The Orthopedic Corrector is similar to a Bionator --  the exception being that there are two additional expansion screws added to the appliance. The addition of these screws eliminates the need for construction of a second appliance (in severely retruded skeletal Class II or TMJ-involved cases). After the third or fourth month of wear (when the patient’s muscles have readjusted to their new position), the screws can be activated. Turning them in unison moves the anterior cap forward. This allows the mandible to be advanced even further as treatment progresses. The Orthopedic Corrector I is used to increase the vertical in deep overbite cases, while the Orthopedic Corrector II is used to close open bites. Note: Wax bite requirements for this appliance remain the same as for the regular Bionator.