Press "print" for body parts.

Rapid-prototyping machines are, in effect, three-dimensional printers. They build up layer upon layer of a plastic, ceramic or metal, either by squirting the material out of a nozzle in a controlled way or by melting successive layers of powders using a laser. Originally developed to help designers and engineers visualize their inventions before going to the trouble of actually building them, the machines have now become so sophisticated that it is possible to print devices with moving parts. Medical and dental specialists were quick to spot an opportunity. Rapid-prototyping machines have, for example, shortened the casting process for facial and cranial plates used in reconstructive surgery, says Robin Richards at the department of medical physics at University College, London. Terry Wohlers, an American rapid-prototyping expert, believes it is only a matter of time before such machines become common fixtures in hospitals, with doctors and surgeons using them almost as routinely as they currently use X-rays. Wilhelm Meiners and his colleagues at the Fraunhofer Institute for Laser Technology in Aachen, Germany, are one group working to extend the technology to print reconstructive facial plates and even load-bearing artificial joints, such as hips, which could be customized for each patient. Meanwhile, researchers at Advanced Ceramics Research in Tucson, Arizona, are developing rapid prototyping to create replacement bones, with funding from America's Office of Naval Research.