The Optimizing Dsigns And Mechanics Analyses Of Stresses Distribution For The Edentuous Mandibular Overdenture Which Be Retained By Three Different Attachments

Objective:To establish a three-dimensional finite element model of edentulous mandible, in this model four implants were inserted and telescopic crown and bar clasp and associated of telescopic crown and bar clasp were applied. The stress distribution on the cortical bone around the implants were analyzed and compared quantitively by the means of three-dimensional finite element, simulate the stresses distribution of mandibular implant overdentures that were supported by 4 implants and retained by different attachments; The applying designs of telescopic crown and bar clasp and associated of all the two were analyzed, thereby the optimum designs were determined concerning of telescopic crows and bar clasp, which providing determinate theory gist and practical applying reference for clinical implanting treatment of edentulous jaws patiens.Methods:The suitable edentulous mandible sample were scanned by advanced CT, and the DICOM database of edentulous mandible were built. The data of edentulous mandibular CT scanning images of which slice thickness was lmm were managed and analysed by the modeling software of CATIA. The finite element mandible models were buil by 3-D finite element software of ABAQUS. Moreover, four ITI implants (4.1×10mm) were inserted symmetrily into each model. These models were loaded with vertical and static loading to simulate the stress status of implant overdenture and simulated stress distribution on the cortical bone in peri-implants of the designs in which telescopic crown and bar clasp attachment were applied together. The stress distribution of each model were analyzed qualitatively and compared quantitively. Thereby the optimum designs were determined concerning of implant location and bar clasp connection.Results:Two models were established. according to experimental design the four implants distributed symmetricly in different position,1,3 tooth position and 2,4 tooth position. Mechanical loading test results show:the modelⅠand modelⅡaccurate noninvasive, by the formation of the data and graph, images can be duplicated, with good structural similarity. The stress loading plane can be simulated as the experimental design in the four implants top. The 4 implantswere connected as a whole by the planar structures, the elastic modulus of plane and the elastic modulus of denture underpinning is equal. And between the implants the corresponding constraints can be joined according to our experiment designed. The results show that:(1) edentulate chin chin hole area before use socket crown, pole card and two joint type adherent body overdenture, palatal implant surrounding the stress distributions is relatively balanced and reasonable. (2) There is no statistic differences between the two type of attachment in the front of the foramina mentale of the mandible.Conclusion:(1) The accurate and compact method for establishing the three dimensional finite element models of edentulous mandible with 4 implants can be provided by he applying of CT scanning and modeling software. The models can be applied to the correlative study of biomechanics (2)There is no statistic differences between the two type of attachment in the front of the foramina mentale of the mandible.