Underbite: lower teeth in front of the upper teeth

What causes an underbite?

An underbite usually comes from a mix of genetics, growth patterns, and environmental factors, such as:

• A larger lower jaw or a smaller upper jaw
• Tongue thrusting or breathing through the mouth most of the time
• Thumb sucking or pacifier use that goes on for a long time
• Baby teeth that are slow to fall out
• Upper teeth that are impacted (unable to come in) or missing

In most cases, the jaws grow unevenly. The lower jaw grows faster or longer than the upper jaw, which creates the underbite.

How do I know if my child has an underbite?

You might notice:

• The bottom teeth overlapping the top teeth when your child bites down
• A chin that looks prominent or seems to “jut forward”
• Trouble chewing certain foods
• Speech changes, especially with “s” or “sh” sounds
• Jaw pain or discomfort

Underbites are often easier to correct while a child is still growing, which is why an early evaluation matters.

Why does early treatment matter for an underbite?

An underbite can get worse as a child grows, especially if the jaw imbalance continues. Without treatment, it may lead to:

• Uneven wear on the teeth
• TMJ (jaw joint) pain or clicking
• Receding gums or bone loss
• Facial asymmetry
• Trouble chewing or speaking clearly

In severe cases, adults with an untreated underbite may need surgery to realign the jaws.

How do you fix an underbite?

Treatment depends on your child’s age and how severe the underbite is. Common options include:

• Braces with elastics to guide the jaws into line
• Palatal expanders, for younger children
• Reverse pull headgear, which encourages the upper jaw to grow forward
• Reshaping or removing a tooth, in certain cases
• Jaw surgery, for teens or adults with a severe underbite who have stopped growing

An early orthodontic consultation can show which options fit your child, and it often makes treatment simpler later on.

When is surgery used to correct an underbite?

Your orthodontic team at Families First Pediatric Dentistry & Orthodontics will always look for the least invasive treatment plan that can correct your child’s bite. Most common bite problems can be corrected with braces and retainers, but certain irregularities can’t be corrected with orthodontic appliances alone.

For an underbite or another malocclusion, jaw surgery may be an option once growth stops, which happens at different ages for different people. An oral surgeon can move the jaw into a better position by adding or removing bone. In most cases, the surgery is done from inside the mouth, so it leaves no visible scars.

When should my child see an orthodontist?

If your child’s lower teeth sit in front of their top teeth, or their chin looks more prominent than you’d expect, it’s time for an orthodontic consultation. At Families First, we offer free consultations that include imaging and treatment guidance from our orthodontists.

Our orthodontic team will walk you through the options for your child’s bite, growth stage, and long-term oral health.

Other signs a child may need braces: Crowded teeth, Deep overbite, Missing lateral incisors, Open bite, Overjet, Spacing of teeth.