An implant made from titanium is designed [5] to support the structural configuration of bone, making it less stiff that traditional implants. It also promotes ingrowth into surrounding bones.
Titanium alloy Ti6Al4V, was used by researchers at the Fraunhofer Institute for Manufacturing and Advanced Materials (IFAM) in Dresden, Germany. Scientists created the foam using a powder metallurgy-based molding process often used to create ceramic filters for aluminum casting. Open-cell polyurethane foams are saturated with a solution consisting of a binding medium and a fine titanium powder. The powder cleaves to the cellular structures of the foams. The polyurethane and binding agents are then vaporized. What remains is a semblance of the foam structures, which is then sintered.
The mechanical properties of titanium foams made this way closely approach those of the human bone, says Peter Quadbeck, a researcher at the institute and lead for the project. Such bone-like rigidity allows for stress forces to be transmitted. And, with the new formation of bone cells, it also fosters healing of the implant. Consequently, stress can and should be applied to the implant immediately after insertion.
In the TiFoam project, researchers concentrated on demonstrating the viability of titanium foam for replacement of defective vertebral bodies. The foam could also be suitable for repairing other severely stressed bones. In addition to the materials scientists from the Fraunhofer institutes IFAM and the Institute for Ceramic Technologies and Systems (Dresden), physicians from the medical center at the Technical University of Dresden and from several companies were involved in developing the foam. Project partner InnoTERE has announced that it will soon develop and manufacture TiFoam-based bone implants.