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.