Does the Presence or Position of Lower Third Molars Alter the Risk of Mandibular Angle or Condylar Fractures?

Abstract

The purpose of this study was to determine whether a relation exists between the presence of mandibular third molars (M3s) and mandibular angle and condylar fractures and whether the risk of these fractures varies with M3 position. A retrospective cohort study was conducted in patients with mandibular fractures presenting to the oral and maxillofacial surgery service from April 2007 to March 2012. Data sources were patients' hospital charts and panoramic radiographs. Predictor variables were the presence and position of M3s. M3 position was based on the Pell and Gregory classification and angulation was determined by measuring the angle between the long axis of the M3 and the mandibular occlusal plane. Outcome variables were the presence of angle and condylar fractures. Other study variables included age, gender, and fracture etiology. Data were analyzed using the χ(2) test and Student t test. The study sample consisted of 446 patients with 731 mandibular fractures. Results showed that the risk of mandibular angle fracture was significantly higher in patients and mandible sides with impacted M3s (P < .001), whereas the risk of condylar fracture was significantly higher in patients and mandible sides lacking impacted M3s (P < .001). A relation between the position of M3s to angle or condylar fractures could not be found (P > .05). The presence of impacted M3s increased the risk of angle fracture and simultaneously decreased the risk of condylar fracture. However, no relation appeared to exist between M3 position and fracture pattern.