Abstract
Our aim was to analyze the effect of headgear on upper airway dimension and hyoid bone position on non-extraction patients with Class II division 1 malocclusion. Ninety patients with Class II division 1 malocclusion were included and divided into three groups (Group A: treated with headgears and Class II traction; Group B: performed with Class II traction; and Group C: no treatment). The lateral projection was measured at the beginning and end of treatment. Cephalometric analyses of the dentofacial structure, upper airway dimension and hyoid bone position were performed before and after treatment. The data were analyzed by paired t-test and independent sample t-test. SNA significantly decreased in Group A after treatment (P<0.01), and SNB, ANB and Wits significantly changed in Group A and Group B. L1-MP, L1-NB and Z angle significantly increased, while overjet, overbite and lower lip measurements significantly decreased in Group A and Group B. In upper airway measurements, V-LPW, PNS-V, PNS-U and T-V significantly increased for three groups. Moreover, the hyoid bone position had a change in Group A and Group B. The upper airway dimensions were not decreased by headgear treatment or Class II traction in patients with Class II division 1 malocclusion. Class II traction treatment affected the position of the hyoid bone.
