| Computer Aided Design (CAD) is a new technology, which comes from the close combination of computer science, basic mathematics, data processing technique, computer graphics and the specialized knowledge, experience, and originality of designers. Scientists can apply this technology to get the best design promptly and perfectly on the way of man-machine dialogue. Expert system is an intelligent deductive system on the basis of the knowledge library, which involves the study on knowledge obtaining, knowledge library, deductive controlling mechanism and intelligent manipulating panel, and combines artificial intelligence with field knowledge. However, the present computer aided expert systems for designing Removed Partial Dentures are all explored on the basis of 2-D model of dentition defect, the results of which are plane images. Furthermore, limited by the established base, it is difficult for them to combine with computer technology of 3-D image, which is more and more perfect in recent years. As a result, there is no 3-D computer aided expert systems for designing Removed Partial Dentures reported. In this research, a kind of computerized 3-D model of dentition defect, vivid in shape and color, was set up firstly, which could imitate dentition defect. Then, on the basis of this model, we explored a 3-D computer aided expert system for designing Removed Partial Dentures.This study includes four parts as follows:Part I Computer aided 3-D reconstruction of dentition defectMaterials and methods: A series of cross-sectional images was acquired by scanning a skull specimen from coronal plane and sagittal plane with routine CT. Then, using the method of surface drawing, and on the basis of these data, a computerized 3-D model of dentition defect was established by creating through axes of teeth, modifying and putting materials and lights in 3D Studio Max.Results: A computerized 3-D model of dentition defect, including mandible and maxillary, was established. In computer, the 3-D model could imitate any classification of dentition defect promptly andaccurately, and be rotated, enlarged and shrunk in any direction. Conclusion: It is a new method to establish a computerized 3-D model of dentition defect. It made a foundation for the exploration of 3-D computer aided expert systems for designing dentures and the development of Computer Aided Instruction (CAI).Part II Establishing a 3-D model library of component parts ofRemoved Partial DenturesMaterials and methods: Firstly, according to the routine structure of Removed Partial Dentures, we carefully classified its component parts, and on the basis of designing needs for dentition defects of Kennedy I ~ IV, determined the number and drawing plan of all sorts of these component parts. At the second step, on the basis of the 3-D model of dentition defect, we made 3-D models of component parts of Removed Partial Dentures according to the determined drawing plan and gave name to them in 3D Studio Max. Finally, after changing these 3-D models into *.3DS files, the 3-D model library of component parts of Removed Partial Dentures was set up.Results: A 3-D model library of component parts of Removed Partial Dentures was set up.Conclusion: It is a new method to establish a 3-D model library of component parts of Removed Partial Dentures by using 3D Studio Max. The 3-D model library was retained a port for expanding and updating, and after being changed into other files, it could also be used for biomechanical analysis of denture component parts as fundamental figure parameters in prosthodontics.Part III Establishing a knowledge library of Removed PartialDenture designingMaterials and methods: After collecting lots of cases of Removed Partial Dentures and experience of experts, we summary some principles. Then, on the basis of these principles, we compiled the correspondingrelations between the diagnosis of dentition defect and denture designing, which would guide selecting component parts of Removed Partial Dentures from the 3-D model li... |
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