An underbite is a bite where the lower front teeth sit in front of the upper front teeth when you close. It can come from the teeth, the jaws or both. Many underbites are easiest to correct while a child is still growing, though adults have options too.
Parents sometimes notice an underbite in a young child’s photos, and adults may have lived with one for years without knowing whether it can be fixed. Either way, the first question is the same: is the problem in the position of the teeth, or in how the upper and lower jaws have grown? Below we explain the difference, the signs to look for, how treatment changes with age, and what to expect from an orthodontic evaluation.
What Is an Underbite?
In a typical bite, the upper front teeth rest slightly in front of the lower front teeth. In an underbite, that relationship is reversed, so the lower teeth overlap the upper teeth from the front. Orthodontists sometimes call this an anterior crossbite when only a few front teeth are involved, or a Class III bite when the whole lower arch sits forward of the upper arch.
An underbite is one of several bite problems orthodontists treat. Our braces for kids page lists overbites, underbites, crossbites and open bites among the signs that make an evaluation worthwhile, along with difficulty chewing and jaws that shift, click or pop.
What Causes an Underbite?
Underbites tend to fall into two groups. A dental underbite happens when the teeth are tipped or positioned so the lower front teeth end up ahead of the upper ones, even though the jaws themselves are reasonably balanced. Sometimes a child bites forward into an underbite because a tooth gets in the way, and the jaw slides forward to compensate.
A skeletal underbite happens when the jaws themselves are out of proportion. The upper jaw may be small or set back, the lower jaw may be large or grow forward, or both. Skeletal patterns often run in families, so if a parent or grandparent has an underbite, it is worth having a child checked early. Habits that affect jaw growth, such as long-term mouth breathing or pushing the tongue forward, can also play a role.
Telling these two types apart is the heart of an orthodontic diagnosis, because a dental underbite can often be corrected by moving teeth, while a skeletal one may need help with jaw growth or, in adults, a combined surgical plan.
What Signs of an Underbite Should You Watch For?
Some underbites are obvious: when your child bites down, the lower front teeth sit clearly in front of the upper ones. Others are subtler. In profile, the chin may look prominent or the lower lip may sit ahead of the upper lip. A child may bite with the jaw pushed forward, or the jaw may shift to one side or forward as the teeth come together, which can be a sign that a tooth is guiding the bite into the wrong position.
Functional clues matter as much as appearance. Difficulty biting into foods with the front teeth, chewing mainly on the back teeth, unusual wear or chipping on the front teeth, or jaw discomfort can all point to a bite that is not meeting correctly. Mouth breathing and speech challenges related to jaw alignment are also on our list of signs that make an early visit worthwhile.
Family history is one of the most useful clues for skeletal underbites. If a parent, grandparent or sibling has a prominent lower jaw or had jaw surgery, mention it at the evaluation. It helps Dr. Razi judge how the jaws are likely to grow and how closely to monitor a young child.
Why Is Early Treatment So Important for Underbites?
Some orthodontic problems are much easier to correct while a child is still growing, and many underbites fall into that group. A child’s jaw bones are more adaptable, so treatment can work with growth instead of against it. The American Association of Orthodontists and Dr. Kaleem Razi both recommend an orthodontic evaluation at age seven, when an orthodontist can spot developing jaw concerns even when they are not obvious to parents.
On our early orthodontic treatment page, we explain that Phase I can redirect and guide jaw growth and improve how the upper and lower jaws fit together. For a child whose upper jaw is narrow or underdeveloped, a palate expander may be part of that plan. Most children complete Phase I in six to twelve months, followed by observation while adult teeth come in.
Early treatment does not always mean braces right away. Many children seen at seven do not need treatment yet. If that is the case, Dr. Razi monitors growth with periodic checkups, and that monitoring is free. Our article comparing Phase 1 and Phase 2 orthodontics explains how the two stages fit together.
| Stage of life | What treatment can focus on | Typical tools |
|---|---|---|
| Young child, still growing | Guiding jaw growth and how the jaws fit together | Phase I care, such as a palatal expander |
| Teen | Aligning teeth and refining the bite | Braces or Invisalign, sometimes with elastics |
| Adult, dental underbite | Moving teeth to correct the overlap | Braces or Invisalign |
| Adult, skeletal underbite | Correcting jaw position | Orthodontics combined with jaw surgery, when needed |
How Is an Underbite Fixed in Teens and Adults?
Once growth slows, treatment shifts from guiding the jaws to moving the teeth. For many dental underbites and mild skeletal ones, braces or clear aligners can tip and reposition the teeth so the upper front teeth sit in front again. Elastics that run between the upper and lower teeth often help with this bite correction. Our braces for adults page notes that adults with crowding, gaps, an overbite, an underbite or a crossbite can often reach a straighter, healthier smile with braces or Invisalign.
When the jaws themselves are significantly out of balance in an adult, moving teeth alone may not be enough to create a healthy bite. In those cases, an orthodontist may recommend a plan that combines braces with jaw surgery performed by an oral surgeon. Whether that is necessary depends on the size of the jaw difference, your goals and your health, and it is a decision made only after a thorough evaluation.
Can Invisalign Fix an Underbite?
For some mild and dental underbites, yes. Invisalign uses attachments and sometimes elastics to guide bite movements. More severe or skeletal cases may be better suited to braces or a combined plan, and Dr. Razi will explain which applies to you.
Frequently Asked Questions
Will a child grow out of an underbite?
Skeletal underbites usually do not correct themselves and can become more noticeable with growth. That is why an evaluation by age seven is so helpful.
Is an underbite only a cosmetic problem?
No. An underbite can affect chewing, wear on the front teeth and how the jaws work together. Treating it supports function as well as appearance.
Does every underbite need surgery?
No. Many underbites are treated with orthodontics alone, especially when treatment starts during growth. Surgery is reserved for adults with significant jaw imbalances.
How do I know which type of underbite I have?
An orthodontic exam with photos and X-rays shows whether the issue is in the teeth, the jaws or both. That answer shapes the whole plan, including timing, the appliances used and whether a surgical consultation is worth discussing.
Get a Clear Answer About Your Child’s Bite
Dr. Kaleem Razi earned his dental degree at the University of Pennsylvania and completed his orthodontic residency at the University of Louisville. If you are a parent noticing an underbite or an adult ready to correct one, schedule a free consultation at our Wheaton or Naperville office, or call (630) 614-1162.