Unerupted lower third molars and their influence on fractures of the mandibular angle and condyle.

Our aim was to assess the influence of the presence and state of impaction of mandibular third molars on the incidence of fractures of the mandibular angle and condyle. We designed a retrospective study of patients who presented for the treatment of mandibular fractures from January 2006 to April 2011. The independent variables were the presence and degree of impaction of lower third molars, and the outcome variables were the incidence of fractures of the mandibular angle and condyle. The information was acquired from hospital records and panoramic radiographs. Personal data included age, sex, mechanism of injuries, and number of fractures of the mandibular angle and condyle. We studied 110 fractures of the mandibular condyle and 80 of the angle. The incidence of fractures of the mandibular angle was higher in the group with incompletely erupted third molars (37/80, p<0.001) and that of condylar fractures was higher in the group without (67/110, p<0.001). An incompletely erupted third molar reduces the risk of condylar fractures and increases the risk of fractures of the mandibular angle.