The Frankel Appliance (also called The Frankel Functional Regulator) is a functional appliance used by growing children that helps create space for permanent teeth by expanding the jaws. It stimulates growth of the lower jaw to better align the upper and lower teeth. The Frankel Appliance is usually prescribed for children with a pronounced Class II malocclusion or an Open Bite. It was developed by Rolf Fränkel in 1950s.
Photo courtesy of Dynaflex.