Miyasaka-Hiraga J, Tanne K, Nakamura S
Department of Orthodontics, Hokkaido University School of Dentistry, Japan.
Br J Orthod. 1994 Nov;21(4):343-8. doi: 10.1179/bjo.21.4.343.
The purpose of this study was to investigate the nature of stress distributions in the craniofacial sutures produced by orthopaedic maxillary protraction forces applied to the upper canines. A three-dimensional finite element model of the craniofacial complex was developed for finite element analysis. An anteriorly directed force of 1.0 kg was applied to the upper canines in three different directions, i.e. parallel, 30 degrees upwards and downwards to the functional occlusal plane. Normal stresses acting on the sutural systems were greatest when force was applied in the 30 degrees upward direction. Furthermore, relatively large compressive stresses were induced in the frontonasal and frontomaxillary sutures, indicating that forward and upward rotation of the nasomaxillary complex was produced with substantial distortion of the complex, by the forces applied in both parallel and 30 degrees upward directions. A 30 degrees downward force produced almost uniform tensile stresses in the zygomaticotemporal and zygomaticomaxillary sutures, with least compressive stresses in the frontonasal and frontomaxillary sutures located in the superior region of the complex. This would indicate a uniform stretch of the nasomaxillary complex in both anterior and inferior directions, with negligible distortion of the complex and would be appropriate for accelerating natural growth of the nasomaxillary complex.
本研究的目的是调查施加于上颌尖牙的正畸上颌前牵引力量在颅面缝中产生的应力分布性质。建立了颅面复合体的三维有限元模型用于有限元分析。在三个不同方向（即平行于功能咬合平面、向上30度和向下30度）对上颌尖牙施加1.0千克向前的力。当在向上30度方向施加力时，作用于缝合系统的正应力最大。此外，额鼻缝和额颌缝中产生了相对较大的压应力，这表明平行和向上30度方向施加的力使鼻上颌复合体向前和向上旋转，同时复合体发生了明显变形。向下30度的力在颧颞缝和颧上颌缝中产生几乎均匀的拉应力，而位于复合体上部区域的额鼻缝和额颌缝中的压应力最小。这表明鼻上颌复合体在前后和上下方向上均匀伸展，复合体变形可忽略不计，这将适合于加速鼻上颌复合体的自然生长。
