A Novel Design Method of Gradient Porous Structure for Stabilized and Lightweight Mandibular Prosthesis

Abstract

Compared to conventional prostheses with homogenous structures, a stress-optimized functionally gradient prosthesis will better adapt to the host bone due to its mechanical and biological advantages. Therefore, this study aimed to investigate the damage resistance of four regular lattice scaffolds and proposed a new gradient algorithm for stabilized and lightweight mandibular prostheses. Scaffolds with four configurations (regular hexahedron, regular octahedron, rhombic dodecahedron, and body-centered cubic) having different porosities underwent finite element analysis to select an optimal unit cell. Meanwhile, a homogenization algorithm was used to control the maximum stress and increase the porosity of the scaffold by adjusting the strut diameters, thereby avoiding fatigue failure and material wastage. Additionally, the effectiveness of the algorithm was verified by compression tests. The results showed that the load transmission capacity of the scaffold was strongly correlated with both configuration and porosity. Scaffolds with regular hexahedron unit cells can withstand stronger loads at the same porosity. The optimized gradient scaffold showed higher porosity and lower maximum stress than the target stress value, and the compression tests also confirmed the simulation results. A mandibular prosthesis was established using a regular hexahedron unit cell, and the strut diameters were gradually changed according to the proposed algorithm and the simulation results. Compared with the initial homogeneous prosthesis, the optimized gradient prosthesis reduced the maximum stress by 24.48% and increased the porosity by 6.82%, providing a better solution for mandibular reconstruction.

Titanium Lattice Structures Produced via Additive Manufacturing for a Bone Scaffold: A Review

“…The results showed a strong correlation between lattice topology and load transmission capacity, while mechanical failure strongly depends on the strut size and configuration; moreover, the computational model results indicated that the optimized scaffold can provide an excellent mechanical environment for bone regeneration. Liu et al [ 130 ] compared conventional prostheses with homogeneous structures to stress-optimized functionally graded devices. They investigated, in silico, the damage resistance of four scaffolds and proposed a novel gradient algorithm for lightweight mandibular devices.…”

Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery

“…Altering the microstructure of the titanium also has implications for the success of the computation model. Through introductions of scaffolding such as tetrahedral or with varying pore and strut size, the models are more customizable [74,80]. These studies answer questions related to the success of changing the material properties of titanium to create more favourable models in relation to mastication and force distributions.…”

Developing Customized Lattice Structures Tailored to Mimic Closely Patients’ Bone Anisotropic Properties and Microarchitecture for Joint Reconstruction Applications

“…A press-fit implant is cementless and has porous features that allow biological fixation, which is important for young active patients. In a recent investigation [12], damage resistance of suggested four lattice structures (regular hexahedron, regular octahedron, rhombic dodecahedron, and body-centered cubic), was studied using gradient algorithm for stabilized and lightweight mandibular prostheses. The introduced algorithm was aided by finite element analysis to select an optimal lattice structure.…”