Virtual bone drilling for dental implant surgery training

Mechanical removal of bone material is the most critical procedure during dental implant surgery because it can jeopardize patient safety in several ways such as damage in the mandibular canal and piercing of the maxillary sinus. With recognition of the effectiveness in virtual training, many simulators with haptic feedback have been proposed. Although there are many varieties in drill bits, most of previously developed simulators consider only a spherically shaped tool due to its simplicity in tool-bone interaction. In this paper, we propose a new simulation method that can handle any arbitrarily shaped tools with multiple contacts between the tool and the bone. The tool is represented by a signed-distance field, and the bone is represented as voxels surrounded by a point shell. Upon chipping away bone elements, the point shell is updated reflecting the deformation of bone in real-time, while the collision detection and the reflected force is efficiently and accurately computed from the distance field encoded in the tool. We also present the experimental results with 12 dental implantologists to evaluate realism of the proposed simulator.