This was an in vitro study, original research article. Materials and Methods: Sixty mandibular premolar human extracted teeth were decoronated at the cementoenamel junction with a diamond disc. Samples were randomly assigned to three groups using a simple random sampling technique (n = 60). Group I – Single-file system (One Curve, MicroMega) (n = 20), Group II – Two-file systems (2Shape, MicroMega) (n = 20), and Group III – Multiple-file system (Hero Gold, MicroMega) (n = 20). Preoperative cone-beam computed tomography (CBCT) scans were obtained after the sample was mounted on a modeling wax sheet. The biomechanical preparation of canals followed the manufacturer’s protocols for every system. Postoperative CBCT scans were obtained. Pre- and postoperative scans were compared at standardized depths (4 mm, 7 mm, and 11 mm) within the canals (coronal, middle, and apical thirds), allowing for a comprehensive assessment of RDT throughout the canal. Statistical Analysis and Results: According to one-way ANOVA, the highest mean was seen in Group I, followed by Group II and Group III. Hence, a statistically significant difference was found between all the groups. Post hoc Tukey’s test was done for intergroup comparison. Conclusions: A single-file system preserved more dentin with less aggressive cutting compared to two-file and multiple-file systems.