If your child's lower teeth sit in front of the upper teeth, or if you have noticed the same thing in your own bite, you are looking at an underbite. This page explains what an underbite is, when Underbite Treatment starts in childhood, and what the options look like for adults.
What is an underbite?
An underbite is when the lower front teeth sit in front of the upper front teeth when you bite down. Dentists also call it a Class III malocclusion. "Malocclusion" just means the bite does not line up the way it should.
A small underbite can be subtle, mostly seen from the side. A deeper underbite changes the way the face looks and the way the teeth wear.
What causes an underbite?
An underbite is most often caused by the way the jaw grew, the way the teeth came through, or a mix of both. Common causes include:
- the lower jaw sitting a little further forward than the upper jaw
- the upper jaw being smaller than usual
- the upper front teeth tilting backwards
- childhood habits such as long-term thumb sucking
- early loss of the upper baby teeth
Some underbites run in families. The treatment is the same either way: plan around the cause, not just the look.
Does an underbite need treatment?
Most underbites do benefit from treatment, because they tend to get a little deeper as the jaw grows. A small underbite in childhood can become a deeper one in the teenage years.
Common effects of an untreated underbite:
- the lower front teeth wear down on the outside
- the upper front teeth wear down on the inside
- the jaw joints (TMJs) get tired and sore
- the face looks heavier in the lower third
- speech can be affected, especially "s" and "t" sounds
- chewing is less efficient at the front
When does early treatment help?
Early treatment helps when the upper jaw is still growing, usually between ages 7 and 11. At this age, the bones are still soft and easy to guide. A small appliance can encourage the upper jaw to grow forward a little, while the lower jaw keeps growing on its own. The result is a better match between the two jaws.
The most common early treatments for an underbite are:
- a face mask, which gently pulls the upper jaw forward
- a palatal expander, which widens the upper jaw so the teeth have more room
- a short course of braces on the upper front teeth, to tip them forward
These are usually part of a two-phase-treatment plan. The first phase guides jaw growth. The second phase, in the early teens, lines up the adult teeth.
When is adult treatment the better plan?
Adult treatment is the better plan when the underbite was not treated in childhood, or when the jaw growth has finished. Adult bone is denser, so the upper jaw cannot be moved forward with a face mask any more. The options change.
Our team will talk you through what your case needs and refer you to a trusted surgical partner if surgery is the right plan.
How is the right plan decided?
The right plan is decided with a look, a 3D scan, and a side-view x-ray that shows the jaw position. The records help our team measure the jaw difference, look at the growth stage, and pick the right option.
For children, growth matters most. If the upper jaw is still growing, a face mask is often the best first step.
For adults, the depth of the underbite and the look you want will guide the plan. Some adults mask the bite with aligners. Others want the jaw itself moved, which means a combined orthodontic and surgical plan.
How long does underbite treatment take?
Most underbite cases at our practice take 12 to 24 months, with surgery cases running closer to 24 to 30 months from start to finish. Your specialist will give you a personal time estimate at the consultation.
Will an underbite come back?
Most underbites stay fixed after treatment, but a retainer is needed to keep the teeth in their new position. For children treated early, the second phase in the teenage years lines up the adult teeth.
What questions do patients ask about underbite treatment?
Can an underbite get better on its own? No. Most underbites get a little deeper as the jaw grows. Early treatment can guide the growth in the right direction.
At what age should a child be checked? Around age 7 is a good time for a first orthodontic check. Our team can tell you whether the bite is on track.
Is surgery always needed? No. Many underbites are fixed with orthodontics alone. Surgery is reserved for cases where the jaw difference is large.
Will my face change after treatment? Often, yes. Aligning the bite can balance the lower face. Surgical cases see a bigger change.
How much does underbite treatment cost? The cost depends on the plan. We never quote prices online. After the consultation, we give you a written quote and walk you through payment options such as Afterpay, DentiCare, humm, and major health funds.
Ready to talk about your underbite?
If you have noticed an underbite in your child or in your own bite, our team at Dental Specialists of Turramurra is here. Call (02) 9488 7455 or visit us at Suite 1-2 / 1335 Pacific Highway, Turramurra NSW 2074, Monday to Friday, 9:00 am to 5:00 pm.