Abstract:

BACKGROUND: The construction of the three-dimensional denture model is always the core of the dental computer-aided design/computer-aided manufacture (CAD/CAM) systems; however, the precision and the efficiency of the three-dimensional model closely connected with the data reduction of the large amounts of original point data. The existing point cloud reduction technology cannot completely meet the special requirements of dental treatment.
OBJECTIVE: To efficiently reduce the original point cloud data for the dentures in order to achieve the best effect using the fewest points.
METHODS: The large amounts of original discrete point data were topologically reconstructed by the three-dimensional grid method and formed grids. The plane and quadric were fitted in each grid, and determined by chordal deviation method; grid points need to be retained. Then points in the larger curvature with their curvature and normal vector were retained by the octree subdivision method.
RESULTS AND CONCLUSION: The results showed that this algorithm is simple and efficient; the reduction algorithm method of point cloud is suitable for the scattered and disordered point cloud data were measured in reverse engineering. This method can directly and effectively reduce a large amount of intensive data, and can retain more details in the region of the larger curvature and contains more detailed features. It is indicated that the point cloud data for the dental prosthesis obtained by 3DSS-STD-Ⅱstructured light 3D scanner have the best effect of reduction at λ=0.7, ε=0.000 3 mm.