Page 158 - IJB-8-1

Design Criteria for Patient-Specific Mandibular Implant
Table 5. Solid and FE models of mandibular defect restored with C, B, and A+B reconstructed implants and corresponding bone grafts and
dental implants.
Segment Solid model FE mesh model

C

B

A+B

Corresponding percentage of axial/lateral occlusal forces and boundary condition was shown in the solid model column. FE: Finite element

All materials included cortical, cancellous bones, bone Table 6. Elastic modulus and Poisson’s ratios of all materials
graft, reconstruction implant/screws, and dental implants simulated using finite element analysis.
defined with linear elastic and isotropic properties and Material Elastic Poisson’s Reference
adopted from the relevant literature (Table 6). modulus ratio
Weighted topology optimization was performed for Cortical bone 13,700 MPa 0.30 [3,10,11,17]
structures to define lightweight and structural strengthening Cancellous bone 1370 MPa 0.30
characteristics for the B/C/A+B reconstructed implant . Reconstructed 110 GPa 0.35
[11]
The reconstructed implant core considered the scoping implant and
region for optimizing the process topology with stress fixation screw
constraints to find the objective function for minimizing (Ti6Al4V)
the core volume. Two load conditions (100 N) were Bone graft 13,700 0.3
defined as uniform multiple axial and oblique (45° MPa
incline to the tooth axis from buccal to lingual) contacts Dental implant 110 GPa 0.35
on the teeth according to different segments applied on
the three models to evaluate the mechanical responses.
We assumed 70% of the C segment would be subjected axial bite force was heavier than the lateral force in the
to oblique occlusal forces and 30% would be subjected posterior region [11,19,20] (Table 5). Nodes on the condyle
to axial occlusal forces due to the chewing situation were constrained in all directions in all models to prevent
in the anterior region having more emphasis on lateral movement as the boundary conditions to perform the
force. On the contrary, 40% of the B and A+B segments weighted topology optimization (Table 5). The final
[9]
would be subjected to oblique occlusal forces and 60% weighted topology optimization result summed up the
would be subjected to axial occlusal forces because the compliance of each model for all load cases. Each of these

144 International Journal of Bioprinting (2022)–Volume 8, Issue 1