Abstract An outline and categorization of some of the types of treatment and tooth movement possible with the positioner have been made. Twenty-nine cases in which successful response to tooth positioner therapy was evident in some phase of orthodontic correction were studied. The degree of movement or improvement of tooth position was limited to 3 mm. or less of tipping movement. Rotational correction of incisors, canines, and premolars was possible in certain instances. Virtually all types of correction of occlusion and tooth movement, with the exception of translation or bodily movement, were evidenced. These were correction in interdigitation of cusp, correction of cross-bites, decrease in overbite and overjet, rotation of anterior and posterior teeth, closing of spaces, improvement of midline deviations, and maintenance and retention of the above.