How to Fix an Underbite: Kids, Adults & Surgery

Dental vs. skeletal underbites, early treatment, and when surgery is needed.

If your lower front teeth close in front of your upper front teeth, or your child's chin seems to sit a little further forward each year, you are probably looking at an underbite. Learning how to fix an underbite starts with two simple questions, and the answers usually point to a clear plan.

Underbites are less common than overbites, but they are one of the bite problems where timing matters most. At Montclair Orthodontics in Oakland, board-certified orthodontist Chad Watts, DMD evaluates underbites in children, teens, and adults from across the East Bay. This guide explains what is really behind an underbite, what treatment looks like at each age, and when jaw surgery is (and is not) part of the conversation.

The Quick Answer

An underbite, also called a Class III bite, means your lower front teeth sit in front of your upper front teeth when you bite down. It affects an estimated 5 to 10 percent of people.
The right fix depends on two things: whether the problem is in the teeth or the jaw bones, and whether the jaws are still growing.
Growing children can often have the upper jaw guided forward with an expander paired with a reverse-pull face mask.
Teens and adults with tooth-driven or mild skeletal underbites are often treated with braces and elastics, or clear aligners in select mild cases.
Jaw surgery is generally reserved for significant skeletal underbites after growth is complete.
Only an in-person exam with X-rays can tell which group you are in.

What Is an Underbite?

In a healthy bite, your upper front teeth rest slightly in front of your lower front teeth. An underbite reverses that relationship: the lower front teeth close ahead of the upper ones. Orthodontists call this a Class III malocclusion, which simply means a bite where the lower jaw or lower teeth sit too far forward compared with the upper jaw or upper teeth. It is essentially the opposite of an overbite.

Underbites are more common than many people expect. Both the American Association of Orthodontists and Cleveland Clinic estimate that about 5 to 10 percent of people have one. They range from a barely noticeable edge-to-edge bite to a lower jaw that visibly juts forward. Mild cases may never need treatment. More pronounced cases usually do.

Dental vs. Skeletal Underbite: Why the Cause Decides the Fix

Two people can have underbites that look identical in a mirror and need completely different treatment. That is because an underbite can come from three places:

Dental underbite. The jaws are reasonably balanced, but the front teeth are tipped or positioned so the lower ones end up in front. These often respond well to tooth movement alone.
Skeletal underbite. The jaw bones themselves are mismatched. The lower jaw may be larger or positioned forward, the upper jaw may be underdeveloped, or both.
A combination. Many real-world underbites have both a dental and a skeletal component.

Here is the detail that surprises many parents: in a skeletal underbite, the lower jaw is not always the culprit. Cleveland Clinic notes that an underbite can come from a lower jaw that is larger than the upper jaw, or from an upper jaw that is underdeveloped. That distinction changes the plan, especially in a growing child.

There is also a look-alike. Sometimes the front teeth bump into each other in an awkward spot and the jaw slides forward to close, creating what orthodontists call a pseudo-Class III bite. It can look like a true underbite but often behaves very differently, which is one more reason a professional exam beats a mirror check.

The Two Questions That Decide Your Underbite Treatment

When Dr. Watts evaluates an underbite, almost every recommendation flows from two questions. Is the problem mainly in the teeth or in the jaws? And is the face still growing? Put those together and you get four broad starting points:

Situation	Typical starting point
Dental underbite, still growing	Braces or a small appliance to reposition the front teeth, sometimes as a short early phase
Skeletal underbite, still growing	Growth guidance, such as an expander with a reverse-pull face mask, followed by monitoring through the teen years
Dental or mild skeletal underbite, growth complete	Braces with elastics, or clear aligners in select mild cases
Significant skeletal underbite, growth complete	Orthodontics combined with jaw surgery

Think of this as a starting map, not a diagnosis. Severity, facial balance, gum health, and your own goals all shape the final plan.

How Do You Know If You Have an Underbite?

Some underbites are obvious. Others are subtle enough that only an orthodontic exam catches them. Common signs include:

Lower front teeth that close in front of the upper front teeth, even slightly
A chin or lower jaw that looks more prominent than the upper jaw
Trouble biting into foods like sandwiches or apples with the front teeth
Speech changes, such as a lisp or difficulty with certain sounds
Jaw discomfort, or uneven and faster wear on the front teeth
Biting the inside of the cheek, or difficulty closing the lips comfortably

Because jaw shape tends to run in families, a parent or sibling with an underbite is a good reason to have a child checked early, even if the bite looks only slightly off.

What Causes an Underbite?

Most underbites come down to how the jaws grow, and that is largely inherited. Both the AAO and Cleveland Clinic point to genetics as a leading factor. Other contributors include:

Uneven jaw growth, where the upper jaw grows less than the lower jaw, or the lower jaw grows more than expected
Childhood habits, such as prolonged thumb-sucking, extended pacifier or bottle use, tongue thrusting, and chronic mouth breathing
Injury to the face or jaw that affects how the bones heal or grow
Rarely, growths in the jaw that change how the teeth meet

Habits are worth addressing early, but they are rarely the whole story for a true skeletal underbite. That is why treatment focuses on jaw growth and tooth position rather than habits alone.

