Porous Titanium Alloy Constructs for Mandibular Reconstruction
Abstract
The goal of this study was to develop and validate finite element analysis (FEA) models to predict static and dynamic mechanical properties of porous titanium 6-aluminum 4-vanadium (Ti6Al4V) constructs. Dumbbell-shaped and square prism porous computer models were created with simple cubic unit cell structures with a size of 1 mm and strut thicknesses varying between 250 and 650 µm. The pore diameters ranged between 350 and 750 µm. Constructs were manufactured using selective laser melting (SLM). These constructs were scanned using computed tomography (CT) and scanning electron microscopy (SEM). These constructs were then tested under tensile and flexural static loading using a screw-type universal testing machine and under dynamic flexural loading using a servo-hydraulic testing machine. The FEA models were designed with mechanical properties calibrated to mimic those of the real-life constructs and omit the structural imperfections. The models’ predictions were compared to the real-life mechanical testing results. A novel intraosseous porous implant was designed with numerical models to assess the mechanical properties of the implant under physiological loading conditions. The strength and modulus predictions of the FEA models matched those of the SLM-built constructs within a deviation of < 11 %, while the deviation of the fatigue strength from the numerical models was ≈ 10%. The larger deviations in the toughness predictions of the computer models from the real-life tests were associated with the diminished plastic strain of the SLM-built constructs, which the structural imperfections of the SLM-built constructs might have caused. In addition, SLM-built Ti6Al4V porous constructs with strut thicknesses ranging between 350 and 450 µm were viable for use in the intraosseous mandibular implant design. The implant was intact when exposed to physiological molar clenching. When the implant was exposed to cyclic masticatory forces ranging between 50 and 100 N, its predicted life expectancy was between 4 years at 100 N and 119 years at 50 N, exceeding the time for healthy bone ingrowth to osseointegrate and stabilize within the constructs. The FEA models can swiftly and accurately predict the static and dynamic mechanical properties of SLM-built constructs within a short period, making them suitable for use in clinical settings.