三维有限元模型分析OSAHS患者下颌逐步前伸引起髁状突位置变化和表面应力变化的研究
【摘要】
目的：建立阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者下颌骨和颞下颌关节及上气道的三维有限元模型，通过下颌逐步前伸，观察患者髁状突位置变化及表面应力分布变化，为治疗OSAHS从颞颌关节方面提供参考依据。
方法：对OSAHS患者颞颌关节及上气道行薄层CT扫描，获得患者下颌骨、颞颌关节及上气道DICOM格式的图像信息，采用Mimics三维建模软件、Imageware逆向工程软件、Ansys有限元分析软件建立颞颌关节、下颌骨及上气道的三维有限元模型，然后通过加载下颌骨逐步前伸，观察OSAHS患者髁状突的位置变化及应力分布规律。
结果：建立了OSAHS患者颞颌关节、下颌骨及上气道的三维有限元模型，单元类型采用10节点的Solid 92四面体单元，按要求划分网格后，得到骨密质、骨松质、肌肉和气道的单元数和节点数分别为：562920、50141、336789个单元，544929、84869、303134个节点。通过逐步前伸下颌骨，髁状突的位置及表面应力均发生相应变化，主要表现为关节间隙（前、上、后）的位置变化，髁状突各部位位移及表面应力的变化。
结论：应用螺旋CT技术和联合使用Mimics、Imageware及Ansys有限元分析软件建立OSAHS患者颞颌关节、下颌骨及上气道的三维有限元模型。该模型通过力学相似性验证，证明建立模型有效，其几何相似性较好，使用灵活；通过下颌逐步前伸，对髁状突的位置变化及表面应力分布进行分析，有效展示下颌骨前伸与髁状突位置变化及应力分布规律之间的关系，证实了研究方法的可行性，为临床利用口腔矫治器治疗OSAHS从颞颌关节方面提供理论基础。
【关键词】阻塞性睡眠呼吸暂停低通气综合征；三维有限元法；下颌前伸；髁状突
The three-dimensional Finite Element model analysis of Obstructive Sleep Apnea Hypopnea Syndrome Patient’s condylar position changes and changes in surface stress with mandibular protrusion gradually(https://www.daowen.com)
ABSTRACT
Objective：To construct a three-dimensional finite element model of the mandibular and temporomandibular joint of an Obstructive sleep apnea hypopnea syndrome patient.And then titrated mandibular advancement，observation OSAHS patients condylar position changes and changes in surface stress distributionprovide，find a reference for the treatment of OSAHS from the temporomandibular joint.
Methods：DICOM format image information of an OSAHS patient’s upper airway obtained by thin—section CT scanning and digital image processing were utilized to construct a three-dimensional finite element model by Mimics、Imageware and Ansys software.And then titrated mandibular advancement，observed OSAHS patients condylar position changes and stress distribution law.
Results：A case of OSAHS and the mandible and temporomandibular joint（contains the upper airway and surrounding structures）of three-dimensional finite element model is constructed which is formed by solid 92 tetrahedral unit of a 10-node element.The model has bone cortical 562920 elements，and 544929 nodes，cancellous bone 50141 elements and 84869 nodes，muscle and upper airway 336789 elements and 303134 nodes.After titrated mandibular protruding，condylar position and surface stress change accordingly，mainly as follows：the change of position joint space（the anterior、superior and posterior）and there are various of condylar displacement and surface stress changes.
Conclusion：The three-dimensional finite element model of the temporomandibular joint and mandible of the OSAHS patient was established using spiral CT technology and combined using Mimics，Imageware software and Ansys software，which confirmed the 3-D FEM model could be established through CT.The model has good geometric similarity and good flexibility.The model through mechanical similarity verification to prove effective model geometric similarity is better，and the use of flexible；through the lower jaw gradually protrusive condylar position changes and surface stress distribution analysis，effective showcase mandible protrusion relationship between condylar position changes and stress distribution law，and confirmed the feasibility of the research methods to provide a theoretical basis for the clinical use of oral appliance treatment of OSAHS from temporomandibular joint.
Key words：Obstructive sleep apnea hypopnea syndrome；three-dimensional finite element method；Mandibular advancement；condyle