Does an Underbite Need to Be Fixed?

Not always. A mild underbite that causes no problems may simply be monitored. A moderate or severe underbite, however, tends to create issues over time, including:

Uneven tooth wear, chipping, or cracked teeth
Jaw pain and temporomandibular joint (TMJ) problems, which can bring headaches and facial pain
Hard-to-clean areas that raise the risk of cavities and gum disease
Difficulty chewing or speaking clearly
In some cases, breathing and sleep concerns

Cleveland Clinic also notes that an underbite left untreated in childhood can become more pronounced with age, which is one reason earlier evaluation tends to open more options. Correction protects long-term function first. A more balanced profile is often the welcome bonus.

How to Fix an Underbite in Children: Using the Growth Window

Children have the biggest advantage in underbite treatment: their jaws are still growing, and growth can be guided. Cleveland Clinic describes roughly ages 7 to 10 as the best time to treat, because bone is much easier to influence before it matures. It is also why the AAO recommends that every child have a first orthodontic evaluation by age 7.

Expander and Reverse-Pull Face Mask

When a child's underbite comes from an underdeveloped upper jaw, a common approach pairs a palatal expander with a reverse-pull face mask, sometimes called reverse-pull headgear. The expander widens the upper jaw from the roof of the mouth. The removable face mask applies a gentle forward pull that encourages the upper jaw to grow forward.

The research is encouraging. A 2015 meta-analysis in PLOS ONE found that face mask therapy, with or without expansion, produced meaningful forward movement of the upper jaw compared with untreated children. Findings on exact timing vary, but several reviews point to better results when treatment starts younger, often before about age 10.

Braces and Simpler Fixes for Dental Underbites

Not every childhood underbite is skeletal. When one or two front teeth are simply tipped the wrong way, a short phase of braces for children or a small appliance can often correct it. Removing that bite interference early can also help the jaws grow in a healthier relationship.

Why Growing Kids Are Monitored After Treatment

Jaw growth continues through the teen years, and studies following children after face mask treatment have found that later lower-jaw growth can partly undo early gains. So even after a successful first phase, Dr. Watts monitors growth through adolescence. Some children need a second phase with braces once their permanent teeth arrive, and a small number of strongly skeletal cases may still need surgical correction after growth ends. Knowing that upfront helps families plan without surprises.

Not sure what kind of underbite you are dealing with?

A free consultation with Dr. Watts includes an iTero 3D scan and digital X-rays, so you can see exactly what is behind the bite. Book your visit online in just a few clicks.

How to Fix an Underbite in Teens and Adults

Once the jaws have finished growing, growth guidance is no longer an option. Treatment then depends on how much of the underbite comes from tooth position versus jaw structure.

Braces With Elastics

For dental underbites and many mild skeletal cases, braces are the most versatile tool. Brackets and wires reposition the teeth with precise control, and small rubber bands called elastics, worn between the upper and lower teeth, help guide the bite into a better relationship. The AAO describes braces as a reliable choice when an underbite is mainly related to tooth position. Montclair Orthodontics offers metal braces, mini-diamond braces, Clarity clear braces, and Damon self-ligating braces. If crowding is part of the picture, our crowded teeth guide explains how orthodontists create space.

Orthodontic Camouflage: Correcting the Bite Without Moving the Jaw

When a skeletal underbite is mild to moderate, an orthodontist can sometimes compensate for the jaw difference by positioning the teeth so they meet correctly, even though the jaw bones stay where they are. This is called orthodontic camouflage. It can create a healthy, functional bite without surgery, but it has limits. If the jaw difference is large, camouflage may compromise the result or the profile, and a surgical plan can be the better long-term choice.

Can Invisalign Fix an Underbite?

Sometimes. The AAO notes that clear aligners can work well for mild underbites that are mostly dental rather than skeletal. Invisalign can be paired with attachments and elastics to help shift the bite. For strongly skeletal underbites, braces or a combined surgical plan are usually more predictable. Aligners also only work when they are worn about 20 to 22 hours a day.

If You Were Told Years Ago That Only Surgery Could Help

A fresh evaluation is worth it. Digital records let Dr. Watts show you how much of your underbite is dental and how much is skeletal, and which options are realistic today. Some adults are candidates for non-surgical correction; others learn that surgery is the most reliable path. Either way, you decide with clear information. Our adult braces page covers more about treatment as a grown-up.

When Is Jaw Surgery Needed for an Underbite?

Jaw surgery, called orthognathic surgery, is considered when the jaw bones are significantly out of position and tooth movement alone cannot create a healthy, stable bite. According to the AAO, it is typically performed after the jaw has finished growing and is almost always combined with orthodontic treatment before and after the procedure.

