不同力系统下的上中切牙位移、转动中心及牙周应力的三维有限元研究
FEM Study on Displacement, Position of Rotation Center and Stress Distribution of PDL under Various Loading Force Systems
作者：刘东旭1,王春玲1,傅传云1,张晓燕1,郑效忠2
Author：LIUDong-xu1, WANG Chun-ling1, FUChuan-yun1, ZHANGXiao-yan1, ZHENGXiao-zhong2
收稿日期：2004-06-25 年卷（期）页码：2004,22(03):192-
期刊名称：华西口腔医学杂志
Journal Name：West China Journal of Stomatology
关键字：上中切牙,有限元分析,计算机模拟,牙移动,力系统,
Key words：upper central incisor,finite element analysis,computer simulation,tooth movement,moment force,
基金项目：
山东省卫生厅基金(HZ028)及山东大学跨学科预研项目资助(2002)
中文摘要
目的 研究不同力系统(力矩/后退力)下的上中切牙位移、转动中心及牙周应力分布。方法 建立包括牙齿、牙周膜、硬骨板、松质骨、皮质骨的上中切牙三维有限元模型,采用8节点三维六面体单元,共包括945个单元,1 245个节点。计算13种力系统下的上中切牙位移、转动中心及牙周应力分布。结果 ①牙齿表现为三种典型位移性质,力矩/后退力比值为-9·15∶1、-10·30~-10·50∶1及-10·90∶1时,牙齿分别出现以根尖点为中心转动、平行移动及以切缘为中心转动;②转动中心曲线以横坐标-10·50、纵坐标6·75两直线为渐进线,力矩/后退力比值在-9·15 至-10·90之间变化时,其转动中心变化较大;③以根尖点为转动中心时牙周最大牵张力、压应力分别为1·47×10-2 MPa和-2·81×10-2MPa;平行移动时牙周最大牵张力、压应力分别为1·10×10-2MPa和-1·86×10-2MPa;以切缘为转动中心时牙周最大牵张力、压应力分别为0·96×10-2MPa和-2·58×10-2MPa。结论 ①牙齿的位移与力矩/后退力比值有关;②力矩/后退力比值在-9·15∶1至-10·90∶1之间变化时,应仔细调整力系统,以获得确定的牙齿位移方式;③ 平行移动时,牙周膜应力分布较均匀,最大应力值较小;当上中切牙受到1 N水平力及转矩力,并出现以根尖点及切缘为中心转动时,最大压应力超过牙周膜安全值,可造成上中切牙牙周膜损害。
英文摘要
Objective To investigate the displacement, the position of rotation center and the stress distribution of PDL under different loading force system (Moment/Force ,M/F) by simulating clinical loading force system.Methods Athree-dimensional finite element model of upper central incisor, which consists of 945 isoparametric elements and 1 245 nodes was developed. The displacement, the position of the rotation center and the stress distribution of PDL were analyzed under 13 types of loading force system.Results 1.Different force system led to different types of tooth movement. When M/F= -9.15∶1, -10.30~-10.50∶1 and -10.90∶1, it brought the result of controlled tippingmovement, the bodilymovement and the rootmovement|2. The graph of the center rotationwas a hyperbolic asymptotic line:Mx/Fy= -10.50 (horizontal axis) and L=6.75(vertical axis). Moreover, a little change of M/F between -9.15 and -10.90 led to apparent change of the position of rotation center. 3. The maximum strain and stress during the tipping movement were 1.47×10-2MPa and -2.81×10-2MPa, and during the bodily movement the results were 1.10×10-2MPa and -1.86×10-2MPa, while during the root movement were 0.96×10-2MPa and -2.58×10-2MPa.Con- clusion 1. Different force system (M/F) leads to differenttypes of toothmovement. 2. It is necessaryto adjustthe force system accurately to obtain prescient tooth movement, especiallywhenM/F changes between-9.15∶1 and-10.90∶1. 3. This study sug- gested that the tooth movement style and the force system (M/F) should be controlled to protect the periodontal tissue.
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