Custom-made appliances, or braces, are prescribed and designed by the orthodontist according to the problem being treated. They may be removable or fixed (cemented and/or bonded to the teeth). They may be made of metal, ceramic or plastic. By placing a constant, gentle force in a carefully controlled direction, braces can slowly move teeth through their supporting bone to a new desirable position.

Orthopedic appliances, such as headgear, bionator, Herbst and maxillary expansion appliances, use carefully directed forces to guide the growth and development of jaws in children and/or teenagers. For example, an upper jaw expansion appliance can dramatically widen a narrow upper jaw in a matter of months. Over the course of orthodontic treatment, a headgear or Herbst appliance can dramatically reduce the protrusion of upper incisor teeth (the top four front teeth) or retrusion of the lower jaw (a lower jaw that is too far behind the upper jaw), while making upper and lower jaw lengths more compatible.