Processing, characterization and biological testing of porous titanium obtained by space-holder technique

The high Young’s modulus of titanium with respect to that one of the bone is the main cause of the stress-shielding phenomenon, which promotes bone resorption around implants. Development of implants with a low Young’s modulus has gained increased importance during the last decade, and the manufacturing of porous titanium is one of the routes to reduce this problem. In this work, porous samples of commercially pure titanium grade IV obtained by powder metallurgy with ammonium bicarbonate (NH4HCO3) as space-holder were studied. Evaluations of porosity and mechanical properties were used to determine the influence of compaction pressure for a fixed NH4HCO3 content. Measurements by ultrasound tests gave Young’s modulus results that were low enough to reduce stress shielding, whilst retaining suitable mechanical strength. Biological tests on porous cp Ti showed good adhesion of osteoblasts inside the pores, which is an indicator of potential improvement of osteointegration.