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:
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).
- how much the appliance is worn
- how quickly the patient is growing
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)
- Twin Block appliance
- Teuscher appliance
- Frankel appliance
- Andreson appliance