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I made my own clear plastic tooth aligners and they worked (amosdudley.com)
943 points by dezork on March 13, 2016 | hide | past | favorite | 133 comments

Not to be a downer, but was any thought given to the safety of the plastic(s) used?

This is something that's in your mouth a lot and constantly exposed to saliva.

The Dimension 1200es mentioned doesn't appear to be specific to medical applications.[0] The product page lists the only compatible thermoplastic being ABSplus-P430. The MSDS for that basically says the stuff is dangerous in molten form, and beyond that there's very little data.[1] The same company makes "Dental and Bio-Compatible" materials for use with their other products, and these appear to have considerably more safety data.[2]

>The aligner steps have been printed, in addition to a “riser” that I added in order to make sure the vacuum forming plastic (sourced from ebay) ...

As another commenter pointed out, the vacuum forming plastic is probably the primary concern because the 3D printer was just used to create the molds. The specific type of vacuum plastic isn't mentioned.

Regardless, very neat project.

[0] http://www.stratasys.com/3d-printers/design-series/dimension...

[1] http://www.stratasys.com/~/media/Main/Files/SDS/P430_ABS_M30...

[2] http://www.stratasys.com/materials/material-safety-data-shee...

I used Keystone PROFORM .030" Retainer Material. Keystone is a dental supplier, so I trust the plastic is biologically inert.

This whole issue should be mentioned in the article, just in case anybody ignorant wants to do this with unsuitable materials.

Good point. I'll add some info about this.

Nice. The only other risk then would be interaction or contamination between the retainer material and the printed mold during the forming process (high heat), but that's probably grasping at straws.

The SDS for the retainer material in case anyone's interested:


The toxicology section is entirely devoid of data, but I doubt that means anything since the product is purpose-built for dental use in the first place. Safety Data Sheets are more oriented towards immediate and occupational hazards anyways.

Taulman Nylon 680 FDA would probably be suitable too, for anyone using a more generic 3D printer. :)

This is a great point to raise. OP, please make sure that both the plastic you used, and the chemicals released as saliva gradually breaks down the plastic, are not going to be harmful. You wouldn't want long-term exposure of your gums to harmful agents. But that's probably the only concern.

Regardless: great job. I'm very impressed by this project -- I love seeing applications of 3d printing. Especially one like this turns an expensive (and slow!) medical procedure into something that can be done easily at home, or cheaply in the office of a trained professional.

> I love seeing applications of 3d printing.

So do we over at Additively (your post made me signup after just reading HN for a while). We publish showcases such as the commercial application of the posted aligners on our site - more curated showcases will be published soon.


Edit: That's the commercial 3d printing use case mentioned (Invisalign isn't the only one):


The plastic used in real Invisalign is HDPE, the same stuff used in plastic water bottles. It can be 3d printed. Real Invisaligns are 3d printed with HDPE (I was a patient).

Hm, It's not really being too heavily "interfaced" with the body. I wouldn't stick it under your skin, but this would probably be fine I think. I'd also think that most things are unsafe in molten form, heh.

If it's friendly toward bacterial growth, you might not want it near your gumline. Oral infections can get nasty fast.

Rubbing drugs on gums is a popular way of administration, as the substances get easily absorbed into blood vessels here.

Well, people put BPA in plastics even though it was known to be toxic because the thought was that the material would bind the BPA in place (i.e. it would always stay in the material).

Awesome work!

The animation definitely seems the most difficult (and subjective), but also the most cool! Body hacking via computed geometry!

Invisalign (align technology) uses almost the same workflow. Market cap $5.89B.

If you could move the workflow over to something based on WebGL / three.js - you could make this accessible to dentists in developing countries. Could be an awesome open source project.

I think "allowing" it to be used in the US would open yourself up to too much liability though :(

Invisalign seems to be mostly used for cosmetic fixes. That doesn't seem too compelling for a dentist in a developing country.

People in developing countries need and want to look good just like everybody else. "Developing country" is pretty much the whole world, except Western Europe, North America, Japan, and Australia / NZ.

Do you imagine people in countries east of Austria as ugly bunch with crooked teeth, because we're developing and never heard of cosmetic dentistry?

