Any appliance that utilises the functional forces from the muscles of the jaw and face to correct the bite is termed a ‘functional appliance’. They have been used in orthodontics since the 1930’s and are used mainly with patients who have prominent upper front teeth and a small lower jaw.

Traditionally these have been a removable plate or fixed piston device, which displaces the lower jaw forward. Functional appliances initially feel quite bulky and will stretch the jaw muscles. Speech and swallowing may be difficult but after a few days the appliance will become more comfortable.

 A Bionator is an example of a removable functional brace.  These are often used to reduce large overjets and reduce the prominence of the upper front teeth.  They can be used at an earlier stage of dental development than the conventional fixed braces and work best if worn consistently both day and night over a 6 – 12 month period.  Fixed appliances may still be needed following a functional brace to achieve individual tooth alignment.