Underbite Correction: Options for Kids and Adults

An underbite, where the lower jaw and lower front teeth sit forward of the upper teeth, is one of the more visible types of bite misalignment, and it is also one that patients and parents tend to ask about with real urgency. The good news is that underbite correction has effective options at every age, though the approach changes significantly depending on whether the jaw is still growing or has finished developing. This guide explains what causes an underbite, why timing matters so much, and what treatment looks like for children, teens, and adults.

At Willow Family Dentistry in Wylie, TX, Dr. Esther B. Jeong evaluates bite development at every comprehensive exam, because an underbite is one of the conditions where early identification genuinely changes the treatment path available later.

What Is an Underbite?

An underbite, known clinically as a Class III malocclusion, is a bite pattern in which the lower jaw and lower front teeth extend beyond the upper jaw and teeth when the mouth is closed. It is essentially the opposite of the more common overbite, where the upper teeth and jaw sit further forward. An underbite can range from mild, affecting only how the front teeth line up, to severe, involving a noticeable forward projection of the entire lower jaw and chin.

Underbites are less common than other bite misalignments. Research places the prevalence of Class III malocclusion at roughly 1% to 5% of the US population, according to studies on dentofacial patterns, making it notably less frequent than overbite-type misalignments. Prevalence varies considerably by ethnicity and region, with some Asian populations showing rates as high as 15% to 23%, according to that same body of research.

According to Healthline, an underbite affects the front teeth and the visible profile of the face, which is why it tends to be one of the more noticeable bite issues and is often identified earlier than some other malocclusions.

What Causes an Underbite?

An underbite is most often caused by an imbalance in jaw growth, either an overgrown lower jaw, an undergrown upper jaw, or a combination of both. Genetics plays the dominant role; a family history of underbite significantly raises the likelihood that a child will develop one. Environmental factors can also contribute, though they are less influential than skeletal growth patterns.

Specific contributing factors include:

• Genetics: Jaw size and growth pattern are strongly inherited, and underbite often runs in families.
• Mandibular overgrowth: The lower jaw grows larger or further forward than typical, pushing the lower teeth ahead of the upper teeth.
• Maxillary underdevelopment: The upper jaw grows less than expected, creating a relative underbite even without excess lower jaw growth.
• Prolonged thumb sucking or tongue thrusting: Can influence jaw and tooth position during development, though this is a less common cause of true underbite than of other bite issues.
• Childhood injury or tumors affecting jaw growth: Less common, but capable of altering the growth pattern of one jaw relative to the other.

Because the cause is so often skeletal rather than purely dental, evaluating an underbite usually involves assessing the jawbones themselves, not just the position of individual teeth. This is part of why imaging plays a bigger role in underbite assessment than in some other orthodontic concerns.

Why Does Treatment Timing Matter So Much for Underbites?

Underbite correction is far more effective when started while the jaw is still growing, because growth itself can be guided with appliances during childhood in ways that are simply not possible once growth has finished. The window for this kind of growth modification typically closes around the early teenage years, after which treatment shifts toward managing the bite that has already developed rather than redirecting how the jaws grow.

This is why the American Academy of Pediatric Dentistry recommends an orthodontic evaluation by age seven. At that age, a developing underbite can sometimes be intercepted with a growth-modification appliance, such as a reverse-pull headgear or a palatal expander combined with other devices, that encourages the upper jaw to grow forward or restrains excessive lower jaw growth. These appliances rely on growth that is actively happening, which is precisely why timing is the single biggest factor in how straightforward treatment will be.

Once jaw growth is complete, typically by the late teens, the same degree of skeletal correction generally cannot be achieved with appliances alone. This does not mean treatment becomes impossible for older teens and adults, but it usually means the goals and methods shift toward camouflaging the bite with tooth movement or, for significant skeletal cases, combining orthodontics with jaw surgery.

This timing principle is one of the clearest examples in dentistry of why "wait and see" is not always the safest default. An underbite that could have been guided with a removable appliance at age eight may require jaw surgery to correct fully at age twenty-five, not because anything went wrong, but because the growth window that made the simpler approach possible has closed. This is exactly the kind of conversation Dr. Jeong has with parents during early evaluations, since understanding the timeline helps families make informed decisions rather than defaulting to inaction.

How Is Underbite Correction Different for Children?

