【作者】 王颖；

【导师】 赵树山；

【作者基本信息】 哈尔滨工业大学 ， 固体力学， 2007， 硕士

【摘要】 正畸牙齿移动是牙冠受力后牙周支持组织细胞反应的结果,牙周组织应力的大小和分布对牙齿的移动具有决定作用。通过对矫治力作用下牙齿及其支持组织的应力应变分析,对研究正畸牙齿的移动规律和更好地制定矫治方案有重要的指导意义。正畸牙及牙周的应力分析在国内外都有较多的研究报道,但是目前这一领域的研究多局限于单个牙齿,缺少对牙列整体的研究。多曲方丝弓(MEAW)技术是临床上用来矫治开颌、反颌等牙齿畸形的有效方法,它主要利用方丝弓控制牙齿的三维位置,“L”形曲的水平和垂直部分可以对需矫治的牙齿分别调整,其弓丝长,形变率低,故力量柔和且持久。本课题运用CT三维重建技术及有限元分析方法,针对牙颌组织的解剖学和生物力学特征,建立了下中切牙及下颌牙列三维有限元模型,分别对下中切牙及下颌牙列施加不同载荷,对下颌牙列是模拟多曲方丝弓形变后对牙齿产生的反作用力等效加载到牙列上,分析比较各种矫治力作用下牙齿的位移和在牙齿及牙周组织上产生的应力,为临床上应用和发展MEAW技术治疗深覆颌做准备。力学分析结果表明:(1)在各种矫治力作用下牙齿受到的应力值最大,牙槽骨次之,牙周膜最小;牙周膜有明显的缓冲作用且三个主应力值变化趋势一致。(2)下中切牙在垂直压入力作用下牙齿整体表现为向下移动,但在舌向出现较小位移,牙体垂直移动的同时伴有倾斜移动,说明在临床应用中要达到理想的沿牙长轴的压低移动是非常困难的。(3) 2N舌向水平力加载于牙冠不同部位,牙齿均表现出倾斜移动,要想实现牙齿的整体移动,需同时施加一个力及一个力矩。(4)下颌使用MEAW弓时,长Ⅲ类牵引在远中竖直后牙方面效果比较好,可实现压低前牙,抬高后牙,打开咬合的治疗目的。更多还原

【Abstract】 During the Orthodontics treatment, when the force loaded on the tooth is applied to the malposed tooth, the periodontal tissues are remold and the alveolar bone moves, finally tooth moves to a new place. The stress distribution in periodontal tissue plays a very important role in determining tooth movement. Therefore, it is useful and important for making treat scheme accurately to know about the pattern of stress and strain distribution of periodontal tissues by finite element method combined with the mechanical behavior of appliance. There are many reports on periodontal tissue stress analysis, but at present stress analysis is confined to single tooth other than dentition.Multiloop Edgewise Arch Wire (MEAW) technique, which was the valid method in the treatment of openbite and crossbite. The main characters of MEAW were: Controlling the tooth positions in three dimension (3D); The level and vertical parts of“L”can adjust the tooth respectively. Its arch wire is long, the changes of the rate is low, the power is soft and last long.In this paper, using CT rebuilding technique , finite element method , a series geometric and finite element models of the submaxilla dentition were developed at unify coordinate including periodontal ligament and alveolar bone, for simulating the anatomy and biomechanical characters of dentognathic tissue. Then loading was loaded on the tooth and the submaxilla dentition, simulating reacting force of the MEAW loaded in brackets was loaded to dentition. By the finite element analysis, the laws of stress on the teeth and displacement of the teeth and their periodontal tissues were shown. It will help to direct the clinical uses and modify MEAW in overbite in future.Conclusion: (1) The highest stresses were observed in the tooth surface, the lowest in the periodontal ligament, the alveolar bone between them. The periodontal ligament plays an important role in the transmission and cushion of forces acting on teeth, and its three kinds of principal stress are consistent. (2) Under vertical loading, the movement trend of tooth is downwards, appearing the smaller displacement at the direction of tongue .The clinical application ideal producing the movement along with the tooth major axis is very difficult. (3) The 2N tongue toward force add to the different part of the tooth , the tooth all expresses an inclination move. To obtain the whole movement of the tooth, a force and a moment are needed at the same time. (4) Using MEAW bow, the long elastics at MEAW the result is better, can carry out pressing the front tooth , the treatment purpose that open to bite is coming true .更多还原