【作者】 蔡留意；

【导师】 刘林嶓； 林久祥；

【作者基本信息】 郑州大学 ， 整形外科， 2012， 博士

【摘要】 目的：分析个体化舌侧矫治器上颌腭部不同位置微种植体滑动法关闭上前牙间隙的生物力学特征；研究上颌后牙区微种植体植入区域牙槽骨的CT特征。方法：建立包含eBrace托槽、牙、牙周膜、牙槽骨、弓丝和微种植体在内的三维有限元模型,分析微种植体在第二双尖牙和第一磨牙间、第一磨牙和第二磨牙间距离牙槽嵴顶2mm、6mm、10mm加力1.5N关闭上前牙间隙时的牙列位移和牙周膜应力特征；调取参加体检的健康成人颌面部CT影像,分别在上颌后牙间距离牙槽嵴顶垂直距离2mm、4mm、6mm、8mm和10mm的CT断面上,测量相应高度上的不同后牙间牙槽骨近远中宽度和颊舌侧厚度,对相应测量结果进行配对t检验。结果：1、建立了包含eBrace托槽、牙、牙周膜、牙槽骨、弓丝和微种植体在内的三维有限元模型；2、在牵引钩位置不变的情况下,利用不同位置的微种植体关闭间隙时,均表现为前牙的内收舌移和伸长下垂的主要趋势,伴有相应的倾斜或扭转；后牙矢状方向非常稳定,水平方向和垂直方向略有轻微变化,基本消除了水平方向和垂直方向典型的“拱形效应”。牙周膜应力区集中体现的部位主要是侧切牙牙颈部和尖牙牙颈部。3、随着微种植体距离牙槽嵴顶位置从10mm到6mm再到2mm,无论是在第二双尖牙和第一磨牙之间或是第一磨牙和第二磨牙之间,UYmax(Y方向最大位移量)、UZmin (Z方向最小位移量)和USUM(总位移量)均有所增加、UXmax(X方向最大位移量)有所减少。微种植体从第二双尖牙和第一磨牙之间到第一磨牙和第二磨牙之间,无论是哪个高度(分别是10mm6mm和2mmm)前后位置比较(从第二双尖牙和第一磨牙之间到第一磨牙和第二磨牙之间),牙列变化趋势也是：UYmax、UZmin和USUM均有所增加、UXmax基本有所减少。4、距离牙槽嵴顶相同高度时,上颌牙槽骨近远中宽度比较：6-5牙(第二双尖牙和第一磨牙)腭侧间最大,其次是7-6牙(第一磨牙和第二磨牙)腭侧,6-5牙(第二双尖牙和第一磨牙)腭侧距牙槽嵴顶8毫米宽度最大,为(6.15±41.72)mm；上颌牙槽骨颊腭侧厚度比较：7-6牙间>6-5牙间>5-4牙间,7-6牙(第一磨牙和第二磨牙)间距牙槽嵴顶6mm颊腭侧厚度最大,为(15.33±1.50)mm。结论：1、eBrace个体化舌侧矫治器利用上颌腭部不同位置微种植体支抗关闭上前牙间隙的三维有限元模型系首创构建,几何相似性强,真实合理实用；2、上颌拔牙舌侧矫治,微种植体可提供稳定有效的支抗保护；3、对于正常唇倾度和正常覆牙合的病例,就前牙内收而言,微种植体距离牙槽嵴顶在2mm位置优于6mm位置再优于10mm位置；微种植体在第一磨牙和第二磨牙间优于在第二双尖牙和第一磨牙间。伴随上前牙的内收舌倾和伸长下垂,临床仍需要前牙有效结扎对抗扭转、弓丝垂直方向的弓状弯曲(gable bend)、弓丝的预置转矩或托槽预置转矩和轴倾度或排牙时的过矫治。4、距离上颌后牙区牙槽嵴顶6毫米左右对颊腭侧常规微种植体植入均是安全、舒适和方便的。腭侧显著优于颊侧。CT检查特别有助于复杂病例的微种植体植入的监控。更多还原

【Abstract】 Objective:To analyze the biomechanical characteristics of the customized lingual bracket system during retracting maxillary anterior teeth with micro-implants and sliding method, study CT characteristics of the alveolar bones in the maxillary posterior regions with micro-implants, and provide anatomical guidance for safe micro-implant operations.Methods:To construct an entire3-D finite element(FEM) model including dentition, periodontal ligament(PDL), alveolar bone, e-Brace brackets, lingual wire and micro-implants according to the design principles of the customized lingual bracket system. By using the3-D FEM model, at different micro-implant loading positions between the second premolar and the first molar or the first molar and the second molar, including2mm、6mm and10mm from the alveolar ridge crest, the dentition movement tendency and the stress distribution in PDL were analyzed by sliding closing space mechanic. Thirty healthy adults with individual normal occlusion were selected from the people examined with256slices Computer Tomography (CT). The alveolar width and thickness were measured at2mm、4mm、6mm、8mm and10mm from the alveolar ridge crest and analyzed by Paired T test.Results:1. An entire3-D FEM model was constructed including dentition, PDL, alveolar bone, eBrace brackets, lingual wire and micro-implants.2. As micro-implants began to close the extraction space at different positions, the main side effect was the extrusion of the maxillary anterior teeth accompanied with corresponding rotation and lingual inclination. The posterior teeth were generally stable in saggital direction and the bowling effect was basically eliminated at horizontal direction and vertical direction. The stress distribution in the PDL for the space closure stage in the eBrace customized lingual system mainly focused on lateral cervix and canine cervix.3. With the distance between micro-implants and the alveolar ridge crests changing from10mm to6mm and then to2mm, UYmax, UZmin and USUM all increased, whereas UXmax decreased, whether they are located between the second premolar and the first molar or between the first molar and the second molar. Likewise, UYmax, UZmin and USUM all increased, whereas UXmax basically decreased, with the micro-implants located at the same height (10mm,6mm or2mm, relative to the alveolar ridge crests), changing from the position between the second premolar and the first molar to the position between the first molar and the second molar.4. At the same height relative to the alveolar ridge crests,the width between mesio and distal of maxillary bone:the biggest region was between the second premolar and the first molar on the palatal side, and the second biggest was between the second molar and the first molar on the palatal side. The widest position was (6.15±1.72mm) at8mm plane from the alveolar ridge crest. The buccal-lingual alveolar thickness:the one between the second molar and the first molar was thicker than the one between the first molar and the second premolar, which is thicker than the one between the second premolar and the first premolar. The thickest position was (15.33±1.50mm) at6mm plane from the alveolar ridge crest between the second molar and the first molar. Conclusions:1. The originated eBrace customized lingual3-D FEM model has high geometrical similarity, and is hence reasonable, reliable and practical.2. The micro-implants provided stable and effective anchorages.3. While closing the extraction space on the conditions of normal anterior inclination and overbite, the micro-implant works better at2mm from the alveolar ridge crest than at6mm where it works better than at10mm, no matter it is between the second premolar and the first molar or between the first molar and the second molar. The implanting position between the first molar and the second molar is preferred to that between the second premolar and the first molar at the same height, whether at10mm or6mm or2mm from the alveolar ridge crest. Considering maxillary anterior teeth rotation、lingual inclination and torque loss, effective ligature, or torque control, gable bend or additional torque, has to be operated to resist side effects.4. The usual micro-implant operation at6mm plane from the alveolar ridge crest of all the alveolar bones of the maxillary posterior regions is safe, comfortable and convenient in healthy adults. The palatal region is better than the buccal region for easy micro-implant operations.256slices CT is much helpful for complicated micro-implant operations.更多还原