Non-surgical Endodontic Retreatment of a Large Periapical Lesion With External Apical Resorption Using Calcium Silicate-Based Materials: A Case Report

Large periapical lesions associated with previously treated teeth and external apical resorption can present a clinical challenge during endodontic retreatment.Although surgical intervention may be considered in selected cases, orthograde retreatment can provide a conservative treatment option when adequate disinfection and apical sealing can be achieved.A 30-year-old male patient presented with a chief complaint of pain in the maxillary left anterior region for the past one month, associated with a previously root canaltreated maxillary left central incisor (tooth 21), which exhibited an inadequately obturated canal, a large periapical radiolucency measuring approximately 12 × 10 mm, a pre-existing lateral root perforation, and external apical resorption.Non-surgical endodontic retreatment was performed following the removal of the previous root filling and chemomechanical preparation.The working length was established at 21 mm, and the canal was prepared to a final apical size corresponding to ProTaper Gold F4 (Dentsply Sirona, Ballaigues, Switzerland).Sodium hypochlorite, ethylenediaminetetraacetic acid, ultrasonic activation, and calcium hydroxide medication were used to facilitate canal disinfection.Because of the enlarged and resorbed apical region, a 4-mm mineral trioxide aggregate apical plug was placed to establish an apical barrier.The remaining canal was obturated using thermoplasticized gutta-percha backfill with CeraSeal calcium silicatebased bioceramic sealer (Meta Biomed Co., Ltd., Cheongju-si, Republic of Korea).At the three-month followup, the patient was asymptomatic, and radiographic examination revealed an approximately 2-mm reduction in the dimensions of the periapical radiolucency, with the lesion measuring approximately 10 × 8 mm.Further clinical and radiographic follow-up at six, 12, and 24 months is planned to evaluate the progression and stability of periapical healing.This case suggests that orthograde retreatment with appropriate disinfection and establishment of an apical barrier may be considered a conservative treatment option in selected previously treated teeth associated with large periapical lesions and external apical resorption.