Building individual 3D dental models for patients is critical for the accurate localization and quantitative evaluation of computer dental restoration. A novel 3D tooth reconstruction method based on level set active contour model is proposed for the characteristics of teeth morphologic change and permutation of oral CT image sequences. Different models are adopted for different parts of tooth slices in the mapping mechanism between layers. A single hybrid level set model combined with the prior shape constraint energy

the edge gradient energy based on flux model

and the local region energy based on prior intensity is used to segment tooth contour in dental root slices; while a double hybrid level set model combined with regional competitive restraint energy is used for dental crown slices. These segmented contours are then applied to reconstruct 3D dental models. After testing numerous CT tooth slices at different positions

the results demonstrate that the proposed method provides better segmentation outcome and higher percentage accuracy than existing methods. The mean similarity index can reach 96%. The proposed hybrid level set model can efficiently overcome the interference of pulp cavity and alveolar bone as well as the problem of uneven intensity. Furthermore

the method can create a relatively accurate reconstruction of the 3D models for each individual tooth

which can lay a solid foundation for dental restoration planning and biomechanical analysis.