Posterior crossbite - treatment and stability
A 12.8 year-old Caucasian girl presented for treatment complaining of an unpleasant\nsmile. This patient showed oral breathing, lip incompetence, and atypical swallowing\naided by the mentonian musculature. Additionally, an increased facial lower third and a\nconvex profile were verified. Intraoral evaluation showed a Class II, division 1\nmalocclusion, and bilateral posterior crossbite ( and , ).\nThe treatment plan proposed was palatal expansion, performed by a modified Haas-type\nexpander (), aiming at increasing the\nmaxillary transversal dimension to correct the bilateral posterior crossbite. Activation\nof the screw was initiated immediately after appliance insertion with a complete turn.\nAfter that (), the patient was instructed\nto keep the activation with 2/4 turns in the morning and 2/4 turns in the afternoon,\nduring eight days. The expander was passively maintained for a period of three months,\nfollowed by a removable retainer, which was used for another six months. At that time, a\ncomprehensive orthodontic treatment was initiated in order to improve the results\nobtained after expansion (). The whole\ntreatment, including maxillary expansion and the comprehensive phase, lasted about 1\nyear and 3 months, when a Hawley appliance and a 3x3 retainer were installed ( and ). The patient has been followed up for 21 years, and has as yet maintained\nstability of the results achieved with maxillary expansion (-).