| Purpose The purpose of the present study is to use three-dimensional finite element analysis method, to assess what extent implant length and bone quality affect the stress distribution is transferred to bone around the implant; provide a reference and help for industry design and clinical choice of implant.Methods The models were established using finite element analysis software ANSYS14.0:(1)three-dimensional geometric model of two types of bone; particularly by giving the jaw bone of the relevant material properties, maintaining the same size in the two jaw bone models, but changing the thickness of the cortical bone and elastic modulus of cancellous bone, and then give two three-dimensional geometric models of the jaw bone. One of bone block model approximately type 2 bone, another bone block model approximately type 3-4 bone;(2) three-dimensional geometric model of three different lengths(6mm, 11 mm, 16mm) of the threaded implant on the basis of Astra Tech implant offered by DENTSPLY company. In the end, Build two groups of six experimental models:(1) three different lengths of implant in approximately type 2 bone model;(2) three different lengths of implants in approximately type 3-4 bone model. During the experiment, from the perspective of oral biomechanics, to assess the effect of implant length and bone quality on the interface between bone and implant stress magnitude and distribution, calculate and record of the maximum equivalent stress values of the interface between bone and implant for the various three-dimensional finite element model. Observed and compared the implant-bone interfacial stresses distribution in two bone models as the implant length changes.Results This study used APDL command statements of finite element analysis software ANSYS14.0 parameterized modeling method, simple and quick to obtain high precision three-dimensional finite element models. Including two models of bone and three models of different length and threaded with implants; and assembly to give six experimental models. Since the primary goal of this study was not to evaluate stress distribution at the implant-abutment or the abutment-prosthesis interface, the bone was modeled as one simplified cuboid, and the abutment with the crown restoration was omitted. The implants were modeled on Astra Tech implant on the basis of provided by DENTSPLY company, between the implant-bone interface are fully osseointegration, the implant and bone interface is no relative sliding, the bone and implant were presumed to be continuous, homogeneous and isotropic; and material deformation are small deformationRespectively six experimental models is applied to the vertical(with the long axis of the implant into the 0 °) the size of the concentrated load of 100 N in the finite element analysis software ANSYS14.0. In the vertical concentrated load of 100 N, in two bone models, there are some differences in stress distribution the implant between bone. The maximum equivalent stress between the implant-bone interface was decreased with the increase of the length of implants. At the approximate type 2 bone model, the maximum equivalent stress values more significantly decreases with the increase of the length of implants. In addition, the comparison of the two groups of bone model, the maximum equivalent strain in the jaw bone is a corresponding increase with the decrease of the elastic modulus of cancellous bone.Conclusions Implant length and bone quality can affect the interface between the implant and bone stress magnitude and distribution. Results of this study may provide some help to choice implant in clinical work of dentist. Meanwhile, the improved design of the implant also has a certain reference value. |
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