A deep bite is a malocclusion in which the upper front teeth excessively overlap the bottom front teeth when back teeth are closed. This is also called an overbite or closed bite.
While a deep bite may or may not be an esthetic concern for most patients, its presence usually indicates there are other problems that should be addressed.
The most common is a small lower jaw. When the lower jaw is shorter than the upper, the upper teeth are further “forward” and the lower teeth continue to grow until they hit the back of the upper teeth (the cingulae) or the roof of the mouth. Additionally, as the lower front teeth grow up under the top ones, they often get squeezed together creating crowding and alignment issues.
Another cause of a deep bite is a missing lower tooth. This creates a condition similar to having a short lower jaw. Finally, extremely strong biting muscles, common in patients who clench or grind their teeth, can deepen the bite.