RME’s are generally used expand a narrow upper arch. The RME is ‘glued’ around a back molar tooth on each side of the mouth, and removed after the expansion process has occurred and has stabilised. A key is used to turn the expander at the times directed by the orthodontist. Marking the times on a calendar and ‘ticking‘ once this has occurred allows you to record the appliance activation. It is normal for a space to suddenly appear between the front teeth, this is temporary.