A Rapid Palatal Expander (RPE) is an orthodontic appliance that puts pressure on the upper jaw (maxilla) to separate the mid palatal suture by turning a midline screw. It makes the maxilla wider and creat space. RPEs are used often to correct posterior crossbites.
This procedure is better to be done at a younger age before the palatal suture becomes fused. With adults, Surgically Assisted Rapid Palatal Expander (SARPE) is needed, which combines an RPE and surgery performed by an oral surgeon.
A key with a plastic handle is used to turn the midline screw. Instructions are given to a parent, guardian or other person to activate an RPE.
Usually a patient will turn the expander once or twice a day for many days untill the crossbite is eliminated.