This report from NewScientist (8 October 2016) is interesting:
… an ink has been developed that can be used to 3D print bone implants in any size, shape and form – from leg bones to entire skulls. And because the implants are flexible, they can be cut into the perfect shape in the operating theatre.
The ink is made from hydroxyapatite, a mineral found naturally in bone, and PLGA, a polymer that binds the mineral particles together and gives the implants their elasticity. …
Once in place, the implants are rapidly infiltrated by blood vessels and gradually turn into natural bone (Science Translational Medicine, doi.org/bq8r). This offers a cheap and versatile way to repair an injury.
Turns into bone? Wow. I wonder what limitations there might be. Could they print a middle ear and have it work?