Three Dimensional Finite Element Analysis Of The Stress Distribution In The Bone Interface Of The Platform-switching Implant

Objective: Dental implant technique is an ideal technique for the treatment of tooth loss.A satisfactory implant should have good biocompatibility and mechanical compatibility,and can directly contact with the human alveolar bone formation of bone formation,At home and abroad,the study of implant is mainly focused on the bone bonding interface,implant biomechanics and implant materials and surface technology,The platform switching implant is a new kind of implant design in recent years,because of its good stability has become a major direction of clinical research,however,there are few reports about the stress basic research of the implant,three dimensional finite element analysis(FEA)is the most commonly used method in recent years,In this study,the ANSYS finite element analysis software was used to analyze the interface between the implant and the implant bone interface,Through the comparison of different forms of implant bone interface stress distribution and the peak,the platform of common switching planting and implant body stress distribution of the bone interface,to provide the reference for the clinical design and selection of dental implants.Methods: According to the results of CT scanning of adult mandible,the three-dimensional model of mandible was established in ANSYS.Two different implant models were designed,and the geometric model of mandible implant was established,the model is imported into Ansys Workbench in sat format,which can display the whole and each part of the model in Ansys Workbench.All the materials in the material mechanics model are isotropic linear elastic assumption,The degree of freedom of the joints at the top of the condyle of both sides of the mandible was rigidly restrained to prevent the displacement of the mandible.The two kinds of materials in the model did not slide relatively under the load.On the surface of the implant,the uniform load of two kinds of loading conditions were applied to simulate the real stress of the implant:(1)The 100 N uniform load perpendicular to the upper surface of the implant(vertically downward from the occlusal surface).(2)And the axial angle of the implant is 30 degrees down,and the 100 N inclined uniformly distributed load from the buccal side to the lingual side.The application of finite element analysis software ANSYS 10 loading parameters input to the computer for each group was calculated by ANSYS10.0 software,the model after loading the three-dimensional stress image and node stress value,and to analyze the results,observed in the vertical load and inclined loading stress distribution and stress concentration.Resluts:1 The stress peak value of vertical loading implantPlatform switching implant: maximum stress value: 28.780 Mpa;minimum: 0.873 Mpa;difference of 27.907 Mpa.Non platform switching implant: maximum stress value: 44.804 Mpa;minimum: 0.885 Mpa;difference of 43.919 Mpa.The difference between the percentage of 63.54%(Fig.11).2 The stress peak value of inclined loading implantPlatform switching implant: maximum stress value: 105.63Mpa;minimum 1.000 Mpa;difference 104.63019 Mpa.Non platform switching implant: maximum stress value: 113.570Mpa;minimum: 0.391 Mpa;difference 113.179 Mpa.The difference between the percentage of 92.45(Fig.12).According to the loading direction of the inclined loading,the tongue side is compressed,and the buccal side is the tensile zone.It can be seen from the comparison of the lateral equivalent stress nephogram of the inclined load(Fig.17,18)that the equivalent stress level of the two implants under the condition of inclined load appears on the upper edge of the cortical bone,and is larger than the buccal side.The results show that the stress is mainly concentrated on the upper margin of the cortical bone under the condition of inclined loading.The inclined load can be divided into horizontal load and vertical load,so that the whole stress of the upper edge of the cortical bone is compressed under vertical load.As can be seen from the chart,the general control of the implant than the platform switching implant in the switching platform that is the neck of the teeth under greater pressure.3 The results of stress distribution of stress nephogram after loadingAs can be seen from the graph,the maximum equivalent stress of the normal control implant under vertical load and inclined load is larger than that of the platform switching implant.Compared with the normal control of implant implant in the longitudinal equivalent switching platform tilt load stress nephogram of tooth neck withstand greater stress,while the platform switching implant in tooth neck under stress is relatively small.The stress value can be seen in the vertical loading in normal control implant with platform switching implant by the peak stress in the implant,cortical bone and cancellous bone ratio were 155.67%,201.56% and 98.49%.The ratio of peak stress in implant,cortical bone and cancellous bone was 104.32%,230.84% and respectively in the control implant with the same platform.In addition to the fact that the stress of the implant is smaller than that of the normal control implant,it is suggested that the dental neck is the area of stress concentration.By contrast can be seen,in addition to the normal control of quality in the pine planting body with platform switching implant stress little difference in bone,especially in implant bone cortex,normal implants with platform switching implant are affected by stress difference,the stress of cortical bone in inclined loading under the stress of the biggest difference,but did not change the switching platform planting implant stress concentration region.Conclusion:1 Under different loading conditions,the stress peak value of the switching stress of the platform is smaller than that of the non platform switching stress,the stress distribution is more uniform,and it is more favorable to the formation of the bone formation and the location of the osseointegration.2 The stress concentration area of the implant was not changed by the platform switching planting,and the stress concentration area of the implant was still in the neck of the implant,but it decreased the stress peak of the implant.