Actually, the usual place to stereotype as having crooked teeth is the UK, which is firmly in the "developed" group of countries.

To answer your question, no, "crooked teeth" isn't in the usual list of stereotypes people have about Eastern Europeans.

A counterpoint in the form of a "humorous" travel guide for a Eastern European fictional country: http://www.amazon.com/Molvania-Untouched-Modern-Dentistry-Je...

That doesn't answer my question.

IMHO in the UK teeth straighting is perceived as extremely vain. So in the UK straighting teeth is more a taboo than not.

Huh? Orthodontics are free in the UK up til 19, and it's very normal to have braces.

Maybe amongst an older generation who'd have to go out their way to pay for straightening.

Again I show I have been away from home to long.

I'm about 2/3 done with using Invisalign for fixing some pretty severe bite issues. Had I not had anything done, my jaw joint would have continued deteriorating, likely to the point of needing surgery; I was also at higher risk of having teeth break from the added stress (very few of my teeth actually were making proper contact with each other).

The first step of the process was actually removing two of my bottom teeth; the rest of my teeth have then been adjusted to fill the gaps. It's been a long process (almost two years in), and I'm sick of having these stupid plastic things in my mouth all of the time. But it's definitely been more useful than just for cosmetics (though that's a nice side benefit).

I live in a developing country. Most of the dentists here offer Invisalign.

You'd be surprised. I work for a company that manages the technical side of a famiky of brace systems (one of which is a direct competitor to Invision). A lot of activity happening in places I'd least expect.

It is smart that you designed the retainers based on maximum tolerance of tooth movement quoting from a textbook. I suggest you take X ray to make sure no root resorption have occurred. Also for those who want to imitate, measure the length of teeth and compare with the arch length to make sure the teeth can actually "fit" into the arch. I am a dental student.

By "length of teeth", do you mean their width measured along the arch of teeth, or vertically?

In this case: the width. aka the "mesial-distal" length.

Now that is awesome--those things aren't cheap.

I'm going to send this to my dentist (who's cool enough to appreciate it).

It has not once in my life occurred to me to email my dentist.

Welcome to the future!

I know--mine texted me the night after my filling, to see how it was coming along.

She does that for everybody, along with a number of other practices that do her and (would) her profession great credit.

I just got a FAX from mine...

Are you in SF? If so, who is it - I am looking for one :) thx.

Nah, but I found her on Yelp.

I wonder why we avoid dentists? I know we all have the pain stories, but I think there's something else? As I gotten older, I just like to pretend they, along with MD's don't actually exist. What's ironic is I never met a dentist with the ego that seems to come with medical doctors. I've never met a dentist who was not a friendly person. I do feel bad when I can't respond to their questions with a mouth filled with cotton, and instruments.

As to the DIY orthodontic device, this is what I've been waiting for. The day I need a 3D printer haven't quite come, but it's getting close.

I an still awaiting the day I go to the pirate bay, and under Physibles dowload a stl file.

Here's a funny story about dentistry.

I was a thumb sucker. I guess I was nervous? I don't know? I just know I couldn't stop sucking my thumb. It was a horrid habit, and even as a kid I knew it, but just couldn't kick it. I had one baby sitter(the Plumber next door) get so tired of looking at me suck my thumb, while he was watching The Rockford Files; he threatened to cut it off. Well, I inched towards to door quietly, and when I got my hands on the knob, I ran into Donna Oties house, and wouldn't leave her bed. I was 2, or 3? Never forgot that baby sitter. Looking back he was embarrassed, but I literally thought he was going to cut it off. Never quite trusted men since that incident. Even now I find myself trusting women, over men. I think that incident played with my psyche?

O.k. jump to first grade. I'm still sucking my thumb in private. I'm trying to hide it from my parents, but they would catch me. My mom took me to this dentist. His solution was to put two bright stainless bands on my two front incisors. The bands had pin sharp pieces of metal jutting towards my tongue. The theory went--when I put my thumb in my mouth--the needles would prick my thumb making it impossible to suck.

Well, the questions at school never ceased. When one kid found out through my little sister, the bands had tacks on the inside; the jokes were non-stop. I was a strong kid, so the jokes weren't too hurtful, but they still stung. One kid pushed me too far, and I hung him by his feet from the monkey bars. He never talked to me again.

