What is an appliance?
In orthodontics, “appliance” is the general name for devices that apply controlled force to the teeth and jaws or hold them in a particular position. Some appliances only move teeth, while others aim to guide jaw development in growing children. Braces and clear aligners are also orthodontic devices in the broad sense; this page focuses mainly on the other types of appliance.
Removable appliances
These consist of an acrylic base and wires and are put in and taken out by the patient. They are used for limited movements such as moving individual teeth, a small amount of expansion or correcting a single tooth in crossbite. How well they work depends directly on how long they are worn; usually they should be worn at all times except for eating and brushing.
Fixed appliances
Rapid palatal expander
This appliance is fixed to the upper molars and has a screw in the middle. The screw is turned at set intervals to open the palatal suture and widen the upper jaw. For details, see the jaw expansion page.
Fixed functional appliances
These appliances hold the lower jaw forward and stay in the mouth at all times. Because they do not depend on wear, they may be preferred for teenagers who have difficulty with compliance.
Habit-breaking appliances
These are used to help stop habits such as thumb sucking or tongue thrust.
Functional appliances
In growing children, especially with a retruded lower jaw, these are used to support the development of the lower jaw by holding it forward. There are removable and fixed types. Mandibular advancement built into clear aligners works on a similar principle.
Extraoral appliances
A face mask is used at an early age to support forward development of the upper jaw when it lags behind. Extraoral appliances such as headgear may be used in selected cases to limit the forward movement of the upper jaw or the molars. These appliances are usually worn at home and at night.
Space maintainers
When a baby tooth is lost early, a space maintainer stops the neighbouring teeth drifting into the gap and keeps the space for the permanent tooth. It can be fixed or removable.
Retention appliances
These are fixed wires or removable retainers that keep the teeth in their new position after orthodontic treatment. For details, see the retention page.
Appliance care
- Clean removable appliances every day with a soft brush and lukewarm water; hot water can distort them.
- Always keep an appliance in its case when it is out of your mouth.
- Clean carefully around fixed appliances with an interdental brush.
- Avoid hard, sticky and very sugary foods.
- Do not try to fix an appliance that has broken, come loose or is digging in at home; contact the clinic.