【作者】 杨扬；

【导师】 张志伟；

【作者基本信息】 郑州大学 ， 口腔医学（专业学位）， 2018， 硕士

【摘要】 目的:应用CBCT的三维成像技术,研究成人轻度或中度骨性Ⅲ类错下颌双侧第二磨牙远中磨牙后区的三维形态特征,探讨成人骨性Ⅲ类错下颌磨牙后区的形态特征及其影响因素,为成人骨性Ⅲ类错畸形的诊断和制定个性化的治疗方案提供参考。材料与方法:在2015年5月至2017年5月于郑州大学第一附属医院、河南省口腔医院正畸科就诊的初诊病人,在正畸治疗前已于我院放射科拍摄了CBCT的成人骨性Ⅲ类错畸形患者中,根据大视野CBCT生成的头颅侧位片上的下颌平面角大小,选取符合资料纳入标准的骨性Ⅲ类错畸形30例,其中高角10例,均角10例,低角10例,男女各15例,年龄18至34(24.67±4.72)岁。运用CBCT专用软件CS 3D Imaging对图像进行三维重建,并根据测量流程调整测量基准点、线、面,分别测量下颌第二磨牙后间隙(SRL/mm)、下颌第二磨牙远中4mm位置距牙槽嵴顶4mm处牙槽骨宽度(ABW4/mm)及距牙槽嵴顶8mm处牙槽骨宽度(ABW8/mm),并运用SPSS 21.0软件包对所有测量参数进行统计学分析。结果:1.同一个体左右两侧各测量结果无统计学差异(P>0.05),不同性别各测量参数均无统计学差异(P>0.05);2.高角组、均角组、低角组3组的下颌第二磨牙后间隙和下颌第二磨牙后区牙槽骨宽度差异均有统计学意义(P<0.05)。SRL(mm)与ABW4(mm)在低角组、均角组、高角组3组两两比较差异均有统计学意义(P<0.05),测量结果均依次减小。ABW8(mm)低角组大于均角组,低角组大于高角组,差异均有统计学意义(P<0.05);而均角组与高角组间差异无统计学意义(P>0.05)。3.第三磨牙存在组各测量参数均大于第三磨牙缺失组,差异均有统计学意义(P<0.05)。结论:1.不同垂直骨面型第二磨牙后间隙及磨牙后区牙槽骨的宽度存在差异,差异与下颌平面角的大小呈负相关。2.均角和高角骨性Ⅲ类成人患者在制定矫治计划时,应关注磨牙后区的间隙及骨容量的大小。3.第三磨牙的存在对下颌磨牙后区的大小有一定的影响。更多还原

【Abstract】 Objective:Three dimensional imaging techniques of cone beam computer tomographic were used to study the three-dimensional morphological characteristics of the distal posterior region of the mandibular second molar in the mandibular mandible with skeletal III malocclusion.To investigate the morphological difference and its influencing factors in the posterior region of mandibular molar of skeletal class III malocclusion in adult.To provide reference for diagnosis and individualized treatment of skeletal class III malocclusion in adult.Materials and Methods:30 adult patients who are among the newly diagnosed patients at the first affiliated Hospital of Zhengzhou University in the Department of Orthodontics of Henan Stomatology Hospital from May 2015 to May 2017.these patients with skeletal class III malocclusion according to the data inclusion criteria already have cbct in radiology department before orthodontic treatment.According to the size of mandibular plane angle on lateral cranial radiographs produced by large field cbct,30 cases of skeletal III malocclusion in adult were selected,including 10 cases of high angle,10 cases of average angle,10 cases of low angle,15 cases of male and female,aged from 18 to34(24.67 ±4.72)years old.Using cs3 D imaging software to reconstruct the image and adjust the datum point,line,plane,etc.The length of posterior space of second molar(SRL)and the width of alveolar bone at 4mm from the top of alveolar crest(ABW4)were measured,and the width of alveolar bone at 8mm from the top of alveolar crest(ABW8)was measured.All the measured data were analyzed statistically.Results:1.There was no statistical difference between the left and right sides of the same body and between men and women(p > 0.05).2.The measurements in the low angle group were higher than those in the high angle group,and the difference was statistically significant(p < 0.05).The SRL and ABW4 in average angle was higher than those in high angle group,and the difference was statistically significant(p < 0.05).There was no significant difference in ABW8 between the average angle group and high angle group(p > 0.05).3.The measurements in the existence group of the third molar were higher than those in the group of the absence of the third molar,and the difference was statistically significant(p < 0.05).Conclusion:1.The length of the posterior space of the second molar and the width of the alveolar bone in the posterior region of the molar were different among different vertical bone face types,and were negatively correlated with the size of the mandibular plane angle.2.Cbct should be used to guide the clinical design for the treatment of mandibular dentition in the patients with mild and moderate type III malocclusion,especially in the patients with high angle and mean angle.3.The existence of the third molar has a certain effect on the size of the posterior region of the mandibular molar.更多还原