Invisalign Update: What is IPR?

Aiming to correct my teeth - Invisalign

I just entered week 16 of my Invisalign treatment. Two weeks ago, I visited my orthodontist to undergo IPR to create some additional room for movement.

What is IPR?

IPR stands for Interproximal Reduction. IPR is an orthodontic procedure wherein tooth enamel is reduced to facilitate treatment. Interproximal Reduction is a common orthodontic procedure that you could encounter with traditional metal braces, lingual braces, or other clear aligner brands.

In short – they remove a bit of your tooth via what is essentially sanding. IPR:

  • Creates space without tooth extraction
  • Makes teeth fit together better

In my case, the procedure killed two birds with one diamond disc (see below).

What IPR Entails

Depending on the space required your orthodontist may use several different tools to execute an IPR procedure.


For 0.1mm adjustments, a thin, flat, tape-like file is threaded between the teeth and moved back-and-forth to file.

If your treatment plan calls for adjustments greater than 0.1mm, your orthodontist will use what is essentially a dremel-like tool to do this with a diamond disc. The disc is carefully situated as appropriate and used to etch away the enamel in question.

That Sounds … Horrible

Yes – it does. I won’t sugarcoat it; the dremel-like sounds like a drill in your mouth. There’s no way around it. The sound and sensation that accompany the procedure is unnerving. Doubly so if you’ve had cavity work and whatnot done. That sound and vibration is reminiscent that ilk.

THAT SAID – this procedure does NOT require any anesthetic. It should never, ever be painful. It is uncomfortable from a mental perspective, but not a physical one. If you experience physical discomfort, alert your doctor to any pain immediately so he or she may stop.

Pain Aside, What’s the Risk?

Strong tooth enamel protects from tooth decay and cavities. Theoretically, an irresponsibly-executed Interproximal Reduction procedure could result in compromised enamel. Yep – it’s possible.

A properly-trained, experienced provider will not be likely to make this mistake. Trained providers will err on the side of caution and remove less.

Patients likely do more damage to their tooth enamel with their eating, drinking, and overzealous brushing habits than this procedure will.

What Else Should I Know About IPR as a Patient?

Although it doesn’t physically hurt there is another uncomfortable aspect. Removing enamel in this fashion produces a particular unpleasant smell. It only lasts while abrasion is being applied (don’t worry, you won’t have bad breath). For some reason, it bothered me more than anything else about the process.

At first, you may notice the gap IPR creates. With your aligner trays in, it isn’t visible. Without my trays, I didn’t feel that mine was unsightly or highly visible to others. I mostly noticed how the space felt to my tongue while eating. It wasn’t uncomfortable, just different.

Your orthodontist may not execute all necessary IPR in one appointment. Your treatment plan may require multiple IPR appointments at different stages of your treatment.

The Bottom Line

My IPR procedure was weird but not painful. My subsequent trays have already made use of the space that was created. I go in for my next IPR treatment in the first week of December, around tray 20.