Objective: Establish cranio-facial complex-teeth model to analyse the stress distribution of craniofacial sutures by different protraction directions during maxillary protraction with palatal expansion. Methods: Three-dimension finite element models for cranio-facial complex-teeth was constructed using mimics, Geo-magic. The protraction forces of 1000 g at the mesial canine, with the angle 10o,20o,30o,40o,50°,60°crossing Frankfort Plane were applied with palatal expansion. The stress distribution of the craniofacial sutures were analysed by using ANSYS 10.0 software package. Results: With the protraction angle increasing, the stress distributions of frontozygomatic suture has no regulayion, and the min-stress is at 20°;the stress distributions of zygomaticomaxillaris suture is unconspicuous; the stress distributions of zygomaticotemporalis suture and sphenomaxillary suture is decreasing ,and so is nasomaxillary suture; the stress distributions of the maxillary sutures is similar at the 40°～50°. Conclusions: When maxillary protraction with palatal expansion, different force directions have a different effect on Craniofacial Sutures. The maxillary rotates from anticlockwise to clockwise with the protraction angle increasing, and the rotation is unconspicuous at 40°～50°.%目的:建立颅面复合体-牙列的模型,分析上颌前牵引联合腭部扩弓时,其牵引角度的不同对颅面骨缝应力分布的影响.方法:利用Mimics、Geo-magic软件建立颅面复合体-牙列的有限元模型,在进行腭部扩展的同时与尖牙近中处施加1000 g作用力,方向分别与眶耳平面成10°,20°,30°,40°,50°,60°,采用ANSYS 10.0软件分析复合体各骨缝的主应力变化.结果:随着牵引角度的逐渐增大,颧颌缝,颧额缝主应力变化趋势不明显；在20°的牵引角度主应力最小；颧颞缝、蝶上颌缝的主应力基本线性减小；鼻上颌缝的主应力基本线性增大；在40°～50°的牵引角度时,各主应力接近.结论:在伴有腭部扩弓的情况下,不同的牵引角度对颅面骨缝的影响不同,随着牵引角度的增大,上颌骨由前上旋转逐渐变为前下,在40°～50°时,上颌骨旋转不明显.
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