Upper Airway Dimensions in Class II Malocclusion

Abstract

To study the effects of cervical headgear treatment of Class II division 1 malocclusion on upper airway structures in children. Forty children aged 9.1 (7.2-11.5) years with Class II division 1 malocclusion were treated using a cervical headgear as the only treatment appliance. The headgear consisted of a long outer bow bent 15 degrees upward and a large inner bow expanded 10 mm larger than the intermolar distance. Lateral cephalograms were taken before and after the treatment. Upper airway structures were estimated from the cephalograms. The results were compared to cross-sectional data of 80 age-matched controls with a Class I molar relationship. A Class I molar relationship was achieved in all treated children. The mean treatment time was 1.6 (0.3-3.1) years. The Class II malocclusion was accompanied by a similar or wider nasopharyngeal space than in the controls but narrower oro- and hypopharyngeal spaces. The retropalatal area was widened by the treatment (P < .05), whereas the rest of the oropharynx and hypopharynx remained narrower than in the controls. Before the treatment, the mandibular plane was in a more horizontal position than in the controls, but during the treatment, it rotated to a position similar to that of the controls. Class II division 1 malocclusion is associated with a narrower upper airway structure even without retrognathia. Headgear treatment is associated with an increase in the retropalatal airway space.