关键词: 骨性Ⅱ类, 锥形束CT, 上气道, 舌骨位置

Abstract: Objective　To study the relationship of upper airway morphology and hyoid bone position with cranial and maxillofacial bone morphology in patients with skeletal class Ⅱ by CBCT. Methods　The CBCT imaging data of 60 patients were selected according to the inclusion criteria，and the 60 cases were divided into skeletal class I group，skeletal class Ⅱ maxillary protrusion group and skeletal class Ⅱ mandibular retraction group，20 cases in each group. Three-dimensional reconstruction of the upper airway was performed using Dolphin 11.95 software. The morphology of the jaw，the shape of the upper airway and the position of the hyoid bone were measured. The data were statistically analyzed. Results　The volume and minimum cross-sectional area of the upper airway nasopharyngeal and palato pharyngeal segments were positively correlated with the SNA and ANS-PNS distances，and the volume and the area increased with the maxillary protrusion of skeletal class Ⅱ. The volume and minimum cross-sectional area of the upper airway hyold pharyngeal and throat segments were positively correlated with SNB and mandibular length （Go-Gn），and the volume and the area decreased with the mandibular retraction of sdeletal class Ⅱ. There was a statistical difference among the three groups in the H-VPS measurement of the position of the hyoid bone （P < 0.05）. Conclusion　The morphology of the upper airway segments is closely related to the surrounding cranial and maxillofacial bone morphology. The relationship among the upper airway，the jaw bone and the hyoid bone is inseparable.

Key words: skeletal class Ⅱ, CBCT, upper airway, hyoid bone position