The Bionator is a removable appliance used to help correct an “class III” by promoting lower jaw growth. Since a Bionator is primarily an orthopedic appliance, which influences the growth of bone. The appliance should be used during a period of maximum growth. Usually the younger the patient's age when it is used, the more change observed over a period of growth. If the patient doesn't grow during use of the Bionator, only changes in tooth position will be seen. When a patient reaches the stage we call skeletal maturity, this appliance is no longer effective at influencing jaw growth.