Skeletal and dental changes after maxillary expansion in the mixed dentition.

The purpose of this study was to compare skeletal and dental aspects of three different expansion methods in the mixed dentition period in sagittal, vertical, and transversal planes, treatment periods, complications, and relapse tendencies in early periods. Patients with unilateral or bilateral posterior crossbites in the mixed dentition were studied. They were divided into three groups of 10 patients in each group. The first group received treatment with removable plates for semirapid maxillary expansion; the second group with quad-helix appliances for slow maxillary expansion; and the third group with conventional fixed hyrax appliances for rapid maxillary expansion (RME). Lateral and posteroanterior cephalometric films, occlusal films, and dental casts were taken before and after expansion, and after retention with the same appliances. Cephalometric and dental cast analyses were made. Both skeletal and dental changes were observed after all three expansion methods.