成人下颌磨牙后间隙与第三磨牙关系的三维研究  

Association between adult mandibular third molar and retromolar space:a three-dimensional study

作　　者：郭学强 刘新强[1] 王铮 赵睿 孔蕾 Guo Xueqiang;Liu Xinqiang;Wang Zheng;Zhao Rui;Kong Lei(Department of Orthodontics,The Affiliated Hospital of Qingdao University,School of Stomatology of Qingdao University,Qingdao 266003,China)

机构地区：[1]青岛大学附属医院口腔正畸科,青岛大学口腔医学院,山东青岛266003

出　　处：《中华口腔正畸学杂志》2021年第2期74-79,共6页Chinese Journal of Orthodontics

摘　　要：目的测量成人下颌磨牙后区大小并分析其与第三磨牙状态的关系。方法采用CBCT对86例成年骨性Ⅰ类均角患者根据第三磨牙状态进行分组,从三维方向对右侧下颌磨牙后间隙进行测量。在水平面上沿POL线(第一磨牙与第二磨牙颊尖连线)测量下颌平面(以及从下颌平面向根方2mm的平面)处第二磨牙牙冠到升支前缘的最短距离。牙根层面的测量以釉牙骨质界为参考,在其根方2.4.6.8、10 mm的水平面上沿POL线测量第二磨牙牙根与下颌骨舌侧内层骨皮质的最短距离。结果无第三磨牙组、正常萌出组、水平阻生组、近中阻生组、垂直阻生组牙冠部的远移可用间隙均大于根部;在所有的测量平面上,正常萌出组和垂直阻生组的可利用间隙都不小于无第三磨牙组、水平阻生组、近中阻生组。结论成年骨性Ⅰ类均角患者的下颌磨牙远移,应更多地考虑下颌磨牙后舌侧骨皮质的影响,而参考CBCT比二维影像资料具有更高的准确性。另外,下颌第三磨牙的萌出、阻生状态也会对下颌磨牙远移产生不同影响。Objective To investigate the size of mandibular retromolar space,and its relation with the status of the third molar.Methods Using cone beam computed tomography,the right posterior retromolar region were measured in three dimensions in 86 adult patients with a skeletal ClassI normodivergent pattern.All patients were divided based on the different status of the right third molar.Distance between second molar crown to the anterior border of the ramus was measured at the crown level and 2 mm apically lower level along the posterior occlusal line(POL,which connects the buccal cusps of the mandibular first and second molars).Distance between second molar root to lingual inner cortical bone was measured at levels of 2 mm,4 mm,6 mm,8 mm and 10 mm apically to the CEJ border along the POL,respectively.Results In all groups(no third molar group,normal eruption group,horizontal impaction group,mesial impaction group,and vertical impaction group)the distance at the crown levels were significantly larger than that at root levels.Among all measurement levels,the space measured in normal eruption group and vertical impaction group were no less than that in the other three groups(no third molar group,horizontal impaction group and mesial impaction group).Conclusions When considering the distalization of mandibular molars,more attention should be directed to the lingual cortical bone of the mandible.The diagnosis accuracy of cone-beam computed tomography is higher compared with that of two dimensional radiographs.In addition,different status of third molars,whether eruption of impaction,can also affect molar distalization.

关 键 词：磨牙后间隙 第三磨牙 磨牙远移 

分 类 号：R783.5[医药卫生—口腔医学]