Finite Element Analysis of the Jaw-Teeth/Dental Implant System: A Note About Geometrical and Material Modeling

A critical comparison of several Finite Element models is presented, with reference to the analysis of the stress and strain states around a tooth or a fixed dental implant. Such an analysis, if performed on a full, three-dimensional geometry of the jaw-tooth/dental implant system, requires significant computational resources, and it is therefore often done on simplified models, whose validity can be questionable. On the other side, the use of simplified models is adequate — almost mandatory — when detailed results are needed, or when geometrical and material nonlinearities, as well as other complicating factors, are to be taken into account. The first issue addressed here is that of the correct boundary conditions to apply to simplified models in order to obtain results reasonably resembling those given by a full, three-dimensional numerical analysis. It is shown that several simplified models can give acceptable results in terms of stress distribution in the cortical bone, in the proximity of the studied tooth/implant, but that only the study of three-dimensional portions of the total jawtooth/implant system can lead to accurate enough results for stresses far from the tooth/implant or, in any case, in the trabecular bone. A second issue is that of the importance, on the stress state around a loaded tooth or fixed implant, of the presence of the surrounding teeth. It is shown that such a presence has a non-negligible influence, and that, therefore, simplified models describing isolated teeth or implants have only comparative value. Finally, some comments are given about the material properties definition, with special reference to the inclusion of the periodontal ligament into the Finite Element model. 1 Professor of Engineering Department of Nuclear Engineering, Politecnico di Milano Piazza Leonardo da Vinci, 32 — 20133 Milano, Italy 2 Professor of Engineering (Corresponding Author) Department of Civil Engineering, University of Brescia Via Branze, 38 — 25123 Brescia, Italy