An overbite is when your top front teeth stick out over your bottom front teeth more than they normally should. Everyone's top teeth naturally overlap their bottom teeth a little bit when they bite down, but an overbite means this overlap is more pronounced.

You might notice an overbite when someone smiles or talks: their upper teeth extend noticeably forward, sometimes covering most of their lower teeth. Some people call this being “buck-toothed,” though that's not a particularly kind or respectful way to describe it.

Overbites happen for different reasons. Sometimes it's hereditary, meaning you inherit the tendency from your parents just like you might inherit their eye color. Other causes include thumb-sucking as a young child, losing baby teeth too early, or the way your jaw naturally grows.

Many people with overbites don't need any treatment, but orthodontists (dentists who specialize in straightening teeth) can correct more severe overbites using braces or other devices. They do this both to improve appearance and because a significant overbite can make chewing difficult or cause jaw pain.

The opposite condition, where bottom teeth stick out past the top ones, is called an underbite.