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

• Published in: American journal of orthodontics and dentofacial orthopedics 2020-02, Vol.157 (2), p.205-211
• Main Authors: Oliveira, Paula Moreira, Cheib-Vilefort, Paula Loureiro, de Pársia Gontijo, Henrique, Melgaço, Camilo Aquino, Franchi, Lorenzo, McNamara, James A., Souki, Bernardo Quiroga
• Format: Article
• Language: English
• Subjects: Adolescent; Cephalometry; Child; Cone-Beam Computed Tomography; Dentistry; Humans; Malocclusion, Angle Class II - diagnostic imaging; Malocclusion, Angle Class II - therapy; Mandible; Mandibular Advancement; Oropharynx; Orthodontic Appliances, Functional
• ISSN: 0889-5406; 1097-6752
• DOI: 10.1016/j.ajodo.2019.03.021

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). 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. 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. 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. •Oropharynx volume increased significantly after Herbst appliance therapy.•The oropharynx volume of comparison patients with Class II malocclusion was stable in the observation period.•Nasal cavity and nasopharynx volumes were stable after Herbst appliance therapy.