Resolution of Mental Nerve Paresthesia Associated With a Large Periapical Lesion Following Nonsurgical Endodontic Retreatment: A Case Report With 6-Year Follow-Up.

Mental nerve paresthesia of odontogenic origin is an uncommon yet clinically significant presentation. Although malignancy remains the primary concern in the differential diagnosis of lower lip numbness, large periapical lesions of endodontic origin represent an underrecognized but treatable etiology. This case report describes the successful resolution of mental nerve paresthesia associated with a large periapical lesion through nonsurgical endodontic retreatment, with follow-up extending over 6 years. A 30-year-old systemically healthy male presented with a 1-week history of numbness affecting the left lower lip and chin. Clinical examination of tooth 36 revealed a defective composite restoration overlying a previously treated root canal. Neurosensory assessment demonstrated hypoesthesia confined to the distribution of the left mental nerve, with no swelling, sinus tract, or tenderness detected. Nonsurgical endodontic retreatment was performed under local anesthesia. Copious 2% sodium hypochlorite irrigation was carried out, followed by calcium hydroxide placement as an interappointment medicament. At the second appointment 2 weeks later, the patient reported complete resolution of the paresthesia. Obturation was completed using warm vertical compaction of gutta-percha with a bioceramic sealer, followed by coronal restoration. Periapical bone fill and substantial reduction in lesion size were evident at 9 months. Progressive periapical healing was observed at 3 years on periapical and panoramic radiographs. At 5 years, further radiographic resolution was evident, although a small residual radiolucent area remained. At the six-year follow-up, CBCT evaluation in the axial, sagittal, and coronal planes demonstrated substantial three-dimensional bone regeneration and marked reduction of the periapical lesion. The tooth remained functional throughout the follow-up period, with no recurrence of symptoms.