In vivo evaluation of apical third enlargements to twice and thrice larger than initial apical binding file in final treatment outcome

Root canal treatment is a critical procedure in endodontics, aimed at eliminating microorganisms and pathological debris from the root canal system to prevent reinfection and ensure the health of the periradicular tissues. A total of 180 patients with asymptomatic apical periodontitis (PAI score ≥3) were included in this randomized clinical trial. Patients were divided into two main groups, each with three subgroups based on the biomechanical preparation of the canals using different file sizes and tapers. Biomechanical preparation was followed by intracanal medicament placement, and patients were recalled for obturation and final restoration. Postoperative pain was assessed using the Visual Analog Scale (VAS) at 6, 12, 24, 48 and 72 hours post-treatment. Periapical healing was evaluated using the Periapical Index (PAI) at 3,6 and 12 months post-treatment. While larger apical preparation sizes and tapers can enhance periapical healing, excessive enlargement beyond three sizes larger than the IABF does not significantly improve outcomes. Optimal root canal treatment should balance adequate cleaning and disinfection with the preservation of tooth structure.