How to Fix an Underbite: Causes, Treatment Options, and Cost
An underbite is a bite in which the lower teeth sit in front of the upper teeth when the jaws close. In a growing child it is often corrected by guiding upper jaw growth forward. In an adult with a severe underbite, braces combined with jaw surgery is the reliable correction. Timing changes the options more than any other condition.
Dr. Jenée Kaplan, DDS
Orthodontic residency and a Master’s degree at Loma Linda University. Member of the American Association of Orthodontists, the American Dental Association, and the California Dental Association.
What is an underbite?
In a normal bite the upper arch sits slightly outside the lower one all the way around. An underbite reverses that at the front: the lower incisors close ahead of the uppers instead of behind them. It may involve only one or two teeth, or the whole front segment, and in some patients the reverse extends to the back teeth as well.
Underbites come in two varieties that look similar and behave completely differently. A dental underbite is a matter of tooth angle — upper front teeth tipped back, lower ones tipped forward, on jaws that are proportionally fine. A skeletal underbite is a matter of jaw size or position, usually an upper jaw that grew too little rather than a lower jaw that grew too much, which is the opposite of what most patients assume.
Of the eight conditions on this site, this is the one where age changes the answer most. The same underbite is a straightforward growth-guidance case at eight and a surgical conversation at twenty-two.
What causes an underbite?
- Inherited jaw proportion
- The dominant cause, and often visible across generations in family photographs. A deficient upper jaw or a prominent lower one is inherited in the same way height is.
- A narrow or retruded upper jaw
- Most skeletal underbites are an upper-jaw shortfall. This is worth knowing because it is the more treatable half of the equation — upper jaw growth can be encouraged in a child, whereas slowing lower jaw growth cannot be done reliably.
- Airway and habit
- Chronic mouth breathing and a low resting tongue position deprive the upper arch of the outward pressure that normally widens it, and a forward-posturing jaw can become habitual. These do not create a skeletal underbite on their own, but they shape how one develops.
- A single tooth erupting in reverse
- Sometimes one upper incisor comes in behind the lower teeth and the patient shifts the jaw to avoid the collision. That functional shift can look like a jaw problem and is not one — it resolves once the tooth is moved.
Why does an untreated underbite matter?
- Wear on the wrong surfaces. In a reverse bite the enamel contacts that were never designed to take load do the work, and the lower front teeth in particular wear at the back edge where it is hard to see and hard to restore.
- Gum recession. Lower front teeth pushed forward of the arch sit in thin bone with thin gum over it. Recession there is common, progressive, and much easier to prevent than to repair.
- Chewing efficiency. Front teeth in a reverse relationship cannot shear. Patients compensate by tearing with the canines or cutting food smaller, usually without noticing they have adapted.
- Jaw strain. A bite the patient has to posture around loads the joint and the muscles asymmetrically. This is where an underbite and jaw pain often turn up together.
- Speech. A significant underbite can affect s, sh and f sounds because it changes where the tongue and lip meet the teeth. Where speech is a concern it is evaluated properly, not assumed from the bite alone.
How is an underbite treated?
Upper jaw growth guidance in a child
For a growing child, an expander to widen the upper jaw, often paired with an appliance that pulls it forward, can normalize the relationship while the bones are still responsive. It treats the cause rather than disguising it, and it depends entirely on growth still being available.
Who it suits: Children roughly seven to ten with a skeletal underbite. Time-sensitive in a way little else here is — the same appliance in the same child produces a fraction of the result four years later, and none at all in an adult.
Braces to correct tooth position
Where the jaws are proportionally acceptable and the problem is tooth angle, braces upright the upper incisors and retract the lower ones into a normal relationship. In mild skeletal cases the same mechanics camouflage the difference to an outcome the patient is happy with.
Who it suits: Dental underbites at any age, and mild skeletal ones where the patient prefers camouflage to surgery after hearing what each achieves. Not appropriate for a large skeletal discrepancy — pushing teeth that far compromises the gum and relapses.
Clear aligners
Aligners handle mild underbites and single-tooth reverse bites well, with elastics where a small amount of bite correction is needed. The trays are removable, which matters to adults who did not want this conversation to end in brackets.
