Orthodontic arch expansion is indicated when the upper jaw is too narrow on one or both sides resulting in the upper teeth improperly positioned, biting inside the lower teeth. This is called a crossbite.
Arch expansion is the optimal treatment for a narrow upper jaw that results in a crossbite. Expansion of the upper jaw is usually possible in individuals before 18 years of age. The upper jaw, or maxilla, consists of two halves which are joined by a suture along the roof of the mouth. Prior to fusion at the suture, separation of the two halves, or expansion, is possible. Since jaw growth is still active, new bone will fill in the "gap" produced by the newly separated halves. This is part of the healing process, and usually will take between two and five months.
Two types of fixed appliances are used in our office for expansion. One is called a Quad-Helix, and the other a Haas-Type Palatal Expander. Our office activates the Quad-Helix prior to cementation, and either the patient or a family member will activate the Haas appliance with a "key" once or twice per day for 4-6 weeks. Both are usually cemented to the upper six-year permanent molars. These appliances are often used for 4-6 months prior to further treatment.
The benefits of orthodontic arch expansion include both improvement of the bite and an increase in jaw size which may help provide space for upper and even lower crowded teeth.