Journal of Prevention and Treatment for Stomatological Diseases ›› 2019, Vol. 27 ›› Issue (3): 178-184.DOI: 10.12016/j.issn.2096-1456.2019.03.007

• Prevention and Treatment Practice • Previous Articles     Next Articles

Finite element analysis of torque control efficiency of a homemade four-curved auxiliary arch for anterior teeth

YANG Pingzhu1,WEN Xiujie1(),NIE Xin2,ZHAO Qian1,WANG Yingying1,ZENG Qiuyun1,ZHU Lin1,Li Jun1   

  1. 1.Department of Stomatology, Army Characteristic Medical Center, Chongqing 400042, China
    2.Department of Maxillofacial Surgery, the Affiliated Stomatology Hospital of Wenzhou Medical University, Wenzhou 325035, China
  • Received:2018-09-30 Revised:2018-10-22 Online:2019-03-20 Published:2019-03-20
  • Contact: Xiujie WEN

自制四曲辅弓控制前牙转矩效能的有限元分析

杨苹珠1,温秀杰1(),聂鑫2,赵茜1,王莹莹1,曾湫雲1,朱林1,李骏1   

  1. 1.陆军特色医学中心口腔科,重庆(400042)
    2.温州医科大学附属口腔医院颌面外科,浙江 温州(325035)
  • 通讯作者: 温秀杰
  • 作者简介:杨苹珠,医师,在读硕士研究生,Email:343531361@qq.com
  • 基金资助:
    国家自然科学基金项目(81470032);军事口腔医学国家重点实验室开放课题(2014KB14)

Abstract:

Objective To analyze the initial displacement of the upper central incisor and stress distribution of periodontal ligament under different torque values of upper incisors under the action of a four-curved auxiliary arch to provide a reliable basis for the safety of clinical application of four-curved auxiliary arches.Methods A three-dimensional finite element model for torque control of upper anterior teeth with a homemade quadrilateral auxiliary arch was established. Four different states were analyzed: molar ligation without extraction space (group A), microimplant ligation without extraction space (group B), molar recovery with extraction space closure (group C) (the adductive traction force was set at 115 g) and microimplant recovery with extraction space closure (group D) (the adductive traction force was set at 115 g). When four types of torque (0.5 N, 1.0 N, 1.5 N, and 2.0 N) were applied. The initial displacement of upper central incisors and the stress distribution of periodontal ligament in 16 groups (A1-A4, B1-B4, C1-C4, D1-D4) were observed.Results Under different conditions, as the strength of the four-curve auxiliary arch increases, the maxillary anterior teeth has crown labial inclination and a root lingual inclination. The displacement of the incisor tip increases with the increase in the loading force of the torque auxiliary arch, and the displacement of the incisor root apex increases as the force increases. The difference in incisor-apex displacement distance in A1-A4, B1-B4, C1-C4, D2 and D4 groups increased as the torque force increases, while the difference between the D3 group and D1 and D2 groups decreased slightly. The stress of the cervical periodontal ligament of the upper central incisor did not exceed the stress of the periodontal ligament in the following groups: A1, A2, B1, B2, B3, C1, C2, D1, and D2. The stress of the lip side of the upper central incisor did exceed the stress of the periodontal ligament in the following groups: A3, A4, B4, C3, C4, D3, and D4. In other words, when using the four-curved auxiliary arch as an implant anchorage, the force applied in the absence of extraction space should not exceed 1.5 N, and the force applied in the adduction of extraction space should not exceed 1.0 N. When using the nonimplant anchorage, the force applied in the absence of extraction space and the adduction of extraction space should not exceed 1.0 N. In addition, the range of force should not exceed the maximum stress of the periodontal ligament in the cervical region such that the effective and safe torque movement can be achieved. Under other stress conditions, the stress of the labial and cervical periodontal ligament of the upper central incisor exceeded the stress value (2.6 × 10-2MPa). The stress value of periodontal ligament was 2.6 × 10-2MPa in all groups.Conclusion A four-curved auxiliary arch has a significant effect on the upper anterior teeth, and the use of microimplants can better control root movement such that the crown of upper central incisors cannot be excessively lip inclined.

Key words: Four-curved auxiliary bow, Anterior teeth, Torque force, Three-dimensional finite element, Periodontium, Malocclusion, Implant anchorage, Stress analysis

摘要:

目的 分析四曲辅弓作用上前牙不同转矩力值时,上中切牙的位移初始变化和牙周膜的应力分布状态,为四曲辅弓临床应用的安全性提供依据。方法 建立自制四曲辅弓对上前牙转矩控制的三维有限元模型,分析四种不同状态:无拔牙间隙磨牙回扎(A组)、无拔牙间隙微种植体回扎(B组)、关闭拔牙间隙磨牙回收(C组)(内收牵引力设定为115 g)和关闭拔牙间隙微种植体回收(D组)(内收牵引力设定为115 g),并分别施加4种转矩力(0.5 N、1.0 N、1.5 N、2.0 N)时,A1~A4、B1~B4、C1~C4、D1~D4 共16组上中切牙的位移初始变化和牙周膜的应力分布状态。结果 在不同状态下,随着四曲辅弓力量的增加,上中切牙牙根舌向移位,牙冠唇向移位。中切牙的切端位移值随着转矩辅弓加载力量的增大而增大,中切牙的根尖位移值随着力量的增大而增大。中切牙的切端-根尖移动距离差值A1~A4组、B1~B4组、C1~C4组、D2、D4组随着转矩力量增加,位移差增大;D3组根尖与切端位移差值较D1、D2组略减小。上中切牙唇侧牙颈部牙周膜未超过牙周膜应力组:A1、A2、B1、B2、B3、C1、C2、D1、D2,上中切牙周膜唇侧牙颈部超过牙周膜应力组:A3、A4、B4、C3、C4、D3、D4。即四曲辅弓在运用种植体支抗时,无拔牙间隙时施加力量不超过1.5 N,拔牙间隙内收时施加力量不超过1.0 N;在非种植体支抗时,无拔牙间隙时和拔牙间隙内收时施加力量均不超过1.0 N,在以上力值范围均未超过牙颈部牙周膜最大应力值,可达到有效安全的转矩移动;而在其余力值作用条件下,上中切牙的唇侧牙颈部牙周膜超过应力值(2.6 × 10-2MPa)。所有分组根尖部均未超过牙周膜应力值2.6×10-2MPa。结论 四曲辅弓作用于上前牙效果显著,配合微种植体的运用可以更好进行控根移动使上中切牙牙冠不过度唇倾。

关键词: 四曲辅弓, 前牙, 转矩力, 三维有限元, 牙周膜, 错頜畸形, 种植体支抗, 应力分析

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