Who it suits: Mild to moderate dental underbites in a patient who will wear trays twenty-two hours a day. Not a substitute for surgery in a skeletal case, and any presentation suggesting otherwise should be treated skeptically.
Surgical orthodontics
For a severe skeletal underbite in a finished skeleton, braces align each arch and an oral and maxillofacial surgeon moves the upper jaw forward, the lower jaw back, or both. It is planned jointly from the start, with the surgical position decided before the first bracket is placed.
Who it suits: Adults whose underbite is skeletal and large. It is a real operation with real recovery, and it is also the only approach that gives a normal bite in those cases rather than a compromise. Patients get told which category they are in plainly.
When is an underbite treated, and at what age?
Children, roughly seven to nine
This is the evaluation that changes the most. An underbite identified while the upper jaw can still be widened and advanced is often corrected without surgery ever entering the picture. Missing the window does not make treatment impossible; it changes what treatment has to be. Early correction does not guarantee the result holds, either — the lower jaw keeps growing, and some children treated successfully at eight still need a surgical conversation in their late teens. It changes the odds substantially; it does not close the question.
Teenagers
Some growth usually remains, though the lower jaw often keeps growing into the late teens in exactly the cases where that is unwelcome. Planning frequently involves waiting and monitoring growth rather than starting and finishing early, and that patience is deliberate rather than delay.
Adults
Growth is finished, so the choice is camouflage with braces or aligners, or surgical correction. Both are legitimate. The job of the consultation is to say honestly what each one will and will not achieve for that specific face and bite, and then let the patient choose.
What does it cost to fix an underbite?
Orthodontic fees are quoted per case rather than per condition, because two people with the same diagnosis can need very different treatment. These are the factors that move the number up or down, so you know what you are being quoted on:
- Whether growth guidance in childhood replaces comprehensive treatment later, or precedes it.
- Camouflage with braces or aligners versus a combined surgical plan — a difference in kind, not degree.
- Surgical cases carry separate surgeon, anaesthesia, and facility fees beyond the orthodontic fee.
- Treatment length, which in growth-dependent cases includes monitoring visits over several years.
- Medical as well as dental insurance, since jaw surgery for a functional skeletal problem is sometimes a medical benefit rather than an orthodontic one.
Ask for the fee, the payment schedule, and your insurance benefit in writing at the consultation, before you decide anything. Any orthodontic practice should give you all three without being pressed.
When should you see an orthodontist about an underbite?
- As early as an underbite is noticed, and no later than age seven. This is the condition where early evaluation changes the outcome most, because upper jaw growth can be used and cannot be recovered.
- If a child shifts the jaw sideways or forward to bring the teeth together.
- If one upper front tooth is erupting behind the lower teeth — that is worth an appointment now rather than at the next cleaning.
- In an adult, if the lower teeth sit ahead of the uppers and there is wear on the front teeth, gum recession, or jaw discomfort.
Questions patients ask about underbites
Can an underbite be fixed without surgery?
Frequently, yes. In a growing child, guiding upper jaw growth corrects many underbites with no surgery at all. In adults, braces or aligners can camouflage a mild to moderate underbite. Surgery becomes the honest answer when the skeletal difference is large and growth is finished.
What is the best age to treat an underbite?
Roughly seven to nine, while the upper jaw still responds to widening and forward traction. That is earlier than for most orthodontic problems, and it is the reason the profession recommends a first evaluation at seven rather than waiting for all the adult teeth.
Is an underbite caused by the lower jaw being too big?
Usually not. Most skeletal underbites are an upper jaw that grew too little, which is the more treatable half. Records taken at the examination measure both jaws, so the plan addresses the one actually at fault rather than the one that is easier to see in a mirror.
Will an underbite get worse over time?
In a growing patient it often does, because the lower jaw is typically the last part of the face to finish growing. In an adult the bite is usually stable, but the wear and gum recession it causes keep accumulating, which is why adults are treated for damage control as much as appearance.
Do clear aligners work for an underbite?
For mild dental underbites and single reverse teeth, yes, and they do it well. For a large skeletal underbite, no — no removable tray moves a jaw. Any plan that promises otherwise is worth a second opinion, and asking to see the measurements it is based on.