Finite element analysis of dental implant as orthodontic anchorage

The purpose of this three-dimensional (3D) finite element study was to investigate orthodontic loading simulation on a single endosseous implant and its surrounding osseous structure, to analyze the resultant stresses and to identify the changes in the bone adjacent to the implant following orthodontic loading. Two models were constructed using finite element method consisting of endosseous dental implant and the surrounding bone. In the first model, the contact between the implant and the bone was simulated showing no osseointegration, while the second model showed 100% osseointegration. Simulated horizontal loads of 20 N, at 90° from the long axis, were applied to the top of the implant. The study simulated loads in a horizontal direction, similar to a distalmesial orthodontic movement. In the first model, the stress was mainly concentrated at the neck of the implant and at the closest surrounding bone. In the second model, the stress was chiefly concentrated at the neck of the implant at the level of the cortical superficial bone. The stresses decreased in the cancellous bone area. On the implant, the highest stress concentration was at the first cervical thread decreasing uniformly to the apex. The stress distribution on the mesial and distal sides showed that the maximum compressive stress was localized mesially and the maximum tensile stress distally. If both models are compared, it can be observed that the stresses were less and more evenly distributed in model 1 (initial stability) than in model 2 when osseointegration was assumed. A lack of bony support for the implant represents an unfavorable situation from biomechanical point of view that should be considered and solved. As clinical problems mostly occur at the marginal bone region (bacterial plaque accumulation, overcontoured abutments, infections, osseous defects), attention should be focused on this region. When osseointegrated implants are primarily used as anchorage for orthodontic purposes and then as fixed prosthesis, the functional and structural union of titanium to bone should be preserved.