Interproximal reduction (Teeth stripping, shaving.) -

What types of orthodontic cases require it? | How is the procedure performed? | Procedure timing (with Invisalign® vs. conventional braces.) | Risks and side effects. | Illustrations and pictures.

What is teeth stripping / interproximal reduction?

"Stripping" refers to a procedure where your dentist trims off a small thickness of tooth enamel from selected teeth where (if in proper alignment) they would normally touch against each other. The overall goal is to narrow the teeth.

Equivalent terms.

There are several additional words and phrases used to refer to this process. They include teeth shaving, interdental reduction, interproximal reduction (IPR) and, most precisely, interproximal enamel reduction.

With this last term, the word enamel is included as an indication that the trimming is confined to just the enamel layer of a tooth (its outer covering).

As we explain below in our risks and side effects section, this is an important stipulation for this procedure.

When is this procedure needed?

Shaving down the width of teeth may be needed for a number of reasons and we outline some of the more common ones below.
Before your treatment is begun, your dentist should be able to tell you if they expect that this procedure will be needed.

Applications for interproximal reduction.

a) Proclined incisors.

This condition refers to the situation where the patient's front teeth (their incisors) are flared out (forward). Narrowing the teeth makes it possible for the orthodontist to pull them back into a more normal arrangement.

b) Overjet correction.

Overjet refers to the situation where the upper teeth are protruded (the lower teeth occupy a position some distance behind the uppers that overlap them). In some cases, tooth stripping can be used to narrow the width of the upper teeth, so they can be pulled back into a more regular alignment with the lowers.

Animation showing how crowded teeth can be stripped (reduced in width) and then realigned.

The teeth are first stripped (narrowed), then realigned.

c) Resolving tooth crowding.

In cases where the underlying problem is tooth crowding, interproximal reduction can be used to create the space needed to realign the crooked teeth. (See animation.)

d) Tooth-size discrepancies.

The corresponding teeth on a person's left and right sides are usually mirrored images of each other. In cases where there's a width discrepancy between paired teeth, shaving their width can be used to resolve it.

The justification for interproximal reduction.

You might be concerned that your dentist plans to shave off a portion of your misaligned, but otherwise healthy, teeth. But when compared to other available options, trimming off a little bit of tooth enamel frequently makes the obvious better choice.

Possible alternatives.

As an example of what we mean, take the case where a patient's teeth are crowded. In this situation, the orthodontist will need to find a way of creating additional space into which the crooked teeth can be realigned. However, there are only so many options available.

  • Space can sometimes be made by flaring the patient's teeth forward, or slanting them backward or to the side. But making these types of changes can result in an alignment that is inherently unstable and its risk for relapse high.
  • Space can also be gained by extracting (pulling) selected teeth. However, doing so may create more space than is needed, not to mention that one or more teeth are lost.

So, with this type of case, and especially in situations where just a small amount of space is needed, tooth stripping can provide a very practical, possibly even conservative, solution.

Risks, side effects and concerns.

Doesn't trimming your teeth damage them?

Obviously, when interproximal reduction is performed some thickness of the tooth's enamel is lost.

The question then becomes, does shaving off this amount of enamel damage the tooth?

a) Tooth stripping approximates normal wear.

As a rationale for why the amount of enamel removed doesn't constitute actual tooth damage, consider the following explanation:

  • Every tooth is anchored in your jawbone by a ligament. And this ligament allows for small amounts of tooth movement.
  • As movement takes place continuously over time, some tooth-to-tooth wear occurs. And in fact, it's normal for the contact points of teeth to wear flatter as we age.

Since the contact points of crowded teeth have not yet experienced this type of wear (because they're misaligned), the portion of the tooth that is shaved off during the stripping process simply approximates that amount of tooth enamel loss that would have occurred if they had originally been in proper alignment.


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b) Are stripped teeth more likely to experience problems or side effects?

Interproximal reduction has been used by orthodontists for decades. And over the years, many dental researchers have evaluated its long-term effects in search of risks and problem issues.

