Progress-of-civilization Dep’t

CAD-CAM comes to dental crowns.

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 [1] it leaves more of the tooth for future use than the traditional method and; [2] 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.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact:

11 thoughts on “Progress-of-civilization Dep’t”


    “In charting a better path for the economy, policy makers should remind themselves of two essential and oft-forgotten virtues,” Warsh said in today’s remarks. “Greater humility in the conduct of policy and stronger faith in the underlying resilience of the U.S. economy.”

    Perhaps Mark Kleiman is in dire need of greater humility. Last time I checked, you were not a doctor (or even a dentist). You are however, quite prone to believing that policy interventions are always necessary and have very little (if any) faith in the U.S. economy. Please stop talking about things you don’t understand, it’s pretentious.

    1. Gee…

      And here I was thinking this post was about the wonders of science and technology, and touches on the next big thing: 3D printing.
      That’s when just about every manufacturing job disappears.
      And not even cheap Chinese labor will be competitive…

      What will people do then?
      How will we distribute the wealth?
      Will we find a way to pay people to write agressive, ad hominem, off-topic blog comments?
      That’s probably not a good model to turn to. As in a few years Siri will be able to do that even better than Anonymous above…

      Maybe we will go the way of the Greeks:

      Yiannis Makridakis, 40, a Greek novelist whose work touches on themes of tradition and regionalism, represents a different strain of refugee, with a more political tinge. He said he moved from Athens to Chios in 2010 as an act of defiance against a global financial system he found unsustainable. He bought property with a well and grows his own vegetables. “I came to the conclusion that I want to live this insignificant life of mine as one human being among others,” Mr. Makridakis said on a sunny afternoon, looking down from his balcony on the rooftops of his village, Volissos, and the blue sea below. “According to the old ways, where people work to secure their basic needs.”

    2. Amazing! Hard to pack so much misunderstanding into so few words. First, note that the post didn’t propose any policy. Second, notice that I was quoting. As it happens, my correspondent has both an MD and an MPH, and does health care finance policy for a living.

      No wonder you choose to remain anonymous; if I were writing such drivel, I wouldn’t want my name on it, either.

      1. And perhaps one day you’ll explain to us your exuberant support of quantitative easing. Good luck quoting other people and trying to pass that off as some type of policy recommendation… some people actually look for evidence and try to do a cost/benefit analysis (which you’re also not very good at).

  2. About four years ago I had two dental crowns installed. Both were milled in-house by the dentist on his brand-new very expensive machine. He charged me his standard rate for the crowns. At the time, I questioned the whole notion of equipment ownership by the practitioner, but didn’t know what else to do. The first crown failed after a month. Its replacement and the second one failed within the first year. I now go to a different dentist, who uses a lab to manufacture the permanent crown. That way, if the crown is defective, I have a dentist on my side who wants the lab to fix the problem.

  3. 3D printers aren’t that expensive. I’m a little surprised this isn’t more common, it is an awesome idea.

  4. I have two crowns that were made in exactly the same way, over 5 years ago. Don’t exactly know what they are made of, but they haven’t given me a bit of trouble since. Nor were they particularly expensive. The dentist seems to be doing fine, too, by the way.

  5. I have had an old fashioned crown in for almost twenty years now. I’m not familiar with the issue, so I can’t really say how common that is. But I’m guessing the process is more flash than progress. How many crowns does an average dentist really do? Anyhow, it is interesting. 3D modeling is neato.

  6. The Swedish website Pirate Bay now posts ripped-off designs for 3D printers, opening a new front in the IP wars. H/t Slate.

  7. The crucial thing for dentists, from what I’ve read, is the time savings. When you make the metal one from a mold (of what sorta kinda used to be the exterior profile of the tooth maybe) the dentist spends an hour or more fiddling with the fit to all the surrounding teeth. With the 3d-milled version, much less, maybe more. At a couple hundred bucks an hour for direct patient time, that kinda adds up. As does the not paying a lab.

    And (assuming access to relatively cheap capital) such a machine doesn’t have to see that much use to be profitable. The per-hour operating costs are negligible compared to the value added, so (back of the envelope) figure a gain of $200-500 per crown, by a crown a week, and you have $10K-$25K of cash flow available to finance repayment. In a big shared practice where the rate is more like a few crowns a week or a crown a day, whee!

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