Overbite

Overbite in the AAO glossary’s own words

The Glossary of Orthodontic Terms of the American Association of Orthodontists (AAO) defines overbite this way: “The upper front teeth excessively overlap the bottom front teeth when back teeth are closed. Also called a closed bite or deep bite.” The definition turns on the word excessively, and it describes the overlap with the back teeth together. Closed bite and deep bite, the other names the entry gives, are the same bite under different labels.

Overjet, the term overbite is confused with

Overjet is the term overbite gets confused with, and the AAO points this out itself: its article on deep bites notes that the vertical overlap is often confused with an overjet, which it describes as a horizontal distance. The AAO glossary defines overjet separately: “The upper front teeth protrude in front of the bottom front teeth when back teeth are closed. Sometimes called buck teeth.” Overbite is about how far the upper front teeth come down over the lower ones, and overjet about how far they stand out in front of them. Buck teeth, the everyday name, belongs to overjet, not to overbite.

How much overlap is natural

A small overlap of the front teeth is part of a proper bite, and overbite in the AAO glossary’s sense means an overlap past that. The AAO’s article on common types of bite problems draws the line plainly: “A small amount of overlap is natural in a proper bite, but this condition arises when the overlap is more than typical.” Elsewhere the AAO speaks of a deep overbite or an excessive overbite, using overbite for the overlap itself and the added word for the problem. Either way, the overlap a proper bite has is not the problem, and whether yours goes past it is a judgment the orthodontist makes.

What braces or aligners can do about an overbite is taken up on the overbite answer page, and overjet and deep bite are defined alongside it among the bite entries of the glossary.