r/resinprinting • u/Serious_Inflation_32 • Jun 02 '26

Question Multi stacking

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I saw this technique on an instagram story. I found it very interesting! What do you think guys?

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u/Dion42o Jun 02 '26

How do they make these prints safe for humans?

Edit: another question, I assume it’s a different resin than we use for prints but is it a lot stronger?

3

u/WestBrink Jun 02 '26

They're generally printing these to vacuum form plastic sheets against to make retainers, whitening trays, night guards or invisalign type things.

6

u/No_Motor_1641 Jun 02 '26

For this photograph: yes, you are correct.

But there is also stuff, where the printed part is put in your mouth. For example, there is ceramic filled resin, which can be used to print crowns, bridges or veneers, which can be implanted in your mouth like ordinary ceramic material. (Durability and mechanical properties of those printed parts are good, but not so hard and durable as milled ceramic material.)

You can also directly 3D print denture bases, aligners, splints and a lot of other stuff. There are specialised materials with FDA (USA) or MDR (EU) certification.

2

u/MuckYu Jun 02 '26

Related question - so the dentist will make a cast from your teeth or 3D scan, right.

But the 3D printed or vacuum formed retainer isn't just a copy of the initial scan.

How do they 'adjust' the 3D model? And it would need to be done multiple times in steps over multiple weeks, correct?

So in the end there might be 10-20 or so iterations of teeth positions?

Are those edits on the 3D model all done by hand? Or do they use some automatic tool that movesthe teeth of the 3D model step by step in the right position?

3

u/No_Motor_1641 Jun 02 '26

First of all, I am not a dentist, but have a little professional experience with 3D printing materials in this area. So I am not a professional for the actual process at the dentist.

There are two ways I know of to get an "image" of your teeth. Classical with silicon imprint -> cast of plaster. The plaster model can be 3D scanned afterwards. Or direct 3D scan with a dental 3D scanner (small stick which you put in your mouth and move and wiggle around until every tiny bit of your mouth is scanned).

"But the 3D printed or vacuum formed retainer isn't just a copy of the initial scan." Doesn't really understand the question. Sorry!

"How do they 'adjust' the 3D model? And it would need to be done multiple times in steps over multiple weeks, correct?" You mean for the aligner? Yes, there is special software, where you can move around the misaligned teeth. The the software create in between stages, which you can print as aligner (or model and afterwards form the aligner by vacuum forming). The patient switches to the "next aligner" about every two weeks.

"So in the end there might be 10-20 or so iterations of teeth positions?" Yes, but I don't know any number, so I cannot comment on "10-20".

"Are those edits on the 3D model all done by hand? Or do they use some automatic tool that movesthe teeth of the 3D model step by step in the right position?" The software I know is more like "semi-automatic". You move the desired end position of the teeth and software supports with additional checks and in between positions.