两种常用加力方式对种植钉压低上前牙力学行为影响的三维有限元分析

Comparison of the Intrution Effects of Two Commonly Used Loading Approaches on the Maxillary Incisors:A 3-dimensional Finite Element Analysis

目的:使用三维有限元法分析种植钉压低上前牙时两种常用加力方式对上前牙力学行为的影响,为正畸临床提供生物力学依据。方法:建立含有托槽、弓丝、上前牙、牙周膜和牙槽骨的三维有限元模型。设定加力方式:方式1:起点为弓丝中点,终点为前鼻棘下。方式2:起点为中切牙与侧切牙间弓丝的中点,终点为与前鼻棘等高的中切牙与侧切牙间牙槽骨。分析牙周膜的主应力分布及牙齿的初始位移。结果:方式2的牙周膜应力分布更均匀。两种加力方式下,上切牙均发生唇倾。加力点两侧的牙齿向加力点倾斜。结论:将种植钉植入中切牙与侧切牙之间施加压低力更为合理。压低过程中需注意前牙转矩的控制,并使用较粗的不锈钢丝作为主弓丝。

Objective： To compare the effects of two loading approaches on incisor intrusion with 3--dimension finite element method. Methods： Three dimensional finite element models, comprising brackets, archwire, maxillary anterior teeth and part of maxilla were constructed. The force direction was simulated as in clinical practice. Then three dimensional movement tendency of teeth and stress distribution in periodontal membrane was calculated and analyzed. Results： The stress distribution in PDL was more well--distributed when miniscrows were placed between the central and lateral incisors, in which the intrution forces were loaded bilaterally. Upper incisors proclined no matter which loading approach was performed. The anterior teeth tipped towards the loading location. Conclusion： loading bilaterally is better than loading centrally. We should increase torque when necessary. Rrigid stainless steel should be selected as archwire to prevent teeth from tipping misallaterally.