Abstract: Aiming at the problem of low efficiency of teeth arrangement by artificial teeth in virtual orthodontics treatment technology, this paper proposes an automatic alignment method for malocclusion based on fitting optimization. Firstly, we create a coordinate system for the input dental model, define single tooth feature points and establish the local coordinate system of teeth. On this basis, the position and posture of each tooth in the dentition is analyzed from a lower dimension. The weighted fitting optimization method is employed to calculate the coordinate translation and local axis rotation of tooth which forms the association constraints of the position, posture of teeth and the spatial dental curves. Then, combined with the collision detection method of rectangular bounding box, we design an iterative algorithm based on method of steepest descent to adjust the position and posture of teeth within the constraints of spatial dental curves. The experimental results show that the teeth alignment is similar to artificial alignment of teeth, and the alignment efficiency is highly improved. The proposed method is not only more like clinical orthodontics, but also reduces the total cost of teeth movement compared with the existing teeth alignment method.

Key words: virtual orthodontics, automatic teeth alignment, weighted fitting, optimization