Overbite: what it is and how Invisalign corrects it

Overbite, overjet, and why the words matter

Two different things get called an overbite, and it helps to separate them.

• Overbite is the vertical overlap: how far the upper front teeth come down over the lower ones when you bite together. A couple of millimetres is normal. When the upper teeth cover half or more of the lower teeth, dentists call it a deep bite.
• Overjet is the horizontal gap: how far the upper front teeth sit in front of the lower ones. A large overjet is what people often mean by "buck teeth" or "teeth that stick out".

Many people have some of both. The animation on this page shows a deep bite being corrected: the lower teeth reappear as the upper front teeth are lifted and the lower ones are levelled.

How to tell if you have a deep bite

Bite together naturally and look in a mirror. If you can barely see your lower front teeth, or cannot see them at all, the bite is deep. Other signs are the edges of the lower front teeth touching the gum behind the upper teeth, a sore patch on the roof of the mouth behind the front teeth, worn or chipped edges on the lower incisors, and a smile that shows a lot of upper gum. For overjet, look at your profile: upper teeth that sit well ahead of the lower lip, or a lower lip that tucks behind the upper teeth, are the usual clues.

What causes it

Mostly the shape you were born with: the size and position of the two jaws relative to each other. A lower jaw that sits a little back, or upper front teeth that have over-erupted because nothing stopped them, both deepen the bite. Habits in childhood, thumb sucking and prolonged dummy use in particular, push the upper teeth forwards and increase the overjet. Grinding wears the back teeth down over the years, which lets the front teeth overlap further. Missing back teeth do the same.

Why it is worth correcting

A deep bite is not just a look. The lower front teeth wear against the backs of the upper ones, and the upper teeth chip and thin at the edges. The lower incisors can bite into the gum behind the upper teeth and cause recession. Some people with a deep bite get jaw ache or tension because the lower jaw is held back. A large overjet leaves the upper front teeth exposed and more likely to be damaged in a fall or a knock. Correcting the bite spreads the load across all the teeth again, which protects them.

How Invisalign corrects a deep bite

The main movements are intrusion, pushing the upper and lower front teeth slightly up into the bone so they overlap less, and levelling, bringing the back teeth into a position that supports the bite. Aligners do this with small tooth-coloured attachments on the front teeth and, in many plans, built-in "precision bite ramps": small shelves on the inside of the upper aligners that the lower teeth touch first, which encourages the front teeth to intrude and the back teeth to settle. Where the overjet is the bigger problem, the upper front teeth are moved back along the arch, sometimes with space created by polishing between teeth, sometimes with the back teeth moved further back first.

Deep bites respond well to aligners because intrusion is a movement aligners are good at. They do need planning in the right order, which is why Louise maps each stage herself before anything is made.

When something more is needed

Where the bite is deep because the lower jaw itself sits a long way back, moving the teeth can improve the look and the function but cannot change the jaw. In a growing teenager, a functional appliance worn for a period can guide the lower jaw forwards and is sometimes the right first step. In an adult with a large skeletal difference, the complete correction would involve jaw surgery, and most people choose a good tooth-position compromise instead. Louise will tell you which situation you are in at the consultation, and refer you to a specialist orthodontist if that is the honest advice.

What treatment looks like here

A mild deep bite with some crowding is often a Moderate case, nine to twelve months. A deep bite with a large overjet, or one where the back teeth need levelling too, is usually Comprehensive, twelve to eighteen months with unlimited aligners and refinements included. You see the planned bite on screen before you start.

At Clear Braces Solihull every Invisalign package includes your consultation, iTero scan, X-ray, Dental Monitoring, Vivera retainers, professional whitening and twelve months of aftercare, in one written price. Interest-free monthly payments are available.

Questions people ask

What is the difference between an overbite and an overjet?

Overbite is how far the upper teeth come down over the lower ones; overjet is how far they stick out in front. A deep bite is a large overbite; buck teeth are a large overjet. Many people have some of both.

Can Invisalign fix an overbite?

Most deep bites and moderate overjets, yes. Very large jaw differences may need a functional appliance in a teenager or, rarely, surgery in an adult. Louise will tell you which applies to you.

How long does overbite treatment take?

Usually nine to eighteen months, depending on how much the front teeth need to move and whether the back teeth need levelling.

Do I need attachments for an overbite?

Almost always, on a few front teeth. Many plans also use small bite ramps built into the aligners. Both are discreet.

Will correcting my bite stop my jaw ache?

Sometimes. Jaw pain has many causes, and Louise will tell you honestly whether your bite is likely to be one of them rather than promise it will.

Is a deep bite dangerous?

Not dangerous, but over the years it wears the front teeth and can damage the gum behind the upper teeth. Correcting it is as much about protecting your teeth as how they look.