A Primary Study Of Efficiently Establishing Personalized Maxillary Three-dimensional Finite Element Model Based On The CBCT

Objective:The author on the basis of CBCT data studies the impact of different material properties gradient distribution on the mechanical property of maxillary finite-element model to provide the scientific and reasonable attached material for maxillary model, effectively establishes the individual jaw bones 3D finite element model and offers the related theoretical basis for the future finite element research on edentulous jaw maxilla implant prosthesis design as well as exploring a way for the rapid and effective establishment of jaw bones 3D finite element model. Methods:The author conducts a rapid succession cone beam CT scan for a patient with maxillary toothless jaw(from calvarium to the bottom of chin) for the three-dimensional reconstruction of the upper jaw bone in Mimics. After processing by Geomagic software, import the generate body grid maxillary three-dimensional model in Abaqus software, and then return to Mimics adopt automatic assignment method with attached materials and distribute material properties according to 4, 6, 10, 50, 100 various gradient as the experimental groups M1, M2, M3, M4, M5 respectively, and regard the maxillary model M6 established by traditional manual assignment method as the control group. And last re-import Abaqus software to conduct finite element analysis in accordance with the same loading conditions.Validation : Establish three-dimensional finite element model of maxillary toothless jaw in 6 implant restorations of UG NX. The author gives rigid constraints to maxillary top region, and brings 100 N vertical static load to the cantilever beam end on both sides of the upper structure and conducts the finite element analysis on the maxillary model in both optimized modeling method and traditional modeling method by applying the finite element analysis software Abaqus for its implant restoration of different length of cantilever beam design to verify the validity of modeling for the optimized modeling program. Results:When exert the horizontal static load 400 N in the middle of maxilla, the peak values of maxillary models with 50 gradients and 100 gradients in the stress concentrated part are close with fine material distribution. In the same computer configuration requirements, the required time for establishing the finite element model for the same group maxilla C BCT data increases with the growing of gradient.The validation results show that the calculating results of using traditional method and preferred method are effective, the difference degrees of peak stress using traditional method is obviously greater than the preferred method. Conclusion:Material property divisions of finite element model should not be too much or too less, in terms of effectively establishing the individual jaw bones 3D finite element model, the division of 50 gradients can not only ensure the accuracy of calculation result but also improve the modeling and calculation speed relatively.Through the analysis results o f validation, for the same clinical outcomes finite element analysis, the calculation results variation of maxillary model established by 50 gradient CT value assigned material method are small, and the stress distribution is more uniform, the model quality is high.