The unerupted or impacted third molar--a critical appraisal of its pathologic potential.

The prophylactic removal of asymptomatic unerupted or impacted third molars constitutes a major proportion of all oral surgical procedures. Patients are advised to have this preventive surgery on the basis that such teeth, if retained, are likely to cause certain pathologic lesions. The evidence in the scientific literature on the prevalence of dentigerous cysts, mural ameloblastoma, epidermoid carcinoma and root resorption indicates that this concern is exaggerated. The retrospective data on the reasons for extractions of third molars confirm this conclusion. Until there are prospective studies which demonstrate a significant patient benefit from surgery exceeding the risks of retention, the practice should be discontinued. Third molars should be removed only where there is a defined pathologic indication.