3D Cone Beam Computed Tomography Evaluation Of Upper Airway Growing Stage In Skeletal Class Ⅱ Patients With High Angle Malocclusion

Objective: Through the three-dimensional data analysis of the upper airway in different bone ages of the patients with skeletal class II high angle malocclusion,In order to obtain the characteristics of growth and development of the upper airway,which provided the basis for the selection of the timing and prognosis of orthodontic treatment.Methods: 47 patients with skeletal class II high angle malocclusion were selected from the Stomatology Department of The Second Hospital of Dalian Medical University,The age range of the patients was 7-20 years old.According to Quantitative Cervical Vertebral Maturation(QCVM),the patients were divided into 4 groups(QCVM I : accelerated period;QCVM II: peak period;QCVM III : deceleration period;QCVM IV : end period).CBCT was performed in all patients,and the image data were imported into Invivo Dental 5.0(Anatomage,USA)for 3D reconstruction of the upper airway model.The height,volume,minimum cross-sectional area,sagittal and coronal length of upper airway were measured and analyzed by SPSS Statistics 26.0 software.The data were first Normality test and then analyzed for Pearson correlation.After controlling for influence factors,the researchers compared the upper airway height,volume,minimum cross-sectional area,sagittal and coronal length of each segment in adjacent groups,independent sample t-test or independent sample nonparametric test was used.Results:(1)In the pearson correlation analysis between gender and all measures,gender was significantly correlated with the minimum cross-sectional area of the glossopharyngeal segment(p < 0.05).The degree of correlation was moderately small(r=0.298),and the minimum cross-sectional area of the glossopharyngeal segment was greater in men than in women.(2)UTH in QCVM III was smaller than that in QCVM IV(p < 0.05),EBH and H total in QCVM III were significantly smaller than that in QCVM IV(p < 0.01),and H total in QCVM I was smaller than that in QCVM II(p < 0.05).The height of upper airway increased with the development of QCVM,and UTH,EBH and H total increased the fastest in QCVM IV.(3)ETV,EBV,ET Min CSA and EB Min CSA in QCVM II were smaller than those in QCVM III(p < 0.05).The minimum cross-sectional area of upper airway was in glossopharyngeal segment,and the minimum volume was in hypopharyngeal segment.ETV,EBV,ET Min CSA and EB Min CSA increased significantly in QCVM II,while ET Min CSA decreased after QCVM I.(4)UTL,ETL,EBL in QCVM II were less than that in QCVM III(p < 0.05),UTW,ETW in QCVM III were less than that in QCVM IV(p < 0.05),PNSL in QCVM III was significantly smaller than that in QCVM IV(p < 0.01).The sagittal and coronal length of upper airway sections increased gradually with the development of QCVM.UTL,ETL,EBL increased significantly in QCVM III,while UTW,ETW,PNSL increased significantly in QCVM IV.Conclusion:1.The minimal cross-sectional area of glossopharyngeal segment of upper airway in patients with skeletal class II high angle was correlated with gender,and the minimal cross-sectional area of glossopharyngeal segment of male was larger than that of female.2.The peak period of upper airway height growth and development was in QCVM IV in patients with skeletal class II high angle malocclusion.3.The peak period of upper airway volume growth and development was in QCVM III.The sagittal length of the lower bound of each segment increases obviously inQCVM III.The sagittal length of the upper boundary of the palatopharyngeal segmentand the coronal length of the lower boundary of the palatopharyngeal and glossopharyngeal segments reached their peak in QCVM IV.4.The stricture of upper airway in patients with skeletal class II high angle was in the glossopharyngeal segment.5.According to the growth and development of upper airway,the best time for treatment of skeletal class II high angle malocclusion is QCVM III.