Some of the most common orthodontic appliances are explained here:
Fixed appliances:
Fixed space maintainers are used to keep open a gap made by prematurely losing a milk tooth. The space maintainers keep the space open until the permanent tooth erupts so that the other teeth do not shift into a different position. A band is attached to the neighboring tooth and a wire is extended to the tooth on the other side of the space to keep the gap open.
Special fixed appliances can be used to control intensive thumb sucking or tongue thrusting. These appliances are attached to the teeth by bands.
Removable appliances:
Removable space maintainers serve the same function as fixed space maintainers. They are made from an acrylic base that fits over the jaw, and uses plastic or wire branches that wrap around specific teeth to keep the gap from the missing tooth open.
Jaw repositioning appliances, also called splints, are worn on either the top or bottom jaw to aid in training the jaw to close in a more desired position. They may also be used to treat temporomandibular joint disorders (TMJ).
Lip and cheek bumpers are designed to keep the lips or cheeks away from the teeth. The bumpers relieve the pressure lip and cheek muscles can exert on the teeth, minimising discomfort and structural damage.
A palatal expander is used to widen the dental arch of the upper jaw. It is a plastic plate that fits over the palate. Tightened screws in the plate forces the joints in the bones of the palate to open lengthways and widen.