Evaluation of the presence of mandibular third molars as a risk factor for mandibular angle fractures

Background: Mandibular fractures are influenced by various factors including the direction and impact of force, occlusal loading pattern, and biomechanical factors such as bone density and anatomical structures creating weak areas. Many studies have reported an increased risk of mandibular angle fractures in the presence of the mandibular third molars. However, there have been no formal assessments of this subject and the relationship between fracture risk and the mandibular third molar remains unclear. In this scenario we conducted the present study to evaluate the relationship between the presence of mandibular third molar and risk for angle fracture. Objectives: This study was designed toinvestigate the impact of the presence of mandibular third molar and the risk of angle fracture. Methods: This is a hospital based case control study. 100 patients who sought treatment in the Department of Oral and Maxillofacial Surgery for mandibular fracture over a period of one year extending from March 2015 to February 2016 were taken. The whole sample was divided in to two groups of 50 patients each.First group (Study group) consisted of patients with mandibular angle fracture. Second group(Control group) consisted of patients with fractures other than angle fracture. Data were collected for the age, sex, mechanism of injury, mandibular fractures, and associated fractures of the facial skeleton and of the mandibular third molars. Using data and panoramic radiographs collected from the patients, the presence of third molars as well as incidence of mandibular angle fractures was determined. All the measurements were recorded in the pre-designed and structured proforma. Statistical analysis of the differences between groups was analyzed with the chi square test. Results: A statistically significant relation is present between overall incidence of mandibular angle fractures and the presence of mandibular third molar. In group I, third molars were present in 90% (45/50) of all fractures. In group II, 40% patients had mandibular third molars whereas the remaining 60% were without 3rd molars. These results signifies that the presence of third molar increases the chance of mandibular angle fractures, more so significantly (p=0.001) when it is impacted. Conclusion: On the basis of results of the present study, it can be concluded that the risk of angle fractures was higher when the mandibular third molar was present. Mandibular angle fractures are more likely to occur when third molar is impacted or in erupting stages than when it is fully erupted.