Dr. Greg Jorgensen
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Rio Rancho, NM 87124

The Jorgensen Orthodontics Blog

My Orthodontic Expander Made a Huge Gap Between My Teeth

Posted by Dr. Jorgensen on January 25th, 2013

Over the past couple of decades there has been a shift in orthodontics from extracting teeth to expanding the arches when there is crowding present. Expanders work great, but there are some side effects that catch parents by surprise. One of them is the appearance and disappearance of a gap between the front teeth.

The palate or roof of the mouth is made up of two bones joined together down the center by a junction called a suture. When a patient is young, this suture is made up of stretchable cartilage that is the area where growth takes place (a “growth plate”). After skeletal maturation somewhere between 14 and 17 years of age, this suture fuses and the palate becomes a single solid structure. Expanders take advantage of the presence of the growth plate if they are used before it is fused. One sign that the expander has actually moved the two halves of the palate apart is the appearance of a space between the front teeth. The central incisors are located on different sides of the growth plate and they spread apart as the palate is expanded. The result is a visible gap between the teeth. This gap is normal and desirable.

After the expander has provided the desired amount of expansion, the orthodontist will typically leave it in place for several months holding the two halves of the palate apart while new bone develops between them. Upon removal of the expander, there is always some relapse or loss of arch width. Most orthodontists over-correct by a few millimeters in anticipation of this change.

During this stabilization period, the gap created during expansion tends to close on its own. This happens slowly over time, but it shocks many parents the first time they notice it is smaller or gone altogether. Understandably, many parents call our office worried that the expander has slipped and that the benefits achieved during the activation phase have been lost.

During palatal expansion there are two forces on the teeth. The force created by the expander pushes the palate apart and a gap appears between the teeth. At the same time there is an opposite force acting on the teeth produced by the gum tissues. Just like other soft tissues in the body, the gums are elastic. As the expander pushes outward, the gum tissue starts pulling the teeth back together. You can tell this is happening by comparing the size of the gap between the teeth with the amount of expansion visible on the expander. Rarely will the size of the gap between the teeth ever get as large as the distance between the two sides of the expander because the teeth start moving back together even before expansion is complete. Another sign that the front teeth are being pulled back together is that they get sore and feel a little loose during expansion for no obvious reason (just like when braces are moving them). Now you know that they are being pulled back together by the elastic fibers in your gum tissue. In fact, it is not uncommon for the gap between the two front teeth to be completely closed by the time the expander is removed.

Knowing ahead of time that an expander will create a gap between the front teeth and that it will go away on its own is reassuring when it happens. Understanding what is normal will save you some worry and an unnecessary phone call to your orthodontist. If what you see in your mouth or in the mouth of your child does not seem to follow the pattern described however, give your orthodontic office a call and let them know. It is better to be safe than sorry!

NOTE: The author, Dr. Greg Jorgensen, is a board-certified orthodontist who is in the private practice of orthodontics in Rio Rancho, New Mexico (a suburb on the westside of Albuquerque). He was trained at BYU, Washington University in St. Louis, and the University of Iowa in the United States. Dr. Jorgensen’s 25 years of specialty practice and 10,000 finished cases qualify him an expert in two-phase treatment, extraction and non-extraction therapy, functional orthodontics, clear aligners (Invisalign), and multiple bracket systems (including conventional braces, Damon and other self-ligating brackets, Suresmile, and lingual braces). This blog for informational purposes only and is designed to help consumers understand currently accepted orthodontic concepts. It is not a venue for debating alternative treatment theories. Dr. Jorgensen is licensed to diagnose and treat patients only in the state of New Mexico. He cannot diagnose cases described in comments nor can he select treatment plans for readers. Because he has over 25,000 readers each month, it is impossible for him respond to all questions. Please read all of the comments associated with each article as most of the questions he receives each week have been asked and answered previously. The opinions expressed here are protected by copyright laws and can only be used with written permission from the author.

206 comments so far in response to “My Orthodontic Expander Made a Huge Gap Between My Teeth”

  1. Alfredo says:

    I have been using my expander for a month now for the first 2 weeks I noticed a gap between my teeth but now I don’t have that gap between my teeth anymore!? What should I do?

  2. Wei says:

    Hi Dr. Jorgensen,
    my daugther just turns to 6 years old. She had Orthodontic evaluation last week. Her doctor said that she needs to wear the expander to make more room for her future teeth to come down. She lost her two bottom teech when she was five and half. At that time, we had to extract two her extra bottom teeth in order to give space to her permanent teeth to come out. From her Xray, I could see her permanent teeth are very crowded in her bone or gum. Her doctor wants her to wear the expander right now. My question are:
    – Is it too early to let her wear right now? Can we wait until her two top permanent teeth come out? (she still has her baby teeth on the top, We think she is too young to suffer these.)
    – Is the expander going to change her facial appearance?
    Thank you so much!

    • For me, the best time to begin expansion is after the permanent first molars are fully erupted. That usually occurs around 6 years of age. As for changes in her facial appearance, there will be some temporary changes, but the faces adapts well and everything reverts to normal in a short time.

  3. PAM says:

    My daughter is 15 and she had the top braces and a w arch placed in her mouth yesterday. She is supposed to go back in 6 weeks to have arch removed and herbst appliance will be addded. She already has a gap in her two front teeth will this get bigger.

  4. sarah chan says:

    My daughter just got her expander installed in her upper jaw, and she is 11 years old. I was wondering whether or not 11 years old is a bit late to correct her under bite problem? Does she need addition procedures such as braces after the expander remove in continuing correct her under bite problem? What is the next step after expander remove. How long would it take for my daughter to wear this expander? Does she still jaw surgery after expander remove?

    • An expander can help widen the upper jaw, but it does nothing for increasing the length. In fact, under bites are genetic in nature and there is very little that can be done to change the jaw size. If the discrepancy is mild to moderate, elastics, springs, a facemask, or springs may move the teeth enough to compensate. If the problem is severe however, surgery is sometimes the only way. Your daughter is too young to be able to predict what she will need, but the timing of the expander is good if her upper jaw was narrow.

  5. DGMullins says:

    My daughter (13) will be getting braces for a mild overbite and to correct spacing issues. She actually has too much space between her top teeth, with a gap in front and on the sides. The orthodontist recommends an expander for both upper and lower teeth, though she does not have a crossbite or an abnormally narrow palate. He says it will “widen her smile” and that other than discomfort, there are no down sides.

    Is this common? Should I be alarmed?


    • I would not be alarmed, but I would ask questions. If your daughter has no crossbite, normal arch forms, and extra space, I would ask why the expander is needed. The arches can be widened with wires and braces alone.

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