I still had these bands on my teeth in third grade, but I had grinded down the sharp points with my dad's Sears file. I could still suck my thumb, but I knew I needed to stop.

I talked my parents into taking the bands off. I can still see my mother, "But _____, you are going to be buck toothed!" My father was on my side, and we got them off. Actually, my father bent the pins up a bit so I would be more comfortable eating. He did this early on. I think he knew the anti-thumb sucking pins were wrong, but you didn't want to upset mom back then?

I finally got the pins off in fourth grade. It felt good!

I noticed one lingering side effect of the device; I couldn't smile naturally. Yes, if something was really amusing I would smile, but my hand instinctively went over my mouth. To this day, I can't smile. I can try to smile, but it just comes out looking fake. I'm middle aged now, and I have maybe 10 pictures of myself. I got through high school without my picture being taken. I got through middle shool without my picture taken. My college girlfriend had a picture of me, but she literally had come to tears in order for that Polaroid shot. The DMV, and Costco has my picture--that's it. All these years, I managed to duck, or avoid the camera. Crazy huh?

I used to wonder why people avoided dentists, but recently I cracked a molar and had to go to see a dentist.

I was recommended a dentist in town, I showed up to a nice office full of nice people, they looked at my tooth and said they might be able to save it. So far, it was a pretty good experience.

Then it got weird. They took me to a room with a business person who would discuss my "payment options and treatment plan". I got this weird pushy salesman vibe, where they said it would be between ~$900 - ~$1,700 to salvage the tooth. I asked if we could just do an extraction but they only responded with "Oh you don't want to do that!" (playfully) but legitimately not saying it was an option.

So being uninformed and kind of surprised I just went along with it. She had me sign some paper saying I accepted the treatment plan (another red flag) and said she would "waive" my fees for that day (since you know, I'll be back tomorrow with 10x the fees).

Then, the next day I show up for my procedure, and the tooth is cracked too far down for them to salvage it, so the dentist decides he is going to do an extraction.

Ended up with just a $200 bill, and boy was a excited.

They of course tried to set up some kind of maintenance plan where I come in every quarter for checkups, but I declined.

Overall it just feels weird to have such a sales focus feel with something more medical related, and I didn't appreciate being steered away from all of my options, they could have just set me up with an extraction from the beginning. It's my mouth, why can't I decide if I'd save $2,000 to lose a molar.

Not to defend your particular dentist, but...

> I asked if we could just do an extraction but they only responded with "Oh you don't want to do that!" (playfully) but legitimately not saying it was an option.

I think dentists are culturally and by training pre-disposed to keeping your real teeth in your mouth. I've asked different dentists why and they get a hand-wavy, but they all say it's better if your real teeth are in there. This even happened in a scenario where I wanted a tooth removed and an implant put in - they would have made more money saying yes to me, but they pushed me towards other options.

It's because there are risks, up to infections that eats your face and might kill you, and the implant does not last forever.

I'm starting to get old, and I have realised that the trick is to keep all your body parts together until everything gives up at once :-)

It's because your jaw will change shape when there is a void an it can affect other teeth in the row. Also if you remove a tooth on the lower jaw, the corresponding tooth above on the upper jaw can start to travel downwards in the absence of a bite.

Those are valid reasons to avoid having a gap instead of a tooth, but should make no difference in the heavily-repaired-but-"real" vs implant tooth question that the parent poster had.

My experience with "dentists these days" matches yours. I go in for a checkup, and instead I'm getting sales pitches for mouth guards and alignment thinggys, and electric toothbrushes and all sorts of obviously high-margin dental accessories. And then there's the "well we usually recommend quarterly visits, but will accept twice a year" when I explicitly tell them my insurance only allows one visit a year. I basically say no to everything, and they try to guilt trip me into a bunch of optional procedures for a half an hour. Finally, eventually, they grudgingly clean my teeth.

It's like a shady auto mechanic for people who don't know anything about cars. You go in for an oil change, and they of course identify all sorts of optional repairs, making them sound super scary. "I'm not saying this small oil pan gasket leak will leave you by the side of the road, but you don't want to get behind on preventative maintenance!" Same tactic.

The icing on the cake is when, fast forward a few months, my insurance company sends me notice that they won't cover the visit because the dentist wrote the work up as "orthodontic prep" instead of "standard cleaning" so I need to contact them to get it corrected... and on and on...

I remember when you could go to the dentist, get a cleaning, be out of there in 45 minutes and be down about $100.

There are some dentists out there that are still like this.

Last fall I finally went in for a cleaning after several years of putting it off. At one point I asked the dentist about teeth whitening and he told me that they can do it, but the over-the-counter whitening strips work fine and I should save my money.

Refreshing to hear an answer like that.

There are plenty of good dentists, and the internet has made it much easier to compare. Not sure if there's a well-reputed review site for healthcare professionals, but Yelp has worked well for me.

>My experience with "dentists these days" matches yours. I go in for a checkup, and instead I'm getting sales pitches for mouth guards and alignment thinggys, and electric toothbrushes and all sorts of obviously high-margin dental accessories.

I'm going to agree and disagree with this one.

I went a few times to a "dental spa" a couple years ago which was trying to sell me a "night guard" for $900, claiming I was grinding my teeth at night. Their prices for other stuff were pretty high too.

My current dentist pushed me hard to get an electric toothbrush, either from her office or elsewhere. They even gave me a sample brushhead and let me try it out in their office, using some purple pills to show how much cleaner the electric toothbrush made my teeth. Her price actually wasn't that bad compared to Target/Walmart, but I ended up getting a nice Oral-B on Amazon on Black Friday. Guess what? The dentist was right! Now my teeth constantly feel like I just got a polishing at the dentist. I got another Oral-B for my wife on Amazon (it was only $30-35), and she loves it.

Seriously, get an electric toothbrush; it makes a huge difference. You don't need to waste time getting a full polishing when you use one of these daily.

But as for the night guard, my current dentist hasn't tried to sell me one of those. And they recommend twice-a-year visits, which is what my insurance pays for.

It sounds like you need to find a new dentist.

Some dentists can be pretty scummy. My mother in her early 60s didn't have dental insurance and went to a local dentist that was affordable for cleaning. She had a little bit pain in her mouth and her dentist recommended extracting all the teeth and replacing with implants for $1000s! She calls me up and I go visit with her to get an better idea. He gets ticked off because he though we were ready to go right ahead. I was appalled how he could care more about his profit than someones health.

I remembered my own dentist complaining about some swollen gums in my mouth and wanted to surgically treat it because it had gotten too bad. I just told him to deep clean in and lets see in a 6 months. I started regularly flossing and using mouthwash during this time. By 6 months he was surprised that it all recovered with a little cleaning.

Anyway, I took my mother from that place to my own dentist, have them clean her teeth properly and now 10 years later all her teeth are still there any have no pain.

In summary, I don't had trust in most dentists to do what is right for you.

The Frontline episode on this topic is worth a watch http://www.pbs.org/wgbh/frontline/film/dollars-and-dentists/

My mom went to the dentist for (the beginnings of) a tooth infection and they tried to sell her a mouth guard that probably cost $1000 or so. There was no evidence at all that she was grinding her teeth.

a lot of medical professionals are scummy. there's a word for it: quackery.

That is a standard scam. My wife accidentally went to a random dental office and went through the same thing. Luckily she had the common sense to not sign anything. Then we went on the web and found dozens of people saying the place did that to everyone. She went to a recommended dentist and had it repaired with caps for a tenth the asking amount.

I know us Brits always harp on about the National Health Service, but if you can find a dentist with NHS spaces available locally then you're in good hands.

But they're not without their commercial incentives either. And the waiting times can go into weeks for non-urgent work. Still, the costs are negligible in comparison. We perhaps pay in other ways...

I'm in the US. I've always waited weeks for non-urgent work.

I'm in Norway, I never have to wait more than a few days unless I ask for an appointment at a specific time of day.

Last time I went to my dentist it was because of a cracked filling (old amalgam), not in any pain, just a bit sensitive so not urgent, waited about four days.

Dentist declared that a crown was necessary but they didn't have a slot just then so would it be alright if I came back after lunch to have it fitted. The crown is manufactured on site using three d imaging and a fancy milling machine.

