Underbite, crossbite and open bite: braces, aligners or jaw surgery?

The short answer

Braces, and in many cases aligners with elastics, can treat an underbite, a crossbite or an open bite when the problem lies in the position of the teeth. When the cause is the jaws themselves — a skeletal problem — orthodontics alone may not be enough, and jaw surgery alongside braces is the treatment the American Association of Orthodontists describes. Which kind you have is decided by an orthodontist from X-rays and records, not from a photograph or a quiz.

The makers' claims run wider than the regulators' caution, and the gap matters if you are paying. This page lays both out as read on 18 Oct 2026, defines each bite problem in the AAO's own terms, and shows how one state Medicaid programme scores them when it decides whether treatment is funded at all.

Three bite problems, defined

Underbite. The AAO's glossary says the lower front teeth or jaw sit ahead of the upper front teeth or jaw, and that this is also known as a Class III malocclusion — one where the lower teeth or jaw are positioned ahead relative to the upper.

Crossbite. Upper back teeth are in crossbite, the glossary says, if they come in and contact inside or outside the lower back teeth; lower front teeth are in crossbite if they come in in front of the upper front teeth. A crossbite can involve a single tooth or a group of teeth.

Open bite. A malocclusion in which teeth do not make contact with each other. With an anterior open bite, the front teeth do not touch when the back teeth are closed; with a posterior open bite, the back teeth do not touch when the front teeth are closed.

Notice that a single front tooth in crossbite and a whole lower jaw sitting forward can both be described in the same words. That is why the label on its own tells you very little about treatment or cost. The overbite, the fourth common bite question, has its own chapter.

Teeth or jaw: the distinction that decides everything

A bite can be off because the teeth are tilted or placed wrongly on jaws that are the right size and shape — a dental problem — or because the jaws themselves are out of proportion or position — a skeletal one. Braces and aligners move teeth. Where the jaws themselves are the problem, the AAO's answer is surgery to reposition them, with orthodontic treatment before and after.

Align Technology's own guide to open bite makes the same split. It lists causes including tongue thrusting, digit sucking, mouth breathing, genetics affecting jaw growth, and jaw injuries, and says jaw surgery may be necessary for more severe cases caused by jaw position rather than tooth position. That is a sentence worth noting, because it comes from a company that sells aligners.

Telling the two apart is what the AAO's diagnostic records are for. Its glossary lists them as a health history, an examination, a scan or models of the teeth, photographs, and panoramic and cephalometric X-rays. The cephalometric X-ray is the side view of the skull that shows the jaws in relation to each other — the image no smartphone picture can replace.

What braces do for each

With fixed braces, the orthodontist has direct control of every tooth through brackets and wire, and elastics running between the upper and lower teeth add force in directions braces alone cannot manage. The AAO describes elastics as essential for correcting bite issues, which is exactly what all three of these are. How elastics work, and the rules for wearing them, are covered in this site's chapter on orthodontic rubber bands.

For a crossbite in the upper back teeth, a common tool is a palate expander, which widens the upper jaw while it is still growing; the expander chapter covers what that is billed under. For a growing child with an underbite, timing is part of the treatment, which is why the AAO recommends a first orthodontic check-up by age 7.

What aligners can do — and what the makers say

The regulator is more cautious than the marketing. The FDA's consumer page places clear aligners in the mild-to-moderate range — crowding, spacing and some bite problems — and says harder cases may call for fixed braces or another approach; it also lists, as a limitation, that aligners may fall short on complex cases.

The makers describe their products more broadly. Ormco's FAQ says orthodontists use Spark aligners for open bite, deep bite, overbite, underbite, crossbite, crowding and spacing. Align's open-bite guide names braces, clear aligners and surgery as options depending on severity. Both are true statements about what a system can be used for; neither is a statement about your case.

In practice, aligner treatment for a bite problem usually means aligners plus elastics, attachments and sometimes several rounds of refinement trays. Ask how many trays and refinements the plan expects, because that is where an aligner quote for a bite case most often grows.

Children: why the age matters

Bite problems are easier to read, and sometimes easier to influence, while a child is still growing. The AAO recommends a first orthodontic check-up by age 7, when children have a mix of baby and permanent teeth, and says that if a parent notices something that looks off earlier there is no need to wait.

Several of the warning signs the AAO lists for parents belong to this page: difficulty chewing or biting, mouth breathing, the jaw shifting or clicking — which it links to a bite problem and to jaw pain — and constant cheek biting, which it says can mean the upper and lower teeth are not fitting together properly. None of those is a diagnosis; each is a reason to book the check-up.

The AAO also lists the questions a first exam should answer: whether there is a problem and what it is, what the options are, how long treatment would take, and what it would cost. If the answer to the first question is that it is too early, the useful follow-up is when to come back. What children's treatment is billed at is set out in the chapter on braces for kids.

When jaw surgery comes in

The AAO describes surgical orthodontics, or orthognathic surgery, as corrective jaw surgery to remedy skeletal problems that affect the ability to bite, chew and speak. It is a team effort: the orthodontist refers you to an oral surgeon before orthodontic treatment begins, braces are usually fitted first to line the teeth up for the new jaw position, and orthodontic treatment continues for a while afterwards.

The AAO calls these major surgeries that will likely require an overnight stay in a hospital or surgical centre, and says most patients should plan a week off school or work, with dietary changes for the first few weeks. That is a medical procedure with its own costs and its own coverage questions — often under medical rather than dental insurance — and the oral surgeon's office is the place to price it.

What insurers and Medicaid call medically necessary

Coverage for these problems turns on whether the bite is judged a handicap or a cosmetic concern, and public programmes write that test down. Oregon's Medicaid programme publishes the scoring form its dentists submit with a prior-authorisation request: the Handicapping Labio-Lingual Deviation (HLD) Index, California Modification, revised December 2024.

Read the table for its logic rather than its numbers. A front crossbite earns automatic approval only when it is damaging the gum; a two-sided back crossbite scores nothing at all; and an underbite is measured to the millimetre. The form also asks whether the patient has had a general dental exam, finished treatment for decay and is free of gum disease. Other states use their own versions and thresholds, so treat Oregon's as an example of the method, not the rule where you live.

Private plans are less explicit but follow the same idea. The 2026 UnitedHealthcare FEDVIP brochure excludes services used exclusively to alter vertical dimension or restore or maintain the occlusion, and every brochure read for this site requires services to be necessary for the treatment of a covered condition. What the lifetime orthodontic maximums then reach is set out in the lifetime-maximum chapter, and the course lines themselves are on the cost working.

Questions for the consultation

1. Is my bite problem dental, skeletal, or both — and what in my X-rays tells you that?
2. Could braces alone correct it, could aligners with elastics, and would either leave a compromise?
3. If surgery is an option, would it be now or after growth stops, and who would do it?
4. How many months, and for aligners how many trays and refinements, does the plan expect?
5. Will you submit a pre-treatment estimate, and does my bite meet my plan's or programme's criteria?