Removal of wisdom teeth is a very common procedure with a very low complication rate. Injury to the inferior alveolar nerve (IAN) is a rare complication of mandibular (lower) third molar extractions. The incidence of neurosensory disturbances post-operatively is 0.5% to 8%, whereas the incidence of persistent injury has been reported to approximate up to 1%. Most typically injury to this nerve results in altered sensation most noticeable on the skin of the lower lip and chin of the affected side. This is a sensory nerve and injury does not result in cosmetic changes or paralysis. The accessibility of cone beam CT scanning has allowed much better visualization of anatomic structures and is now the standard of care in assessment of higher risk third molars that are in close approximation to the mandibular canal.
The procedure involves removal of the crown of lower third molar and retaining the root portion of the tooth. The overlying tissue can thus heal allowing for a hygienic situation with the remaining roots sealed away from the oral flora. Moreover, since the roots are minimally manipulated, there is lessened risk to the adjacent nerve and resultant complications. In some cases the roots have to be removed during surgery if mobile or occasionally subsequently yet, fortunately, they often erupt away from the adjacent nerve. In our experience, infection or other complications which require a secondary surgery to remove the residual roots have been rare.
The standard of care is to provide patients with treatment options and when such high risk cases present, a coronectomy should be considered in addition to extraction or observation. We will provide education of clinical and radiographic findings allowing patients to make the best personalized treatment plan. In our practice we have had very good experience with this procedure thus far and undoubtedly prevented a number of nerve injuries and the associated morbidity.