“摇椅形”方弓配合前牙区垂直牵引作用下牙齿应力分布与移动趋势的光弹性研究

目的利用三维光弹应力分析法研究"摇椅形"方弓配合前牙区垂直牵引作用下,下颌牙齿牙槽骨的应力分布规律和移动趋势。方法制作上下颌三维光弹模型,对模型加载"摇椅形"不锈钢方丝配合前牙区垂直牵引力,将下颌实验模型单颗牙进行三维方向冻结切片,利用三维切力差法,计算单颗牙牙槽骨各点应力值。结果在"摇椅形"方弓配合前牙区垂直牵引作用下,各牙齿均未受到较大正畸力。17整体龈向压低,颊向移动,冠向远中旋转,近中颊向远中舌向扭转。16整体龈向压低,颊向移动,冠向远中旋转。15整体向伸长,冠向远中旋转,冠颊向根舌向转矩。13整体向伸长,冠唇向根舌向转矩。12为向伸长,冠唇向根舌向转矩。结论"摇椅形"方弓配合前牙区垂直牵引可以用来矫治开,随着弓丝直径增加,摇椅角度要减小。对于采用拔除双尖牙矫治的开患者,利用"摇椅形"不锈钢方丝配合前牙区垂直牵引关闭拔牙间隙可以满足开矫治机理的五个方面。

Photoelastic analysis of stress distribution and movement tendency of teeth using stainless rectangular reverse-curve arch wires with vertical elastics in anterior teeth area

Objective To investigate the stress distribution and movement tendency of lower teeth using stainless rectangular reverse-curve arch wires with vertical elastics in anterior teeth area by three-dimensional photoelastic analysis.Methods Establish photoelastical model of full teeth as human body,loading by stainless rectangular reverse-curve arch wires with vertical elastics in anterior teeth.Blade every freezing model-tooth by three-dimensions,examine the stress of every point of alveolar bone by three-dimensions shear-equation method,investigate the stress distribution regularity of per-tooth.Results Forces produced by stainless rectangular reverse-curve arch wires with vertical elastics in anterior teeth area were not too high.The second molar was intruded and moved buccally on bodily and the crown was rotated to distal,the mesial side was rotated buccally and the distal side was rotated lingually.The first molar was intruded and moved buccally on bodily and the crown was inclined to distal.The second pre-molar was extruded and the crown was rotated to distal,and inclined as positive torque.The canine was extruded slightly and inclined as positive torque.The lateral incisor was extruded and inclined as positive torque.Conclusion Stainless rectangular reverse-curve arch wires with vertical elastics in anterior teeth area can be used for open bite treatment.The depth of reverse-curve should be lower when the diameter of arch wires increased.Using stainless rectangular reverse-curve arch wires with vertical elastics in anterior teeth area meet five of mechanisms of open bite treatment by extracting the bicuspid teeth.