You should go in for checkups. An extraction has long-term side effects that should be monitored.

I've been on this planet for quite some time and while I'm sure some side effects are possible, I've never once heard of anyone having a problem, whereas I've heard numerous stories of people having extreme difficulty paying for dental procedures.

Smiling is incredibly important! Didn't put that part in on a lark- I really am noticeably happier for feeling like I can unselfconsciously smile.

they're not, but this blog post made it seem like they're worth the money.

I don't know how I feel about this post. I don't know if I can consider it a diy project when he has access to equipment beyond the reach of most ppl. if I had access to an orthodontist lab and build my own retainer using their equipment is that considered diy?

The only equipment here that might be an issue for most people is the laser scanner. I'm not sure where I'd find one of those outside a university that's accurate enough. The Makerbot one is pretty shitty.

Everything else could be pretty easily sourced. Shapeways can 3d print with very good resolution. You can buy a vacuum forming machine from Ebay for 100 bucks for exactly this purpose, or make one yourself with a heat gun, wood, and a shop vac (there's tutorials on youtube).

I don't think equipment access makes or breaks a diy project. As long as you did-it-yourself, it's diy.

This is really amazing, man. It's honestly the first 3D printing application I've seen that I can see quickly improving thousands of lives. Just to think of all the people who right now can't afford this procedure, that soon will be able to... it's just really wonderful.

Next I need someone to do orthopedic shoe inserts. Mine cost $600 and only fit my running shoes.

I'm a physician, and I used to get custom made ones, until I found these for around $45 in the US: https://www.drscholls.com/productsandbrands/customfitorthoti...

I was having foot pain a few years ago and decided to give those a try before shelling out to see a podiatrist/get custom orthotics. My foot pain was gone within a week and only came back on one occasion; when I bought new shoes and forgot to put them in the new pair.

Still, I've wondered if I'm missing out by not getting custom inserts. It sounds like (at least in your case) there was no major difference?

Wiiv[0] was recently crowdfunded. They make custom 3D-printed orthotic inserts created from photographic information via your smartphone. Sadly it won't be generally available for quite some time yet, but I have my hopes up.

There's also Superfeet[1]. They're not custom, but there's many options.

[0] https://wiivv.com/

[1] https://www.superfeet.com/

Have you ever tried cheap generic inserts?

Yes, I have McDonald's size arches and off-the-shelf ones aren't sufficient. Going to look into some of these other suggestions though.

He scans his teeth, animates how he wants them to move in blender, and then 3D prints each frame. That is absolutely brilliant.

It looks like the author took into account the safety of the plastic in creating these, which is a good thing. Maybe more so than dentists. You know "silver" fillings aka dental amalgum? They are 50% mercury by weight and are still being used. Supposedly safe because it is inhalation of mercury that is poisonous. Removal of those fillings with a drill can be dangerous. When some guy told me about this and was talking about it being the next asbestos/mesothelioma, I was thinking "sure! That sounds like conspiracy crap!" Then I looked it up on the FDA site like he suggested:


Anti-vaxxers are idiots and it is obvious that vaccines don't cause autism (original study was a fraud). The health benefit of vaccines is as undeniable as the lack of correlation to autism.

That said, dental amalgum is a chunk of mercury in your mouth. FDA says it is safe for people over 6yrs old, but I personally will stay away from it for any future dental work.

The thing about the mercury amalgam fillings is: why even bother any more? Modern resin fillings are mercury-free, plus they look far better and are nearly indistinguishable from real tooth. They're stronger too: I have a resin "filling" that's actually filling in a chip on one of my front teeth, meaning this filling is actually shaped into a sharp biting edge. It's been there for a year now and works fine. You can't make tooth repairs like that with amalgam.

Amalgam is just plain obsolete, regardless of how safe it may or may not be. So why anyone still uses it, I have no idea; I can only guess they're cheaper than the resin fillings, so they're used for low-income patients, or by shitty (or old-timer) dentists trying to improve their bottom line.

Price, yes. I got mine when I was a student and had no cash; I had a hole in my tooth and had to get it filled for the lowest cost I could.

If I have to get more... It'll be resin. The amalgam ones I've got have lasted a long time though, and I don't seem to have any new holes now that I've quit drinking so much soda every day :)

This is just amazing. I was waiting for how it might go horribly wrong, but the guy's mouth looks great.

