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 physicallyweak and fractured easily, i.e., angle and condyle. Recent studies demonstrated the correlation of the risk ofmandibular angle fractures to the presence of the mandibular third molars. The aim of the present study was toevaluate the mandibular angular cortical thickness in relation to the presence and eruption status of mandibularthird 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 panoramicradiograph of 160 Iraqi subjects aged from (20-28) years, they were divided equally into four groups according to thestatus of mandibular third molar which were: Subjects with agenesis of mandibular third molar, subjects withcompletely erupted mandibular third molar, subjects with complete bony impacted mandibular third molar andsubjects with extracted mandibular third molar.Results: Subjects with agenesis registered the greatest value in the mean angular cortical thickness followed bysubjects 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 positivelinear correlation with the extraction duration.Conclusion: The measurement of the angular cortical thickness was greatly affected by the presence and eruptionstatus of mandibular third molar, such measurements registered its highest values in subjects with third molar agenesisand its lowest values in subjects with complete bony impacted third molar.