Adult patients who have cross bite are very likely to be advised to undergo surgically assisted rapid maxillary expansion. This happens because their growth phase had passed already and the use of an orthodontic appliance installed at the roof of the mouth may not show desirable results. Therefore, the surgery releases the osseous resistance and the patient activates the appliance daily in order to the expansion to happen. Of course this is just one phase of the whole treatment because the orthodontic treatment will proceed and will close the space created between the upper incisors. If the problem is diagnosed precociously it is possible to expand the maxilla without surgical procedure.