Depending on the case, an oral and maxillofacial surgeon may reposition the upper jaw, the lower jaw, or both. The orthodontist aligns the teeth beforehand so they fit together precisely once the jaws are moved, then fine-tunes the bite afterward. The key takeaway: surgery is the exception, not the default. The AAO notes that many underbites, especially mild ones caught early, are treated without it.

How Long Does Underbite Treatment Take?

There is no single answer, because the plan depends on age and cause. As a general guide:

An early growth-guidance phase for a child usually runs for months rather than years, followed by monitoring.
Comprehensive braces or aligner treatment for teens and adults takes longer and depends on severity and consistency.
Surgical cases include orthodontics before and after the procedure, so they take the longest overall.

Our orthodontic timeline guide walks through each stage of treatment. After any underbite correction, consistent retainer wear is what protects the result.

When to See an Orthodontist About an Underbite

Book an evaluation if any of these apply to you or your child:

Your child is 7 or older and has never had an orthodontic evaluation
The lower front teeth close in front of the upper front teeth, even slightly
An underbite runs in your family and you notice early signs in your child
Front teeth are chipping, wearing unevenly, or the jaw is often sore
Biting, chewing, or certain speech sounds are difficult
You were told years ago that you needed surgery and want an updated opinion

An evaluation does not commit you to treatment. Sometimes the best plan is simply to watch growth and check back.

Underbite Care for Oakland, Piedmont, Lamorinda, and Emeryville Families

Families throughout the East Bay come to Montclair Orthodontics, near Montclair Village in Oakland, because underbite treatment works best when diagnosis, growth timing, and every treatment option are under one roof. Board-certified orthodontist Chad Watts, DMD, completed his orthodontic training during eight years in the U.S. Air Force and has a special focus on airway and sleep health, a useful perspective since Cleveland Clinic lists breathing and sleep problems among possible underbite complications.

The practice uses an iTero intraoral 3D scanner and digital X-rays for precise, comfortable records, and is known for fast treatment times, easy financing, and lower price points. Montclair Orthodontics has served East Bay families since 1994, treating children, teens, and adults in a welcoming setting.

Insurance and Payment Options

Montclair Orthodontics is in-network with Delta Dental and helps every patient make the most of their orthodontic benefits.

We Accept All Major Insurance Plans

We also accept all major carriers, including MetLife, Cigna, Aetna, Guardian, United Healthcare, and Blue Cross Blue Shield. Our team will verify your coverage, explain your benefits in plain language, and walk you through easy financing so cost does not stand between your family and a healthy bite. If surgery is part of your plan, ask us how your orthodontic and medical coverage may apply to different parts of treatment.

Frequently Asked Questions About Underbites

Can an underbite fix itself?

A true skeletal underbite does not correct itself, and Cleveland Clinic notes that an untreated underbite can become more pronounced with age. A bite that only looks like an underbite because the jaw slides forward may behave differently, which is why an exam is more useful than waiting.

What is the best age to treat an underbite?

For growth-related underbites, earlier is generally better. Cleveland Clinic points to roughly ages 7 to 10, and the AAO recommends a first orthodontic evaluation by age 7. Adults can still be treated; the options simply shift from growth guidance to tooth movement or surgery.

Can braces alone fix an underbite?

Braces, usually with elastics, can fully correct many dental underbites and some mild skeletal ones. Larger skeletal differences may need growth guidance in children or a combined surgical plan in adults.

Is Invisalign an option for an underbite?

In select mild, mostly dental cases, yes. Clear aligners with attachments and elastics can improve the bite. Strongly skeletal underbites are usually treated more predictably with braces, and sometimes surgery.

How do I know if I need jaw surgery for my underbite?

Only a full evaluation can tell. X-rays and a 3D scan show how far apart the jaws are and whether tooth movement can create a stable, healthy bite. Surgery is generally reserved for significant skeletal underbites after growth is complete.

Can an underbite affect breathing or sleep?

It can in some cases. Cleveland Clinic lists breathing difficulty and sleep apnea among possible complications. If your child snores, breathes through the mouth, or seems tired during the day, mention it at the evaluation.

Why does my child need monitoring after early underbite treatment?

Jaws keep growing through the teen years, and research shows later lower-jaw growth can partly reverse early gains. Regular checks let your orthodontist spot changes and plan a second phase if needed.

Is fixing an underbite only cosmetic?

No. A moderate or severe underbite can cause uneven tooth wear, jaw pain, chewing and speech difficulty, and harder-to-clean areas that raise the risk of decay and gum disease. Improved facial balance is a benefit, but function comes first.

Take the First Step Toward a Balanced Bite

An underbite is common, well understood, and treatable at every age. The sooner it is evaluated, the more options you tend to have, especially for a growing child. Whether you are asking for yourself or your child, the best first step is a clear diagnosis.

Ready to find out how to fix your underbite?

Schedule a free consultation with board-certified orthodontist Dr. Chad Watts at Montclair Orthodontics in Oakland. Book online here, or call our office to find a time that works for you.

This article is for general education and isn’t medical advice. A consultation is the best way to get recommendations for your specific smile.

Sources