Extraoral forces are used in many Class II treatments in order to increase or modify anchorage. The contact on the dental
arch is usually on first molars but with patients who have a vertical growth or in patients who have lost these molars, the Asher
extraoral force allows to achieve the anterior retrusion without the inconveniences of other kind of mechanics (intermaxillary
elastics, distalizers…). The Asher extraoral force is applied to the canine zone and is very well tolerated by the patients. This
article describes the adjustment and the activation of this simple but effective appliance and its indications.
(Rev Esp Ortod. 2002;32(4):337-343)