A simple orthodontic appliance for dealing with a common canine problem

A case report is presented. It is of the treatment of a canine which has erupted into a difficult position (Figs 1a, b). It shows how the analysis of the movement required involves an understanding of the theoretical principles of 'centre of mass' and 'line of force' and how when these principles are applied a relatively simple removable-cum-fixed appliance can be designed to execute the movements required.