中文摘要：

目的：研究3种不同截骨方式下牙支持式外科辅助上颌骨快速扩弓中颅颌面部各解剖部位的位移情况。方法：建立3种不同截骨方式的牙支持式外科辅助上颌骨快速扩弓系统的三维有限元模型,模型上选取21个解剖结构,加载横向7mm扩弓量,比较分析颅面部各个解剖部位在X（矢状向）、Y（水平向）、Z（垂直向）方向的位移分布情况。结果：矢状向：上颌骨各解剖结构都有明显向前位移的趋势,而且随着手术范围的增大,颅颌面部各解剖结构向前移动的趋势越来越明显。水平向正面观,颅颌面复合体呈金字塔样打开,鼻腔底部有明显扩大;面观,支抗牙颊尖的位移最大,牙的位移大于相应区域牙槽骨的位移,手术范围的增大可以使上颌骨后部有明显的扩展。垂直向观,上颌骨正中区域的腭板有向下移动的趋势,上颌骨的侧方结构如支抗牙和牙槽骨都向上移动。结论：牙支持式扩弓器行横向扩弓时会出现牙的代偿和骨骼的倾斜和旋转。随着手术范围的增大,支抗牙和牙槽骨区域水平向的位移也随之增大。

英文摘要：

PURPOSE： The aim of this study was to investigate the displacement distribution of various anatomic structures of the craniofacial complex during surgically assisted tooth-borne rapid maxillary expansion（SARME）.METHODS： Three-dimensional finite element models of craniofacial complex with a tooth-borne appliance were generated,combined with three different types of SARME osteotomies.Displacements were measured at 21 anatomical structures of the craniofacial complex when 7mm transverse expansion was executed.Displacement distribution of these anatomical structures in X（sagittal）,Y（transversal） and Z（vertical） directions were then analysed and compared.RESULTS： In sagittal plane,various structures representative of the maxilla presented forward displacement.Forward displacement of various craniofacial structures was more evident with more extensive surgery.In transversal plane,pyramidal displacement of maxilla away from the midline was evident from the frontal view.Lateral walls of the nasal cavity separated more widely.Viewed occlusally,the displacement of buccal cusps of the first premolar and first molar were more than that of the buccal dentoalveolar tissue.The posterior part of the palatal plate expanded more widely with more extensive surgery.In vertical plane,palatal plate typical of the medial parts of the maxilla indicated downward displacement while the lateral structures of the maxilla such as anchorage teeth and the adjacent dentoalveolar tissue displaced upward.CONCLUSION： During surgically assisted tooth-borne rapid maxillary expansion（SARME）,the maxilla showed displacement,tipping and lateral rotation in three dimensions.Anchorage molars and maxilla expanded more widely with more extensive surgery.