Three-Dimensional Finite Element Analysis of Osseointegrated Implants Placed in Bone of Different Densities With Cemented Fixed Prosthetic Restoration
A key factor for a successful dental implant is the manner in which stresses are transferred to the surrounding bone. Strength of bone is directly related to its density. Maximum stresses are reported to be incurred by the crestal cortical bone surrounding the implant. Displacement of implants is significantly higher in soft cancellous bone than dense bone. Implants are often placed in bone of different densities to support fixed dental prostheses. This study was aimed at assessing stress and deformation generated by osseointegrated implants placed in bone of different densities on a cemented fixed prosthesis when subjected to static and dynamic loading. A 3-dimensional finite element analysis was done on a computer-aided design model simulating maxillary bone segment with 2 different bone densities (D2 and D4). The effect of loading was evaluated at the implant–bone interface, implant–abutment interface, abutment, implant abutment connecting screw, cementing medium, and fixed prosthesis. Stresses were calculated using von Mises criteria calibrated in megapascals and deformation in millimeters. These were represented in color-coded maps from blue to red (showing minimum to maximum stress/deformation), depicted as contour lines with different colors connecting stress/deformation points. The study found greater von Mises stress in D2 than D4 bone, and in D2 bone the component with higher stress was the implant. Deformation was greater in D4 than D2 bone, and in D4 bone the abutment-prosthesis interface showed more deformation.
Microcomputerized tomography scanned images (implant [a], abutment [b], connecting screw [c]).
Meshed model.
Mesh convergence depicting the accuracy of the model—increase in nodes and elements—the finer the mesh.
Loading condition/application.
Figures 5 and 6. von Mises equivalent stress (mpa) and deformation (mL) in implant under dynamic loading. Figures 7 and 8. von Mises equivalent stress and deformation in implant under static loading. Figures 9 and 10. von Mises equivalent stress and deformation at implant–bone interface under dynamic loading. Figures 11 and 12. von Mises equivalent stress and deformation in implant–bone interface under static loading.
Figures 13 and 14. von Mises equivalent stress (mpa) and deformation (mL) in abutment under dynamic loading. Figures 15 and 16. von Mises equivalent stress and deformation in abutment under static loading. Figures 17 and 18. von Mises equivalent stress and deformation in implant–abutment connecting screw under dynamic loading. Figures 19 and 20. von Mises equivalent stress and deformation in implant–abutment connecting screw under static loading.
Figures 21 and 22. von Mises equivalent stress and deformation in cementing medium under dynamic loading. Figures 23 and 24. von Mises equivalent stress and deformation (in millimeters) in cementing medium under static loading. Figures 25 and 26. von Mises equivalent stress and deformation in abutment–prosthesis interface under dynamic loading.
Figures 27 and 28. von Mises equivalent stress and deformation in abutment prosthesis interface under static loading. Figures 29 and 30. von Mises equivalent stress and deformation in entire unit under dynamic loading. Figures 31 and 32. von Mises equivalent stress and deformation in entire unit under static loading.
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