title: Directional forces revisited.
authors.forename: J H
authors.initials: JH
authors.lastname: Hickham
mesh_terms: D004867:Equipment Design; D005115:Extraoral Traction Appliances / Q000009:adverse effects; D006801:Humans; D009968:Orthodontic Appliances, Removable / Q000009:adverse effects; D013314:Stress, Mechanical