Orthodontic movement of a canine into an adjoining extraction site

The orthodontic movement of a canine tooth into an adjoining extraction site using a removable appliance is calculated using the finite element method (FEM). The calculated movements are compared, using a reflex plotter, with actual clinical measurements made on several patients. In both cases, wide variations in tooth displacement and hence rotation are found. The most important variable indicated by FEM appears to be the angle at which the load acts on the tooth. The position and magnitude of load have only a minor influence.