A Haas Expander is a fixed (not removaable) palate expander that applies most of its force to the palate to achieve expansion. It is used mainly in growing children. It comprises an acrylic plate that is attached to bands that fit over two or four molars. The plate contains an expansion screw, which you turn periodically with an Expander Key. The device continually applies a gentle force to the tissues of the palate, resulting in expansion of the upper jaw. The Haas Expander was popularized by Andrew Haas, an American orthodontist, in 1956.
Photo courtesy of Dynaflex.« Back to Glossary Index