Research On Simulation And Optimization Method For Tooth Movement In Virtual Orthodontics

Path planning for tooth movement is a very important part in the virtual orthodontics treatment system. The method to design the path of tooth movement is a very complicated problem which not only guarantees a collision-free path with minimum traveling distance but also requires smoothness and clearance. Thus, an approach for the path planning based on the A* algorithm and iterative algorithm is proposed in the paper, by analyzing the technology of orthodontics and the merits and shortcomings of various path planning methods.Firstly, the characteristic and research situation of path planning for tooth movement at home and abroad is introduced. The research methods and the key technologies are summarized. By analyzing the advantages and defaults of the existing algorithms, a proper model for tooth movement path planning is built, which made an important basis for the research on path planning for tooth movement in the thesis.Secondly, based on comparing kinds of solving methods about path planning, the A* optimization algorithm is selected firstly in the path planning for tooth movement, and then combine with iterative algorithm to solve this path planning problem. On the one hand, the definition of path planning for tooth movement is introduced. The ? function is used to fit tooth's dental arch curve. Proper collision detection algorithm has been selected in the path planning for tooth movement by analyzing of various collision detection approaches. On the other hand, the basic principles of A* algorithm are introduced. According to the characteristic of path planning problem, every component of the algorithm is analyzed carefully including found the OPEN table and the CLOSED table, to get the collision points between each adjacent tooth in three dimension space and also the heuristic function is selected based on analysis carefully. At last, we use A* algorithm combined with iteration algorithm to solve this problem of the path planning on tooth movement. Finally, the results which obtained by the A* algorithm are divided into M stages which are assumed to be the initial data of iterative algorithm and then iterate these coordinates combined with some constraints. At last, the final path information on tooth movement is established based on the final iterative date. Finally, the visualization of the entire orthodontics treatment is realized according to those paths on tooth movement.