Automatic mesh fusion for dental crowns and roots in a computer-aided orthodontics system

In computer-aided orthodontics systems, an essential task is to present tooth models. Model data may come from different sources. A laser scanner can generate a relatively fine mesh of the dental crown, while a CBCT (cone beam computerized tomography) scanner can generate a mesh complete but coarser. To combine both advantages, it is natural to consider fusing the fine crown with the coarser but complete root. Since data sources are different, the sizes and vertex densities of the two kinds of meshes don´t match well. This paper presents an automatic method to address these problems and fuse the fine crowns with the coarse roots. First, the root part of the CBCT generated mesh is extracted according to the laser scanned crown mesh. Then, the two parts are connected via a Bezier surface. The mesh of the transitional part is constructed by triangulating sampling points over the Bezier surface, and subsequently faired using the mean curvature flow method. The proposed method can generate meshes with a fine crown and a complete root, which will facilitate the subsequent orthodontics planning process.