The primary function of this orthodontic appliance is to move the upper first molars back in order to make room for crowded or protruding front teeth. It is worn with orthodontic headgear. There are two wire bows on the facebow: an internal wire bow and an external wire bow.


Surgery that involves cutting part of the gum tissue around teeth to reduce the chance of relapse or post-orthodontic tooth movement.

Fixed Appliances

An orthodontic appliance that is bonded or cemented to the teeth and cannot be or should not be removed by the patient.

Forsus Spring

An orthodontic appliance with a fixed spring mechanism that moves the lower jaw forward, typically to correct an overjet (protruding upper teeth). Additionally, it can be used as an anchor for other movements.


This is the tissue that attaches the lip to the tongue or to the upper jaw. It is possible for a large frenum to cause spacing between the front teeth or to cause the tongue to be “tied.” A large frenum may cause the gum tissue on the lower front teeth to recede.


Frenectomy is the surgical removal or repositioning of the frenum. To relieve the symptoms of “tongue-tied,” this procedure will relax and eliminate excessive tissue.


Refers to the act of biting, chewing, and speaking. Correctly positioned teeth and jaws facilitate proper function.

Functional Appliances

A type of orthodontic appliance that uses jaw movement and muscle action to place selective forces on teeth and jaws. In most cases, they can be removed. Alternatively, they are referred to as orthopedic appliances with names such as orthopedic corrector, activator, bionator, Frankel, Herbst, or twin block appliances.