The extrusion of root canal cement containing paraformaldehyde into the inferior alveolar nerve canal resulting in infection and numbness.

A 30-year-old man was referred for management of prolonged anaesthesia in the right mandibular region following root canal treatment. Panoramic and cone beam computed tomography findings revealed that overextruded root canal cement had penetrated into the inferior alveolar nerve canal beyond the distal root of the mandibular right second molar (tooth 47). The root canal cement contained paraformaldehyde. Initially, the patient refused surgical removal of the cement. However, after 3.5 months, the patient returned with an acute infection in the same region. After resolution of the acute abscess and root canal retreatment, surgical treatment was performed under general anaesthesia. Granulation tissue and necrotic bone were found associated with the cement.