A common form of malocclusion is an underbite, where the lower teeth sit in front of the upper teeth when the mouth is closed. Some underbites are mild and barely noticeable, while others are more pronounced and can affect chewing, speech, and long-term dental health.

Knowing the causes, symptoms and treatment options for an underbite can help you understand whether it may need professional care. At Oasis Dental Studio in the Gold Coast, Brisbane, Melbourne and Pottsville, our team provides assessments and tailored treatment plans for both adults and children with bite alignment issues.

What Is an Underbite?

An underbite is a type of malocclusion where the lower jaw protrudes further forward than the upper jaw. This causes the lower front teeth to overlap or extend beyond the upper front teeth. While it can be purely a dental issue (teeth angled or positioned incorrectly), in many cases it also involves the jaw structure.

Dentists usually classify underbites based on their severity:

Mild underbite – the lower front teeth just slightly overlap the upper front teeth.
Moderate underbite – the lower teeth extend more noticeably past the uppers.
Severe underbite – the entire lower jaw sits well forward of the upper jaw, creating a more obvious misalignment.

Even mild underbites can sometimes cause wear or uneven pressure on the teeth. Severe cases often require orthodontic or surgical correction, particularly when linked to jaw growth differences.

Causes of an Underbite

There isn’t just one single cause of an underbite, as it usually develops from a mix of genetics, habits, and growth factors.

Genetics and jaw shape

The most common factor is inherited jaw structure. If one or both parents have an underbite, their child may inherit a similar alignment. Some families naturally have lower jaws that are slightly longer or upper jaws that are smaller, increasing the chance of this malocclusion.

Childhood habits

Certain habits in early childhood can influence jaw and tooth development. Extended thumb sucking, prolonged use of dummies or bottles, or tongue thrusting can put pressure on teeth and gradually push them out of alignment.

Tooth crowding or spacing

If permanent teeth erupt out of position, or if baby teeth are lost too early, the remaining teeth can drift into irregular positions. This can contribute to underbite formation even without jaw discrepancies.

Injury or trauma

Jaw injuries that disrupt bone alignment or cause abnormal healing may result in an underbite if the jaw shifts forward during recovery.

Medical conditions

In some cases, conditions that affect jaw development, such as cleft lip and palate, can be linked with underbite. Growth disorders affecting the bones of the face may also contribute.

Symptoms of an Underbite

The most obvious symptom of an underbite is visual – the way the lower teeth extend in front of the upper teeth. However, an underbite can cause a range of other issues, both functional and dental.

The visible signs of an underbite:

Lower jaw appears more prominent or protruding
Lower teeth visible when lips are closed
Misaligned bite when chewing or speaking

The functional issues of an underbite:

Difficulty biting into certain foods, especially with front teeth
Uneven chewing, leading to wear on back teeth
Speech difficulties such as lisping or unclear pronunciation
Increased chance of tooth grinding (bruxism)

The potential dental and oral health concerns of an underbite:

Faster wear on enamel due to uneven pressure
Risk of chipped teeth or cracked restorations
Jaw pain or temporomandibular joint (TMJ) discomfort
Gum irritation where teeth do not meet properly

How an Underbite Is Diagnosed

Your dentist can accurately diagnose an underbite through a comprehensive routine examination.

To assist in the diagnostic process, your dentist may:

Conduct a visual assessment of how the teeth and jaws align when biting down
Take dental X-rays to evaluate tooth roots and jaw bone structure
Take photographs and impressions to record the bite and plan treatment
Use 3D scans or digital models in more complex cases requiring orthodontic or surgical planning

Early diagnosis in childhood often makes treatment easier, as growth can be guided with orthodontic appliances. However, adults can also benefit from treatment to improve function and prevent complications.

Types of Underbite

Dentists often distinguish between two main types, based on whether the problem is primarily dental or skeletal.

Dental underbite

A dental underbite occurs when the teeth themselves are angled or positioned incorrectly, but the jaws are otherwise normal in size and shape. These cases are generally easier to treat with orthodontics alone.

