3D Orthodontic Treatment Simulation with Tooth Segmentation and Alignment

This paper presents the development of three-dimensional computer aided orthodontic software using Borland C++ Builder® and OpenGL with the purpose of creating the 3D orthodontic treatment simulation. The method consists of 4 main steps as follows: the dental cast produced by 3D scanner (CT scanner has been used in this paper) in STL format was transformed from unindexed data to an indexed data and taken as input in the first step. The cast model can be displayed in various views while user can move the model to any directions as required. Second step is to segment the teeth by locating landmarks on tooth surface and fit the landmark positions with cubic spline technique along with searching the nearest triangle of the model at each spline vertices. After that, the 3D region growing technique is applied to separate specific tooth area from the dental cast. Third step is to rearrange the segmented teeth to align with standard arch form curves using translation and rotation tool developed to let the user interaction with ease. Finally, the 3D bracket models were designed and registered to fit and lie along the surface of alignment teeth. The result has shown that the 3D orthodontic treatment simulation can be applied as a guideline of treatment preview for the patients. It is also a training tool for orthodontists, residents and students to enhance the experience through simulation before taking actual orthodontic planning.