CBCT Analysis of Dento-Skeletal Changes after Rapid versus Slow Maxillary Expansion on Deciduous Teeth: A Randomized Clinical Trial

Abstract

The aim of the present study was to compare skeletal and dental changes after rapid maxillary expansion (RME) and slow maxillary expansion (SME) performed by a Leaf Expander (LE) with upper deciduous teeth as anchorage and using 3D CBCT (Cone Beam Computed Tomography) analysis. Mixed dentition patients were randomly divided in two groups, according to the different expansion used anchored on maxillary primary second molars: the RME group (n = 16) was treated with a Hyrax type expander, whereas the SME group (n = 16) was treated with an LE expander. CBCT scans were performed before (T1) and after treatment (T2) and analyzed with a custom landmarks system. A paired t-test was used for intragroup analysis between T1 and T2, and a Student t-test was used for intergroup analysis; statistical significance was set at 0.05. Both RME and SME groups showed a statistically significant increase in dental and skeletal diameters. Group comparisons between T1 and T2 showed a significant expansion rate in the RME group for upper permanent molars (p = 0.025) but not for deciduous molars (p = 0.790). Moreover, RME showed higher increases for skeletal expansion evaluated at nasal walls (p = 0.041), whereas at pterygoid plates did not show any significant differences compared with the SME group (p = 0.849). A significant transverse expansion could be achieved with the expander anchored on deciduous teeth. RME and SME produced effective both skeletal and dentoalveolar transverse expansion; RME produced more anterior expansion than SME but less control regarding the permanent molar decompensation. SME by LE therefore could be an efficient and helpful alternative in the treatment of transverse maxillary deficiency in growing patients.

Skeletal and Dentoalveolar Changes in Growing Patients Treated with Rapid Maxillary Expansion Measured in 3D Cone-Beam Computed Tomography

“…In previous studies [30,33,61], it has been observed that the size of the nasal structures is affected by the expansion of the maxilla, and the nasal base width (NBW) increases between 1.7mm and 2.39mm; in our study, we found similar values to those studies, with an increase of 1.28 ± 0.64mm on average. The authors agree that the changes observed in the studies are small, and the standard deviations are wide [8].…”

“…On the other hand, it was observed that MA was lower in studies using MARPE and SARPE [12,14,15,82], except for Altug et al (2006) [83] who found higher MA in the SARPE group than in the RME group, and the MA had higher values in the SME group when comparing it to the RME group [33], although their MA values in the RME group were lower than in our study. Regarding the skeletal parameters, studies found the higher increases in the NBW with MARPE and SARPE and the lowest increases with SME [12,14,15,33]. Similar values to those observed in our study for maxillary width (JR-JL) and SO with RME were observed in studies with MARPE and SARPE [12,15,83].…”

“…When comparing these values with those observed in studies using different expansion appliances, studies using mini-screw-assisted rapid palatal expansion (MARPE) or surgically assisted rapid palatal expansion (SARPE) found similar values to those found in our study with RME, with 5.34-5.8 mm of IMW increase [12,82], while other studies found lower values of 3.70-4.91 mm [13,14]. The higher values of IMW increase were observed by Altug et al ( 2006) [83] with 7.81 for both RME and SARPE groups, and other studies showed lower increases of 0.98-2.2mm using slow maxillary expansion (SME) appliances [33,35]. On the other hand, it was observed that MA was lower in studies using MARPE and SARPE [12,14,15,82], except for Altug et al (2006) [83] who found higher MA in the SARPE group than in the RME group, and the MA had higher values in the SME group when comparing it to the RME group [33], although their MA values in the RME group were lower than in our study.…”

“…The higher values of IMW increase were observed by Altug et al ( 2006) [83] with 7.81 for both RME and SARPE groups, and other studies showed lower increases of 0.98-2.2mm using slow maxillary expansion (SME) appliances [33,35]. On the other hand, it was observed that MA was lower in studies using MARPE and SARPE [12,14,15,82], except for Altug et al (2006) [83] who found higher MA in the SARPE group than in the RME group, and the MA had higher values in the SME group when comparing it to the RME group [33], although their MA values in the RME group were lower than in our study. Regarding the skeletal parameters, studies found the higher increases in the NBW with MARPE and SARPE and the lowest increases with SME [12,14,15,33].…”

“…Traditionally, studies about changes after RME have been based on occlusal radiographs and frontal cephalometry, as these are the means commonly used in diagnosis and during orthodontic treatment [22][23][24][25][26]. However, with the advent of CBCT, a more accurate and replicable assessment of anatomical structures in all three planes of space has been achieved [12][13][14][15][27][28][29][30][31][32][33][34][35]. On the other hand, there is an increasing interest in the evaluation of dental and skeletal changes as well as changes in the nasal cavity after RME with CBCT in growing patients [12,[27][28][29][30]32,[36][37][38][39][40][41][42][43][44].…”