Is There a Safe Zone for Lateral Border Fixation of Mandibular Angle Fractures?

Abstract

Study Design: Cross-sectional study design. Objective: There are multiple accepted treatment options for internal fixation of mandibular angle fractures. The purpose of this study was to determine if there is a safe zone for lateral border fixation of mandibular angle fractures. Methods: One hundred coronal images of facial computed tomography (CT) scans were reviewed on patients between the ages of 18 to 48. Measurements were taken in the area of the second and third molar region related to the inferior border to the superior extent of the inferior alveolar canal and apex of the second molar root, along with buccal cortical measurements to the inferior alveolar canal and apical third of the second molar root. Results: The average measurement of the inferior border in the second molar area to the inferior alveolar canal and apex of the root was 1.12 cm (0.70-1.77) and 1.39 cm (0.91-2.30), respectively. The average measurement of the inferior border of the third molar to the inferior alveolar canal was 1.26 cm (0.78-1.83). The average measurement of the buccal cortex of the second molar to the inferior alveolar canal and apical one-third of the root was 0.64 cm (0.34-1.25) and 0.59 cm (0.33-0.98), respectively. The average measurement of the third molar buccal cortex to the inferior alveolar canal was 0.45 cm (0.18-0.98). Conclusion: In the area of the second molar region, there is no ubiquitous safe zone for screw placement, cortical bone thickness is more critical than vertical placement of the fixation plate and screws. In the third molar region, cortical bone thickness and vertical orientation may provide a safe zone for screw placement.