A new 3D contour extraction method for tooth cavity in a dental CAD/CAM system

In dental CAD/CAM system, tooth restoration produces customized tooth with a prepared cavity, while the prosthetic tooth fitting is firstly determined by the contour feature of the cavity, the cavity contour extraction of the tooth is one of the important issue. In order to accurately extract the cavity contour, a new Three-Dimension (3D) optimal path searching algorithm based on Intelligent Scissors theory is presented. In this algorithm, the 3D tooth is firstly formulated as a weighted model, by calculating the minimum weigh sum of the local cost from a start point to an end point in the cavity edge, the initial optimal contour can be acquired. Then through restricting the path searching range and searching direction, a desired contour can be extracted dynamically. The cases study results show that the algorithm produces a 3D mathematically piece-wise optimal contour on the cavity edge, which can be used directly for tooth design. This method simplifies the tooth design processes and increases the design efficiency.