Using Reverse Engineering Technique To Reconstructs The Three-Dimensional Finite Element Model Of Dentulous Mandible With Fixed Appliance

Objective: To explore the method of use the reverse engineering technique to reconstructs the three-dimensional finite element model of dentulous mandible, which contain fixed appliance.Materials and method: Seclect a skull specimen of a young man, which conserved all dentulous.The occluding relation is ClassⅠand arcus dentalis form is symmetry. Spiral CT was used to scan the skull specimen, scan condition is 140kV, 400mA, 1500mS, the horizontal distinguish is 1024×1024。Scan plan is vertical of the labial surface, scan thickness is 0.85 mm. 127 pictures was procured, and out put with Dicom files.Input Dicom files to the Mimics 8.1 software, select suitable threshold of CT value to reverse the model of teeth and mandible. Out put the model to cloud point files.Then input the cloud point files to reverse engineering software Catia. The model can be identified by the FEA(Finite Element Method) software was accomplished. The teeth model is reverse to S1. The mandibula model si reverse to S2.Use the scan plan as the bracket base plan (P1). Make the bracket on the bracket undersurface plan (P2). The wideness of the bracket slot is 2.5mm on the incisor, 3.2mm on the premolar, 4mm on the molar. The height of bracket slot is 0.56mm (0.022 inch). The depth of bracket slot is 0.711mm (0.028 inch). The bracket undersurface sickness is 0.5mm.Make the arch wire model as the stander specification. ( 0.016inch×0.022inch,0.017inch×0.022inch……)At last the models of teeth, bracket and the mandibula were inputted tothe FEA software Abqus 8.0, and the three-dimensional meshes were created respectively.Results: The fine 3D FEA model of teeth, brackets and the mandibula were constructed successfully. After 3D meshing, the model has 234058 nodes and 1136506 elements. The arch wires and brackets'models has 36506 nodes and 17838 elements.