The Study On Upper Airway In Patients With Skeletal Class â…¡ Malocclusion By CBCT

Objective: To study the differences of upper airway dimensions in adolescenes withdifferent sagittal skeletal patterns and to evaluate the changes of upper airwaydimension and morphology in Class Ⅱ retrognathic children after functionaltreatment for investigating correlation between the craniofacial and upper airway.Methods: Cone beam CT datas of68adolescenes（11~16years）were collected anddivided into three groups according to the ANB angle. Three groups were matched forage and sex and each subject presented a normodivergent skeletal pattern. Upperairway volume, cross-sectional area, sagittal diameter and lateral diameter weremeasured by Dolphin11.5software and two-dimensional lateral cephalograms werecreated and analyzed. Airway dimensions were compared among different groupswith one-way analysis of variance (ANOVA), and the correlation between airwaydimensions and craniofacial variables was analysed with Pearson analyses. Sixteenskeletal Class Ⅱ retrognathic children were selected and treated by the Twin-blockappliance. Upper airway volume, cross-sectional area, sagittal diameter and lateraldiameter were measured by Dolphin11.5software and paired-samples t test wasemployed to compare the airway changes. Results: Compared with adolescents inClass Ⅰ and Class Ⅲ malocclusion, adolescents in Class Ⅱ had a smaller volumeof total airway, velopharynx, glossopharynx and oropharynx, cross-sectional area ofSP and TE and minimum cross-sectional area of oropharynx, sagittal diameter andlateral diameter of SP and lateral diameter of TE（P<0.05）. Volume of total airway,velopharynx, glossopharynx and oropharynx, and minimum cross-sectional area oforopharynx had a negative correlation with ANB angle and a positive correlation withCo-Gn or Ar-Gn（P<0.05）. There was no significantly correlation between upperairway and ANS-PNS, NA-AP or FH-NP（P>0.05）.Skeletal Class Ⅱ retrognathic children had a larger volume of total airway,velopharynx, glossopharynx and oropharynx, a larger cross-sectional area of SP, TEand minimum area of oropharynx and a larger sagittal diameter and lateral diameter of SP, a large lateral diameter of TE（P<0.05）after functional treatment. There were nosignificantly changes of cross-sectional area of HP, sagittal diameter and lateraldiameter of HP, and sagittal diameter of TE（P>0.05）.Conclusion: Adolescents with skeletal sagittal Class Ⅱ malocclusion had a smallerupper airway than adolescents with Class Ⅰ and Class Ⅲ malocclusion. Thedimensions of the upper airway were affected by the ANB angle and mandible length.Skeletal Class Ⅱ retrognathic children had a larger upper airway after functionaltreatment.