Late-onset inferior alveolar nerve paresthesia two years after coronectomy associated with progressive root...

Coronectomy is a nerve-sparing technique used to reduce the risk of inferior alveolar nerve (IAN) injury during removal of mandibular third molar (M3) in close proximity to the mandibular canal. This case describes a 45-year-old female with a history of an uneventful coronectomy of the right M3 performed 2 years earlier, currently presenting with a late-onset inferior alveolar nerve (IAN) paresthesia and discomfort at the same site. Intraoral examination showed partial exposure of the retained roots to the oral cavity and the clinical neurosensory examination confirmed Level A paresthesia of the right lower lip and chin, characterised by loss of light touch and directional discrimination. Follow-up imaging revealed approximately 2.4 mm of migration of the retained roots towards the oral cavity. In the absence of clinical or radiographic signs of infection, the radiographic findings strongly supported a mechanical etiology. A secondary surgical procedure was performed to section and remove the roots individually, preserving the nerve, resulting in complete sensory recovery within one month. This case highlights that late-onset sensory disturbance may still occur after an initially uneventful coronectomy, in cases having intimate root-canal relationships. Timely surgical management, when indicated, may result in complete neurological recovery, as observed in this patient.