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ABSTRACT Fractures of the mandibular angle are common and mandibular third molars are frequently implicated in their pathogenesis. The study was done to investigate this cause and effect relationship. The objectives were to measure the relationship between presence and status of mandibular third molar (M3) and mandibular angle fracture. Study design was descriptive. It was carried out in the Department of Oral and Maxillofacial Surgery, Punjab Dental Hospital, attached with de,Montmoren- cy College of Dentistry, Lahore. 87 patients with clinical and radiographic diagnosis of mandibular fracture formed the study group. The predictor variable was the presence or absence of mandibular third molar. The outcome variable was the presence or absence of angle fracture. Hemi mandibles containing a third molar were seen to have a 2.3 times increased risk of having an angle fracture (p= 0.49) than a hemi mandible without a third molar.
A significant association between third molar depth and risk of angle fractures was seen (p = 0.001). The presence and depth of mandibular third molar is associated with an increased risk for mandibular angle fracture.
Key Words: Mandibular third molar, impacted teeth, mandibular angle fracture, mandibular frac- ture, maxillofacial trauma.
INTRODUCTION Mandibular fractures are one of the commonest maxillofacial bony injuries.1 Multiple factors such as the size, direction, nature, and surface area of the impacting force are known to influence the pattern of mandibular fractures. Other factors that are thought to be responsible include the presence of soft tissue bulk and biomechanical characteristics of the mandible, such as bone density, mass, and normal or pathologic anatomic structures creating weak areas within the bone.2 Fractures of the mandibular angle are common and comprise 18-44% of all mandibular fractures.3,4 The presence of mandibular third molar (M3) has been hypothesized to be a risk factor for fracture at the mandibular angle. Multiple studies report a 2 to 3-fold increased risk for mandibular angle fractures when M3s are present.5,6 Finite element analysis using micro-CT in cadaver mandibles has also shown that in a mandible with third molar (M3), stress is concentrated around the root apex of the third molar, which alters the concentration and propagation of stress in the mandible, which increases risk of an angle fracture.7 It has been hypothesized that M3 weakens the...