A friend, whose professional interests are in health services delivery and finance, writes:
Over the last several decades, I’ve had four dental crowns. In each case, the dentist put in a temporary, a distant laboratory turned the mold into a metal cap, and I returned for its later installation.
This week, I underwent a CAD-CAM process. A fiber optic probe takes photos of the stump until a 3-D picture of the site stabilizes. The computer designs the prosthesis. A milling machine cuts it out of a block of “resin” (looks like plastic to me), just like a lens grinding machine. The dentist installed this permanent cap before the novocaine wore off.
Looking up the technology afterwards, I read that  it leaves more of the tooth for future use than the traditional method and;  under excessive pressure, the resin is designed to break instead of the remaining tooth. Both developments lengthen the useful lifespan of the stump, a good thing. However, I’m nervous about the doctor’s recommendations when he has an expensive piece of equipment to pay off. The physicians have struggled with the equipment ownership issue without success.