C. Angell was the first person to publish a paper about palatal expansion in 1860 in Dental Cosmos. He placed a screw between the maxillary premolars of a 14-year-old girl for 2 weeks. When she returned, he observed expansion in her upper arch. In 1877, Walter Coffin developed the Coffin Spring for the purpose of arch expansion. In 1889, J. H. McQyillen who was the President of the American Dental Association at that time, opposed Angell's idea regarding arch expansion. Goddard, in 1890, and Landsberger, in 1910, revisited the idea of arch expansion. Goddard standardized the expansion protocol in adjusting the expander twice a day for 3 weeks. Dr. Andrew J Haas reintroduced his expansion device to United States in 1956 called Haas Expander. He was also one of the first people to report lowering of mandible with bite opening and increase in nasal width and gain in arch perimeter. Robert M. Ricketts introduced the Quad Helix in 1975 which was a modification of the W Spring. Biederman introduced the tooth-borne Hyrax Expander in 1968. Cohen and Silverman were first ones to introduce the Bonded type of expander in 1973. See also List of orthodontic functional appliances List of palatal expanders SARPE References Orthodontic appliances Dental equipment