Research On Discrete Modeling Technology Of Personalized Tooth Preparation Guide

With the promotion and application of digital technology in the field of prosthodontics,the clinical tooth preparation model begins to change from the traditional manual mode to the auxiliary device mode gradually.With the digital device of tooth preparation guide,it can not only improve the accuracy of tooth preparation,but also can increase the efficiency of surgery significantly,which will become the mainstream treatment manner in future certainly.According to the clinical application characteristics of the tooth preparation guide,the key modeling technology of guide is studied.The main contents and results are as follows:(1)In order to obtain gingival line from the tooth model,an adaptive feature line extraction algorithm based on curvature information is proposed.Based on the curvature feature information,the feature points are got,and the search radius is dynamically determined by the correlation coefficient of the mathematical statistics.The feature points are detected by the method of the main direction of the principal component adaptively.Then,the feature points are fitted by Spline curve,and the closed smooth gingival line is obtained.(2)To build the support of guide,a method of sweep modeling based on transition section is proposed.The cross section is inserted at each node of the sweep path curve,and the contour curve on each section is obtained by projection,so the sweep-surface is formed.Then,the closed swept volume is built by inserting random points and Delaunay triangulation method.(3)The discrete parametric modeling technology of the mesh model of the pinacoidal rail is studied.First,the dimension constraints of the pinacoidal rail are determined by analyzing the relationship between the dental bur and the tooth preparation.Then,the model of pinacoidal rail is constructed,and it can be dynamic updated by parameters.On the basis of the above research results,the design module of the personalized tooth preparation guide is developed with VS 2008 and OpenGL.And the effectiveness and stability of the system are verified by an example.