关键词: Twin-block矫治器, 安氏Ⅱ类1分类错, 舌, 气道体积, 最小横截面积

Abstract: PURPOSE: To observe the changes of upper airway and the effect of different tongue position on upper airway volume before and after Twin-block treatment in patients with Class II division 1 malocclusion and mandibular retrusion. METHODS: Thirty-three patients (ages:11.3±0.89) with Class II division 1 malocclusion and mandibular retrusion were included in the study and divided into 2 groups, the control group (12 patients) and experimental group (21 patients). In the experimental group, according to the tongue position shown on cone-beam CT (CBCT), the patients were sub-divided into lower tongue position group and higher tongue position group. Patients in the experimental group were treated with Twin-block appliance, and CBCT was taken before treatment and 8 months after treatment. Patients in the control group underwent CBCT at the first month and eighth month. The changes of oropharyngeal airway volume and the minimal cross-sectional area were measured by using Dolphin software. SPSS 24 software package was used for t test and one-way variance analysis. RESULTS: After 8 months, the airway volume and the minimal cross sectional area of the oropharynx in the control group were not significantly changed, but significantly increased in the experimental group (P<0.001), especially in the higher tongue position group (P<0.05). CONCLUSIONS: Twin-block can significantly increase the oropharyngeal airway volume and minimum cross-sectional area in patients with Class II division 1 malocclusion and mandibular retrusion. In addition, mandibular advancement dose not correlate with airway improvement and the right tongue position has an obvious effect on airway opening in mandibular advancement.

Key words: Twin-block appliance, Class II division 1 malocclusion, Tongue, Airway volume, Minimal cross sectional area