| In order to develop dental CAD/CAM system with independent intellectual property rights , this paper did a number of key technology research about dental CAD/CAM ,based on the results in the previous, the full text of which reads as follows:From the oral anatomy and physiology and CAD technology, the constrained relationship between teeth has been analyzed. Feature points of neighbor teeth have been considered as constrains. According to the characteristics of teeth themselves, suitable controlling structure has been established based on DFFD deformation method, and suitable deformation formulas have been deduced. Feature points of standard teeth have been moved to the constrained locations. Ordinary least Square has been employed to reverse motivation of controlling structure. The aim of constrained deformation has been reached by deformation formulas. An example of deformation has been offered.NURBS local deformation based on Cao En curves has been used to improve local deformation of dental crown. Controlling vectors have been regarded as normal vector of central points in deformation curves. Its influential area is the feature area of this point. In this method, amplitude of central deformation is the biggest in controlling area, where the border is of no deformation. In controlling area, the amplitude deduces smoothly. An example of transformation has been given.By comparison, the shape of teeth has been designed as root canal. The teeth have been restructured reversely. The limit element model has been established. With different length of this shape, stress in the teeth has been analyzed. The results show its advantages and disadvantages. Obviously there are many shortcomings of this method, and improvements are still needed.Finally, full induction and the future were put forward.
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