骨性安氏Ⅲ类错牙合与正常牙合在不同牙合位状态下颅面复合体的三维有限元分析

3-D Finite Element Analysis for Craniofacial Complex in Different Occlusal Positions between Skeletal Class Ⅲ Malocclusion and Individual Normal Occlusion

目的明确颌骨形态的改变在安氏Ⅲ类错牙合高角病例发生、发展中所起的作用,为进一步研究安氏Ⅲ类错牙合高角病例的病因和预后判断因子奠定基础。方法分别选取正常牙合和骨性安氏Ⅲ类错牙合高角复发病例,分别对颅面复合体进行三维重建和在不同牙合位模拟咀嚼肌力进行有限元分析。结果无论在正中牙合位、最大张口位还是最大前伸位,颅面上颌复合体的应力和应变主要集中在关节窝和颧弓根部,在下颌骨主要集中在下颌升支前缘与下颌体交界处的唇侧和舌侧骨板。结论骨性安氏Ⅲ类高角病例颅面复合体形态的改变是机体代偿性适应的结果,与该畸形的复发无关。

Objective To investigate the role of shape change in craniofacial complex during forming high-angle class Ⅲ malocclusion, and to further investigate the pathogenesis and prognosis of high-angle class Ⅲ malocclusion. Methods Two finite element models, normal occlusal model and skeletal high-angle class Ⅲ malocclusion, were included in tiffs study. The strain-stresses on the complexes were analyzed by simulating the forces from raasticatory rauscles in different occlusal positions. Results The distributions of strain-stress were around the acetabulum of temporomandibular joint and the root of zygomatic areh on the eraniomaxillary complex and around tile labial and lingual bone plate on the common boundary between the front of the ramus and the body in the mandible in each different occlusal position （intercuspal position, maximum mouth opening position, protrusive displacement position）. Conclusion The skeletal high-angle class Ⅲ malocclusions were formed by camouflage of craniofacial complex, and the shapes of craniofacial complex had no relationship with the relapse of this kind of malocclusion.