Instaneous Center of Rotation(ICR) was analyzed by defining different M/F ratios applied at the center of clinical crown of the central incisor.

• 用三维有限元分析法研究作用于上颌中切牙托槽部位(距切缘4.；4mm)矫治力系统中力偶矩M与舌向水平力F的比值(即M/F)与牙齿移动瞬间转动中心((ICR)之间的关系。