【作者】 王建新；

【导师】 潘晓婧；

【作者基本信息】 兰州大学 ， 口腔医学（专业学位）， 2018， 硕士

【摘要】 牙槽骨包绕在牙根周围,是构成牙周支持组织的重要结构之一。其厚度和高度决定着牙槽骨的形态特征,厚度変薄、高度降低均会影响正畸治疗牙齿移动方式和移动范围。正畸矫治的目标是功能、稳定及美观,要想达到上述矫治目标,牙根必须位于基底骨的正中央。理想的切牙位置对于维持前牙正常的覆牙合覆盖、后牙咬合关系稳定、面部外貌美观都具有极其重要的作用。因此,不管是为了功能还是为了美观,在治疗前应该对牙槽骨厚度进行评估,进而在矫治过程中准确控制牙根在支持骨组织中的移动,避免牙根吸收、牙龈退缩、骨开裂、骨开窗等不良反应。目的:本实验通过锥形束计算机断层扫描(Cone Beam Computed Tomography,CBCT)技术研究成人安氏Ⅱ类错牙合患者上切牙不同位点的唇侧牙槽骨厚度,为正畸治疗中牙齿移动范围及移动方向的控制提供理论依据。方法:选取100例成人安氏Ⅱ类错牙合患者,分为两组:安氏Ⅱ类1分类错牙合组50例(平均年龄22.21±2.64y),安氏Ⅱ类2分类错牙合组50例(平均年龄22.41±2.94y),以个别正常牙合志愿者50例(22.31±2.84y)作为对照组,所有对象拍摄治疗前CBCT片,然后将所获得的CBCT影像数据导入Invivo 5.0图像处理软件进行三维重建,在牙体长轴矢状面上对上切牙不同位点唇侧牙槽骨厚度进行测量,然后计算唇侧牙槽骨厚度占总牙槽骨厚度的百分比,并进行统计学分析,比较三组间的差异。结果:1.安氏Ⅱ类1分类错牙合组、安氏Ⅱ类2分类错牙合组和个别正常牙合组,三组间头影测量分析值比较结果表明年龄、性别构成比、∠SNA、∠SNB、∠ANB在三组间无统计学差异(P>0.05),其中U1-NA(mm)、U1-NA(°)在安氏Ⅱ类1分类组最大,安氏Ⅱ类2分类组最小,差异具有统计学意义(P<0.05)。2.安氏Ⅱ类1分类错牙合组、安氏Ⅱ类2分类错牙合组和个别正常牙合组,三组组内相比较,上颌切牙左右侧对称牙位的唇侧牙槽骨厚度及占总牙槽骨厚度的百分比无统计学差异(P>0.05);上颌中切牙牙槽骨厚度大于侧切牙,差异具有统计学意义(P<0.05);沿着牙体长轴方向(从颈部至根尖方向),根尖部唇侧牙槽骨厚度最大,根中部和根颈部较小。3.安氏Ⅱ类1分类错牙合组、安氏Ⅱ类2分类错牙合组和个别正常牙合组,三组组间相比较,不同位点的唇侧牙槽骨厚度,个别正常牙合组最大,安氏Ⅱ类1分类组次之,安氏Ⅱ类2分类组最小,其中在根尖部位安氏Ⅱ类1分类组最大,个别正常牙合组次之,安氏Ⅱ类2分类组最小。结论:上切牙唇侧牙槽骨厚度与错牙合的类型有关,除中切牙根尖区外,其它部位唇侧牙槽骨厚度均小于2mm,唇侧牙槽骨厚度占相应部位总牙槽骨厚度的百分比不足20%。因此,在正畸矫治开始之前,应通过CBCT仔细分析牙根周围牙槽骨的厚度,尤其是对安氏Ⅱ类2分类错牙合组上颌切牙进行压低移动时应慎重考虑牙槽骨的限度,进而确定牙齿的移动方式和移动量,避免牙周组织损害。更多还原

【Abstract】 The alveolar bone around the root is one of the important structures of periodontal supporting tissue.Its thickness and height determine the morphological characteristics of alveolar bone,thickness and height decrease will affect the movement way and movement range of teeth during orthodontic treatment.The goal of orthodontic treatment is to be function,stability and beauty.in order to achieve this goal,the root must be in the center of the base bone.The ideal incisor position has important role for maintaining the normal occlusion of the anterior teeth,the stability of occlusion relationship of the posterior teeth,and the appearance of the facial beauty,so whether it’s for function or beauty,the thickness of alveolar bone should be evaluated before treatment,and the movement of root in supporting bone tissue was accurately controlled during orthodontic treatment,avoiding root absorption,gingival retraction,bone dehiscence,bone fenestration and other adverse reactions.Objective:The purpose of this study is to measure the labial alveolar bone thickness at different sites of adult patients with Angle class II malocclusion in upper incisors with CBCT,in order to provide a theoretical basis for the control of the range and direction of tooth movement during orthodontic treatment.Methods:The sample consisted of 100 adult patients with Angle classⅡmalocclusion: Angle classⅡdivision 1 malocclusion 50 patients(average age: 22.21±2.64 years);Angle class Ⅱ division 2malocclusion 50 patients(average age: 22.41±2.94 years),with 50 normal occlusion volunteers(average age: 22.31±2.84 years)were used as the control group.CBCT images were taken before orthodontic treatment,and then imported the acquired CBCT image data into the Invivo 5.0 image processing software for 3D reconstruction,measuring the thickness of the alveolar bone on the maxillary labial side on the sagittal plane of the tooth body,and then calculating the percentage of labial alveolar bone thickness to the total alveolar bone thickness,Statistical analysis was carriedout to differences among the three groups.Results:1.The results of cephalometric analysis showed that the age,Sex composition ratio,∠SNA,∠SNB,∠ ANB had no statistical difference among the three groups(P > 0.05).The U1-NA(mm),U1-NA(°)in Angle classⅡdivision 1 malocclusion group were the largest,in the Angle class II division 2 malocclusion groups were the lowest,the difference was statistically significant(P<0.05).2.The labial alveolar bone thickness and the percentage of labial alveolar bone thickness to the total alveolar bone thickness in left and right symmetrical teeth of maxillary incisors had no significant difference(P >0.05),among three groups;The alveolar bone thickness of maxillary central incisors was statistically greater than the lateral incisors(P<0.05);along the long axis of the tooth(from the neck to the apical direction),labial alveolar bone thickness was thinner in the middle and largest in the apex.3.The thickness of labial alveolar bone at different sites was the largest in individual normal occlusion group,followed by Angle classⅡ division 1 malocclusion group,and the smallest in Angle classⅡdivision 2 malocclusion group;however,in the apical position,The labial alveolar bone thickness was the largest in Angle class Ⅱ division 1 malocclusion group,followed by individual normal occlusion group,and the smallest in Angle class Ⅱ division 2 malocclusion group.Conclusion:The labial alveolar bone thickness in upper incisors was related to the type of malocclusion.The labial alveolar bone thickness was less than 2 mm except in the apical area of central incisor.The percentage of alveolar bone thickness to total alveolar bone thickness was less than 20%.Therefore,before orthodontic treatment begins,the thickness of alveolar bone around the root should be carefully analyzed by CBCT,especially in classⅡdivision 2 malocclusion group,the limitation of alveolar bone should be carefully considered when the maxillary incisors were intruded,and then determine the way of teeth movement and the amount of movement to avoid periodontal tissue damage.更多还原