I think this is an excellent point. I have had several crowns over the years and my dentist is very aware of proper color match. Is there a material applied to the crown or denture after modeling or is the color dependent upon the color of the 3-D material itself? At any rate, this seems to be an ideal application for 3-D printing and another example of technology being used to benefit mankind. I think it's great. Thank you Ann for posting this piece.
From my reading, dentists in China,Russia and other countries that don't have money to waste on gold seem to do just fine with non-precious alloys. (unless, I suppose, their patients routinely gargle with battery acid) It is true that pure nickel (alloy 200) will cause an allergic reaction in a small minority of people, but even for them, incorporating the nickel in alloys such as Inconel binds up the nickel so it apparently is not a problem. The amount of corrosion, while perhaps not "zero" is insignificant during a human lifetime. Remember that orthodontic braces are made of 300-series stainless which is far less corrosion resistant than the Inconel group yet they and don't dissolve in people's mouths. Saliva just ain't that nasty.
It is my understanding that a main attraction of gold is that the capital equipment to cast it into dental parts is quite cheap. Thus the dental lab gets off with minimal expense and passes the high cost of the metal on to the patient. One would hope that CNC technology would change that.
If you look at the galvanic table of metals, gold is way up near the top, stainless steel is below it. Stainless steel can be "passivated" to bring it closer to Gold, but passivation is a layer only a few atoms thick, one scratch and it will rust. The body has water and salt, condictive, just add two different metals and you get a battery, and one of them will corrode. Braces are "temporary" and removable for cleaning.
The Chinese put melamine in their infant formula to save money, I wouldn't use them as an example of healthy frugality. Every Russian I have ever met had a mouth full of gold crowns, so I'm not sure about that information.
If you want inexpensive but safe go ceramic(zirconium). Not galvanically active, nontoxic, easy to machine. The amount of gold in a crown is just a few grams, you couldn't fit an ounce in your mouth if you got all your teeth capped. Better to save money somewhere else and stay healthy.
I agree, Elizabeth. In many instances, the 3D printer seemed like a produict in search of a solution. Cool technology, but really, do we need one? The idea of smaller dentists using this makes a ton of sense.
I know what you mean, Rob. I personally don't see the excitement around 3D printing, but now that it's starting to be used for more useful purposes, I can see the draw. In my mind it seemed more like a hobbyist, self-indulgent thing--like a friend just told me he is going to provide files online so people could 3D print some of his company's designs at home for fun. But when the auto industry and now the dental industry is starting to use 3D printing as a way to make things cheaper and more efficient, it makes more sense, as you point out.
Hi, Ann- we haven't talked for a while; In the time gap I've learned about three new 3D processes I hadn't previously been aware of --- just FYI (,,,but I bet you already know these,,,)
1. MakerBot – Yes, I heard of them, but recently saw & handled their FDM parts and learned the apparatus is only $2,200 to own. It prints ABS in .004" layers [100 microns]. Fantastic capability at that price.
2. 3D-Touch - Also FDM, also runs ABS, also .004", but a little higher priced apparatus at $3,900. (So many similar features considered, I think Maker-Bot may have them beat).
3. EnvisionTec, based in Germany (and Detroit) makes a printer using a patented technology called voxilation (volume-pixilation). It seems to be a cross between FDM and Objet PolyJet printing with very fine Z-step resolution at .001" [25 microns]. While Objet has long had superior Z resolution (about half that much at 10 microns), the compelling point was the machine cost was advertised at $40,000, significantly lower than previous Objet prices. That is, until I read your article showing Objet now at $39,000. Wondering if EnvisionTec forced Objet to that price-point-?
Great question! I was wondering the same thing. Seems like that could be a greater cost than the "printing". Maybe that's why all of the analysts are bearish and assess Stratasys as a Sell right now? I wish someone had the answer to this question.
There is another area where 3D printing makes sense, Elizabeth -- prototypes. Design News has covered 3D applications related to prototypes. Plus, comments on the 3D printing stories indicate that 3D printing can actually save money as companies produce prototypes.
Optomec's third America Makes project for metal 3D printing teams the LENS process company with GE Aviation, Lockheed, and other big aerospace names to develop guidelines for repairing high-value flight-critical Air Force components.
A self-propelled robot developed by a team of researchers headed by MIT promises to detect leaks quickly and accurately in gas pipelines, eliminating the likelihood of dangerous explosions. The robot may also be useful in water and petroleum pipe leak detection.
Aerojet Rocketdyne has built and successfully hot-fire tested an entire 3D-printed rocket engine. In other news, NASA's 3D-printed rocket engine injectors survived tests generating a record 20,000 pounds of thrust. Some performed equally well or better than welded parts.
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