IPR (interproximal reduction) in clear aligner treatment means removing a very small fraction of a millimeter of enamel from the surfaces where neighboring teeth touch, which creates controlled space between the teeth. It is also commonly called teeth filing, shaving or stripping. The goal is to provide the room that crowded or protruding teeth need to line up, without removing teeth and often without extractions. On this page you will find why and when IPR is planned, how it is done, what it feels like, and whether it harms the teeth. This is a general informational guide; the decision for you is made after an examination.
Why is IPR done in clear aligner treatment?
For teeth to move, there has to be room where they are going. When there is not enough room in the jaw, that space can be created in three ways: widening the arch or moving teeth backward, extracting teeth, or lightly thinning the enamel between the teeth. IPR is one of these options and usually comes up when the space needed is limited.
In the Invisalign system, the treatment plan is prepared in a three-dimensional software called ClinCheck. In this plan the doctor sees how much enamel reduction is planned on which tooth surface and at what stage of treatment it will be done. If IPR is needed, it is marked on the plan, and you can discuss this detail with your doctor at the consultation.
In which situations may IPR be needed?
IPR is not done for every clear aligner patient. The doctor decides whether it is needed by evaluating your intraoral scan, X-rays and tooth shapes together. In general, it comes up in these situations:
- Mild to moderate crowding: When the teeth need a little more room to line up. For details, see treating crowded teeth with clear aligners.
- Tooth shape and size mismatch: Lightly reshaping tooth surfaces to reduce the dark triangular gaps at the gumline in triangular-shaped teeth.
- Mismatch between the upper and lower dental arches: When a small space adjustment is needed so that the teeth close together properly.
- Balance when closing gaps: In some cases, to balance tooth sizes.
- Cases where treatment without extractions is the goal: As an option to proceed without extracting teeth when the space needed is small.
If the space needed is greater, IPR alone may not be enough; these situations depend on the doctor's evaluation.
How is IPR done?
The procedure is done in the dental chair and does not require a separate operation or a hospital setting. The method varies depending on the doctor and the tooth structure; the general flow is as follows:
- Preparation: The teeth are cleaned and the surfaces marked in the plan are identified. If needed, a small separator is used to keep the spaces between the teeth open.
- Enamel thinning: The planned amount of enamel is removed from the tooth surface using thin abrasive strips, thin discs or fine-tipped instruments. The gums and cheeks are protected during this step.
- Measurement: The space created is checked with thin measuring strips to confirm that the target value has been reached.
- Polishing: The surfaces are smoothed. Most doctors also apply fluoride at this stage.
- Aligner check: The aligner is placed to check that it seats properly.
The duration depends on how many surfaces will be treated. It can generally be completed in a single session or spread across several check-up appointments during treatment. When it is done in stages, only the areas needed at that point are treated each time.
What does IPR feel like during and after the procedure?
Because the procedure is done in the enamel layer, most people do not need anesthesia. Patients usually describe vibration, mild pressure and a feeling of stretching between the teeth. Discomfort may increase in people whose teeth are sensitive to cold or in areas with gum inflammation; in that case, simply tell your doctor, and the procedure can be slowed down or a different method can be chosen for that area.
In the first days after the procedure, the teeth may be slightly sensitive to heat, cold or sweets. This eases quickly in most people. If the sensitivity lasts longer or gets worse, you should call the clinic without waiting for a check-up appointment.
Does IPR harm the teeth?
This is the most frequently asked question. Enamel is the hard outermost layer of the tooth and does not regenerate in the body, so the amount removed matters. In orthodontics, IPR is applied in a limited, measured amount based on the enamel thickness between the teeth; the doctor determines this limit by looking at your tooth structure. When it is done with the appropriate technique and the surfaces are polished and supported with fluoride, there are studies showing that it does not markedly increase the risk of cavities and sensitivity. However, this is not a certainty that applies to every tooth; enamel thickness varies from person to person and from tooth to tooth.
For this reason, the safety of IPR depends largely on the following:
- Planning the amount to be removed in advance and keeping it limited according to the tooth,
- Polishing the surfaces well after the procedure,
- Maintaining oral hygiene regularly throughout treatment,
- Monitoring the spaces between the teeth at check-ups.
