Burger
Journalpaper

A porous TiAl6V4 implant material for medical application

Abstract

Increased durability of permanent TiAl6V4 implants still remains a requirement for the patient’s well-being. One way to achieve a better bone-material connection is to enable bone “ingrowth” into the implant. Therefore, a new porous TiAl6V4 material was produced via Metal Injection Moulding (MIM). Specimens with four different porosities were produced using gas-atomised spherical TiAl6V4 with different powder particle diameters: namely “Small“ (<45 μm), “Medium” (45-63 μm), “Mix” (90% 125-180 μm + 10% < 45 μm), and “Large” (125-180 μm). Tensile tests, compression tests and resonant ultrasound spectroscopy (RUS) were used to analyse mechanical properties. These tests revealed an increasing Young’s-modulus with decreasing porosity, i.e., “Large” and “Mix” exhibit mechanical properties closer to bone than to bulk material. By applying X-ray tomography (3D volume) and optical metallographic methods (2D volume and dimensions) the pores were dissected. The pore analysis of the “Mix” and “Large” samples showed pore volumes between 29% and 34%, respectively, with pore diameters ranging up to 175 μm and even above 200 μm for “Large“. Material cytotoxicity on bone cell lines (SaOs-2 and MG-63) and primary cells (human bone derived cells, HBDC) was studied by MTT assays and highlighted an increasing viability with higher porosity.
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