Asymmetric space closure

Abstract In a vertically slotted 0.022 × 0.028 inch edgewise system, the use of a two-dimensional ribbon arch—0.022 × 0.016 inch from lateral incisor to lateral incisor and 0.016 × 0.022 inch from the canine to the molars—plus an uprighting spring on the canine maintained incisor position while unilaterally protracting a molar-premolar unit by means of sliding mechanics. Five degrees of labial crown torque was placed in the incisor portion of the wire and the uprighting spring exerted a force of 200 to 250 g. The intra-arch force applied to protract the molar-premolar unit was 300 to 350 g.