CHAPTER 12 Setting up Stage II
Preformed arches are available and represent a considerable time saving. Made from .020 (or .022) inch Bow-Flex high tensile stainless steel, selection is similar to that described for Stage I, using the intraoral measure to determine the desired distance between the cuspid circles. However, in Stage II, the cuspid circles require to be somewhat further mesially from the canine brackets (Fig. 12.1). This is so as not to obstruct the possible placement of brakes on the canines, when the arms of the Side-Winders will point mesially. Mid-way between the canine and lateral incisor brackets is therefore the best place for the cuspid circles. The position of these circles will not require any subsequent adjustment.
Archform will be essentially similar to Stage I, with the anterior curvature extending distal to the canines (Fig. 12.2). However, there will be no anchor bends, and there is no need to incorporate any expansion unless, of course, a crossbite is being corrected. A straight posterior leg is preferred down the buccal segments, which avoids the complex double curvature when combining a vertical bite sweep with a buccal convexity.
Whether or not vertical bite sweeps will be required will depend on the initial degree of overbite. If the overbite was originally decreased, the archwires can be fitted flat, whereas a case that started with an increased overbite will need bite sweeps, in order to retain the overbite reduction gained during the first stage. Th/>