含矫治器的下牙列及下颌骨三维有限元模型的建立

Establishment of three-dimensional finite element model of mandibular dentition and mandible with incorporated appliances

目的寻求一种较快建立包含矫治器的下牙列及下颌骨三维有限元模型的方法,为牙齿移动生物力学的研究提供数学模型。方法利用薄层CT技术对已使用直丝弓矫治器排齐的下牙列进行扫描,通过数字影像的转换,结合Ansys三维有限元专用软件对CT断层影像进行分析处理和加工。结果建立了较理想的三维有限元模型,包含下颌骨、下牙列、牙周膜、牙槽骨(皮质骨、松质骨)、托槽、弓丝,建成后的有限元模型还可以根据不同的研究目的和要求添加和删除组织或矫治器,以及改变其特性。结论该有限元模型能较真实地模拟实际情况,具有较好的力学和几何学相似性,可被用来进行牙齿移动的生物力学的研究。

Objectives To explore an easier and more precise method for the reconstruction of the three-dimensional finite element model comprising the mandibular dentition and the mandible with incorporated appliances, so as to offer a mathematic model for the study on the biomechanics of moving teeth. Methods The mandibular dentition aligned with the straight wire appliances was scanned with the thin-layer CT technique to obtain the CT tomographic images, which were converted into digital images and were analyzed and processed by the specialized software named Ansys for three-dimensional finite element. Results An ideal three-dimensional finite element model, consisting of mandible, mandibular dentition, periodontal membrane, alveolar bone（ cancellous and compact bone）, bracket and arch wire, was reconstructed. Moreover, some tissues and appliances could be appended or deleted in the reconstructed finite element model according to the purposes and requirements of a study. Conclusion The finite element model, simulating the actual conditions precisely and boasting of mechanical and geometric similarity, could be used to the study on the biomechanies of movement of the teeth.