Targeted endodontic microsurgery for persistent apical periodontitis following failed endodontic therapy

Persistent apical periodontitis in previously treated teeth poses a significant clinical challenge. The use of diagnostic imaging, biocompatible materials, and microsurgical techniques offers promising solutions for addressing complex endodontic failures. This case report presents the management of a 20-year-old healthy woman who presented with persistent pain and tenderness in the left mandibular posterior region. The first molar had undergone initial root canal treatment in 2017 and was followed by retreatment in 2019, yet continued to exhibit recurrent periapical lesions despite prior apparent healing. Clinical examination revealed tenderness on percussion and palpation with periapical radiolucency located 4 mm superior to the mandibular nerve, as observed on cone-beam computed tomography (CBCT) imaging. A diagnosis of symptomatic apical periodontitis in a previously treated tooth was established. Selective retreatment of the mesial canals was attempted but failed to resolve symptoms, leading to the decision to perform targeted endodontic microsurgery (EMS). CBCT imaging and a three-dimensional-printed surgical guide were used for precise osteotomy and root-end management. Under magnification, retrograde preparation and filling were performed, addressing the previously undebrided mid-mesial canal and isthmus, with mineral trioxide aggregate. The flap was closed with sutures, and postoperative care included analgesics and chlorhexidine rinses were prescribed. At the 6-month follow-up, radiographic evidence confirmed complete periapical healing, and the patient remained asymptomatic with no recurrence over a 1-year period. This case highlights the effectiveness of targeted EMS as a minimally invasive and precise intervention, leading to successful healing and symptom resolution. The integration of modern endodontic technologies is crucial for predictable outcomes in similar cases.