Objective: Cone-beam computed tomography (CBCT) is a reliable method of assessing the oral cavity and upper airways. We conducted this study to examine the changes introduced by rapid maxillary expansion in the nasal cavity, nasopharynx, and oropharynx as seen with images obtained by CBCT. Materials and Methods: We evaluated 15 patients with maxillary width deficiency treated with RME. Patients were subjected to CBCT at the beginning of RME and after the retention period of 4 months. Results: The nasal cavity presented a significant transverse increase in the lower third, in the anterior (1.08 mm 6 0.15), medium (1.28 mm 6 0.15), and posterior regions (0.77 mm 6 0.12). No significant change occurred in the nasopharynx in volume (P 5 .11), median sagittal area (P 5 .33), or lower axial area (P 5 .29) resulting from the RME. A significant change was noted in the oropharynx in volume (P 5 .05), median sagittal area (P 5 .01), and lower axial area (P 5 .04) before and immediately after the RME. Conclusions: RME is able to increase the transverse width of the nasal cavity, but it does not have the same effect in the nasopharynx. Changes noted in the oropharynx may be due to the lack of a standardized position of the head and tongue at the time of image acquisition. (Angle Orthod. 2012;82:458-463.)

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Objectives: To compare, using cone-beam computed tomography, the dentoskeletal changes in rapid maxillary expansion with tooth-bone-borne (Hybrid Hyrax) and tooth-borne (Hyrax) appliances.Setting and sample population: Forty-two patients who met the eligibility criteria (aged 11-14 years; transverse maxillary deficiency, posterior crossbite, and presence of upper first premolars and molars) were screened and allocated into two groups: HHG (treatment with Hybrid Hyrax) and HG (treatment with Hyrax). Main outcome measures:The primary outcomes included nasomaxillary dimensional changes. CBCT was performed before and 3 months after the activation phase.Measurements were performed using Dolphin ® . Baseline data were compared using one-way ANOVA. For intergroup comparison, ANCOVA was used to analyze the initial age, appliance activations (mm), and mid-palatal suture maturation data as covariates. Statistical significance was set at 5%. Results:The premolar region in HHG showed increased skeletal changes than in HG, with the difference being 1.5 mm (0.5; 2.6) in the nasal cavity (P = .004), 1.4 mm (0.3; 2.5) in the nasal floor (P = .019), and 1.1 mm (0.2; 2.1) in the maxilla (P = .022). The molar region in HHG showed increased skeletal changes with the difference being 0.9 mm (0.2; 1.5) in the nasal cavity (P = .005), and 0.9 mm (0; 1.8) in the maxilla (P = .042) than in HG. Premolar inclination was higher in HG. Conclusion:Hybrid Hyrax showed more skeletal changes and fewer dental side effects, especially in the first premolar region. The amount of activation influenced the higher nasal skeletal changes in the Hybrid hyrax group. K E Y W O R D Scone-beam computed tomography, maxillary expansion, orthodontic anchorage technique | INTRODUC TI ONPosterior crossbite associated with maxillary transverse deficiency is among the most discussed topics in orthodontics, with the prevalence being 13.3% in patients with mixed dentition. 1 Such discrepancies, if left untreated, may cause deviations in facial growth, compromising esthetics and resulting in a functional deviation of the mandible. 2 Therefore, early correction is important,

Background The use of skeletal anchorage devices for maxillary protraction in patients with class III malocclusion due to deficiency in the middle third of the face has been shown to be a promising approach to treatment of these patients. The aim of this study was to evaluate the treatment of class III patients with maxillary retrusion, using orthodontic mini-implants (MI) associated with intermaxillary elastics in comparison with the rapid maxillary expansion and facemask protocol (RME/FM). Methods In this prospective non-randomized clinical trial, the sample of 24 participants between 7 and 12 years of age (median age of 10.0 years and interquartile range = 3.0 years), at the stage prior to the pre-pubertal growth spurt, was divided in two groups. In group facemask (FM) ( n = 12), the individuals received orthopedic treatment with RME/FM. In group MI ( n = 12), two mini-implants were inserted in the region close to the maxillary first molar roots, and the other two in the region of the mandibular canines. Initial and final lateral teleradiographs were taken for cephalometric evaluation of all the cases. Statistical analysis included the Mann-Whitney, Wilcoxon, and Fisher’s exact tests. The level of significance was 5% (α = 0.05). Results Improvement was verified in the facial profile and occlusion of the participants, showing advancement of the maxilla in the two groups, with significant differences ( P ≤ 0.05) between T0 and T1 in the following measurements: SNA, ANB, Wits, Co-A, Co-Gn, NAP, A-Npog, overjet, and molar relationship. There was no statistically significant intergroup difference ( P > 0.05) in the cephalometric measurements evaluated, but the time of treatment was significant, and was faster for group MI. Conclusions The protocol with mini-implants may be an option for the correction of Class III due to maxillary deficiency.

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