Study On The Effects Of Extraction And Non-extraction Treatment On The Upper Airway And Surrounding Tissues Of Skeletal Class Ⅱ Hyperdivergent Patients

Objective:To analyze the changes of the upper airway and its surrounding tissues of skeletal Class Ⅱ hyperdivergent adolescent and adult patients before and after orthodontic extraction or non-extraction treatment by the lateral cephalometric radiographs.To explore different orthodontic treatment methods on the upper airway of adolescent and adult patients and provide reference for clinical diagnosis and treatment.Methods:120 cases of skeletal Class Ⅱ hyperdivergent patients were collected from the Department of Orthodontics of the Stomatology Hospital of Jilin University between January 2013 and January 2019.They were divided into extraction group and non-extraction group based on different treatment methods,and 60 cases in each group.According to Hassel and Farman’s improved cervical vertebra stage method,the growth and development were determined and the patients were divided into adolescent and adult.There were 30 adolescents and 30 adults in the extraction group,30 adolescents and 30 adults in the non-extraction group,respectively.The Dolphin software was used to trace,measure anddigitize pretreatment and posttreatment lateral cephalograms about the upper airway,hyoid bone and craniomaxillofacial structures.The data were all collected and SPSS 23.0 statistical software was applied for statistical analysis.The difference of date before and after treatment was compared by paired sample t-test in each group.The effects of extraction or non-extraction and growth and development on upper airway and surrounding structures in skeletal Class Ⅱ hyperdivergent patients were further analyzed.Results:1.In the extraction group after treatment,as for the adults,U-MPW,V-LPW,U1-SN and L1-MP reduced,while OP-SN and U1-L1 increased;as for the adolescents,ANB,U1-SN,L1-MP reduced,while PNS-UPW,PNS-V,H-S,OP-SN,U1-L1 increased.The difference was statistically significant(P <0.05).2.In the non-extraction group after treatment,as for the adults,ANB reduced,while OP-SN,L1-MP increased;as for the adolescents,ANB reduced,while PNS-V,H-S,OP-SN increased.The difference was statistically significant(P<0.05).Conclusion:1.The sagittal diameter of the upper airway tended to narrow after extraction,especially in the oropharyngeal and hypopharyngeal,but the sagittal diameter of the upper airway did not change significantly in thenon-extraction group.2.For the skeletal Class Ⅱ hyperdivergent adolescents,no matter extraction or non-extraction treatment,the sagittal diameter and vertical height of the upper airway increased to a certain extent due to growth and development,so the extraction treatment had little adverse effect on the upper airway of the skeletal Class Ⅱ hyperdivergent adolescents.3.The position of hyoid in skeletal Class Ⅱ hyperdivergent adults and adolescents was almost not affected by orthodontic treatment,but the position of hyoid of adolescents tended to move downward and forward.