The aim of this study was to describe and compare the dentofacial changes obtained with the Haas type banded and rigid acrylic bonded RME therapies. Lateral and posteroanterior radiographs, and dental casts of 30 growing children who had unilateral or bilateral posterior crossbite were analysed. The study groups consisted of 21 cases treated with acrylic bonded and 9 cases treated with Haas type banded RME appliances. Results revealed that lower nasal width, basal maxillary width and intermolar width were increased in both groups. Increase in the inclination of the upper molars in the transversal direction was more in the banded group compared to the bonded group (p < 0.05) Overbite was markedly reduced in the banded group (-2.51 mm), while slightly decreased in the bonded group (-0.61 mm), and the difference between the two groups was statistically significant (p < 0.01). The findings of this study suggest that the rigid acrylic bonded RME appliance may be an acceptable alternative compared to the conventional banded RME appliance, especially in cases with insufficient overbite.

Keywords: Maxillary expansion, lateral and posteroanterior cephalographs