First post…I’m a dentist and I’m looking for a way to create an STL model from an impression STL. I have the ability to create an STL of an impression that was taken of the patient’s teeth. What I’d like to do is reverse this and have the actual digital model as if I were pouring the impression in plaster. I’ve attached a photo of an impression STL and a model STL like I hope to generate. Any help would be greatly appreciated!


First - I’m a fan of using Blender 3D because I’ve been using it for years. Yes, it has a steep learning curve, but I offer this as a thought on how this can be done.

If you have the impression object:

  • Import it into Blender
  • Add a cube around the same size
  • Move the cube over the impression object (so the bottom of it is still visible)
  • With the cube selected, add a modifier - Boolean
  • Change the modifier to be Difference and select the impression object as the other object
  • Click on Apply
  • Move the impression object out of the way and you should have a model of the teeth
  • Maybe a little clean up to get rid of other parts of the cube that you don’t want
  • Select the teeth object and export as .stl.

I’m sure you can do something similar with many other 3D programs.

I hope this helps give you an idea how you can use the impression object to subtract from another object.




My dad is a dentist too. We’re experimenting a lot with teeth guides.

If you just want to “invert” few stl-models, just send the files I’ll do this for you.

If you have more models, it would be better to automate this process.

This can be done very easy, because mouth-models are similar.

I’m dentist too. So need invert my stl models to calculate palatal area. how are doing this?