Tanne K, Matsubara S
Department of Orthodontics, Hiroshima University School of Dentistry, Japan.
Angle Orthod. 1996;66(2):125-30. doi: 10.1043/0003-3219(1996)066<0125:ABTDOO>2.3.CO;2.
This study was designed to investigate biomechanical responses of the sutures in the nasomaxillary complex to orthopedic headgear forces applied in various directions. A three-dimensional analytic model of the craniofacial complex was used for finite element analysis. A posteriorly-directed force of 1.0 Kgf was applied to the maxillary first molars in 30 degrees inferior, parallel, and 30 degrees, 52.4 degrees and 60 degrees superior directions to the functional occlusal plane. Mean principal and shear stresses were evaluated at the sphenozygomatic, temporozygomatic, sphenomaxillary, frontomaxillary and frontozygomatic sutures and lamina cribrosa. As the force direction passed closer to the center of resistance (CRe) of the complex (52.4 degrees superior direction). normal stresses approached a certain level of uniform compressive stress (-2.5 gf/mm2) with gradual decrease in shear stresses, whereas variation in these stresses produced by the forces applied in other horizontal and inferior directions was greater. It is shown that stresses in the nasomaxillary sutures are varied by the direction of headgear force. Directing the line of force closer the CRe may produce the most optimal sutural modification effective for controlling forward and downward maxillary growth.
本研究旨在调查鼻上颌复合体中缝线对不同方向施加的矫形头帽力的生物力学反应。使用颅面复合体的三维分析模型进行有限元分析。在上颌第一磨牙上施加1.0千克力，力的方向分别为功能咬合平面下方30度、平行、上方30度、52.4度和60度。评估蝶颧缝、颞颧缝、蝶上颌缝、额上颌缝和额颧缝以及筛板处的平均主应力和剪应力。随着力的方向更靠近复合体的阻力中心（CRe）（上方52.4度方向），正应力接近一定水平的均匀压应力（-2.5克/平方毫米），剪应力逐渐减小，而在其他水平和下方方向施加的力所产生的这些应力变化更大。结果表明，鼻上颌缝线处的应力会因头帽力的方向而变化。将力线导向更靠近CRe的位置可能会产生最优化的缝线改变，从而有效地控制上颌向前和向下生长。
