Biomedical Engineering Reference
In-Depth Information
Fig. 9
Mandible CAD
Model with a TMJ implant in
left
condyle
The final model of the mandible was obtained with dedicated CAD software
(Solidworks, Dassault Systems). A solid homogeneous polymeric model was
considered which, due to the nature of the study, does not compromise the results
and discussion. Ichim et al. [
35
]andLiuetal.[
53
] concluded that the thickness of
the mandible cortical bone and cancellous bone does not have significant influence
on the strain distribution in the external surface. The polymeric model enabled us to
obtain the geometric model. However, we considered real cortical bone properties
for the FE simulations applied by other studies [
20
,
27
,
35
].
The CAD model of the implants was obtained based on an experimental implant
designed at the University of Bordeaux and is depicted in Fig.
9
. This implant has a
straight geometry and seven holes aligned for the screws. The diameter of the holes
is 2.1 mm.
3.2
FE Model
The next step is to discretize the CAD model into Finite elements; the FEM is
composed of 71,280 tetrahedral linear elements with four nodes and 51,245 degrees
of freedom (DOF) (Fig.
10
). The model we analyzed had teeth but other authors
conclude that these in fact have marginal influence on the biomechanics of the
mandible and particularly on the behavior of the condyles [
54
]. This hypothesis was
validated through experimental studies by Mesnard et al. [
27
] which also defined
the boundary conditions applied in FE simulations. For the convergence tests, the
maximal displacements and the maximal equivalent strains were assessed in the
