What Is Interproximal Reduction? 

Interproximal Reduction—also known as IPR, tooth polishing, stripping, or slenderization—is a very routine orthodontic procedure. It is commonly used as a strategy to make space to align crowded teeth. IPR involves removing small amounts of outer enamel tooth surface between two adjacent teeth.

Before we go more in-depth about interproximal reduction, let’s discuss the rationale behind it. In orthodontic treatment, a strategy needs to be in place to create space for dental crowding. 

The two simplest options are:

  • Expansion of the dental arches
  • Proclination (or forward movement) of the teeth 


Expansion of dental arches

The expansion of the dental arches means moving the back teeth outwards, thereby creating a wider arch and more space. This can be done in two ways:

  1. Palatal Expander — The first way involves using a palatal expander, which moves the jaws in addition to the teeth. The caveat to this method is that there is an age limitation for this strategy. If the upper (maxillary) suture is fused/calcified, the palatal expander will not work and we are only left with dental expansion as the jaw is not getting wider. 
  2. Dental Expansion — A valid option, but there are limits to this approach as well. The more you move a tooth outwards, the thinner the underlying gum tissue becomes. This can result in gum recession if done excessively.


Proclination of the teeth 

Proclination of the teeth means angling the teeth outwards. There is an optimal angle teeth should have. This varies depending on a number of factors, such as jaw position and tooth shape. Ideally, teeth should be somewhat upright and not angled forward excessively. However, the jaws are a fixed size and if all the teeth are to remain and space is needed, teeth can angle outwards to fit in.

If both the above-mentioned options have been considered and exhausted, the next approach involves removing tooth structure. 

In cases where removing a tiny bit of tooth structure will help, interproximal reduction is usually the best and most conservative approach. In cases where more space is needed, extraction of teeth should also be considered.

So let’s focus now on interproximal reduction. While it is one of the most common methods to create space in orthodontics, it also has other purposes. For example, it is a solution to help minimize black triangles. By polishing off a thin amount of enamel on triangular-shaped teeth, it allows the teeth to be pushed together tighter, reducing the triangle in between them. Another use of interproximal reduction, for example, is to help coordinate upper and lower midlines. 

Image provided by Dr. Brian Anderson


Frequently Asked Questions on Interproximal Reduction (IPR) 

Now let’s address a few of the most commonly asked questions:


“How is Interproximal Reduction Performed?”

At Walt Orthodontics, IPR is performed by hand, using flexible diamond-coated strips that are worked back and forth between your teeth like a fingernail file, or using a rotary instrument in a handpiece that oscillates. Very minimal amounts are usually done by hand, but when more space is needed, the handpiece is the more efficient approach.



“How Much Enamel is Removed During Interproximal Reduction?”

In the grand scheme of things,  very little enamel is removed. The most common amount ranges from 0.2 mm to 1 mm between each teeth (this amount is divided between two teeth). For example, if 1 mm is done at a contact point, 0.5 mm is removed from each tooth. 


“Does Interproximal Reduction Hurt?”

The simple answer is no. There are no nerve endings in enamel. Hence, anesthesia is not required. That being said, the feeling of putting a strip or file in between the teeth can create a tight pressure feeling. Also, the handpiece that oscillates can cause a temporary ringing sensation.


“Is Interproximal Reduction Noticeable?”

No! The amount removed is so small that spaces are not evident to an unsuspecting eye. If you examine your teeth up close, you may see a very tiny space, but most patients do not notice any visible change after the procedure. The teeth look basically the exact same. Furthermore, if you use  Invisalign® treatment, no spaces are evident with your aligner in place. 


“Is Interproximal Reduction Safe?” 

This is by far the most common question we get relating to the topic along with “Does interproximal reduction damage or compromise the long term health of a tooth?” The answer is no! Polishing enamel is very common. For example, a lot of people have rough edges on their teeth and request that the dentist or orthodontist smooth off these edges. Interproximal reduction is the same thing, just in between the teeth.

Research has consistently shown that interproximal reduction is a very safe and routine procedure. In long term, there is no increased risk of cavities, periodontal disease, or tooth sensitivity. It is widely accepted that 50% of interproximal enamel can be safely removed without consequence, and the amounts done for interproximal reduction are considerably less than 50%. Any “exposed” enamel after the procedure is naturally remineralized from regular fluoride intake. 


Next Steps — Considering Interproximal Reduction

If you’re having issues with crowding, interproximal reduction (IPR) might be a cost-effective approach for you. To be 100% sure, always consult with your orthodontist first.

Walt Orthodontics in Vaughan might be the solution for you, our doctors and staff are leaders in the orthodontic profession and bring exceptional expertise in any orthodontic-based treatments.

Have questions? Reach out, set up a COVID friendly virtual appointment, or utilize our live chat option on our website. 

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