The facemask appliance, also known as reverse pull headgear, is a type of growth modification appliance. Its primary use is for children that have deficient upper jaw growth that has resulted in an underbite. The orthodontic appliance runs across the roof of the mouth and attaches to rubber bands that extend forward out of the mouth and attach to the part that rests on the face. Typically facemasks are worn in the evenings and while the patient is asleep. If worn consistently, a gentle force from the rubber bands pulls the upper jaw and teeth forward to a more balanced and functional position. Facemasks are generally well received by children and comfortable. Occasionally the felt pads may need to be replaced to provide additional cushion on the chin or forehead.