直丝弓滑动法关闭拔牙间隙的三维有限元模型的建立

目的基于CT法结合Mimics医学图像处理系统快速建立三维有限元模型的思路,探索建立几何相似性良好、可灵活调整、模拟直丝弓技术滑动法关闭拔牙间隙的生物力学数值分析模型。方法以牙列完整的成人上颌骨为标本,通过螺旋CT扫描后将图像传输至Mimics系统进行牙列及上颌骨的三维重建,并按东方人预成直丝弓矫治器的数据将牙齿调整至完全排齐、整平。再运用ABAQUS前处理程序生成矫治弓丝和托槽,通过布尔运算生成最后的模型。结果获得的“直丝弓-上牙列-上颌骨、模型具有良好几何相似性,可根据研究需要进行调整,并能有效反映直丝弓矫治器滑动法关闭间隙的生物力学状况。在模型上以2N的力加载后,上前牙出现舌向初始位移,舌侧牙周膜出现压应力区。结论建立了符合预定目标的三维有限元数值模型,为进一步研究直丝弓技术滑动法关闭拔牙间隙的生物力学问题提供了一个有益的工具。

Construction of Three-dimensional Finite Element Model of Space Closing Mechanics Using Sliding Method Treated with Straight Wire Appliance

Objective To set up the smart adjustable three-dimensional finite element model with high geometric similarity of space closing mechanics using sliding method treated with straight wire appliance rapidly based on the Materialise's interactive medical image control system(Mimics).Method An adult skull was selected for CT scanning and the data were imported into the Mimics for 3-D reconstruction.Firstly,the position of the tooth was adjusted to fully align according to parameters of the Opa-K straight wire appliance system;Secondly,the wire and the bracket were established in the ABAQUS's pre-processing program and were assembled to the tooth by boolean operation.Results The smart adjustable three-dimensional finite element model were constructed with high geometric similarity of space closing mechanics using sliding method treated with straight wire appliance.Lingual tipping displacement was found with lateral and central incisors and the pressure zones were formed in the periodontal membrane of the lingual side of the incisors under 2N load.Conclusions The model is effective and feasible,and it could provide the effective method for further investigation for space closing mechanics using sliding method treated with straight wire appliance.