Endodontic Microsurgery for a Mandibular First Molar With a Large Lateral Canal in Mesial Root: A Case Report

Introduction: The lateral canal that occurs in the mesial root of the mandibular first molar is relatively rare. Herein we reported a rare case about a large lateral canal located in the middle of the mesial root of mandibular molar. Case report: A 38-year-old woman presented with symptomatic apical periodontitis and J-shaped bone defect similar to vertical root fracture on the mesial root of tooth #30. Endodontic microsurgery was chosen to make a clear diagnosis and treatment. The procedure was carried out with apicoectomy, root-end and lateral canal preparation, and retrograde filling. At the 1-year follow-up, clinical examination and the radiograph showed complete healing. Discussion: The untreated mesiobuccal root canal with large lateral canal was found to be the cause of the J-shaped bone defect.