目的 分析不同牵引位点进行骨性支抗前牵引上颌时骨缝应力分布特征，以期指导临床。方法 建立包含种植体的儿童颅面三维有限元模型，在上颌骨自近中向远中选取四个种植体植入部位设定不同牵引位点（乳侧切牙远中、第一乳磨牙近中、第一磨牙近中、第一磨牙远中），分析比较在不同牵引位点的前牵引力（与平面前下成角30°，500g/侧）作用下各骨缝的应力分布。结果 额颌缝应力值在工况2中最大（2.819×10-2-1.477×10-3MPa），鼻颌缝在工况1中最大（9.24×10-4-5.296×10-6MPa），颧颌缝在工况4中最大（1.313×10-2-3.947×10-4MPa），颧额缝在工况4中最大（3.169×10-2-4.952×10-4MPa），颧颞缝在工况3中最大（1.587×10-2-1.148×10-3MPa），腭中缝在工况1中最大（7.300×10-4-6.479×10-6MPa）。结论 当牵引位点置于乳侧切牙远中和第一乳磨牙近中时，对改善鼻根部凹陷明显的面容有积极意义。将牵引位点置于第一磨牙近中或远中时，对临床上改善上颌基骨部位凹陷有积极意义。
Objective To evaluate the influence of stress distribution on bone-anchored maxillary protraction with different protraction sites using biomechanical method, to direct the clinical. Method To build a three-dimensional finite element model of children’s head which includes implant anchorages. Four position of implants (distal of primary lateral incisor, mesial of maxillary first primary molar, mesial of maxillary first molar, distal of maxillary first molar) were loaded separately. The finite element models were loaded as 500g each side and 30° forward direction to the occlusal plane. Stress distribution of each sutures were analysed. Results The maximum stress value of Frontomaxillary Suture was in condition II (2.819×10-2-1.477×10-3MPa). The maximum stress value of Nasomaxillary Suture was in condition I (9.24×10-4-5.296×10-6MPa). The maximum stress value of Zygomaticomaxillary Suture was in condition IV (1.313×10-2-3.947×10-4MPa). The maximum stress value of Zygomaticofrontalis Suture was in condition IV (3.169×10-2-4.952×10-4MPa). The maximum stress value of Zygomaticotemporal Suture was in condition III (1.587×10-2-1.148×10-3MPa). The maximum stress value of Medianpalatine Suture was in condition I (7.300×10-4-6.479×10-6MPa). Conclusions It could improve class III profile especially in the nose root when the protraction sites were put in the distal maxillary primary lateral incisor and the mesial maxillary first primary molar. It is of positive significance to improve class III profile especially in the maxillary basal bone of the midface when the protraction sites were put in the mesial or distal maxillary first molar.