A Study On The Craniofacial Vertical Growth Changes In Children With High Facial Angle With Skeletal Class Ⅰ And Ⅱ Malocclusion Mandibular Retrution

Objective:To study the changes of facial height with cervical vertebral bone age in high facial angle children with skeletal Class I and II malocclusion and mandibular retrusion,and to provide reference for clinical diagnosis and treatment of orthodontics.Method:Cephalometric radiographs of initial-visit patients aged 8¹8 with GoGn-SN>37.7°were selected from January 2017 to December 2018 at the orthodontic Department of the Affiliated Stomatological Hospital of Nanchang University.298subjects were included according to SNA angle,SNB angle ANB angle and cervical vertebral bone age:177 patients with skeletal Class I malocclusion and 121 patients with skeletal Class II malocclusion and mandibular retrusion,184 women and 114men,60 patients with QCVM stage 1,95 patients with QCVM stage 2,88 patients with QCVM stage 3 and 55 patients with QCVM stage 4.Winceph 8.0 software was used to measure 5 vertical facial height（N-ANS,ANS-Me,N-Me,S-Go,Ar-Go）and 3proportions（N-ANS/N-Me,ANS-Me/N-Me,S-Go/N-Me）of the subjects.The statistical processing was carried out with SPSS 23.0:Multiple linear regression analysis was used to analyze the vertical facial measurement items as dependent variables（expressed by Y1^Y8）,sagittal facial type,gender and cervical vertebral bone age as independent variables（expressed by X1,X2,X3）.A multiple linear regression model and regression equation were established to study the relationship between sagittal facial type,gender,cervical vertebral bone age and vertical facial measurement items.Variance analysis was used to test the multiple linear regression equation,and the level of linear correlation between dependent variables and argument in the model is evaluated by the complex correlation coefficient R value,the coefficients in the regression equation were analyzed to study the characteristics of vertical facial parameters of high angle patients with different sagittal facial type,gender and cervical vertebral age.Result:1.In this experiment,eight measurement items were studied and the corresponding regression models were established with each measurement item as dependent variable.The following five regression models have statistical significance:（1）Y1=46.628+（0.110X1）+（3.174X2）+（1.443X3）;（2）Y2=56.583+（-0.100X1）+（4.435X2）+（3.383X3）;（3）Y3=101.586+（-0.978X1）+（7.581X2）+（3.883X3）;（4）Y4=59.948+（-0.640X1）+（6.105X2）+（3.023X3）;（5）Y5=34.470+（-0.970X1）+（2.969X2）+（1.831X3）;Y1represents dependent variable N-ANS、Y2represents dependent variable ANS-Me、Y3represents dependent variable N-Me、Y4represents dependent variable S-Go、Y5represents dependent variable Ar-Go.2.In this experiment,the regression coefficients（slope）of independent variables in regression equation were P_（X1）<0.05,P_（X2）<0.001,P_（X3）<0.001 respectively,suggestingthatthedifferencebetweenslopeand0hasstatistical significance,meanwhile that there is a liner relationship between independent variables（X1,X2,X3）and dependent variables（Y1^Y5）.Conclusion:In this experiment,we studied the vertical height of high facial angle adolescents during their growth and development horizontally,and drew the following conclusions:1.Vertical craniofacial height（N-ANS,ANS-Me,N-Me,S-Go,Ar-Go）of patients with skeletal Class I and II malocclusion,high facial angle and mandibular retrusion increased linearly from QCVM1 to QCVM4,and the mandibular height of patients with mandibular retraction of Class II malocclusion was smaller than that of patients with Class I malocclusion,but the anterior-inferior height larger than that of patients with Class I malocclusion.2.High facial angle patients’vertical plane height（N-ANS,ANS-Me,N-Me,S-Go,Ar-Go）increases linearly from QCVM1 to QCVM4,and males are larger than females.There are gender differences in the development of vertical craniofacial height.