Abstract: Objective: To establish a three-dimensional finite element model for physiological anchorage Spee-wire System appliance and analyze the stress. Methods: A Volunteer of individual normal occlusion was selected. The data of the person by CT scanning was imported into the software of Mimics l7.0, to obtain three dimensional model of teeth and jaw bone (cortical bone and cancellous bone) by three dimensional reconstruction method. The three dimensional model was put into reversely engineering software Geomagic studio through the format of STL and refined. The appliance of three-dimensional model was obtained by the design of NX software. Arch wire was defined as geometrically nonlinear. Teeth, jaws, appliance and wire model were imported into the NX software by the format of stp to assemble and meshed with ANSYS l5.0 software. Ultimately, a whole model of three dimensional finite element of the teeth, jaws, physiological anchorage Spee-wire System appliance and arch wire was built. Results: A whole model of three dimensional finite element of the teeth, jaws, physiological anchorage Spee-wire System appliance and arch wire was built. The situation of force and tooth movement in orthodontic clinic was simulated. Conclusion: The finite element model with physiological resistance controlling appliance was authentic, accurate and strong similarity of geometric, which could simulate distribution of stress and displacement trend in clinical and be conducive to the understanding application of the technology in clinic.

Key words: Physiological anchorage, Spee-wire system , The finite element analysis, Modeling