Abstract:

Abstract:Objective To analyze the stress state of magnetic attachment in mandibular complete overdenture supported by nature roots and implant,and to provide neference for designing of clinical prosthodentics.Methods Three-dimensional finite models (model,Ⅱ,Ⅲ) of three groups of mandibular overdentures depending on the different location of the implant and natural tooth root，placing three pairs of magnetic attachment,were constructed by application of CT scanning,computer photo processing system,and Solidworks　finite element model building   software.The natural teeth and implant neck bone stress of the models in three groups under different stress were calculated and compared.Results The stress of the bone around the implant in the area of molar teeth in model with both sides of the implants under oblique load (Model Ⅱ)  was significantly increased compared with the model with one side of the implant(Model Ⅲ).The supporting bone stress of oblique load was increased compared with the vertical load;among them under the oblique load at one side’s molar teeth,the stress of the bone around the implant in the area of molar teeth in modelⅠ,modelⅡ and model Ⅲ was increased about 30％,43%,and 55%.Conclusion When there only one nature teeth remain,two implants should be at least added,one in the area of opposite cuspid,and the other in the area of  molar teeth of the same side.The magnetic attachment is better than other kinds of attachment in preventing the damage of abutment when it suffers inclined load.

Key words: magnetic attachment, overdenture;finite element , model;stress analysis