Underbite treatment in children typically uses growth-modification appliances designed to either restrain lower jaw growth, encourage upper jaw growth, or both, taking advantage of the active growth window before it closes. The specific appliance depends on the underlying cause and the child's growth pattern, which is assessed through clinical exam and imaging.

Common pediatric approaches include:

1. Reverse-pull headgear (face mask): Worn for a set number of hours daily, this appliance applies forward pressure to help the upper jaw grow into better alignment with the lower jaw.
2. Palatal expansion: Often used alongside a face mask when the upper jaw is also narrow, widening it to create room and improve the bite relationship.
3. Chin cup: Used less frequently today, this appliance applies gentle backward pressure to the chin to help restrain excessive lower jaw growth.
4. Braces: Often used after growth modification, or for milder cases, to fine-tune the position of individual teeth.

According to the American Dental Association's MouthHealthy resource, early orthodontic evaluation allows dentists to identify developing bite problems and intervene while treatment options remain broadest. For underbite specifically, this principle applies more strongly than for almost any other orthodontic concern.

Can Underbite Be Corrected in Teens and Adults?

Underbite can be corrected in teens and adults, though the approach depends on whether the case is primarily dental, meaning tooth position, or skeletal, meaning the jawbones themselves are mismatched. Mild dental underbites can often be improved with braces or clear aligners alone. More significant skeletal underbites in adults may require a combination of orthodontics and corrective jaw surgery for full correction.

For a mild to moderate underbite where the jaw discrepancy is limited, orthodontic tooth movement can shift the front teeth into a better relationship, improving both function and appearance without surgery. Our comparison of Invisalign versus braces covers how these treatments work for adult patients more broadly.

For a significant skeletal underbite, orthodontics alone typically cannot move the jawbones themselves into a different position. In these cases, orthognathic surgery performed in coordination with an oral surgeon, combined with orthodontic treatment before and after, achieves the correction that braces or aligners cannot accomplish on their own. Not every adult underbite requires surgery, and a thorough evaluation is the only way to know which category applies to your specific case. Our overview of adult braces options discusses the broader adult orthodontic landscape.

What Happens If an Underbite Is Left Untreated?

An untreated underbite can lead to uneven tooth wear, chewing and speech difficulty, jaw joint strain, and in more severe cases, a noticeable change to facial profile and self-confidence. Because an underbite affects how the front teeth meet, the teeth often contact at awkward angles, accelerating wear on specific surfaces over years of normal biting and chewing.

The functional effects can also extend beyond the teeth themselves. A significant jaw misalignment changes how the muscles of the jaw work together, which can contribute to jaw joint discomfort, clicking, or fatigue over time. Speech can be affected when the front teeth do not meet properly, particularly with certain consonant sounds. And because an underbite is visible in profile, it is one of the bite issues most likely to affect how a person feels about their smile and facial appearance.

None of this means every underbite needs aggressive treatment, but it does mean an underbite is worth a proper evaluation rather than being dismissed as purely cosmetic. Many mild underbites function well for years without intervention, while others quietly accelerate wear and strain that only become apparent decades later. The only way to know which category a particular underbite falls into is a clinical assessment. Our article on crossbite, a related but distinct bite misalignment, covers similar themes around why bite problems are worth addressing rather than ignoring.

How Do You Get an Underbite Evaluated?

Getting an underbite evaluated starts with a dental exam and bite assessment, often supported by X-rays or other imaging to understand whether the cause is primarily dental or skeletal. For children, this evaluation should happen by age seven if an underbite is suspected, since the active growth window is the most valuable time to intervene.

For teens and adults, an evaluation focuses on understanding the severity of the discrepancy and outlining whether orthodontics alone can achieve the desired result or whether a surgical consultation should be part of the conversation. There is no universal answer, and an honest assessment is more useful than guessing based on appearance alone.

Willow Family Dentistry evaluates bite development for patients of every age. Whether you are bringing in a young child for a first orthodontic check or are an adult exploring options for a lifelong underbite, Dr. Jeong can outline a clear, honest path forward.

Further Reading

Underbite correction connects to the broader picture of bite alignment and jaw development. The articles below go deeper on related conditions and treatment options.

• Teeth Shifting in Adults: Why It Happens and What to Do
• Invisalign Candidacy: 7 Questions to Ask in Wylie, TX
• Full Mouth Reconstruction in Wylie, TX

Results may vary. Please consult with Dr. Jeong for personalized treatment recommendations.