title: The OPA: a device for vertical control.
mesh_terms: D000202:Activator Appliances; D002648:Child; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D008312:Malocclusion, Angle Class II / Q000503:physiopathology / Q000628:therapy*; D008445:Maxillofacial Development; D009968:Orthodontic Appliances, Removable; D010347:Patient Care Planning; D011312:Pressure