A Nance Appliance is a small acrylic plate that fits against the front of your upper palate, and is attached to your molars with bands. It can be fixed (cemented in place) or removable. It is used to help maintain the position of certain teeth in the upper arch after an extraction or (in cases of children) premature loss of baby teeth. The Nance Appliance prevents your molars from moving forward, or prevents your canines and incisors from moving backward — and therefore maintains space between specific teeth. In children where the top permanent teeth have not yet erupted, the Orthodontist might use a Nance Appliance to maintain space for those permanent teeth to come in properly.
You usually need to wear a Nance Appliance for several months to a year, depending on what your Orthodontist is trying to accomplish.