摘要
采用三维有限元法比较分析后倾弯多曲方丝弓、理想弓和 Ni Ti弓在无牵引力、长 类牵引力作用下的矫治效果 ,在此基础上研究多曲方丝弓的整体力学特性 ,揭示多曲方丝弓技术矫治特点 ,探讨其作用机理。结果表明 :(1)无牵引力时 ,以第一、二前磨牙之间为界 ,多曲方丝弓矫治分别使前后牙向前后倾斜 ,且对前牙有压低作用 ;理想弓 (ss方弓 )与 Ni Ti弓矫治力的方向相同但大小不同 ,Ni Ti弓的作用更趋柔和 ,对前牙有轻微伸长作用 ,对后牙有一定压低作用 ,且使磨牙后倾、其余牙前倾。 (2 )长 类牵引时 ,三种弓丝对后牙的后倾作用有所增大 ,但 Ni Ti弓增加比例最大 ;多曲弓使切牙前倾 ,其余牙均向后倾 ;理想弓和 Ni Ti弓则没改变牙的倾斜方向。 (3)无论是预应力单独作用或预应力与牵引力同时作用 ,在牙根上产生的最大压应力均呈现出理想弓矫治时最大、Ni Ti弓居中而多曲弓最小。由此从理论上证明 ,多曲方丝弓矫治技术有利于下颌 Spee氏曲线的整平和牙齿的个别调控 ;对牵引力的传递作用强 ;同时矫治力柔和持久。
This study is designed to theoretically evaluate the treatment effects of MEAW with tip back bends on the mandible dentition when used as a finishing archwire without elastic and with long class Ⅲ elastics respectively, and to compare them with those of stalnless-steel wire and shape-memory wire. The finite element analysis （FEA） method was adopted and the findings were as follows： （1） In the case of no elastics, the MEAW rotates the second premolar, the first molar and the second molar distally while rotating other teeth mesially, and depresses anterior teeth. However, the stalnless-steel wire and the shape-memory wire rotate molars distally while rotating other teeth mesially. Furthermore, they extrude anterior teeth and depress posterior teeth. （2） The MEAW with tip back bends and long class Ⅲ elastics inclines and rotates posterior teeth more distally than the MEAW with only tip back bends does. In the case of tip back bends and long class Ⅲelastics loaded together, the shape-memory wire inclines teeth in greater strength as compared with the stalnless-steel wire. （3） The stress level of tooth root is the lowest with MEAW, the highest with stalnless-steel wire, and is middle with the shapememory wire. From these results, it is suggested that： （1） The MEAW therapy technique is effective for leveling the curve of Spee and regulating tooth respectively. （2） The MEAW therapy technique can transfer therapy force efficiently. （3） The MEAW is considered to be suitable for treating openbite malocclusion to make the posterior teeth upright because it effectively rotates teeth distally through the force of posterior bends and long class Ⅲ elastics. （4） The loaded force on the teeth is more soft and permanent in the MEAW than in the stainless-steel wire and the shape-memory wire.
出处
《生物医学工程学杂志》
EI
CAS
CSCD
北大核心
2005年第1期86-90,共5页
Journal of Biomedical Engineering
关键词
多曲方丝弓
生物力学
三维有限元
口轻矫治技术
MEAW therapy technique Stalnless-steel wire Shape-memory wire Load deflection rate （LDR） Three-dimensional finite element analysis
