Invisalign and 3D Printing | Hacker News Reader

Invisalign and 3D Printing

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17 pointsandrewbryk14 comments

I am on aligner 11/15, so I am almost done with Invisalign. And before anyone thinks they can do this at home, there are two points to consider. Invisalign needs attachments to help move your teeth along. Just this Monday, my dentist had to redo the attachment on #10. Also, if your teeth need a little more room, your dentist will sand your teeth down as well. Attachments are temporary, but sanding your teeth down is permanent!

The article glosses over that Invisalign already uses 3D printers! Thousands of jaws have been 3D printed as part of the Invisalign manufacturing process. The clear brace is molded on the 3D printed jaw.

I suspect that's true. I recently had invisalign and when I lost one they got one printed locally. the material was thicker and less precise than the original.

also, of interest, my dentist said they couldn't number the trays 1,2,3,4... because that was patented. the numbers were like 1a, 1b, 2a, 2b.

I recently discovered that the technology has developed to the extent that I can inexpensively purchase the materials needed for a variety of useful items to self-assemble in my backyard.

Despite the ability to grow peppers and cucumbers myself, I still buy them at the store because it is only worthwhile as an entertaining hobby and practitioners skilled in the art can produce the same items more efficiently.

It's interesting how much micro fabrication technology has infiltrated the dentists' offices. When I needed a couple of crowns a few years back, my dentist was able to make my permanent ones on the spot (while I waited). He used a hand-held 3d scanner and then a small CNC mill machined out the pieces. I'd presume other components will quickly move that way as well.

Interesting, my dentist sends the permanent crown out to a lab who apparently guarantees fit based off the mold impressions. The turn around time is about 2-3 weeks. For those of you fortunate enough to not have any crowns, a temporary crown created while in the dentist chair is worn in the interim. A temporary crown takes about 15-30 minutes to make.

I bet out sourcing that allows him to see more patients. I wonder what the economics look like between the two options on the dentist's end.

He previously out-sourced the work, in the traditional way (I'm unfortunate to have 12 crowns done by him). This is much, much better - the machining took 30 minutes, and he worked on other patients in the mean-time. He indicated his profit margins per crown were higher, while the price to me was lower. As I was heading out to Europe the next week, having permanent crowns made my life much more enjoyable. =)

I think the big drawback was that he had to pay for the machines and software - he indicated that he would have them paid off in a year or two.

The handheld scanner and mill are key. My dentist and I also spoke about 3D printing, and he said you need 50 micron resolution or better, which 3D scanning and milling can do, but not 3D printing. You want the best fit possible, otherwise the piece will fail.

Yeah, I don't think low-cost 3D printing is yet where it needs to be for this purpose - but PLA definitely is the wrong choice. I wonder if the sinterized metal/ceramic printers have higher resolution. (Admittedly, I have little knowledge of this class of printer. And, generally, I still prefer subtractive machining for precision parts.)

"So far the only physical thing created is the models by the orthodontist."

Actually at this point, the dentist can take the models entirely digitally. My dentist did this a few months ago with a new scanning machine. There was nothing physical sent.

3D printers are not accurate enough at this time to print such a detailed object. I am printing a large project with many interlocking pieces. The prints are always slightly too large due to the bulge of the deposited plastic as it cools. You can compensate by making the piece slightly smaller, but it is never a perfect fit. In addition, the smallest layer right now is .1 mm, which is not detailed enough for a tooth mold. For a tooth mold, I would want it perfect.

Which is why the article says "in the next five years"

I thought this would be a "look at me I made my own Invisalign trays!" post; I had no idea the process took this long.

I think 3d printing has some way to go before this is possible. A 3d printed denture would not have the material properties required to align teeth and maintain integrity in a human mouth.

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