微种植体支抗远移上颌磨牙的三维有限元研究

发布时间：2019-03-06 21:51

【摘要】：目的本研究通过建立包含上牙列、牙周膜、牙槽骨、直丝弓矫治器以及颊侧牙根间微种植体支抗的三维有限元研究模型,对三种远移上颌磨牙的方式进行有限元力学分析,包括微种植体支抗远移上颌第二磨牙,微种植体支抗同时远移上颌第一和第二磨牙,以及微种植体支抗整体远移上牙列,为正畸临床远中移动上颌磨牙提供生物力学参考。方法利用锥形束CT(cone beam CT,CBCT)扫描获取上颌骨和上牙列的CT图像,通过一系列计算机辅助设计软件和有限元分析软件建立包含上牙列、牙周膜、牙槽骨、直丝弓矫治器以及颊侧牙根间微种植支抗的三维有限元研究模型,并模拟三种远移上颌磨牙的方式:(1)在上颌第一磨牙与第二磨牙之间模拟镍钛推簧推力2.5N,将牵引钩与微种植钉头部固定连接,以模拟微种植体支抗远移上颌第二磨牙;(2)在上颌第二前磨牙与第一磨牙之间模拟镍钛推簧推力2.5N,将牵引钩与微种植钉头部固定连接,以模拟微种植体支抗同时远移上颌第一和二磨牙;(3)在牵引钩与微种植钉头部之间施加相互牵引力2.5N,以模拟微种植体支抗整体远移上牙列。利用有限元分析软件计算出所有牙齿在三维方向上的初始位移量以及牙周膜的范式应力分布。结果本研究建立了精确度较高的颊侧牙根间微种植体支抗远移上颌磨牙的三维有限元研究模型,该支抗系统下的有限元计算结果显示,(1)单独远移上颌第二磨牙时,第二磨牙存在明显的矢状向的远中倾斜移动、水平向的颊向倾斜和远中旋转移动,以及垂直向的远中压低,前牙支抗控制良好;(2)同时远移上颌第一和第二磨牙时,第一和第二磨牙均存在明显的矢状向的远中倾斜移动、水平向的颊向倾斜和远中旋转移动以及垂直向的远中压低,但上述移动中倾斜的趋势以及位移量均较单独远移第二磨牙时小,而前牙在矢状向上的支抗控制稍弱,出现少量的唇倾;(3)整体远移上牙列时,牙弓两侧少量外扩。矢状向上牙列整体发生远中移动,远中位移量从中切牙到第二磨牙递减。前牙段出现明显的舌向倾斜移动,后牙出现较少量的远中倾斜移动,垂直向切牙明显压低。(4)三种方式远移磨牙的牙周膜最大范式应力值分别是18kPa、14kPa、4kPa。结论在本研究所建立的颊侧牙根间微种植体支抗远移磨牙系统中,(1)不同的远移磨牙的方式会对上牙列的位移量和牙周膜的应力分布产生不同的影响;(2)相同推力的作用下,远移单颗磨牙比同时远移两颗磨牙时的矢状向初始位移量更高,前牙的支抗控制更好,但其磨牙的倾斜程度更明显;(3)上牙列的整体远移可能会引起前牙明显的舌倾,需要尤其注意前牙的转矩控制。
[Abstract]:Objective to establish a three-dimensional finite element model including upper dentition, periodontal ligament, alveolar bone, straight wire appliance and buccal interroot implant Anchorage, and to analyze the mechanics of three kinds of distal maxillary molars by finite element method (FEM). It includes microimplant Anchorage for distal maxillary second molars, microimplant Anchorage for both maxillary first and second molars, and microimplant Anchorage for whole distal maxillary molars, which provides biomechanical reference for distal maxillary molar movement in orthodontic clinic. Methods the CT images of maxillary bone and maxillary dentition were obtained by cone beam CT (cone beam CT,CBCT) scanning, and a series of computer aided design software and finite element analysis software were used to establish the images of maxillary dentition, periodontal ligament and alveolar bone. The three-dimensional finite element model of orthodontic appliance and buccal interroot micro-implant Anchorage was studied, and three kinds of distal maxillary molars were simulated. (1) Ni-Ti push spring thrust 2.5N was simulated between the maxillary first molar and the second molar, and the results were as follows: (1) Niti push spring thrust was simulated between the maxillary first molars and the second molars. The traction hook was fixed with the head of the micro-implant nail to simulate the support resistance of the micro-implant to move the maxillary second molar. (2) Ni-Ti spring thrust 2.5 N was simulated between the second maxillary premolar and the first molar, and the traction hook was fixed with the micro-implant nail head to simulate the Anchorage of the micro-implant to move the maxillary first and second molars at the same time. (3) the traction force 2.5 N was applied between the traction hook and the head of the microimplant nail to simulate the whole distal upper dentition of the microimplant. The initial displacement of all teeth in three-dimensional direction and the normal stress distribution of periodontal ligament were calculated by finite element analysis software. Results the three-dimensional finite element model of buccal interroot microimplant Anchorage of maxillary molars with high accuracy was established. The results of finite element calculation under this Anchorage system showed that: (1) when the second maxillary molar was moved far away, the results of the finite element analysis showed that: (1) when the maxillary second molar was moved far away, the results of the finite element calculation under this Anchorage system showed that: The second molar had obvious sagittal distally inclined movement, horizontal buccal tilt and distal rotation, as well as vertical distal and middle depression, and the anterior tooth Anchorage was well controlled. (2) when the maxillary first and second molars were moved at the same time, both the first and second molars had obvious sagittal distally inclined movement, horizontal buccal tilt and distal rotation movement, and vertical distal and middle depression. However, the tendency of tilt and displacement in the above movement were smaller than those in the second molar alone, while the Anchorage control of the anterior teeth in the sagittal direction was slightly weaker, and a small amount of lip inclination appeared. (3) when the whole distal upper dentition was moved, a small amount of external expansion was observed on both sides of the arch. The sagittal upward dentition moves distally, and the distal displacement decreases from the incisor to the second molar. (4) the maximum normal stress of periodontal ligament of the distal molars was 18 KPA, 14 KPA, and 4 KPA, respectively, and the vertical incisor was significantly depressed in the posterior teeth. (4) the maximal normal stress values of the periodontal ligament in the distal molars were 18 KPA, 14 KPA and 4 KPA, respectively, and that in the anterior tooth segment was significantly tilted toward the tongue, and that in the posterior teeth was slightly distally inclined. Conclusion in the buccal interroot microimplant system established in this study, (1) different modes of distal molar migration have different effects on the displacement of upper dentition and the stress distribution of periodontal ligament. [WT5 "HZ] conclusion: (1) different modes of distal molar movement have different effects on the displacement of upper dentition and the stress distribution of periodontal ligament. (2) under the same thrust, the sagittal initial displacement of the single molar was higher than that of the two molars at the same time, and the Anchorage control of the anterior teeth was better, but the inclination of the molars was more obvious than that of the two molars at the same time. (3) the whole distal movement of the upper dentition may cause obvious tongue tilting of the anterior teeth, so the torque control of the anterior teeth should be paid special attention.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R783.6

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