多曲方丝弓配合前牙区垂直牵引下颌牙齿移动趋势的光弹性研究

目的应用三维光弹实验法研究多曲方丝弓配合前牙区垂直牵引下颌牙齿的移动趋势。方法建立与人体物理性能相似的1∶1的全牙光弹模型，对模型进行多曲方丝弓配合前牙区垂直牵引力加载，将加载后的光弹模型进行三维方向冻结切片，利用三维切力差法计算下颌牙弓上牙槽骨各点的应力值，分析单颗牙牙周组织应力分布规律及运动趋势。结果│7 的运动趋势是整体龈向压低，远中移动，冠舌向根颊向转矩，冠向远中旋转。│6的运动趋势是整体远中移动，冠向远中旋转，近中颊向远中舌向扭转。│5 的移动趋势是向伸长，冠向近中根向远中倾斜，冠舌向根颊向转矩，且整体受力较小。│3 的运动趋势是轻度压低，冠唇向根舌向转矩。│2 的运动趋势是向伸长，冠唇向根舌向转矩。结论多曲方丝弓可以在三维方向控制单颗牙齿的移动。

Photoelastic analysis of movement tendency of lower teeth using multiloop edgewise archwire with vertical elastics in anterior teeth area

Objective To investigate the movement tendency of lower teeth using multiloop edgewise archwire(MEAW)with vertical elastics in anterior teeth area by three-dimensions photoelastic analysis. Methods The photoelastical model of full teeth as human body on physical parameter and dimension was established and loaded by MEAW with vertical elastics in anterior teeth area similar with clinic. Every freezing model-tooth was bladed by anteroposterior axes and vertical axes, the stress of every point of alveolar bone was calculated by three-dimensions shear-equation method. The stress distribution regularity of per-tooth was analyzed to describe their move tendency. Results The lower second molar was intrused and rotated to distal and inclined as negative torque. The lower first molar moved and rotated to distal, the mesial rotate to buccally and the distal rotate to lingually. The lower second pre-molar was extruded and inclined as crown to mesial and root to distal, inclined as negative torque. The lower canine was intrused slightly and inclined as positive torque. The lower lateral incisor was extruded and moved and inclined as positive torque. Conclusion Using MEAW with several"L"loop can control the movement of every tooth in three dimension.