What is IPR in clear aligner treatment?

If your dentist has mentioned IPR, you may have pictured something far more dramatic than it is. IPR stands for interproximal reduction, and in IPR aligners treatment it simply means polishing away a very thin layer of enamel from the sides of selected teeth to create a little extra space. It is a common, planned part of many clear aligner cases, and understanding it usually takes the worry away.

What IPR actually is

Every tooth is covered in enamel, the hard outer layer. Where two teeth touch, the dentist can smooth and slim the contact area by a fraction of a millimetre using fine polishing strips, thin discs or a special bur. The goal is not to change the shape of your teeth in any visible way. It is to free up small amounts of space so teeth can line up without being pushed outwards.

You may also hear it called slenderising, stripping, enamel reduction or reproximation. They all describe the same idea.

Why IPR is used with clear aligners

Teeth need room to move. When they are crowded, the space has to come from somewhere. Your dentist has a few options, often used together:

• Gentle arch expansion, widening the arch slightly where it is safe to do so
• Moving front teeth slightly forward, within healthy limits
• IPR, creating small spaces between selected teeth
• Extractions, in more severe cases, decided after a full assessment

IPR is useful because it creates space exactly where it is needed without changing the overall shape of the arch. It can also help in other situations:

• Reducing the small dark triangles that can appear between front teeth when they are straightened
• Correcting differences in tooth size between the upper and lower teeth, so the bite fits better
• Smoothing contacts so aligners can guide teeth past each other more easily

If crowding is your main concern, our guide to clear aligners for crowded teeth explains how all these options fit together.

How IPR is planned in IPR aligners treatment

IPR is not decided on the day. It is part of the digital treatment plan. When your dentist sends your scan to the lab, the 3D setup shows how each tooth will move, stage by stage, and where any space will come from.

At Alignova, IPR is planned into the setup and shown on a staged IPR chart. The chart tells your dentist which contacts to polish, how much, and at which aligner stage. Your dentist reviews this, can ask for changes, and approves the plan before anything is manufactured. You can read more about this step in how it works.

IPR is often carried out in stages rather than all at once, because some contacts are easier to reach once teeth have started to untangle.

What happens during an IPR appointment

1. Your dentist checks the IPR chart for that stage.
2. They may place a small gauge between the teeth to measure the existing contact.
3. Fine strips or a thin disc are used to polish the contact area. You will feel vibration or a light scraping sensation.
4. The space is measured again to make sure it matches the plan.
5. The surfaces are smoothed and polished, and a fluoride product may be applied.

Most people do not need an injection. The enamel has no nerves, and the amount removed is very small.

Does IPR hurt?

Most patients describe IPR as odd rather than painful. You may feel pressure, hear a rasping noise and notice the strip between your teeth. Some people feel brief sensitivity to cold afterwards, which usually settles quickly. If you are anxious, tell your dentist; they can pause, explain each step and work at a pace you are comfortable with.

For more on what aligner treatment feels like overall, see do clear aligners hurt?

Is IPR safe for my teeth?

When planned properly and carried out by a trained dentist, IPR stays within the enamel and is a well-established technique. Your dentist will consider the thickness of your enamel, your gum health, existing fillings and crowns, and how many contacts are involved before planning it.

Polished enamel surfaces are smooth, which helps them stay clean. Good brushing and flossing remain important, as they always are. Our article on oral hygiene with clear aligners covers this in detail.

Will I see gaps after IPR?

Sometimes, briefly. IPR creates space that the following aligners are designed to use. In some cases a small gap is visible for a short while until the teeth move into it. This is planned and expected. If a gap seems larger than you were told, or does not close as the stages progress, mention it to your dentist at your next check.

Caring for your teeth after IPR

• Use a soft toothbrush and fluoride toothpaste.
• Floss gently; the contacts may feel different at first.
• If your teeth feel sensitive, a sensitivity toothpaste can help. Ask your dentist.
• Put your aligners back in as instructed so the new space is used as planned.
• Keep wearing aligners for the full daily time your dentist recommends.

Frequently asked questions

Does every aligner patient need IPR?

No. Many cases need none. Whether you need it depends on how much space your teeth need and where it can best come from. Your dentist will show you in your plan.

Can IPR be done on any tooth?

It is most often planned on front and side teeth. Your dentist chooses contacts based on the plan, the shape of each tooth and the health of the enamel and gums.

Will my teeth look smaller after IPR?

No. The amount polished is very small and spread across contacts, so the change is not noticeable. What you see is straighter teeth.

Can I refuse IPR?

You can always discuss alternatives. Your dentist will explain what other ways of creating space would mean for your plan and result.

Clear aligners are a prescription treatment. Whether they suit you is decided by a licensed dentist or orthodontist after an examination.

Take the free smile check and a partner dentist will contact you about an assessment.