Looks like quite a bit of an overbite, though.

There is an important issue missing in the article (beyond the warning notice): the occlusion. The modification of the dental structure requires a whole functional analysis that goes beyond the teeth.

Anyway, the future is promising and the issues could be solved taking into account all the factors.

Would you please elaborate more in layman's terms?

Your occlusion/teeth position is not arbitrary and it impacts other parts of the system like the maxilla, the mandible, and even your tongue. Changing it only based on aesthetics can unbalance the forces that you were applying before the treatment and other issues can appear.

This doesn't mean that every dentist really cares about this issue but you should search for a professional who cares about this.

Occlusion ~= how your upper and lower teeth fit together when you close your mouth.

I came across an article here on HN about mail-order Invisalign companies at a fraction of the price. I'm about half way through and very happy with the progress so far. Just thought I'd give a heads-up if anyone is interested


I guess this:

Straighter Teeth by Mail - https://news.ycombinator.com/item?id=8998267

Also from a while back:

Invisalign and 3D Printing - https://news.ycombinator.com/item?id=6373936

This was the article: http://mobile.nytimes.com/blogs/well/2015/02/01/a-trip-to-th...

I went with smilecareclub. They're pretty hands-off but it gets the job done and is a good value

I used to think ClearCorrect's competitive advantage was that they were much much cheaper than Invisalign so they could steal market share, but it appears they are now in the same ballpark. The ClearCorrect website says doctors set their own fees which can range from $1,000 to $7,000 USD.

Thanks for the link. It allowed me learn of even cheaper options.

I wonder how this works, they added brackets on my teeth that act as anchors. Definitely worth the try, I believe that I paid 3k for my treatments, this is ~600. Amazing

They do not add brackets / anchors but they do use a straight-across aligned as opposed to a more trimmed "scalloped" aligner. The straight across gets a bit more turning force because it goes higher up and covers a bit of your gums. I'm no expert so I don't know if that's the whole story. They definitely filter out people with more complicated alignment issues so that could play a role as well.

The work he did with the impressions, to me, suggests he has experience as / knows someone who is a dental technician. If he didn't, wow, he independently figured out some of their key techniques.

My grandfather used to make dentures, and that casting in the 4th photo looks exactly like the impressions my GF would make. They also used these hinges so they could mate the upper to the lower, so they could adjust any collisions that occurred while opening and closing the mouth.

Nope, no prior experience. It's quite easy, if you have an impression tray (I had to mock it up in 3d and print one). The instructions for alginate are right on the bag.

The rest was just reading freely available docs on how to make castings.

Hey! Recent NJIT alumn - great to see something so creative like this come from my home turf. Really impressive work!


Having recently done invisalign, I think this is brilliant, but I would have had a really hard time sticking with it through the pain. I would worry too much that I was doing damage. My case was quite a bit more severe, however, so maybe it's less of a big deal if the movements are minor.

This also seems to have whitened his teeth at the same time ;), typical "before, after".

But on a serious note, I had braces, after the were remove a wire was placed behind my teeth to keep them in place. It didn't stick to one of my ceramic teeth I had from an accident in my youth. The wire was removed and after some months my front two teeth were as far apart as ever. Ok, the overbite didn't return but things will move back at least to some degree over time.

As mentioned before, I myself would never just put any plastic material in my mouth with all the bad things known about plasticisers, bpa/bps, etc.

I've been using 30% Carbamide Peroxide whitening gel in the trays for about 30 minutes a day. So yes, they are whiter.

Could you share a link if it can be bought online?

I had braces at a young age and, like most people, have to wear a retainer at night to prevent our teeth from returning to their natural position. Did you?

Another option....have a dentist bind composite material to the couple teeth out of alignment.

Had two teeth done for under $500 10 years ago.

It's a stop gap until braces are an option financially.

Now THIS is a hack.

How soon before the FDA says this is illegal or the medical industrial complex lobbies congress to make this illegal?

It seems likely that there would already be FDA regulation in the U.S. if you marketed this to another person, plus unauthorized practice of dentistry considerations if you didn't have the relevant professional training and licensing. But my impression is that these regulations don't apply to medical devices that you make and use yourself on your own body.

