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yogipatel | 10 years ago

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.

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