Most of the time, orthodontic treatment involves moving the teeth into better positions with braces or clear aligners. While these are the most familiar appliances used in orthodontic treatment, we may also recommend devices called “functional appliances” to help correct more serious bite problems. Functional appliances are designed to harness natural forces (such as those produced by muscular activity and jaw growth) to bring the bite into better alignment. Examples of functional appliances include the Activator, Bionator, Twin Block and Herbst appliances.
Some of these devices are fixed in the mouth (like braces), and can't be taken out at home; others are more like retainers, and can be removed as recommended. But in general, all functional appliances have a few things in common. Instead of acting primarily on the teeth, they work by re-positioning the mandible (lower jaw) in a way that helps the bite develop in a better orientation; depending on what type of correction is needed, a particular type of appliance may be recommended. Also, these appliances are most effective when used while the jaw is still developing — in other words, around the time of puberty in children, before growth is complete. However, some can be used in adults as well.
The use of functional appliances is a key feature of interceptive orthodontics. In this treatment method, we take advantage of the body's natural growth patterns to guide the development of the jaws in a more favourable way. Early orthodontic treatment may reduce the time you need to wear braces — and it can also help you get a smile that looks great, and a bite that works the way it should. Other appliances used in interceptive orthodontics include palatal expanders and headgear. In some instances, functional appliances can be used an as alternative to headgear; some functional appliances may also incorporate a palatal expander.