Stress Distribution Around Platform-switching Implants Studied By Three-dimensional Finite Element Analysis

The success and survival of the dental implant are highly dependent on the oral soft and hard tissue’s integration with the implant, It was observed that bone resorption was occurred around the neck of implant, which serious impact on the implant’s long-term stability and soft tissue esthetics. However,the mention of plateform switching concept break traditional views that the crestal bone inevitability absorped after implants restoration.There are many reasons that lead to the implant bone resorption, however the biomechanical factors is the main one. Platform switching can spread the stress of the neck bone, which can reduce bone resorption.Objective To understand the bone’s stress distribution around the platform switching implant, through the software of drawing and image analysis,to built the finite element model of two types of implant abutment connection, platform matching and platform switching,analyze the biomechanical characteristics of implants, while to compare the stresses around the implant after connection with different materials of the abutment, provide the basis for the clinical choose.Methods Use CATIA professional drawing software, build implant-supported three-dimensional model of maxillary first premolar, analysising the different stress distribution between platform-matching and platform-switching about abutments, central screw, cortical bone, cancellous bone.,the maximum stress distribution.with different materials crown around the implants.Results (1) Two models within the peri-implant bone tissue maximum von Mises stress in the vertical load, respectively11.74Mpa and14.54Mpa, oblique loading, respectively30.95Mpa and36.57Mpa, maximum stress are concentrated in the implant neck bone cortex, PS model with the model of PM implant,the abutment,the central screw, cancellous bone of the maximum von Mises stress values in the vertical load,respectively31.56Mpa and28.82Mpa,35.87Mpa an31.28Mpa,13.95Mpa and12.19Mpa,3.730Mpa and4.820Mpa,oblique loading, respectively277.1Mpa and219.4Mpa,313.6Mpa and286.7Mpa,171.2Mpa and119.2Mpa,4.116Mpa and3.910Mpa.(2) The stress distribution around various parts of implants of two models is similar, and concentrated in the cortical bone implant neck, Zirconia abutments compared with conventional titanium abutments, both the abutments and the peri-implant bone of the stress distribution is no significant difference.Conclusions (1)Platform-switching peri-implant bone tissue stresses decreases compare to the platform matching, but the abutment, the central screw, the implant stress increases.(2) stress various parts around the implants increased significantly in the oblique load conditions, particularly the abutment and peri-implant are obvious. It should minimize the size of oblique loading, so as not to stress too much the implant neck, leading to bone resorption or implant failure.(3) The stress cloud are similar between the titanium abutments and zirconia abutment, the stress distribution was less affected by the material of the abutment.Platform conversion using zirconium oxide abutments Zirconia crown after implant neck did not have too much stress, it is a ideal non-metallic materials of the implant upper structure,...