Functional Appliances

Functional appliances are devices used to correct a significant disharmony in the relationship between the upper and lower jaws. They work by influencing the growth and development of a growing patient.

The most common use of a functional appliance is to encourage the forward growth of a retrusive or "under-developed" lower jaw. The functional appliance holds the lower jaw forward over a period until the teeth, jaws and joints have "adapted" and the desired jaw position has been obtained.

The effectiveness of a functional appliance depends on:

  • how much the appliance is worn
  • how quickly the patient is growing
Functional appliances align the jaws not the teeth, so they are usually used as a first stage of treatment (in a growing patient with a significant jaw disharmony) prior to the alignment of the teeth with fixed appliances (braces).

The most common types of functional appliance are listed below:

Fixed functional appliances:

  • Herbst appliance (pictured)
  • Cantilever bite jumper
  • Fixed Twin Bock appliance

Removable functional appliances:

  • Bionator (pictured)
  • Activator
  • Twin Block appliance
  • Teuscher appliance
  • Frankel appliance
  • Andreson appliance



    © Australian Society of Orthodontists