Why Do Palate Expanders Cause a Gap Between the Front Teeth?

This post may contain affiliate links. As an Amazon Associate BracesKnowHow.com earns from qualifying purchases.

Palate expanders are a fantastic treatment option for orthodontic patients. By using a palate expander, we can often avoid the need for extractions and achieve permanent results, especially when we intervene early. And this is thanks to the generous space they create on the dental arch, usually in the form of a large gap.

Today, I want to discuss why and how palate expanders create these unsightly gaps between the front incisors. Most patients are worried about them, but gaps are to be expected, and we have all the tools we need to close them once the treatment is complete. Want to learn more? Keep reading!

How do palate expanders work (& cause Front Gaps)?

Palate expanders work by applying pressure to the upper jaw, which can cause the intermaxillary suture to open and, eventually, new bone to form.

The expander is attached to the teeth in the upper arch and has a screw in the middle that needs to be turned to adjust the pressure. As the expander applies pressure to the upper jaw, the two halves of the maxilla are gradually pushed apart, creating more space.

In many cases, the suture opens in a V shape, resulting in more expansion in the front of the mouth. In adults and surgical expansion, the maxillary halves may open in a more parallel manner.

If you were to take an X-ray of the gap that’s forming between the maxillary halves, you’d see there’s no bone there, at least not yet, because the expansion happens at such a fast rate (hence the name RPE – rapid palatal expansion).

This is a good thing to remember when worrying about gaps and closing them as soon as possible. So let’s talk gaps – when can you expect to see one, and how long will it last?

What is the Intermaxillary suture

Before we get into how palate expanders work to create gaps, let’s talk about the intermaxillary suture. This is the joint that connects the two halves of the upper jaw, known as the maxilla. This joint is guilty of the large gap that’s opening between your teeth.

The intermaxillary suture is a flexible structure that allows for growth and expansion of the upper jaw during childhood. This flexibility is important because it allows the upper jaw to adapt and grow to accommodate the developing teeth.

When you’re young, the padding of the suture is made of cartilage, which makes it easy to open and expand when necessary. As you get older, the cartilage is replaced by bone, and the suture fuses completely.

On a side note, it’s still possible to reopen a completely fused adult suture using surgical maxillary expansion. This is thanks to interdigitation, a complex mechanism of interlocking of the cranial bones, which allows the sutures to open without breaking.

When does the suture fuse completely?

So why even care about this joint, and what does it have to do with you? Well, it becomes really important the older you are.

The intermaxillary suture typically fuses completely by the end of puberty, meaning that the upper jaw can no longer grow and expand naturally. This is why the best time to intervene for easy maxillary expansion is before puberty hits.

Depending on the suture’s maturation stage, some patients have a suture that’s easier to open (and we get a larger gap), while others don’t benefit from the same expansion, or the suture won’t open at all.

Check this article on the right age to get a palate expander for your child for more details.

When To expect a gap and how long will it last?

As we explained, one of the side effects of palate expanders is the appearance of a gap between the front teeth, as the intermaxillary suture opens and the two front teeth start to move apart.

You can expect to see a gap develop in the first couple of weeks of wearing the expander. The gap will gradually get larger as long as you keep turning the screw, typically for a few more weeks. The gap can get as large as 8-10 mm, depending on how crowded the teeth are.

I know that seems like a lot, but it’s perfectly normal. In fact, we’re excited when we see that amount of expansion in our offices.

It’s important to note that the gap will not last forever. After a few weeks, when you stop turning the screw, you will notice your front teeth start to shift towards each other, gradually closing the gap. This is because of the transseptal fibers, which are tiny fibers that connect the roots of the front teeth to their neighboring teeth.

These fibers can stretch and allow the teeth to move apart during the expansion, but they also play an important role in helping to bring them back to their place. The transseptal fibers will not cause the gap to completely close – remember, we don’t have much bone in there, not during the first 3 months anyway.

For this reason, we don’t want to close the gap too soon, or it can result in loose front teeth that don’t have enough bone around them. However, after 3-6 months, new bone will form in the gap, allowing the teeth to become strong and stable.

Most patients who get a palate expander will eventually need braces or aligners, either immediately after the expander or at the appropriate age. Until then, they may get a retainer to maintain the expansion. The braces or aligners will help with gap closure.

If your orthodontist is about to close your gaps with braces soon, note that gaps are harder to close in patients who already have straight teeth, as opposed to patients with crowding. Crowded teeth will always shift faster into the gap, often even before it’s time for braces.

In summary:

  • Expect a small gap in as little as 2 weeks after wearing your expander.
  • The gap will gradually get larger as you turn the screw and it can reach 8mm or more.
  • Part of the gap will disappear naturally thanks to transseptal fibers pulling incisors together.
  • If you have a lot of crowding, you may not notice a gap at all, or it will quickly close and alleviate crowding.
  • If you already have spacing or straight teeth, the gap will take longer to close.
  • You’ll most likely need braces to complete the results and close the gap.

Potential side effects of palate expanders

Palate expanders are generally safe and well-tolerated, but as with any medical treatment, there are potential side effects that patients should be aware of. These include:

  • Pain and Discomfort: During the initial adjustment phase, patients may experience mild to moderate discomfort, including soreness, tenderness, and pressure at molar and incisor level. This discomfort usually lasts for a few days to a week and can be managed with over-the-counter pain relievers, such as acetaminophen or ibuprofen. Use orthodontic wax or silicone for any parts of the expander that may be hurting your cheeks.
  • Speech Impediments: While wearing a palate expander, patients may experience changes in their speech, such as a lisp. This is due to the gap that is created between the front teeth, and the expander itself. However, most patients adjust to the expander within a couple of weeks, and their speech returns to normal once the gap is closed.
  • Difficulty Chewing and Tender Incisors: Some patients may experience difficulty chewing or biting down while wearing a palate expander, particularly during the initial adjustment phase. In addition, the incisors may become tender or sensitive due to the expansion caused by the device. Stick to soft meals and cut your food into small pieces.

It is important to note that the gap created by a palate expander is a normal and expected part of the treatment process, and it will eventually close on its own as the teeth shift and the bone fills in. In most cases, the gap will close within a few months after the expander is removed.

However, a fixed gap doesn’t mean the treatment is complete. You or your child may still need braces to fix the bite and fine-tune all the details.


Palate expanders are a valuable orthodontic tool that can help correct a variety of dental issues, including overcrowding and crossbites. While the creation of a gap between the front teeth may seem concerning at first, it is a normal and expected part of the treatment process, and the gap will eventually close on its own.

Patients should be aware of the potential side effects associated with palate expanders, but in general, the benefits of this treatment far outweigh the risks. If you have any concerns or questions about palate expanders or any other orthodontic treatment, be sure to discuss them with your dentist or orthodontist.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *