Finite Element Modeling for Orthodontic Biomechanical Simulation Based on Reverse Engineering: A Case Study

In order to improve the validity and feasibility of the solid model of oral tissue, a new method is provided based on reverse engineering. Biomechanical simulation with FEM is an important technique for orthodontic force analysis and evaluation, as well as treatment design. As the base of FEM simulation, the solid geometrical models of oral tissue including tooth, Periodontal Ligament (PDL) and alveolar bone are difficult to construct through conventional solid modeling methods because the oral models are very complicated in geometry and topology which are generally represented as triangular meshes. But in many cases, solid model is necessary for FEM performing. So how to construct the solid model of oral tissue with good quality and efficiency is a problem should be faced and solved in orthodontic biomechanical simulation. Aiming at this problem, reverse engineering modeling is adopt to transfer triangular meshes to four-sides surface model and together with techniques of medical image processing, three dimensional triangular meshes calculating, surface fitting and solid modeling, the solid geometrical model of oral cavity for FEM analysis is constructed from CT (computerized tomography) images. With a simulation case of rat molar movement test, the whole procedure of solid modeling based on reverse engineering and some main techniques are presented and the validity and feasibility are proved also by the simulation results.