牙齿正畸路径规划方法研究及可视化开发

发布时间：2018-12-20 10:20

【摘要】：牙齿移动路径规划是虚拟牙齿正畸系统开发过程中的一个重要步骤,能够利用计算机辅助数据可视化技术在临床上模拟医生所提供的矫治方案。根据医生矫治方案及临床需求,依据牙齿移动路径规划方法,通过虚拟牙齿正畸系统设计出患者每个阶段的隐形矫治器,记录每颗牙齿每个步骤的位置,确定其移动旋转量,最后由医生判断矫治方案每个步骤的合理性,确定最终矫治方案,由虚拟牙齿正畸系统输出的数据制定患者隐形矫治器。然而目前虚拟牙齿正畸系统大多是国外引进的,价格较为昂贵,国内隐形矫治技术的相关研究还主要集中于可行性分析或者临床使用效果介绍,而有关牙齿正畸开发及研究相关工作的介绍很少。因此,对牙齿移动的路径规划方法设计及其可视化开发的研究具有重要的理论意义与实用价值。为实现满足正畸医生临床需求开发虚拟牙齿矫正系统的目的,本文从医学CT图像出发,以牙齿移动的路径规划方法设计及其可视化开发为研究重点,在综合考虑了“隐形矫治器”在临床使用上的需求、牙齿临床矫治位置确定、牙齿临床矫治控制可行性等基础上,基于C++语言与OpenGL操作平台数据库完成了牙齿移动的路径规划方法设计及其可视化开发。本文的主要工作如下：首先使用Mimics15.0对牙列CT数据进行三维重建及分割牙齿工作,利用阈值分割法及手动分割法获取每颗牙齿的STL文件,对OpenGL初始窗口建立进行参数设置,完成牙齿STL文件数据显示功能并实现牙齿平移旋转操作。利用OBB包围盒方法对本文的牙齿移动过程进行碰撞检测,确定了OBB包围盒的中心位置坐标、包围盒三轴方向以及包围盒三边边长三个构成OBB包围盒的重要变量。利用分离轴理论确定了牙齿的碰撞检测方法并利用C++语言及OpenGL操作平台实现了OBB包围盒的显示及两颗牙齿的碰撞检测功能。建立下牙颌所有牙齿的坐标系,分别对切牙、尖牙、磨牙提取数量不同的特征点。采用β函数以及已获取的相关牙齿的特征点来拟合牙弓曲线,得到β函数拟合理想牙弓曲线的显示结果。分别确定每颗牙齿从初始位置到理想位置的移动量和旋转量,从而确定患者牙齿的最终矫治理想位置。设计了牙齿矫治路径规划的整体思路流程,提出了单颗牙齿的排牙方法及牙齿矫治过程中的碰撞检测方法。对牙齿矫治过程发生碰撞的检测结果提出了碰撞处理方法,确定了牙齿矫治路径规划的终止条件。最终利用OpenGL操作平台得到牙齿矫治路径规划方法的可视化结果。
[Abstract]:Tooth movement path planning is an important step in the development of virtual tooth orthodontic system. According to the doctor's treatment plan and clinical requirement, according to the method of tooth movement path planning, the invisible appliance of each stage of patients was designed through virtual tooth orthodontic system, and the position of each step of each tooth was recorded, and the amount of movement and rotation was determined. Finally, the rationality of each step of the correction scheme is judged by the doctor, and the final correction scheme is determined, and the patient's invisible appliance is established by the data output from the virtual dental orthodontic system. However, most of the virtual tooth orthodontic systems are imported from abroad, and the price is relatively expensive. The related research of domestic invisible orthodontic technology is mainly focused on feasibility analysis or clinical application effect introduction. However, the development and research of dental orthodontics are seldom introduced. Therefore, the research on path planning and visual development of tooth movement has important theoretical significance and practical value. In order to meet the clinical needs of orthodontists and develop a virtual dental correction system, this paper focuses on the design and visualization of the path planning method of tooth movement based on medical CT images. On the basis of synthetically considering the need of clinical application of "invisible appliance", the determination of clinical orthodontic position of teeth, and the feasibility of clinical orthodontic control of teeth, etc. Based on C language and OpenGL database, the path planning method and visual development of tooth movement are completed. The main work of this paper is as follows: firstly, the Mimics15.0 is used to reconstruct and segment the dentition CT data, and the threshold segmentation method and manual segmentation method are used to obtain the STL files of each tooth, and the initial OpenGL window is set up. Complete tooth STL file data display function and achieve tooth translation rotation operation. The OBB bounding box method is used to detect the tooth movement in this paper. The central position coordinates of the OBB bounding box, the three axis directions of the bounding box and the length of the three sides of the bounding box are determined to be the important variables of the OBB bounding box. The method of tooth collision detection is determined by using the separation axis theory, and the display of OBB bounding box and the collision detection function of two teeth are realized by C language and OpenGL operating platform. The coordinates of all teeth in the lower teeth were established, and the number of characteristic points of incisors, canines and molars were extracted respectively. The curve of dental arch was fitted by 尾 function and the characteristic points of relevant teeth, and the display results of fitting ideal curve of dental arch with 尾 function were obtained. The movement and rotation of each tooth from the initial position to the ideal position were determined, respectively, so as to determine the ideal position for the final correction of the patient's teeth. The overall thinking flow of the path planning of tooth correction is designed, and the method of tooth arrangement and collision detection in the process of tooth correction is put forward. A collision processing method is proposed to detect the collision in the process of tooth correction, and the termination conditions for the path planning of tooth correction are determined. Finally, the visual results of dental correction path planning are obtained by using OpenGL operating platform.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R783.5

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