Also known as ‘plates’, removable functional appliances are orthodontic treatment tools that fit inside the mouth and correct problems with jaw growth or tooth development. They are often the first phase of treatment after an orthodontist detects a problem. Functional appliances are followed by treatment using braces to correct tooth alignment and improve bite as much as possible.

Twin-block appliances

A twin-block appliance makes use of two plates, one for the upper jaw and one for the lower. It encourages a more favourable direction of jaw growth, particularly when the lower jaw is underdeveloped. Twin-block appliances also work to improve the position of upper teeth that stick out too far, and can create more space for crowded teeth.



A bionator is a form of removable appliance that uses a single plate to correct the upper and lower teeth and jaws. It is used to treat overbites by bringing the lower jaw forward. Bionators are a popular option for younger children as they are painless and come in a variety of colours (including glitter sparkles and glow-in-the-dark). This type of plate is usually suitable for patients aged seven years or older.