What Is an Overbite? Normal vs Deep Overbite, Causes and Treatment

When you close your teeth, the upper front teeth sit slightly in front of and over the lower ones. A small overlap is how the bite is meant to work. People often use the word overbite for any bite where the top teeth look prominent, but strictly it describes the vertical overlap, how far down the upper teeth cover the lower ones.

A deep overbite (also called a deep bite) is where that overlap is excessive. The lower teeth can almost disappear behind the upper ones. In some people the lower teeth bite into the gum behind the upper teeth, which can cause soreness and wear.

These two are different measurements and are easily mixed up. Overbite is vertical: how much the upper teeth overlap the lower ones downwards. Overjet is horizontal: how far the upper front teeth stick out in front of the lower ones. A person can have a deep overbite with little overjet, or a big overjet with a normal overbite.

If the problem you see is upper teeth sticking forward, read our guide on overjet teeth. Both are classed as types of bite problem, explained in what malocclusion means.

Causes include inherited jaw shape (for example a lower jaw that is smaller or set back), thumb sucking and prolonged dummy use in childhood, and lower front teeth that have not grown up far enough or have worn down. Missing back teeth can also let the bite close down more than it should.

A mild overbite needs no treatment. It is worth checking if the lower teeth bite into the gum, front teeth are wearing or chipping, the jaw joint is sore, or you dislike how it looks. Treatment depends on the cause and the age: braces with elastics, sometimes extractions, growth guidance in a child, and surgery in some adult skeletal cases. Our guide on braces for overbite explains each route.

Treatment is planned through braces or aligners; see braces and orthodontics for how it works.