Ortho Project : 3D edition (step 3)

Once I get the 3D model from Meshroom, the next challenge was to exploit this model : clean it up a little, isolate teeth and make them move.

For that, I use Blender, another great free and opensource software. However, in the discovering of Blender, I had the impression to work with Photoshop : it’s a powerful tool, but quick hard to event start for a beginner.
The learning was a bit long and I had to read some articles and watch multiples Youtube tutorials.

An important thing is to have a model at the right scale : Meshroom create a 3D model, but I had to scale it. For that, I use a pide-à coulisse to measure precisely the plaster mold and scale the 3D model on Blender.
(I mess up my first scaling, and the first aligner that I made was to small and I felt it on my teeth, it was hurting)
So to improve my scaling, I went back and forth between the 3D model that I 3D printed to re-measure and re-scale.

The useful functions I found were:

      • Ctrl+L : Select all linked vertices, really helpful to remove undesired independants objects
      • Intersect (Knife) tool : to have a plan base, I use this post’s answer
      • Mesh > Clean Up > Decimate Geometry : Reduce the number of vertices and faces on non-essential part of the model. I ended up with a model with 70k vertices (~14Mb)
      • Circle select (c) : To select part of the model to isolate a tooth. Combine with “Esc” to exit the circle tool, I could jungle with selection and moving into the model.
      • Ctrl+H > Hook to new object : Once a tooth selected, I could create a separate object in order to move it later
I also added a reinforcement at the back to strenthen the 3D printed model, and a scale to identify each print.

At this time, I had discussion about my project with 2 people that had aligners. I had learn some interesting informations:

      • The first aligner hurt a little bit more than the others
      • Teeth “naturally” move forward
      • In order to realign front teeth, sometimes I will have to create space by moving back the molars
      • Top and bottow jaw are “linked” : align one of them will have an impact on the other. So I decided to do aligners for the top too (and correct a minor thing)
      • The time between two aligners is around 2 weeks

After, I “just” had to do the animation, in order to have multiples steps to print.
I read here that teeth can move from 0,4 to 1,2/per month. Another website says 0,2mm per week (or 2 degre).
To be prudent, I choose to be under 0,2 mm per week. (or at least try)

For animation, I also had to learn how it works:

      • I > LocRot : Add a keyframe. One at the begining, one at the end (LocRot as LocationRotation)
      • G : move the object
      • R : rotate the object

At the end, the gum is deformed, but only the teeth count, as the aligner only need them. However, I’m a bit skeptical for the last move (front tooth), I may need to work more on it (and slow it down).

The model is clear, and the animation is fine, I solved the second challenge !

Next step, the aligner’s printing !

Ortho Project : Molding (step 1)

[Warning: Do not attempt anything written here; I assume no liability for any actions you take to modify your body. ]

As I don’t have an expensive dentist 3D scanner, the first step is to mold my jaw, in order to have something to scan after. Keeping also a referential of my original jaw is a good idea !
For that I needed:

      • A dental tray (3D printed)
      • Alginate powder
      • White plaster
The 3D model that provide Amos is nice, so let’s keep it !

The alginate powder is an amazing thing, it captures a lot of details (as your tongue hiding in the back of your mouth during the molding 🙂 )

I bought this alginate powder from Amazon but use local shop if you can. (And if
(If you want orange or mint flavored alginate powder, find some dentist supplier on the web)
About 10gr of it is enough to realize a molding of a jaw (up or down)
It’s pretty easy to mold your jaw, but there is 2 things that you need to pay attention to:

      • This powder stiffens quick, so as soon as it’s pink, it’s time to mold ! (heat and air accelerate the hardening process)
      • Having of mold of the last molars is hard but useful
Yes, putting liquid paste in your mouth seems messy ! But it hardens really fast.
First tries

Keeping the alginate molding in the tray is a good idea ! Altering the mold even by a few tens of millimeters will result in a wrong plaster molding.

Then I used white plaster, from Amazon again, shame.
I circled the tray with some flexible plastic sheet, scoth it and fill it with liquid plaster.
After drying, I removed unnecessary details and plaster with my Dremel.

As you can see, I’ve got some troubles with my front teeth !

The result is really amazing !
I did it two or three times, in order to have the best possible molding (with the maximum shape of the last molar).

Next step, the 3D scan !

Ortho Project : Intro

Since january 2020, I’m working on a new project : orthodentics !
I read an article, years ago, on a student (Amos) that did his own aligners with machines that had access at his university. By this time, it was just an interesting article, because I didn’t have access to this kind of tools. Time has passed, and recently my wife follow an orthodentic programm to realign her teeth, and the idea came back.

Since last year, I’m a proud owner of a 3D-printer, that was the starting point from my point of view, so I studied the subject for weeks and decided to try it !

Also, I have a past with dentists : I’ve seen them to much during my youth. So the idea of avoiding them, and doing a DIM (Do It Myself) project was really attractive.

The idea is to realign my teeth by my own.
For that, I need:

      • Molding tools and skills
      • A 3D scan of my teeth
      • A computer
      • A 3D printer
      • Dental material (plastics sheets)
      • A vacuum thermoforming machine
      • A Dremel-like tool

Except for the computer and the 3D printer, I didn’t have any of the rest and no idea how to do that, so I google-searched !

The 3 big challenges for me were:

      1. Obtaining a 3D scan of my teeth
      2. Manipulate the 3D object and realize the tooth-alignment-animation
      3. Vacuumforming the aligners

Today is 19th of march, I’ve solved the challenges, and I’m wearing an aligner for 1 week now !
Amos article has been very interesting, however I had to adapt some part.

I’m gonna write separate articles for each steps of the process. The idea is to share my project and excitement about it, to also share my result.
But in any way, it’s not meant to be a DIY tutorial.
As I share Amos recommandation, I’ll just copy-paste his warning.

[Warning: Do not attempt anything written here; I assume no liability for any actions you take to modify your body. ]