Influence of angular position and degree of impaction of third molars on development of symptoms: long-term follow-up under good oral hygiene conditions.

To determine the risk of developing symptoms due to the presence of maxillary and mandibular third molars, we analyzed a reliable population sample by age, and according to third-molar position and impaction level using long-term follow-up data under conditions of good oral hygiene. Of 308 graduates from our dental school, a total of 776 third molars were followed up for periods of 11 to 27 years by means of intraoral radiographs. The development of symptoms, the participant's age, and third-molar angular position and degree of impaction were investigated. For both maxillary and mandibular third molars, the risk of developing a symptom correlated neither with angular position nor with impaction level. The first symptom associated with a third molar developed most frequently in their 20's for both maxilla (16.2%) and mandible (17.5%), with the next highest frequency being in their 30's (12.6%, maxilla; 13.0%, mandible). The status of third molars shows no relation to the subsequent development of symptoms if good oral hygiene is maintained. The low rates of symptom-development do not support removal of asymptomatic third molars.