Haptic rendering for dental training system

Immersion and interaction are two key features of virtual reality systems, which are especially important for medical applications. Based on the requirement of motor skill training in dental surgery, haptic rendering method based on triangle model is investigated in this paper. Multi-rate haptic rendering architecture is proposed to solve the contradiction between fidelity and efficiency requirements. Realtime collision detection algorithm based on spatial partition and time coherence is utilized to enable fast contact determination. Proxy-based collision response algorithm is proposed to compute surface contact point. Cutting force model based on piecewise contact transition model is proposed for dental drilling simulation during tooth preparation. Velocity-driven levels of detail haptic rendering algorithm is proposed to maintain high update rate for complex scenes with a large number of triangles. Hapticvisual collocated dental training prototype is established using half-mirror solution. Typical dental operations have been realized including dental caries exploration, detection of boundary within dental cross-section plane, and dental drilling during tooth preparation. The haptic rendering method is a fundamental technology to improve immersion and interaction of virtual reality training systems, which is useful not only in dental training, but also in other surgical training systems. Supported by National Natural Science Foundation of China (Grant Nos. 60605027, 50575011), National High-Tech Research & Development Program of China (Grant No. 2007AA01Z310)