Skeletal underbite

A skeletal underbite is linked to the jawbones themselves being mismatched in size. For example, the lower jaw may be larger than the upper, or the upper jaw may be underdeveloped. Skeletal underbites are usually more severe and may sometimes require surgical treatment in addition to orthodontics.

Complications if Left Untreated

Not every underbite requires immediate treatment, but moderate to severe cases can create long-term issues if it goes ignored.

Some possible longer-term complications of an underbite can include:

Excessive tooth wear

An uneven bite pattern can slowly wear down enamel faster, due to how the teeth are aligned and the location of the frequent bite force.

Increased dental damage

An underbite can sometimes lead to a higher risk of chips, cracks, or fractures, due to where the teeth are positioned.

Jaw discomfort

The strain that a misaligned bite can put on jaw joints can lead to TMJ dysfunction over time.

Gum recession

Misaligned teeth may put pressure on the gums, which can possibly lead to gum recession.

Speech and chewing difficulties

A misaligned bite can prolong speech and chewing difficulties, or may even worsen them over time.

These complications can generally be prevented if the right treatment approach is taken earlier on, especially if the underbite is present during childhood.

Treatments for an Underbite

Finding the right treatment for a misaligned bite will depend on the severity, the underlying cause, and the age of the patient.

After your dental assessment, your dentist will explain the treatment approach that should be taken, including what to expect throughout the process.

Orthodontic treatment

Braces or clear aligners are the most common solution for mild to moderate underbites. They gradually move the teeth into better alignment over time. For children, expanders or specialised appliances may be used to encourage jaw growth before their adult teeth fully develop.

Restorative dental work

In much milder cases of a bite misalignment, reshaping teeth or adding crowns or veneers may help adjust how the upper and lower teeth meet. These types of treatments may generally be used when only a small correction is needed.

Jaw surgery (orthognathic surgery)

For severe skeletal underbites, surgery may be required to reposition one or both jaws. A surgical approach is typically combined with orthodontics before and after surgery. While more complex, it can significantly improve both the function and the appearance of an overbite.

Tooth extraction

If overcrowding contributes to the underbite, removing one or more teeth may create space to reposition the rest with orthodontics.

How the Severity of Underbites Can Be Prevented

Not all underbites can be prevented, especially those caused by genetics. However, some measures can reduce the risk or severity:

Correcting childhood habits early, such as thumb sucking or prolonged dummy use
Addressing tongue thrusting with early intervention if noticed
Monitoring dental development with regular check-ups
Treating baby teeth problems early to avoid shifting of adult teeth
Using protective gear during sports to reduce jaw injury risk

Early orthodontic evaluation is often recommended by age seven. Detecting developing bite issues early gives the best chance for less invasive correction.

When to See a Dentist

If you’re noticing the common symptoms of an underbite, we recommend seeing your dentist for a routine check-up and dental assessment.

Some of the signs that it may be time to see your dentist include:

The visibility of an underbite, or your child’s visibility of an underbite
Difficulty biting into food or chewing evenly
Speech difficulties linked with jaw or teeth alignment
Ongoing jaw pain or clicking noises when chewing
Excessive wear or damage to teeth

For children, the earlier an underbite is assessed, the easier it may be to treat. Adults can also benefit, even if the treatment plans may need to be more extensive to effectively address the issue.

Get in Touch

An underbite is not something that is visually noticeable – it can affect chewing, speech, and overall dental health. Causes range from genetics to childhood habits, and the severity can vary widely. While mild underbites may only need monitoring, moderate to severe cases often benefit from orthodontic or even surgical treatment.

At Oasis Dental Studio in the Gold Coast, Brisbane, Melbourne and Pottsville, we provide assessments and treatment options tailored to each patient. If you suspect you or your child may have an underbite, booking a consultation is the first step towards understanding your available treatment or long-term management options.

Underbite: Causes, Symptoms and Treatments