Cases that show narrowing in the maxilla should be adequately overexpanded and held in the expanded position for an extended period of time. The maxilla can be expanded until the palatal cusps of the upper arch are in contact with the buccal cusps of the lower arch in the posterior segments (Fig. 10.16A). It is best to expand cases 1 or 2 years prior to full orthodontic treatment, and to maintain this expansion with a palatal bar. Then stability is normally assured.
If expansion is carried out at the beginning of orthodontic treatment, a palatal bar should be placed after the expansion procedures. This palatal bar can remain in position until (he rectangular stainless steel wire has been placed. This wire provides adequate stiffness to maintain the expansion that has been achieved. Torque in the posterior brackets of the upper arch, as well as some additional buccal root torque in the archwire, is beneficial at this time, to allow the posterior segments to settle properly.
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