DICOM Data as a Basis for FEM Simulation in Dentistry - A Technical Review

The aim of the present study was to demonstrate a method of converting CT images into a computable finite element model.The program 3D Slicer was used to separate key areas from the DICOM data of a patient's CTs for the purpose of finite element analysis and then to segment them according to their grayscale values. The resulting digital image in STL format was processed in the program CATIA® to generate a model of a lower molar together with the periodontal ligament (PDL), the surrounding bone and an orthodontic attachment. Discretization was carried out by creating a nodal mesh from the surface models of the tooth, PDL, the bone and the orthodontic appliance. The result of the discretization process was a finite element mesh consisting of a total of 156 982 volume elements (voxels).Using the method described, a mandibular molar together with the PDL and the surrounding bone were isolated from a CT image and prepared for analysis of the initial tooth movement by means of the finite element method. Finally different load situation and orthodontic biomechanics can be simulated and compared.A numerical simulation of the initial tooth movement can be carried out on the basis of a CT image. By using this method it is possible to analyze and compare different load situations in order to achieve as uniform a pressure distribution as possible in the PDL and controlled initial tooth displacement. Finite element analysis of patient data could be used to determine the individual dosage of orthodontic forces.