Attached to the upper molars by cemented bands, the Rapid Palatal Expander is an orthodontic device used to create a wider space in the upper jaw. It is typically used when the upper jaw is too narrow for the lower jaw causing a crossbite. A crossbite can lead to functional problems with the bite and even asymmetrical jaw growth.
When patients are still growing, their connective tissue between the left and right halves of their upper jaw is very responsive to expansion. By simply activating the expander through turning a screw with a special key in the center of the expander, gradual outward pressure is placed on the left and right halves of the upper jaw. This pressure causes an increased amount of bone to grow between the right and left halves of the jaw, ultimately resulting in an increased width.