An expander, also called a rapid palatal expander or RPE, is an orthodontic appliance. It corrects a narrow upper arch that can result in crossbite, crowding, or impacted teeth. It’s designed to widen the upper jaw which will create space and help resolve these common problems.
Additionally, an expander may be used to broaden a smile for aesthetic reasons (to make a prettier smile), to improve breathing, or to shorten the overall time your child is in braces during a 2-phase treatment. Expanders are also sometimes used in the lower arch to upright back teeth.