Rapid Palatal Expansion in Mixed Dentition Stage with Custom Made Modified Expansion Device

The aim of this study was to determine the sagittal, transverse and vertical effects of a custom made Modified Expansion Device on dentofacial structures in patients with severe crowding and narrow upper arches in the mixed dentition. A total of 20 patients ( 13 females and 7 males) with an age range of 8-11 years were selected without regard to their skeletal class and gender. All subjects had mixed dentition (mean age 9.8 years) and needed maxillary expansion. Lateral and frontal cephalometric radiographs, maxillary and mandibular plaster models and occlusal radiographs were obtained from each patients at pre-expansion (T1), post-expansion (T2) and at the end of retention period (T3). Occlusal radiographs were used to demonstrate changes in the midpalatal suture. The measurements were made on the patients' cephalometric films and plaster models. The means and standard deviations for independent and dependent variables were analyzed statistically and evaluated by paired-t test using SPSS 10.1 for windows. In the transverse plane, a significant increase in intercanine width (ICW), interpremolar width (IPW) and intermolar width (IMW) was found. Sagitally, 2mm of maxillary protraotion and significant increase in arch length was noted. Mesial tip was more marked than distal although both were statistically insignificant Extrusion, buccal tipping and other cephalometric variables used for vertical analysis showed insignificant values. We conclude that the custom made modified expansion device with rapid maxillary expansion is an effective appliance for correction of crowding and constricted upper arches as phase I treatment.