This is cool but I can't say I agree with actually doing it. Just because you can do something doesn't mean you should, particularly in matters of health. If you don't have the requisite experience and knowledge and training, it seems risky to go about something like this on your own.

No more risky than changing your car's brake fluid (risk of death if you do it wrong). A lot of services that we have been conditioned into thinking need to be administered by specialized professionals with N years of expensive schooling, can probably be DYI'ed with access to the right equipment / tools.

I expect in the future we'll be hearing a lot of this kind of vague alarmist sentiment coming from well paid practitioners in industries so far untouched by technological competition & outsourcing.

Kudos to him for doing this, but I am slightly concerned that he has introduced overbite [1] in his jaws looking at the before and after pictures :(

[1] https://en.wikipedia.org/wiki/Overbite

I love this project - well done, and the result speaks for itself! It's unfortunate that you were forced to go this somewhat dangerous route due to money. In some countries dental care like that would be paid for by the health insurance.

Made my own as well when I was interning at an othodontist.

There is not really much tech required. You can simply cut apart the gypsum model tooth by tooth and align it perfectly with wax and add space for you gum. Finally create a mold and use medical grade silicone to make the tooth straightener.

Silicone also allows for more movement and gives you control of upper and lower teeth in relation to each other.

While this is not rocket science there are considerations about jaw alignment that would be difficult for the amature to get right the first time around in any but simple misalignments.

This is definitely for the brave, not me.

Not sure what I would do if we didn't have a dental school.

When I go there I am always surprised to find people who actually have insurance who still go there despite all the hassle.

I'm not trying to downplay how much the hacker/geek in me loves this, however, as a former* dental student, I would highly suggest not trying to pull this off on your own.

First, teeth and their movement is more complicated than it might first seem. You have to think about the entire masticatory apparatus, for example:

• There's more root than crown, how does the root move in relation to the tooth? Root resorption is a common problem in orthodontic treatment.

• Is there / will there be enough bone surrounding the tooth to support the intended movement?

• How will the patient's occlusion (how the teeth fit together) be affected? Part of the Invisalign process is to take a bite registration that shows the upper and lower teeth in relation to each other. This is important, and ignoring it can potentially lead to other complications:

- stress fractures

- supraeruption of opposite tooth

- TMJ pain

• Does the patient display any parafunctional habits that will affect the new tooth positions? For example, do they grind, clench, or have abnormal chewing patterns?

• Many Invisalign techniques require the placement of anchors, holds, and various other structures attached to the teeth themselves. They allow for more complex movement than the insert itself would be able to provide.

• Adjustments are often required mid-treatment. Not everybody’s anatomy and biology is exactly the same, so you have to adjust accordingly.

Now, does every general dentist take this into account 100% of the time? No, but they’re at least trained to recognize these situations and compensate for them.

That said, many simple patients don’t require any more thought than the OP put in. It’s a good thing he looked in a text book and realized that there’s a limit to how much you should try to move a tooth at each step before you’re likely to run into problems. And if you do run into problems — do you think a professional is going to come anywhere near your case?

A few issues I have with his technique:

• Unless he poured his stone model immediately after taking the impression, it’s likely there was a decent loss in accuracy. Alginate is very dimensionally precise, but only for about 30 minutes. The material that most dentists use, PVS, is dimensionally stable for much, much longer (not to mention digital “impressions”).

• Vertical resolution of the 3D print does matter. You might be moving teeth in only two dimensions, you’re applying it over three dimensions.

Again, I think it is awesome that someone gave this a shot, and did a fairly good job as well. I’m all for driving the cost of these types of treatments down, as well as promoting a more hacky/open approach to various treatments. Just know there’s more than meets the eye.

* I decided to go back to tech, there’s too little collaboration in dentistry for me to make a career out of it.

Wow this is awesome! Thank you for sharing. Retainers post Invisalign cost between $400-900 for 1 set - total ripoff. This looks like a far cheaper alternative.

Awesome stuff Amos! It's always nice to see creativity and persistence rewarded with successful results. I really enjoy reading these types of posts on HN.

slightly off topic: how is diy tooth alignment going to affect criminal investigations? on all those crime shows on tv (csi, navy cis, ...) they use dental records to identify otherwise unidentifyable bodies. is this method even used in real life and how would they find any records of your teeth if you fixed them yourself?

