Tanne K, Matsubara S, Sakuda M
Department of Orthodontics, Osaka University Faculty of Dentistry, Japan.
Angle Orthod. 1993 Summer;63(2):111-8. doi: 10.1043/0003-3219(1993)063<0111:SDITMC>2.0.CO;2.
The present study was conducted to investigate stress distributions in the maxillary complex from headgear forces by means of three-dimensional finite element analysis. A posteriorly-directed force of 1.0 Kgf was applied to the maxillary first molars in the directions parallel and 30 degrees inferior to the occlusal plane. In the lower regions resisting posterior displacement of the complex, large normal and shear stresses were observed. Meanwhile, the regions resisting upward displacement experienced larger than normal stresses. A downward force produced slightly larger stresses than a parallel force and varied the nature of stresses from compressive to tensile or vice versa in the temporozygomatic suture. Thus, the stress distributions in the sutures varied according to their anatomic locations relative to force directions. The maxillary complex exhibits postero-inferior displacement with clockwise rotation from the horizontal headgear force. This becomes more prominent as the direction of force becomes more inferior.
本研究旨在通过三维有限元分析来研究头帽力作用下上颌复合体中的应力分布情况。在上颌第一磨牙上施加一个1.0千克力向后的力，其方向与咬合平面平行且向下30度。在抵抗复合体向后移位的下部区域，观察到较大的正应力和剪应力。同时，抵抗向上移位的区域承受的应力大于正常应力。向下的力产生的应力略大于平行力，并使颞颧缝处的应力性质从压缩变为拉伸，反之亦然。因此，缝中的应力分布根据其相对于力方向的解剖位置而变化。上颌复合体在水平头帽力作用下表现出向后下移位并伴有顺时针旋转。随着力的方向变得更向下，这种情况变得更加明显。
