Radiographic study of mandibular angular cortical thickness in relation to the presence and eruption status of mandibular third molar

Abstract

Background: Mandible is one of the largest and strongest facial bones but there are some areas which are physically weak and fractured easily, i.e., angle and condyle. Recent studies demonstrated the correlation of the risk of mandibular angle fractures to the presence of the mandibular third molars. The aim of the present study was to evaluate the mandibular angular cortical thickness in relation to the presence and eruption status of mandibular third molar to verify if the mandibular third molar represent a risk factor for angle fracture or not. Materials and methods: The angular cortical thickness was measured using tracing elements and panoramic radiograph of 160 Iraqi subjects aged from (20-28) years, they were divided equally into four groups according to the status of mandibular third molar which were: Subjects with agenesis of mandibular third molar, subjects with completely erupted mandibular third molar, subjects with complete bony impacted mandibular third molar and subjects with extracted mandibular third molar. Results: Subjects with agenesis registered the greatest value in the mean angular cortical thickness followed by subjects with extracted, completely erupted and complete bony impacted mandibular third molar respectively. Extraction of mandibular third molar improved the angular cortical thickness and this effect had a strong positive linear correlation with the extraction duration. Conclusion: The measurement of the angular cortical thickness was greatly affected by the presence and eruption status of mandibular third molar, such measurements registered its highest values in subjects with third molar agenesis and its lowest values in subjects with complete bony impacted third molar.