Overjet

Upper front teeth that protrude in front

The American Association of Orthodontists (AAO) defines overjet in its Glossary of Orthodontic Terms: “The upper front teeth protrude in front of the bottom front teeth when back teeth are closed. Sometimes called buck teeth.” The AAO’s article on deep bites adds that overjet refers to a horizontal distance, which is what separates it from an overbite, a vertical overlap. An overjet is about how far forward the upper front teeth stand when the back teeth are closed, not how far down they come over the lower ones.

The appliance the AAO glossary gives as an example

The AAO glossary’s example of what an orthodontist may use for an overjet is a spring appliance, which it describes as “An orthodontic appliance made of a fixed spring mechanism that moves the lower jaw forward, usually to correct an overjet (protruding upper teeth).” The example moves the lower jaw, a reminder that an overjet is not always a matter of the upper teeth alone. It is the glossary’s illustration, not a treatment plan, and whether a particular overjet calls for any appliance, and which one, is the orthodontist’s call.

Buck teeth and protrusion, the other names for overjet

Buck teeth is the everyday name for an overjet, and the AAO’s article on common types of bite problems uses another, protrusion, describing it from both sides: “protrusion occurs when the front teeth extend too far forward or the lower teeth do not extend far enough forward.” So an overjet can come from upper teeth that sit too far forward or from lower teeth that do not come far enough forward. Buck teeth is not the AAO’s name for overbite, which is a vertical overlap.

Treatment questions about an overjet continue on the overbite question page, and the other bite words are gathered in the glossary of terms.