Functional appliances have been used since the 1930s. Despite this relatively long history, there continues to be much confusion relating to their use, method of appliances alter the arrangement of various muscle groups that influence the function and position of the mandible in order to trasmit forces to the dentition and the basal bone. Typically these muscular forces are generate orthodontic and orthopedic changes.

Functional appliances have been broadly divided into two categories removable and fixed functional appliances. Fixed functional appliances have patients who are non compliant to removable appliances and in patients after the active growth phase has been completed

Classification of fixed functional appliances.