This is done by placing two 45° bends at the ends of the arch wire. These bends are introduced in the tubes of the
molars, provoking rotation in the posterior segment and extrusion in the anterior segment.
At the moment of introduction of the wire in the molar tubes (passive arch), the wire will move incisaly; we must
then place the arch in the slots, and then the extrusion of the anterior segment will begin (active arch). The
diameter of the stainless steel wire can range between 0.016" to 0.020'.