Development of Display System of Individual Mandibular Movement Based on the CT Data

本研究的目的是定量掌握患者下颌运动的情况，并从中找出有用的信息，为咀嚼疾病的诊断和治疗提供依据。通常需要手术侵入来检查髁突周围的下颌骨状况，这给患者带来了很大的身体负担。本研究开发了一种新的系统来呈现人体下颌骨在完整状态下的三维运动。显示系统的基本原理是根据下颌运动数据绘制出患者的下颌模型。利用患者的X线CT数据，通过有限元自动建模方法建立下颌骨和上颌骨模型。模型的唯一表面数据用于绘制图像。我们成功地开发了三维显示系统，它提供了三维动画图像的下颌运动从一个任意方向上的个人计算机上。为提高显示效果，采用OpenGL图形库。本研究还检查了一个有效的指标，明确显示咀嚼疾病。利用多人测量数据，计算了下颌骨髁状突（下颌头）两侧的运动速度分布。速度剖面图清晰显示了下颌骨病变的状态。

The purpose of this research is to grasp quantitative mandibular movement of a patient and find out useful information in the movement for diagnosis and medical treatment of masticatory diseases. It usually requires operative invasion to examine mandibular conditions around condyles, which gives a lot of physical burden to the patient. This study developed a new system to present three-dimensional movement of the human mandible in intact states. The basic principle of the display system is to draw the patient's mandibular model according to the data of mandibular movement. The mandibular and maxillary models were made by an automated modeling method of FEM using the patient's X-ray CT data. The only surface data of the models were used for drawing the images. We successfully developed the three-dimensional display system which presents animated images of three-dimensional mandibular movement from an arbitrary direction on a personal computer. To improve the display performance, OpenGL was applied. This study also examined a valid indicator which clearly showed masticatory diseases. Velocity profiles of the mandibular movement at both sides of condyles (mandibular heads) were computed using several persons' data. The velocity profiles clearly showed the states of mandibular diseases.