Uncommon Inferior Alveolar Nerve Injury Associated with the Mandibular Second Molar: A Case Report

Inferior alveolar nerve injury is most frequently associated with mandibular third molar surgery, while neurosensory complications related to endodontic treatment are uncommon and sparsely reported. Such injuries may occur when mandibular molar roots and associated periapical lesions are located in proximity to the inferior alveolar canal, allowing extruded endodontic materials to affect the nerve. This case adds to the limited scientific literature by describing delayed-onset inferior alveolar nerve sensory impairment following root canal treatment and its recovery after elimination of the causative factor.

A 50-year-old woman presented with numbness of the right lower lip and chin that developed three months after root canal treatment of the mandibular right second molar. Clinical examination and radiographic evaluation using an orthopantomogram and cone beam computed tomography demonstrated extruded gutta-percha extending into the inferior alveolar nerve canal, associated periapical radiolucency, and direct contact between the tooth roots and the nerve. The mandibular right first molar also showed residual roots with periapical pathology. Following informed consent, atraumatic extraction of both teeth was performed, followed by socket debridement and supportive management including vitamin B12 supplementation. At four weeks, neurosensory examination showed persistent anesthesia. Gradual improvement was noted at eight weeks, and near complete recovery of sensation was observed at twelve weeks after extraction.

This case demonstrates that inferior alveolar nerve injury can occur as a rare complication of endodontic treatment of mandibular molars, particularly when extruded filling materials and periapical pathology are present close to the nerve canal. Early recognition, careful radiographic assessment, and timely removal of the etiologic factor may facilitate favorable neurosensory recovery and reduce the risk of permanent sensory deficits.