In some patients, the upper jaw bone (the maxilla) is narrower than the lower jaw bone (the mandible). To correct this problem a palatal expander is used to widen the upper jaw bone and allow a normal relationship between upper and lower teeth. The expander may often reduce the likelihood for having to remove permanent teeth because of crowding.
A common problem orthodontists face is when the upper jaw is narrower than the lower. A palatal expander can widen the upper jaw so that its width aligns with the lower jaw. An expander can also make room for moderately crowded upper teeth and prevent extraction of permanent teeth. A special key will be used to turn the expander. The orthodontist will give you detailed instructions for turning the key and caring for the expander. Your mouth will feel unusually full at first, but with practice, eating and speaking will return to normal.