A crossbite is a bite problem where some upper teeth sit inside the lower teeth when you close, instead of slightly outside them. It can affect a single tooth or a whole side, and orthodontists usually correct it with expanders, braces or clear aligners.
A crossbite is easy to miss. It rarely hurts, and many people only learn they have one when a dentist points it out or when a child’s jaw starts to look a little off center. Because it can shape how the jaws grow and how teeth wear, it is one of the bite problems orthodontists like to catch early.
What Does a Crossbite Look Like?
In a healthy bite, the upper teeth fit just outside the lower teeth all the way around, a bit like a lid sitting over a box. With a crossbite, part of that relationship is reversed. One or more upper teeth land behind or inside their lower partners when you bite together.
Orthodontists describe two main kinds. An anterior crossbite involves the front teeth, where one or more upper front teeth sit behind the lower front teeth. It can look similar to an underbite, but it usually involves only a few teeth rather than the whole jaw. A posterior crossbite involves the back teeth, where upper molars or premolars sit inside the lower ones on one side or both.
You may also hear the terms dental and skeletal. A dental crossbite comes from the position or angle of the teeth themselves. A skeletal crossbite comes from the jaws, most often an upper jaw that is narrower than the lower jaw. The difference matters, because it changes which treatment will work best.
What Causes a Crossbite?
Most crossbites have more than one cause. Genetics plays a large part, since jaw size and shape tend to run in families. A narrow upper jaw is one of the most common reasons back teeth end up biting inside the lower teeth.
Childhood habits can contribute too. Long-term thumb or finger sucking, prolonged pacifier use and a tongue that rests low in the mouth can all influence how the upper jaw develops. Breathing through the mouth instead of the nose, often linked to enlarged tonsils, adenoids or allergies, can change tongue posture and has been associated with a narrower palate. Our post on habits that could be harming your teeth goes into more of these.
Timing of tooth eruption matters as well. Baby teeth lost too early or too late, crowding or a permanent tooth that comes in at an odd angle can push a single tooth into crossbite even when the jaws themselves are well matched.
Why Should a Crossbite Be Treated?
A crossbite is more than a cosmetic concern. When teeth meet in the wrong position, they can rub against each other in ways they were not designed for. Over time, that can wear down enamel, chip edges or put extra pressure on the gums around the affected teeth.
A posterior crossbite on one side often makes the lower jaw slide over to one side so the teeth can fit together. In a growing child, that repeated shift can encourage the jaw to develop unevenly, which can affect facial symmetry. In adults, an uneven bite may add strain to the jaw joints and muscles. Some people with bite problems also report jaw discomfort, which our post on TMJ disorders covers in more detail.
Crossbites can also make chewing less efficient and, in some cases, play a part in certain speech sounds. None of these problems tend to fix themselves, and a skeletal crossbite generally becomes harder to correct once the jaws stop growing.
How Do Orthodontists Fix a Crossbite?
Treatment depends on the type of crossbite, which teeth are involved and the patient’s age. The goal is the same in every case: get the upper teeth back outside the lower teeth so the bite closes evenly and the jaw no longer needs to shift.
For a narrow upper jaw in a child, the usual first step is a palate expander. It gently widens the upper jaw while the bones are still responsive, creating room for the upper back teeth to sit outside the lower ones. Our post on palate expanders and why timing matters explains how expansion works and why it suits younger patients best. At ARCH, this kind of growth guidance is part of the dentofacial orthopedics and two-phase treatment we provide for children.
For a dental crossbite, where the jaws are well matched but a tooth is tipped the wrong way, braces can move the tooth into place. Elastics are often added to help the upper and lower teeth meet correctly. Many dental crossbites can also be treated with clear aligners, sometimes with small attachments bonded to the teeth to help the aligners grip and guide them.
Adults with a skeletal crossbite have fewer options for changing jaw width, because the bones have finished growing. Orthodontists may still improve the bite by moving teeth, and the most severe skeletal cases can call for a combination of orthodontics and jaw surgery.
| Crossbite type | What is happening | Common treatment options |
|---|---|---|
| Anterior dental | One or more upper front teeth tipped behind the lower teeth | Braces or clear aligners to tip the teeth forward |
| Posterior dental | Individual upper back teeth tipped inward | Braces, often with elastics, or clear aligners |
| Posterior skeletal, child | Upper jaw narrower than the lower jaw | Palate expander, then braces or aligners if needed |
| Posterior skeletal, adult | Narrow upper jaw after growth has finished | Tooth movement with braces or aligners; surgery in severe cases |
When Should a Child Be Checked for a Crossbite?
We follow the American Association of Orthodontists recommendation that children see an orthodontist for an evaluation by age seven. By then, the first permanent molars and front teeth are usually erupting, and problems like dental crossbites and crowding can be assessed before they become harder to treat.
A check at seven does not mean treatment starts at seven. Many children simply come back for periodic visits while we watch their growth. When a crossbite is causing the jaw to shift, though, treating it early can guide the jaws toward a better relationship and may make later treatment simpler. Our post on what age is right for braces walks through how we decide on timing.
Can Adults Fix a Crossbite Without Surgery?
Often, yes. Many adult crossbites are dental rather than skeletal, which means the teeth are angled incorrectly while the jaws are reasonably matched. Those cases usually respond well to braces or clear aligners alone.
Even mild skeletal crossbites can sometimes be improved by tipping the upper back teeth outward and the lower back teeth slightly inward until the bite meets correctly. Detailed records help us judge what is realistic. At ARCH, we use digital X-rays and 3D cone beam imaging, described on our technology page, to see the teeth, roots and jaw structure before recommending a plan.
If your crossbite turns out to be more skeletal than dental, your orthodontist will talk through every option honestly, including what can be achieved with orthodontics alone and when a surgical consultation makes sense.
Frequently Asked Questions
Will a crossbite correct itself?
A crossbite rarely goes away on its own, especially when it comes from a narrow upper jaw. In some young children a single baby tooth in crossbite can change as permanent teeth erupt, which is why an early orthodontic check is useful.
Is a crossbite the same as an underbite?
Not quite. An underbite usually means all of the lower front teeth sit ahead of the upper front teeth. An anterior crossbite often involves only one or a few teeth, and a posterior crossbite involves the back teeth instead of the front.
Can Invisalign fix a crossbite?
Many dental crossbites can be corrected with Invisalign, sometimes with attachments or elastics added. Skeletal crossbites from a narrow jaw may need an expander first. Your orthodontist will tell you which applies to your bite.
How long does crossbite treatment take?
It varies with the type of crossbite and the patient’s age. Expansion in a child is typically one stage of a longer plan, while adult treatment with braces or aligners follows the full length of comprehensive orthodontic care.
Schedule a Crossbite Evaluation at ARCH Orthodontics
If you have noticed a tooth biting inside the others, a jaw that shifts to one side or uneven wear on your teeth, an orthodontic exam is the place to start. Our orthodontists see children, teens and adults at offices in Bridgewater, Canton, Hyannis, Hyde Park, Orleans and Westwood. Book a free consultation and we will look at your bite and explain your options.