Comparative Evaluation of Dentinal Microcrack Incidence After Root Canal Preparation by BioRaCe and Edge Taper Platinum

Background and Aim: Preparation of root canal with rotary nickel-titanium (NiTi) instruments may potentially create microcracks that can lead to vertical root fracture. This study aimed to compare the incidence of crack formation by BioRaCe and Edge Taper Platinum systems in the mesiobuccal canals of extracted first mandibular molars. Materials and Methods: In this experimental study, 50 first mandibular molars, which met all the inclusion criteria, with a canal curve of 25-35 degrees, were selected and randomly divided into two groups of 24. Each specimen was mounted in a resin block and a thin layer of silicone impression to simulate the periodontal ligament (PDL) while the apex was exposed. Group A was prepared by BioRaCe, and group B was prepared by Edge Taper Platinum. Two teeth were left unprepared and served as the control. The roots were sectioned horizontally at 3, 6, and 9mm from the apex and evaluated under a stereomicroscope at ×20 magnification. The presence of dentinal defects was examined and analyzed using Mann-Whitney test. Results: BioRaCe rotary files showed more cracks (47.3%) than Edge Taper Platinum (19.5%) at all three levels with a significant difference (P=0.038). No statistically significant difference was found between these two systems at the coronal (9mm from the apex) and apical (3mm from the apex) levels but a significant difference was found between BioRaCe and Edge Taper Platinum in the midroot (6mm from the apex; P=0.014). Conclusion: It seems that the Edge Taper Platinum system causes fewer cracks in curved dentinal walls compared to the BioRaCe system.