In our blog's article on what IPR is you can also read the general framework of the procedure for informational purposes. This page, on the other hand, explains its place in the clear aligner treatment process.
Who should not have IPR?
In some situations IPR is not recommended or is postponed:
- People with active cavities: The cavity is treated first.
- Teeth with thin or worn enamel: The amount that can be removed is insufficient.
- Small and narrow teeth: The enamel that can be removed between the teeth is limited.
- People with a marked gum problem: Gum health must be established first. For details, see gum disease and clear aligners.
- People with high sensitivity: The doctor may prioritize alternative methods.
- Cases requiring a lot of space: IPR alone is not enough; other methods are needed.
This list is not exhaustive; the final decision is based on examination findings.
At what stage of treatment is IPR done?
Two approaches are common. Some doctors open all of the required space at the start of treatment. Others divide the procedure into stages; that is, as the teeth move and the contact points become more apparent, they thin the enamel in small steps in the relevant areas. With the staged approach, the plan is re-evaluated at every check-up according to the current tooth position. Which method suits you is determined by your tooth structure, the distribution of the space needed and the treatment goal. If you would like to see your aligner change routine, the aligner change schedule page offers a general framework.
If IPR is planned, it is good to know that the aligner delivery or check-up appointment may take a little longer. When arranging your appointment around your work or school hours, you can ask your doctor or the clinic team about this in advance.
Key points patients often ask about IPR
Patients mostly wonder whether IPR weakens the teeth, whether the procedure can be reversed, and whether gaps will be left afterward. The amount removed in IPR is small and is kept limited so that it does not weaken the tooth structure. The procedure cannot be reversed because enamel does not regenerate. The closing of the spaces by the end of treatment is the aim of the plan: the room created between the teeth is used together with tooth movement, and at the end of treatment the teeth are aligned so that they touch each other again. Using a retainer, which is needed to keep the teeth in their new position after treatment, is also an integral part of this process.
What should aftercare be like following IPR?
It is important to take care in cleaning the teeth in the treated areas. The general approach is to brush twice a day with fluoride toothpaste, clean between the teeth with floss or an interdental brush, and use fluoride products when the doctor recommends them. It is also important not to put the aligners in without cleaning your teeth after meals, because the aligner holds residue against the tooth surface for hours. For your routine, you can look at the guides on how to clean clear aligners and care products.
What situations may come up during and after IPR?
| Situation | General approach | When to see the doctor |
|---|---|---|
| Vibration and pressure during the procedure | An expected sensation; tell the doctor if needed | If there is sharp pain or unbearable sensitivity |
| Mild sensitivity to cold and heat in the first days | Fluoride toothpaste, continue the care routine | If the sensitivity lasts more than a few days or increases |
| Food getting stuck between the teeth | Clean with floss or an interdental brush | If it is constant or the gums bleed |
| Aligner seats differently in the new space | Use an aligner chewie, according to the doctor's plan | If the aligner does not fully seat on the teeth |
| Color change or stain on the tooth | Do not intervene on your own | At your check-up appointment or as soon as you notice it |
Is IPR the same as tooth filing?
No, it is not the same, although both are procedures that reduce the amount of enamel on a tooth. IPR is a planned procedure done for orthodontic purposes on the surfaces where neighboring teeth touch. Tooth filing or reshaping, on the other hand, is a general term that is also used to correct the length or shape of a tooth for cosmetic purposes. You can read about this distinction and other applications in the article on tooth filing.
What happens if the planned space cannot be achieved?
Sometimes the planned space cannot be achieved as expected during treatment. In that case, the doctor may decide that an additional impression or a change is needed. For general information on renewing the aligner set, see the article on additional aligner sets. The clear aligner treatment page is also useful for the overall flow of treatment.
How is IPR planned at our clinic?
The Invisalign system is used at Funda Sarıkaya Oral and Dental Health Polyclinic. Funda Pekyılmaz Sarıkaya, specialist orthodontist (Uzm. Dt.), evaluates at the consultation whether IPR is needed based on your intraoral scan and X-ray findings; if it is needed, the surfaces on which it will be applied and the stage of treatment at which it will be done are discussed with you. The clinic is located at Park Oran Ofis and is open Monday–Saturday, 09:00–20:00. For an appointment you can call 0312 911 60 36 or write on WhatsApp. This information is general; the decision for you is made after the examination.