Abstract
ABSTRACTObjective: The aim of this study was to estimate the changes in the palate area after rapid maxillary expansion (RME) with the Hyrax expander in growing subjects, using cone beam computed tomography (CBCT). Methods: Fourteen patients (9 girls and 5 boys; mean age = 11.7 ± 2.4 years) who required RME as part of their orthodontic treatment were included in this study. CBCT records had been taken before RME treatment (T0), at the end of active expansion (T1) and after a 6-month retention period (T2). The CBCT scans were manipulated with Dolphin Imaging® version 11.7 Premium software, in which landmarks were positioned and measured in relation to sagittal, coronal and axial planes, to verify the palate surface area. In addition, linear measurements of the palatal depth and width were assessed. These measurements were compared by using analysis of variance (ANOVA) for repeated measures. A p-value smaller than 0.05 was considered statistically significant. Results: The palatal surface area and width significantly increased from T0 to T1, respectively by 9.27% and 9.71%, and both decreased in a non-significant manner from T1 to T2. The palatal depth had non-significant differences at T0, T1 and T2. Conclusions: RME promotes a significant gain in the surface area of the palate and an increase in intermolar width. The Hyrax appliance was effective for the treatment of maxillary atresia in growing patients. There was no vertical alteration of the palate. After a 6-month retention period, the maxilla transverse dimension and the surface area of the palate remained stable.
Highlights
It was concluded that the area of the palate in the crossbite group increased significantly and did not present significant differences when compared to the control group (p > 0.05), suggesting that this increase corresponds to the opening of the suture, since the final result of the palate area resembles that of the control group, in which tooth inclination does not occur
Garrett et al[3] evaluated 30 patients with a mean age of 13.8 years and observed that after Rapid maxillary expansion (RME), 49% of the expansion was a result of anchoring molar inclination, 13% resulted from alveolar inclination, and 38% resulted from maxillary suture opening
According to the findings of this study, it is possible to conclude that RME offers a significant gain in the surface area of the palate and a significant increase in the intermolar width, facts that are directly related to the opening of the midpalatal suture
Summary
Rapid maxillary expansion (RME) is widely used for growing patients in an attempt to correct maxillary constriction.[1,2,3] This effective procedure increases the width of the maxilla as a result of the separation of the palatine bones through the opening of the midpalatal suture, and buccal inclination of the alveolar bone and molars.[4,5] The activation force is capable of acting on the midpalatal suture, and on the circummaxillary sutures.[6,7]Traditionally, radiographs are used to identify dentoskeletal changes after RME.[8,9,10] Through lateral and frontal cephalograms, it is possible to observe that the procedure promotes a downward displacement of the maxilla and an increase in maxillary and nasal widths,[11] which varies according to the age and severity of the case.[8]In recent years, three-dimensional images have been used for the same purposes, but with more advantages.[3,12,13,14,15,16] Cone-beam computed tomography (CBCT) allows greater resolution, minimal distortion, real size and a low radiation dose, when compared to conventional computed tomography.[17].
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