The Fraenkel appliance - avoidance of lower incisor proclination.
D000202:Activator Appliances / Q000009:adverse effects*; D006801:Humans; D007180:Incisor / Q000473:pathology*; D008310:Malocclusion / Q000209:etiology*; D008312:Malocclusion, Angle Class II / Q000628:therapy; D009968:Orthodontic Appliances, Removable / Q000009:adverse effects*; D014087:Tooth Movement Techniques / Q000009:adverse effects