This is awesome! Definitely not the safest thing to do, but I'm glad that they worked.

Cool, that's an idea I'd had in the back of my head for some time too. Good to see someone's gone ahead and done it, and proven the concept. :D

Interesting article. Waterpik is a related product (as in, for teeth and gums) that a dentist recommended. Anyone have experience using it - pros, cons?

I think Waterpiks are better for dental health than toothbrushes and floss combined (although I use ‘em all). They’re basically small-scale pressure washers that obliterate bacterial biofilms, which are the real cause of tooth decay and gum disease and bad breath. Your mouth feels a different kind of clean after 2 minutes with one of these things.

Didn't know about biofilms (bacterial or other) earlier. The basic idea is intuitive (which is why I gargle with salt water regularly), but googled biofilm now and found a lot of info - it is complex. Thanks for mentioning it!

Saw this:



The article says:

"Biofilms have been found to be involved in a wide variety of microbial infections in the body, by one estimate 80% of all infections"

Cheaper and better: http://oralbreeze.com/

I own one and love it.

I like mine. My dentist claims it's good to flush out what's loose after flossing and that waterpik is one of the few companies with enough pressure to actually clean too

Thanks for all the replies; useful.

I'm late to this thread, but I will chime in. I started using a waterpik about 2 years ago. My dental hygienist suggested I try it, because the gaps between my gums and teeth were starting to get deeper, about 2-3 mm. When I came back to the hygienist after 6 months, she told me the gaps were mostly 1-2 mm. I can't recall if I told her before she did the measurements that I'd used the waterpik, so I'm not sure if I biased her. In any case, I'm pretty sure I can also see the improvement in the mirror - at least my gums used to look a little inflamed at the gumline, here and there, and they don't anymore. Also it seemed I was bleeding less at my last cleaning (they usually tell me that I bleed more than average).

One more thing: my hygienist said I didn't have to use the waterpik every day, that it's fine to use it just a few times a week. So I'm trying to use it every other day now. I don't know the pros and cons of using it every day. Are there any long term studies which show that the waterpik is in no way harmful? I don't think so.

PS I didn't floss as a kid, so unfortunately I have tons of dental fillings. I started flossing as an adult, and I'm sure it helped a lot. I still floss once a day.

Thanks for chiming in. Good info. Not sure about those studies. I guess every other day is fine.

Is it me or did it whiten your teeth. I noticed a big difference in upper plaque between the before and after picture.

This is awesome! Thanks for the detailed description.

Are you considering starting a business out of this?

Definitely not, because of liability, and the fact that I have no interest in other people's teeth.

I'm happy to leave it as a piece on my portfolio :)

But it would be great to build open source software that does this at a pushbutton.

this is pretty amazing and daring.

I guess this would work better with those with gaps or very mildly crowded teeth.

Often crowded teeth result in pulling teeth to make room.

Considering opportunity cost of the 100+ hours that probably went into this it would be cheaper to go to a dentist.

He might be able to come up with a better or cheaper method then the currently industry standard though ...

Can you chew food with the aligner on?

I have Invisalign, you can, but it sucks. Kinda feels like eating something that is in a plastic bag that has a little hole in it where you can still taste it.

I thought about the possibility of DIY Invisalign. My ortho basically did this once and gave me trays that he made in-office.

Obligatory: "orthodontists hate him"

Food finds its way up between the aligner and the teeth, and it's very unpleasant. Not recommended.

Drinking is not a problem though.

Most orthodontists will say anything except water is a no-no - coffee and tea will stain your aligners, and they almost always permeate the aligners into your teeth, causing decay until the next brushing. Juice is even more harmful with the sugar and fibre. Also, hot beverages can deform the aligners. I know cases of people who tried having drinks with straws, and realized it wasn't a viable solution. The drink still ends up permeating the aligners.

Nice work. I have braces so...

Very very awesome job :-)

Direct leak into your gums..

Orthodontics is a field known for its protectionism. It'd be pretty foolish but I wouldn't be surprised if you receive a cease and desist.

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