Toward Stable and Realistic Haptic Interaction for Tooth Preparation Simulation

Abstract

In this paper, we present the methods to generate a stable and realistic simulator for dental surgery. First, a simplified force model is derived from grinding theory by considering the complex bur shape and dental handpiece’s dynamic behavior. While the force model can be evaluated very fast to fulfill the high update rate of haptic rendering, it also explains basic haptic sensation features in tooth preparation operation. Second, as direct rendering of this damping-like force model may induce instability of the haptic device, we apply a virtual coupling based method to guarantee the stability in haptic rendering. Furthermore, implicit integration of the bur’s motion equation is utilized to ensure numerical stability. Third, to overcome force discontinuity caused by locally removing tooth materials, we define a two-layer based representation for the bur, where the boundary voxels are adopted to compute forces and the interior voxels are employed to remove materials from teeth. The experimental results agree with the real sensation described by experienced dentists.