A Rapid Maxillary Expander (RME) is a custom-made orthodontic appliance which is bonded to the upper back teeth and is used to widen the upper jaw. The Maxilla (upper jaw bone) has a midline suture (a joint between the bones) in the palate which will usually close at around the age of 16 years in females and 18 years in males. Before this time, maxillary expansion can be simply achieved with an expander appliance alone. After the suture has closed (eg in non growing patients) a surgical procedure may be required to re-open the suture to allow expansion.
Maxillary expansion is used for patients with a narrow upper jaw. When indicated, widening the upper jaw will achieve a better relationship between the upper and lower jaws for normal function and wear, allow for ideal dental and skeletal development and can also create space for crowded teeth.
The expander has a turning device in the middle of the appliance. A key is used to turn the expander which will widen the upper jaw by gradually separating the suture of the palate. The patient or parent will usually perform one turn per day to achieve the desired expansion. Normally the process will last from 3-4 weeks. The expander remains in place for 3-6 months to maintain expansion.
Three appointments are required in preparation for placement of the expander: Placing separating elastics on both sides of upper first molars to make space for molar bands; selecting molar bands for upper first molars and taking an impression or scan of the upper jaw to fabricate the expander; and finally, an appointment to bond the expander to the teeth.
During the turning process, a sensation of pressure around the palate and back teeth is normal. Analgesics such as paracetamol or ibuprofen are effective in reducing discomfort. There will be no visible change in the first several days. As more expansion is achieved, a space will appear between the upper central incisors. This space will begin to close spontaneously after expansion is complete and the remainder of space will be closed with braces.