Any of various structures designed to move and hold irregularly formed teeth into the correct position. A removable appliance has springs and clasps of various forms to move teeth into the correct position. A fixed appliance is made up of springs and bands cemented to the teeth to move them into the correct position. Begg, Edgewise, and Full banded are examples of fixed appliances. A retention appliance is designed to hold the teeth in the corrected position until the alveolar bone has consolidated around them.