Demirel Oğuzhan, Akbulut Aslıhan
Department of Dentomaxillofacial Radiology, School of Dental Medicine, Bahçeşehir University, Sahrayı Cedit Mahallesi, Batman Sk. No: 66, Kadıköy, 34734, Istanbul, Turkey.
Department of Dentomaxillofacial Radiology, Faculty of Dentistry, İstanbul Medipol University, Fatih, Istanbul, Turkey.
Anat Sci Int. 2020 Jan;95(1):134-142. doi: 10.1007/s12565-019-00507-0. Epub 2019 Nov 7.
Mandibular third molar teeth have the highest impaction frequency for several reasons such as lack of space which may be related to the direction of facial growth. Gonial angle is used for the definition of facial growth pattern with some other measures such as mandibular plane angle. Winter and Pell-Gregory classifications are used for defining the level and pattern of mandibular third molar impaction. The aim of this study is to define the relationship between mandibular third molar impaction pattern and gonial angle; also to evaluate relationship between mandibular third molar roots and inferior alveolar canal. Study included 90 patients who had undergone cone beam computed tomography assessment for mandibular third molar impaction. Impacted teeth were grouped according to Pell-Gregory depth (A, B, C) and ramus (1, 2, 3) classification and sub-groups were composed. Winter classification was used for angulation of third molars and their relationship between with inferior alveolar canal was recorded. Gonial angle was measured on panoramic radiographs. Of the evaluated 90 impacted third molars, mesioangular position was the most frequent (34.4%), followed by vertical, horizontal and distoangular positions. Nearly 77% of the impacted third molar roots were related to inferior alveolar canal. While no correlation was determined between gender, age, third molar angulation and gonial angle, C2 sub-group of Pell-Gregory classification showed statistically significant higher gonial angle values. Although no significance was found, gonial angle was higher in level C group. In conclusion, gonial angle is higher in patients with C2 impaction level. Also, although statistically insignificant, Pell-Gregory C group had higher gonial angle averages.
下颌第三磨牙的阻生频率最高，原因有多种，比如空间不足，这可能与面部生长方向有关。下颌角与下颌平面角等其他测量方法一起用于面部生长模式的定义。Winter分类法和Pell-Gregory分类法用于确定下颌第三磨牙阻生的程度和模式。本研究的目的是确定下颌第三磨牙阻生模式与下颌角之间的关系；同时评估下颌第三磨牙牙根与下牙槽神经管之间的关系。研究纳入了90例因下颌第三磨牙阻生接受锥形束计算机断层扫描评估的患者。根据Pell-Gregory深度（A、B、C）和升支（1、2、3）分类对阻生牙进行分组，并组成亚组。采用Winter分类法确定第三磨牙的角度，并记录其与下牙槽神经管之间的关系。在下颌全景片上测量下颌角。在评估的90颗阻生下颌第三磨牙中，近中阻生位置最为常见（34.4%），其次是垂直阻生、水平阻生和远中阻生。近77%的阻生下颌第三磨牙牙根与下牙槽神经管有关。虽然未确定性别、年龄、第三磨牙角度与下颌角之间存在相关性，但Pell-Gregory分类的C2亚组显示下颌角值在统计学上显著更高。虽然未发现显著差异，但C级组的下颌角更高。总之，C2阻生水平患者的下颌角更高。此外，虽然在统计学上不显著，但Pell-Gregory C组的下颌角平均值更高。