A study by Zachrisson (2007) [page references] found no increased incidence of side effects (tooth decay, gum disease, bone problems) in a group of subjects that had had tooth stripping performed more than ten years previously.

c) Even after stripping, the tooth is still encased in enamel.

This is an important point. Interproximal reduction involves just shaving off a layer of enamel, not removing its full thickness.

It's situations where a tooth has lost its entire enamel covering (and therefore has exposed dentin in an area) that issues such as thermal sensitivity and potential for decay become significant risks.

As long as at least some thickness of enamel remains, from a practical standpoint the tooth's risks and expected lifetime experiences should remain relatively unchanged from its previous state.

Animation showing methods a dentist uses for tooth interproximal reduction (stripping).

Teeth can be stripped using either a dental drill or an abrasive strip.

Interproximal enamel reduction - The procedure.

A dentist can perform teeth stripping using various tools.
  • A dental drill - The teeth are trimmed using a spinning diamond-coated bur or disk.
  • By hand - Diamond coated abrasive strips are worked back and forth between the teeth.

The method that's chosen will most likely depend on how much tooth structure needs to be trimmed off.

If it's only a small amount (.3mm or less), the dentist will probably work by hand because it gives them more control over how much enamel is shaved off. For larger reductions, they'll probably use their dental drill.

a) Your dentist will take care not to trim away too much.

From time to time during the stripping process, your dentist will stop and fit a small thickness gauge between your teeth and measure the gap they have created.

Once they have widened the gap enough, they'll document this width in your dental chart. Any future stripping will be documented too, so no tooth has too much enamel removed.

b) What's it feel like when interdental reduction is performed?

Don't worry, having your teeth stripped isn't that big of a deal.

It's a little unpleasant, in the sense that you do feel the tug of the diamond strip between your teeth or the vibration of the drill. But as far as pain goes, there shouldn't be any (no dental anesthetic should be required).

c) Your dentist may need to strip your teeth more than once.

You'll have to ask your dentist about what will be required for your case.

  • They may only need to strip your teeth once over the entire course of your treatment. Or, they may trim on several different occasions, as they find your treatment progress requires.
  • Follow-up trimming may only involve touch-up work. Just using hand tools may offer the dentist more control when removing these smaller amounts.
  • See the "Timing" section below for further discussion.

These crooked teeth were originally touching.

Picture showing lower front teeth that have had interproximal reduction (IPR) performed.

Now that they've been stripped there's room to straighten them.

d) After they've been stripped, will you notice gaps between your teeth?

Sure, after interproximal reduction has been performed you will see small gaps between your teeth. After all, making space is the whole idea of the procedure.
But these spaces should be quite small and probably not all that apparent to others. And, of course, as your treatment progresses your gaps will become smaller and smaller until they are finally fully closed.

Procedure timing.

a) Interproximal reduction as a part of the Invisalign® treatment process.

Due to advances with the Invisalign® system's software, the timing of a patient's interproximal reduction (IPR) has changed.


When the Invisalign® system was first introduced, the typical approach was one where tooth shaving was performed at the beginning of the treatment process.

However, at this point (before any tooth movement had been performed) it was sometimes such that the patient's teeth were so overlapped that the treating dentist had difficulty positioning their tools (bur, strip or disk) in a fashion that didn't inadvertently also damage the neighboring teeth too.


With advances with the Invisalign® system, a process referred to as "staging" can now be used. This simply means that tooth trimming is delayed (staged) until that point during the treatment process when the dentist has their best, or at least better, access to the surfaces being adjusted.

So, for example, since staging is possible the interproximal reduction of teeth that are severely overlapped can be delayed until that point in time when they have been partially straightened, thus making it easier for the dentist to just trim where needed.

b) IPR with conventional braces.

As opposed to the situation where the dentist's treatment actions must conform to the shape/design of their patient's previously fabricated Invisalign® aligners, with conventional braces the dentist can perform tooth stripping at any point during the treatment process.