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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。
OBJECTIVE: To study the displacement of each anatomical site of the cranio-maxillofacial region in 3 kinds of different osteotomy methods assisted by maxillary rapid protraction. Methods: Three-dimensional finite element model of dental support-assisted maxillary rapid expansion system with three different osteotomy methods was established. Twenty-one anatomical structures were selected on the model, and the 7-mm transverse arch was loaded. The anatomic features of the craniofacial region X (sagittal), Y (horizontal), Z (vertical) direction of the displacement distribution. Results: In the sagittal direction, the anatomical structures of the maxilla showed a significant forward displacement. With the increase of the operative range, the anatomical structures of the craniomaxillofacial region moved forward more and more obviously. From the horizontal to the frontal view, the craniomaxillofacial complex was pyramid-like and the bottom of the nasal cavity was obviously enlarged. The maxillary displacement of maxillary teeth was larger than that of the alveolar bone in the corresponding area, Big enough to make the rear of the maxilla significantly expanded. In the vertical view, the palatal plate in the middle of the maxilla tends to move downward, and the lateral structures of the maxilla, such as the support tooth and alveolar bone, move upward. CONCLUSIONS: Dental compensation and skeletal tilt and rotation occur during lateral expansion of dental braces. As the surgical field increases, the horizontal displacement of the support tooth and alveolar bone area also increases.