前方牵引联合腭部扩弓对颅面骨缝应力分布的三维有限元研究

Study of Stress Distribution of Craniofacial Sutures Following Maxillary protraction with Palatal Expansion:-A Three-dimensional FEM Study

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。

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 10°,20°,30°,40°,50°,60°crossing Frankfort Plane were applied with palatal expansion. The stress distribution of the craniofaeial 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 unconsl^icuous; 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 ef- fect on Craniofacial Sutures. The maxillary rotates from anticlockwise to clockwise with the protraction angle increasing, and the rotation is unconspicuous at 40°-50°.