[Treatment of transversal maxillary deficiency -- a case report]

The constriction of the maxilla can be treated different ways, depending on the age of the patient, on the severity of the malocclusion and on the jaw mainly affected by the problem. If the maxilla is 4-5 mm narrower than it should be and the patient is minimum in the late mixed dentiton phase, rapid palatal expansion technique can be carried out. Changes in the maxillary arch can be followed by changes in the mandibular arch. The patient was a 14-year-2-month-old girl at the beginning of the treatment. She had unilateral crossbite on the right side that was caused by the skeletal and dental constriction of the maxilla and the mandibular asymmetry. The upper jaw was 6 mm narrower in the molar and 5 mm narrower in the premolar area than in the mandible. Lateroocclusion couldn't have been recognised. The buccal corridor was big and unesthetic that is a sign of the narrow maxilla. The patient was treated by the hyrax appliance. After overexpansion had been carried out, the achievement was sustained by one month retention. The treatment was carried on with the multiband appliance and with a modified transpalatal arch that extended until the mesial end of the first premolar, that was altered to a transpalatal arch after 3 months retention. The crossbite-problem has been solved, now uprighting of the left mandibular lateral segment is being done. During rapid palatal expansion heavy forces are applied to the teeth and bone. The long-term success of the treatment is also dependant of the treatment basing on the right diagnosis and of the adequate retention periode. According to this case report, rapid maxillary expansion therapy is succesful at the age of 14-15 years.