In making both orthopedic and dental implants, the weight-bearing strength of the material is crucial-it ought not be weaker or stronger than bone. Obviously, weaker material will break, but stronger material will take over the load carrying function and surrounding bone cells will die.  That’s why implants and artificial joints tend to loosen over time. To address this, researchers at North Carolina State University have developed a “metal foam” that has about the same elasticity as bone.  It’s made of steel or a composite of steel and aluminum.  MORE