[Effect of invisalign on anterior and posterior upper airway and maxillary bone changes in the treatment of high-angle skeletal Class Ⅱ malocclusion].

Purpose: To investigate the effect of invisalign on anterior and posterior upper airway and maxillary bone changes in the treatment of high-angle skeletal Class II malocclusion.

Methods: Thirty-seven patients with malocclusion undergoing invisible orthodontic treatment in Hospital of Stomatology of Xi'an Jiaotong University from June 2016 to June 2018 were enrolled. Before and 18 months after correction, the correction effect was evaluated. Cone-beam CT (CBCT) was performed to measure the upper airway volume and tongue position. Cephalometric examination was performed to determine the anteroposterious diameter of the upper airway and the position of hyoid bone. The pre-therapy and post-treatment facial profile images of patients and stars were graded by 0-10 numerical rating scale. SPSS 20.0 software package was used to analyze the data.

Results: After correction, oropharyngeal volume, glossopharyngeal volume and minimum cross-sectional area of upper airway significantly increased(P<0.05). Sagittal diameter of the upper airway at mandibular plane significantly increased after correction (P<0.05). After correction, ANB angle, GoGn-SN angle, OPP-SN angle, Y-axis angle, UI-SN angle, UI-PP angle, UI-AP angle, and UI-AP distance significantly decreased, SNB angle and UI- LI angle significantly increased(P<0.05). The aesthetics scores of facial profile images significantly increased after correlation(P<0.05), which was significantly lower than that of the stars(P<0.05).

Conclusions: Invisalign can effectively correct open upper airway and malocclusion, achieving better treatment results and satisfactory facial aesthetics effect.