Three-dimensional changes of the upper airway in patients with Class II malocclusion treated with the Herbst appliance: A cone-beam computed tomography study.

INTRODUCTION: This study aimed to determine the volumetric effects on the upper airways of growing patients with Class II malocclusion treated with the Herbst appliance (HA). METHODS: Volumetric measurements of the upper airways of 42 skeletal Class II malocclusion patients (mean age: 13.8 ± 1.2 years; ranging from 12.0 to 16.9 years) were assessed using cone-beam computed tomography scans acquired before treatment (T0) and approximately 1 year later (T1). The sample comprised a Herbst appliance group (HA group [HAG]; n = 24), and a comparison group (comparison group [CG]; n = 18) of orthodontic patients who had received dental treatments other than mandibular advancement with dentofacial orthopedics. RESULTS: In CG, nasopharynx and oropharynx volumes decreased slightly during the observation period (9% and 3%, respectively), whereas the nasal cavity volume increased significantly (12%; P = 0.046). In HAG, there was an increase in the volume of all regions (nasal cavity, 5.5%; nasopharynx, 11.7%; and oropharynx, 29.7%). However, only the oropharynx showed a statistically significant increase (P = 0.003), presenting significant volumetric changes along the time (T1-T0) in HAG. CONCLUSION: Mandibular advancement with the HA significantly increased the volume of the oropharynx, but no significant volumetric modifications were observed in the nasal cavity and nasopharynx.

Three-dimensional airway changes after adenotonsillectomy in children with obstructive apnea: Do expectations meet reality?

INTRODUCTION: The assessment of the volumetric changes of the airways after adenotonsillectomy has gained popularity among orthodontists, but the validity of such evaluation is not clear. METHODS: Thirty patients with obstructive sleep apnea diagnosed with the use of polysomnography (PSG) were evaluated according to the Apnea and Hypopnea Index (AHI), the obstructive apnea index (OAI), the oxygen desaturation index (ODI), the lowest oxygen saturation (LSpO2), and the average oxygen saturation (ASpO2). The volume and the minimal cross-section of lower (oropharynx and velopharynx) and upper (nasopharynx) spaces of the airways were calculated. Patients were adenotonsillectomized; posttreatment data were collected after 12 months. Thirty comparison patients also had the volume of airways evaluated. RESULTS: A statistically significant improvement (P < 0.05) of most PSG parameters was observed after adenotonsillectomy: AHI from 14.5 to 5.2, OAI from 9.4 to 5.5, ODI from 14.6 to 6.5, and LSpO2 from 77% to 94%). A significant increase in airway volume of the lower space (from 2571.5 mm3 to 5276.3 mm3) and the upper space (from 726 mm3 to 1056.9 mm3), as well as in the minimal cross-section of the airways (from 98.5 mm2 to 335.8 mm2) was found in adenotonsillectomy patients. No significant volumetric changes of the airways were observed in the comparison patients. No significant correlation was found between PSG parameters and the dimensions of the airways before adenotonsillectomy. No significant correlation was found between changes of the PSG parameters and changes of the dimensions of the airways 12 months after the adenotonsillectomy. CONCLUSIONS: Adenotonsillectomy contributed to the increase of the airway volume and minimal cross-section, and to the improvement of the PSG parameters, but there was no correlation between the magnitude of the anatomic changes and the improvement of the breathing mode.