Byahatti Sujata, Ingafou Mohammed S H
Department of Oral Medicine, Diagnosis and Radiology at Faculty of Dentistry, Garyounis University, Benghazi, Libya.
Dent Res J (Isfahan). 2012 Mar;9(2):152-7. doi: 10.4103/1735-3327.95228.
The aim of the present study is to determine the number of third molars per person, angulation, level, amount of space for eruption of third molar between ramus of mandible and second molar and the eruption status of third molar in a group of Libyan students, with different impaction patterns and agenesis of third molars.
In this descriptive retrospective study, a total of 200 students (100 male and 100 female students of bachelor of dental surgery, Faculty of Dentistry, Garyounis University, Benghazi, Libya) were enrolled. Students who had complete complement of teeth within the age group 17-26 years were selected for this study, while those cases who had history of extraction of any of the teeth or who refused to give consent were excluded. Before starting the study, ethical concern from the ethical committee, IRB and informed consent from each student who underwent radiography were obtained.
The results showed that 5% of third molars were congenitally missing. Approximately 93.5% of the subjects had all four third molars, 1% had two third molars and 0.5% had one third molars with 2.5% having agenesis of all third molars. Third molar agenesis showed predilection for maxilla with higher proportion in females (3%) than males (2.1%). Angular position was maximum with vertical position (5.83%), with least being horizontal impactions. Level of occlusal plane of third molar similar to that of adjacent tooth was seen in 44.74%, below the occlusal plane in 24.76%, totally impacted noted in 30%.
The present study showed that 33% of the teeth were fully erupted and 66% were in various stages of eruption and 5% were congenitally missing in these students.
本研究的目的是确定一组利比亚学生的每人第三磨牙数量、倾斜度、位置、下颌升支与第二磨牙之间第三磨牙萌出空间的大小以及第三磨牙的萌出状态,这些学生具有不同的第三磨牙阻生模式和先天性缺失情况。
在这项描述性回顾性研究中,共纳入200名学生(利比亚班加西加里尤尼斯大学牙科学院口腔外科专业的100名男学生和100名女学生)。本研究选取了年龄在17至26岁之间牙齿完全健全的学生,而有任何牙齿拔除史或拒绝签署知情同意书的病例被排除。在开始研究之前,获得了伦理委员会、机构审查委员会的伦理批准以及每位接受影像学检查学生的知情同意书。
结果显示,5%的第三磨牙先天性缺失。约93.5%的受试者有全部四颗第三磨牙,1%有两颗第三磨牙,0.5%有一颗第三磨牙,2.5%的人所有第三磨牙均先天性缺失。第三磨牙先天性缺失在上颌更常见,女性比例(3%)高于男性(2.1%)。倾斜位置以垂直位最多(5.83%),水平阻生最少。第三磨牙咬合平面与相邻牙齿相似的占44.74%,低于咬合平面的占24.76%,完全阻生的占30%。
本研究表明,这些学生中33%的牙齿完全萌出,66%处于不同的萌出阶段,5%先天性缺失。