Modeling of the occlusal surface of teeth is an important problem in computer-aided design of dental restorations. The designed shape must fit the existing jaw articulation. Also, the design process must be fast to be practical in clinical applications. In this paper we present techniques for automatic adjustment of the occlusal surface of restorations based on the results of articulation simulation. The shape of restorations is changed to avoid interpenetrations with the opponent teeth during functional jaw movements. The 3-D space mapping method is used which guarantees the surface smoothness and preservation of the main topological features of the occlusal surface. To speedup calculations we use rasterizing graphics hardware for computationally involved collision detection between complex surfaces of teeth.