Research On Mandibular Reconstruction And Bio-mechanics Analysis Based On Rapid Prototyping Technology

Mandibular defect reconstruction based on rapid prototyping technology and its force analysis is a synthesis subject, which integrates rapid prototyping, CT scanning and image pro cessing, finite element analysis and so on. It is an intersectional subject composed of mechanical engineering and biomedicine. The development of CT imaging processing and three dimensional reconstruction technology ensure accurate mandibular model with complex profile; meanwhile, rapid prototyping technology can manufact models of high accuracy according to three dimensional models, so as to assist surgical plan, shorten operation time, raise success rate. Thus, it has remarkable practical significance.Based on actual cases of mandibular defects, after the repairation of the mandible, finite element analysis is implemented to evaluate the mechanical properties of the mandibular reconstruction with defects, ensure the best reconstruction; and the solid RP model is manufacted eventually. The research work includes the following aspects:(1) Research on image processing methods is executed directly on DICOM files scanned from spiral CT, which uses CT image processing software-Mimics, to separate mandible by thresholding, region growing, masks editing, calculating and so on. Then, fibular STL files are imported into Mimics to fit with the mandible defect region, so as to achieve the reconstruction and optimization, thus the three dimensional model of reconstructed mandible is obtained.(2) Common methods on medical finite element modeling are discussed and analyzed, data format convertion methods between non-linear finite element software-Abaqus, STL repairation software-Magics and Mimics are researched, to establish the mandibular finite element model. STL files are repaired and triangle meshes are remeshed with Magics, triangular meshes are converted into tetrahedral meshes by Abaqus, anisotropy materials are conferred by calculating CT values in Mimics.(3) Finite element pre-processing, such as boundary conditions, load and so on, are analyzed, and force analysis is carried out later, to test the structural rationality and mechanical properties of the reconstruction, and offer appropriate advice and reference for mandibular reconstruction.(4) Relavant parameters of experimental three-dimensional printing machine(3DP) are researched; the rapid prototyping technological parameters of model positioning and slices are analyzed concentratly, and their influence on material costs, processing time and prototyping precision is compared; then, the RP model is manufacted, and titanium plate used for surgical planning is shaped according to the model.