Titanium Foam Boasts Mechanical Properties of BoneTitanium Foam Boasts Mechanical Properties of Bone
September 14, 2010
A porous titanium foam encourages bone in-growth in implant applications. |
Scientists at the Fraunhofer Institute for Manufacturing and Advanced Materials (Dresden) have developed a titanium foam suited for use in orthopedic implants. Designed to resemble spongiosa found inside bone, the foam's structure fosters bone in-growth for more-secure connections and longer-lasting implants.
Despite having treated surfaces, in many cases, conventional titanium implants result in somewhat fragile bonds that often lead to implant loosening and subsequent revision surgery, according to the researchers. Featuring a matrix of pores and channels, in contrast, the titanium foam's structural configuration encourages, rather than impedes, cells and blood vessel growth through the material's porous passageways. By doing so, the foam's structure encourages bone in-growth and enables more-durable implants by way of forming stronger bonds with bone.
To create the foam structure, the scientists employed a powder metallurgy-based molding process. First, they saturated open-cell polyurethane (PU) foams with a solution containing a binding medium and a fine titanium powder. The powder then clings to the cellular structures of the PU foam; however, the PU and binding agents vaporize. Left behind is the metal powder-covered foam structure, which is ultimately sintered.
"The mechanical properties of titanium foams made this way closely approach those of the human bone," says Peter Quadbeck, who is coordinating the project. "This applies foremost to the balance between extreme durability and minimal rigidity."
So far, the TiFoam project has focused on the use of the material to replace defective vertebral bodies; however, the researchers believe that it can be used for other load-bearing implant applications as well.
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