4d printing has been proved to be feasible now, and there is no practical technology at all. If someone puts it into business now, who will get it? Direct nobel prize, so it's just a bluff. It's good to use 3d printing as an auxiliary medical application. It is feasible to have this application on teeth now.
Tongchuang 3 d
"Focus on large-size 3d printing"
If in doubt, please ask.