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Abstract Current study was performed to evaluate the incidence of mandibular 3rd molars impactions in patients of different skeletal facial types, seen at orthodontic department Khyber College of Dentistry Peshawar. Ninety pretreatment records of orthodontic patients (aged 16-35) including lateral cephalometric radiographs and orthopantomograms were assessed. The degree of impaction was determined by the Pell and Gregory classification system, and the facial type was categorized by the facial axis angle. Results showed that class ll impaction was most common in mesiofacial and dolicofacial patients while in brachifacial class I impaction was mostly observed. Overall impaction rate was more in females and most impactions were in class I and II.
The study concluded that brachyfacial subjects over dolichofacial and mesiofacials provides increased space for full eruption of the mandibular third molars, so decreased mandibular 3rd molar impactions were seen in brachyfacials as compared to the other two groups.
Key Words: Third molar ,impaction, facial type.
INTRODUCTION Third molar is the most common impacted tooth in the jaws.1 The term impaction can be defined as "a tooth which fail to erupt or develop in their proper functional location, obstructed by other tooth, bone or soft tissues within the expected time".2 The impaction rate of 3rd molar varies in different races, also, most authors claim that its incidence is higher in females.3 The impaction rate of 3rd molars is highest than any other tooth in modern population.4 Generally, if not impacted, third molars have been found to erupt between the ages of 17 and 21 years.5 Their eruption time have been reported to vary with races.6 The suggested etiology of the increased rate of impaction is inadequate space in the retromolar area, between the distal surface of 2nd molar and anterior border of ramus of the mandible.7,8 This space inadequacy can be the result of insufficient mandibular growth.9 But according to some studies, despite of sufficient growth, if dentition does not move forward because of lack of interproximal wear (as in modern population), will cause 3rd molar impaction.10 In a previous study, it was shown that after 2nd molar extraction, 3rd molars are rarely observed impacted, suggesting an increase in the eruption space.11 Similarly a recent study showed premolar extraction therapy as a part of orthodontic These...