Used mainly in narrow, “V” shaped arches, this appliance makes it possible to develop the upper arch laterally -- up to 9mm -- with the majority of the movement confined to the anterior region (spanning from cuspid to cuspid). It is typically soldered to bands placed on the first permanent molars and the first bicuspids, but can, however, be designed so that the anterior portion of the appliance is secured with bonding material over a wire. Note: If you find that the posterior crossbite is locked due to a deep bite or tight intercuspation, it is recommend that a lower occlusal splint be placed temporarily to expedite treatment without affecting the mandibular dentition.