3D facial soft tissue changes after rapid maxillary expansion on primary teeth: A randomized clinical trial.

OBJECTIVES: The aim of the present randomized controlled trial (RCT) was therefore the tridimensional evaluation of soft tissue changes after rapid maxillary expansion in growing patients. SETTING AND SAMPLE POPULATION: Treated group comprised 17 patients (10 males and 7 females) with a mean age of 9.8 ± 1.2 years, and control group comprised 17 patients (13 males and 4 females) with a mean age of 9.1 ± 2.1 years. MATERIAL & METHODS: All patients of the treated group underwent maxillary expansion with Haas-type expander while patients of the control group underwent no treatment. 3D facial scans were acquired at T1, at the beginning of treatment or observation period, and at T2, 18 months apart. The mean interval between the timepoints was 18.2 ± 0.4 months. RESULTS: The main differences between groups were reported in the nasal area. Nasal width (Alr-All) significantly increased in the treated group compared with the control. The increase in intereye and mouth width in the study group did not show differences with the control group. No significant differences were reported for lips' protrusion, angular measurements and facial heights between groups. The total nose volume difference was significantly higher in the treated group compared with control, and this result was related mainly to the significant increase in the nasal dorsum volume. CONCLUSION: Maxillary expansion produced significant increase in the nasal base and nasal volumes, but its clinical relevance is still questionable.

Evaluation of masseter muscle in different vertical skeletal patterns in growing patients.

AIM: The present study aimed to evaluate the relationship between masseter size, maxillary intermolar width and craniofacial vertical skeletal pattern. STUDY DESIGN: The study followed a prospective longitudinal design and enrolled 61 subjects (30 males and 31 females), 9-14 years of age (mean age 11.5) at 2-3 CVM stage. The participants were divided into three groups based on their vertical skeletal pattern which was estimated using the Frankfurt-mandibular plane angle: low-angle group (L-A), normal-angle group (N-A), high-angle group (H-A). An additional gender-based distinction was made. Maxillary intermolar width was measured on the maxillary cast of each patient by means of an electronic caliper; masseter volume was estimated by using magnetic resonance (MR) and masseter thickness was measured by means of ultrasonography (US). The US registrations were performed during the relaxation state (RS) and the maximum voluntary contraction (MVC) of the muscle. The indipendent samples T- test was used for sex comparisons; the analysis of variance test (ANOVA) was used to evaluate the differences between the three groups in males and females, and the Pearson r correlation coefficient was employed to assess the correlation between maxillary intermolar width and masseter volume. RESULTS AND CONCLUSION: Maxillary intermolar width, masseter volume and thickness showed significant gender differences; all the tested variables decreased significantly according to the facial vertical pattern, with greater values in females, especially in low- and normal-angle subjects; maxillary intermolar width and masseter volume showed significant correlations, higher in females.

Multimodal airway evaluation in growing patients after rapid maxillary expansion.

AIM: The objective of this study was to evaluate the airway volume of growing patients combining a morphological approach using cone beam computed tomography associated with functional data obtained by polysomnography examination after rapid maxillary expansion treatment. STUDY DESIGN: 22 Caucasian patients (mean age 8.3±0.9 years) undergoing rapid maxillary expansion with Haas type expander banded on second deciduous upper molars were enrolled for this prospective study. Cone beam computed tomography scans and polysomnography exams were collected before placing the appliance (T0) and after 12 months (T1). METHODS: Image processing with airway volume computing and analyses of oxygen saturation and apnoea/hypopnoea index were performed. RESULTS: Airway volume, oxygen saturation and apnea/hypopnea index underwent significant increase over time. However, no significant correlation was seen between their increases. CONCLUSION: The rapid maxillary expansion treatment induced significant increases in the total airway volume and respiratory performance. Functional respiratory parameters should be included in studies evaluating the RME treatment effects on the respiratory performance.