DENTAL OCCLUSION DETERMINATION WITH 3DOF HAPTIC RENDERING by CEN YU HAI Thesis Supervisor: Dr. Wu Wen Medical simulation has become more and more popular since the rapid development of hardware as well as software in computer science. On the other hand, medical simulation has much less risk and cost compared to the traditional surgical training. It is important to provide the conductor an efficient interaction to simulate the experience in reality. In this thesis, we proposed a novel method to calculate the feedback force during the multiple collisions in the interaction process. The impulsive, contact and friction forces are obtained from each collision respectively base on an impulse-based physical model. They were combined to a stable and continuous force output to provide a realistic experience to the user. We implemented a dental occlusion searching system according to this impulse-based method to simulate the procedure of determining the optimal dental occlusion with the help of the three dimensional (3D) graphics display as well as the force feedback. To validate the simulation system, we did a user testing. An accuracy evaluation has also been done to compare the occlusion results of the novices and the orthodontic dentist. iv