Frequency of trigeminal nerve injuries following third molar removal.

PURPOSE To estimate oral and maxillofacial surgery reporting of the frequency of temporary and permanent inferior alveolar and lingual nerve damage from lower third molar extraction and injury etiology, and to identify factors associated with injury rates. MATERIALS AND METHODS A postal survey was sent to all members of the California Association of Oral and Maxillofacial Surgeons requesting information on known instances of inferior alveolar and lingual nerve damage that had occurred in their practices over a 12-month period and known instances of permanent damage over their entire careers. RESULTS Replies were obtained from 535 California Oral and Maxillofacial Surgeons (OMFS) representing 86% of all OMFS in California. Instances of injury to the inferior alveolar nerve in a 12-month period were reported by 94.5% of OMFS; 53% reported instances of lingual nerve injury in a 12-month period. Instances of permanent nerve injury of the inferior alveolar nerve were reported by 78% of OMFS; 46% reported permanent lingual nerve injury occurring during their professional lifetime. The overall estimated self-reported rate of injury was 4 per 1,000 lower third molar extractions for the inferior alveolar nerve and 1 per 1,000 extractions for the lingual nerve for all cases (temporary and permanent). In most cases (80%) of inferior alveolar nerve injury the cause was known, but in a majority of cases of lingual nerve injury (57%) the injury etiology was unknown. Self-reported rates of permanent injury were 1 per 2,500 lower third molar extractions for the inferior alveolar nerve and 1 per 10,000 lower third molar extractions for the lingual nerve. Injury rates were associated with provider experience (ie, extractions per year) and years in practice. CONCLUSION This survey included a high percentage of California OMFS. Injury to the inferior alveolar and lingual nerve was reported by most OMFS in California following lower third molar removal, and many reported cases of permanent nerve injury, frequently with unknown cause.