title: Upper headgear versus lower headgear, yokes, and class III elastics.
abstract: The use of a lower headgear-yoke-Class II mechanism on an average works faster than a maxillary headgear. The distal tipping of the molars is greater with HGY-II which may be the result of the quicker tooth movement. The speed of distalization is probably due to the effect of the constant force of the Class II elastics. An orthopedic change on the maxilla could be seen if one can draw any conclusions from a change of only 1 degrees. A reduction of the SNA angle and a slight clockwise rotation of the palatal plane was noticed. These results agree with earlier investigations about cephalometric changes with headgear therapy. We have come to the conclusion that both methods are indicated. We use the upper headgear especially at a time when a complete therapy is not possible because of noneruption of the permanent teeth. The HGY-II mechanism is indicated when most permanent teeth are available and thus the therapy can be completed in one treatment period.
mesh_terms: D002508:Cephalometry; D002648:Child; D005115:Extraoral Traction Appliances; D006801:Humans; D008310:Malocclusion / Q000628:therapy; D008963:Molar / Q000033:anatomy & histology; D009967:Orthodontic Appliances; D009968:Orthodontic Appliances, Removable; D012408:Rubber; D014087:Tooth Movement Techniques / Q000295:instrumentation*
chemical_list: D012408:Rubber