Influence of Implants Diameter on Bone Stress Distribution of Tooth-implant Supported Fixed Partial Denture

Objective: The aim of this study was to analyze stress distribution in the bone of tooth-implant supported fixed partial denture(FPD) with different implant diameters by using a three-dimensional finite element method.Methods: A volunteer was chosen to have a CT scan,and then the DICOM data was processed by the softwares of Mimics,Imageware and ANSYS respectively.The three-dimensional finite element mode of fixed partial denture,which was supported by the second premolar and the second molar or an implant of different diameters(3.5,4.3,5.0,6.0 mm),was constructed in the left mandible.The values of von Mises stress of bone were obtained,when FPD was loaded with vertical or 45° buccolingual force of 200 N.Results: The values of von Mises stress on bone around tooth/implant and abutment were obtained when the fixed partial dentures were loaded with vertical or 45° buccal-lingual oblique force of 200 N respectively.The values of von Mises stress on bone around the second premolar neck varied indistinctively when the fixed partial dentures were loaded with the same force.In different diameter implant-tooth supported fixed partial denture,the von Mises stress of implant neck and abutment decreased obviously when implant diameter increased from 3.5 mm to 4.3 mm,but showed a slow downtrend as the implant diameter continue increasing.Conclusion: With the increase of implant diameter,the values of von Mises stress on bone around implants and abutment decreased,but that of the nature teeth changed little.Under oblique load,the values of von Mises stress on bone around tooth/implant and abutment increased significantly,which might contribute to the failure of FPD.