Underbite explained: causes, signs, and the best treatment options

If you’ve noticed that your bottom teeth sit in front of your top teeth when you bite down, you might be wondering if you have an underbite. You’re not alone - an underbite is a fairly common dental issue, and it doesn’t just affect how your smile looks. It can also impact your oral health, comfort, and even confidence.

The good news? Underbites can be treated in a variety of ways, and modern solutions are more effective and discreet than ever.

In this article, we’ll break down everything you need to know about underbites: what causes them, how to tell if you have one, and the different treatment options. Whether you’re just starting to explore what an underbite means or you’re thinking about underbite treatment, this guide will give you the insights you need to make an informed decision.

What is an underbite and how severe can it be?

Definition of underbite

An underbite is a type of dental misalignment where the lower front teeth protrude ahead of the upper front teeth when the jaws are closed. In an ideal bite, the upper teeth slightly overlap the lower teeth, but in an underbite, the opposite occurs¹. This condition is also known in orthodontic terms as a Class III malocclusion.

In practical terms, someone with an underbite might appear to have a protruding lower jaw or a “strong chin” profile, as the chin and lower jaw sit forward of where they typically would².

How severe can an underbite be?

Underbites can vary in severity:

You might wonder: are underbites common? While they aren’t extremely prevalent, they do affect a notable percentage of the population. In the UK, the prevalence of Class III malocclusion (underbite) is around 3.2%⁴. This includes both minor underbites that don’t cause trouble and more pronounced cases that may lead to functional issues or require treatment¹.

Signs and symptoms of an underbite

Underbites aren’t just about appearance - they can also cause a variety of symptoms and functional difficulties. If you suspect you have an underbite, here are some signs and symptoms to look for:

Keep in mind that mild underbites may not cause any noticeable pain or functional problems - you might only observe the alignment issue.

Severe underbites, on the other hand, are more likely to lead to multiple of the issues above. If you’re experiencing any of these symptoms and suspect an underbite, it’s wise to consult a dentist or orthodontist.

Common causes of underbite

Underbites can develop for a few different reasons. Their causes are often a mix of genetics and environmental factors. Here are the most common causes, according to orthodontic experts:

Are underbites genetic?

In many cases, underbites are inherited. If one of your parents or close family members has an underbite, you may be more likely to have one as well¹. Genetic factors determine the size and shape of your jaws and teeth. An underbite can result if the upper jaw is too small or the lower jaw is too large, causing the lower teeth to sit in front².

Early childhood habits

Certain prolonged behaviours during early childhood can contribute to an underbite by influencing how the teeth and jaws develop. For example, extended thumb-sucking, using a dummy or bottle beyond age 3, or chronic “tongue thrusting” can place pressure on teeth and jaw bones¹. Over time, these habits may push the developing teeth out of alignment or affect jaw growth, leading to an underbite.

Injury or trauma

A serious injury to the face or jaw can result in an underbite. If the jawbone is broken and heals improperly, the alignment of the upper and lower jaws may be thrown off. Even with good medical care, a fractured jaw doesn’t always heal in the exact original position. As a result, someone who had a jaw injury could develop an underbite if the lower jaw ends up positioned forward of its ideal position when healed¹.

How to fix an underbite?

The approach to an underbite correction depends largely on the severity of the bite and the age of the patient. In all cases, the earlier an underbite is addressed, the easier it can be to correct.

Experts recommend that children with underbite signs get evaluated by an orthodontist around age 7, while the jaw is still growing⁶. Treating an underbite in childhood is often ideal because the jaw bones are still flexible¹. Below, we’ll outline the main options how to correct underbite:

Braces and other orthodontic appliances

Traditional orthodontic treatments, like braces, are a very common and effective way to treat underbites. Underbite braces consist of brackets and wires that attach to the teeth and gradually move them into better alignment. In mild to moderate cases where the jaw sizes are appropriate, braces alone may correct an underbite by adjusting tooth position³. Often, braces are worn for 1-2 years, and afterward a retainer will help maintain the corrected bite position¹. Some modern braces are made from clear or tooth-coloured materials that make them less noticeable on your teeth.

Another method to correct an underbite jaw is the use of orthodontic appliances. These are sometimes called orthopedic appliances or growth modification devices. Сombination of headgear and a palatal expander is the recommended approach for correcting underbites¹. This helps the upper teeth and jaw line up better with the lower jaw.

Can an underbite be fixed with Invisalign® clear aligners?

Clear aligners are a popular modern alternative to braces for straightening teeth. Clear aligner systems like Invisalign® use a series of custom-made, transparent plastic trays that fit snugly over your teeth. These trays are designed to be worn 20–22 hours a day. Each aligner set applies gentle pressure to your teeth, gradually moving them into new positions. Over time, aligners can correct misaligned teeth and improve your bite.

They are nearly invisible when worn, making them an attractive option for all patients who want a more discreet way how to cure underbite than metal braces. Aligners are also removable, so you take them out to eat, drink, and brush your teeth - which means no dietary restrictions and easier brushing/flossing compared to braces.

How to fix an underbite naturally?

This is a common question, especially from adults looking for at-home solutions or parents hoping a child’s underbite will correct itself. The truthful answer is that in most cases, an underbite will not correct itself over time and cannot be fully fixed by anything you do on your own once it has developed.

Minor dental misalignments might be slightly influenced by muscle function, but an established skeletal underbite is a structural problem - you can’t typically reshape your jawbone position through exercise.

That said, these ‘natural’ approaches are aimed more at preventing an underbite than offering an underbite fix:

While you can’t reliably fix an underbite on your own, the role you can play is in prevention and in seeking timely care. Good dental hygiene and health will also ensure that whenever you do address the underbite, your teeth and gums are in the best condition to undergo treatment.

If you or your child has an underbite, it’s best to consult with a dental professional about it rather than relying on home remedies. Early consultation can give you options to correct the underbite with the least invasive methods possible.

FAQ

Overbite vs. Underbite: what’s the difference?

An overbite occurs when the upper front teeth extend significantly over the lower front teeth. In contrast, an underbite is characterized by the lower front teeth protruding beyond the upper front teeth, often due to a forward-positioned lower jaw⁷.

What’s an underbite?

An underbite, medically termed a Class III malocclusion, is a dental condition where the lower teeth extend outward farther than the upper front teeth. This misalignment can affect chewing, speaking, and overall oral health.

Can braces fix an underbite?

Yes, braces can effectively correct underbites, especially in mild to moderate cases. They work by applying continuous pressure to shift teeth into proper alignment. In some instances, additional orthodontic devices or treatments may be necessary to assist the process.

How do you correct an underbite?

Underbite correction methods include:

Can an underbite affect speech?

Yes, an underbite can impact speech. The misalignment may make it challenging to pronounce certain sounds that require the tongue to press against the teeth, such as "t," "d," "n," and "l"⁸.