Abstract: An orthopedic appliance for correcting Class II malocclusions comprises a frontal portion configured to engage the mandibular and maxillary frontal arches and first and second side portions, posterior to the frontal portion, each configured to engage at least some of the maxillary molars. A universal screw assembly interconnects the frontal portions and the first and second side portions and operate to independently adjust the lateral spacing of the side portions from one another and the anterior-posterior spacing of the frontal portion from the side portions. The appliance is expanded in stages to maximize the utilization of corrective lower jaw movements which result from securing the appliance in the patient's upper mouth.