title: [Reversed headgear maxillary protraction appliance--a photoelastic study].
mesh_terms: D004867:Equipment Design; D005115:Extraoral Traction Appliances; D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D008437:Maxilla / Q000033:anatomy & histology / Q000502:physiology*; D008954:Models, Biological; D009968:Orthodontic Appliances, Removable; D012399:Rotation