Correlation Study Between OVD And Craniofacial Hard Tissue Marker Based On55Young People With Normal Occlusion In Jiangxi

Objects: To study the occlusal vertical dimension (Occlusal VerticalDimension, OVD) associated with craniofacial measurement line distance and anglein55adults with normal occlusion in Jiangxi, maybe it can provide guidance forclinical prediction, assessment, quantification and calibration of OVD.Methods:(1) object of study: screening55normal occlusion volunteers, aged20-30years old,27males and28females from students who came fromundergraduate course graduate class in Medical School of Nanchang University inJiangxi and were all Han nationality with the normal occlusion;（2）Cephalometricfilm: to shoot the X-ray measure pictures by the same radiologist who was anexperienced technician;(3) Indirect measurement: putting the digital cephalometricradiographs of the filming into computer software Winceph8.0and using itscorrection software to correct image until the appropriate intensity and brightness inorder to see clearly the external auditory meatus shadow and hard tissue landmarksas the standard, the computer-aided anchor point was completed by author and thecustom project of the software was used to set the OVD correlation measurementproject, and then generated a measured value;(4) Statistical analysis: the measuringresults were analyzed by the test of normality, group test, linear correlation,partial correlation analysis, linear regression, multiple stepwise regression and otherstatistical methods.Result:(1) The average value of ANS-Me was64.99±4.13(95%CI:63.88~66.11), the average value of ANS-Me was66.67±3.95in male group and63.38±3.69in female group, the distribution difference which was analysand by t test wasstatistically significant between the two groups (t=3.191, P=0.002);for the averagevalue of angle measurement, the average value of LA was45.18±2.71(95%CI:44.45~45.91),the average value of LA was45.47±2.69in male group and44.91±2.74in female group, two groups had no significant difference according tothe group t test(t=0.764, P=0.448).(2) ANS-Me had a significant linear correlation and linear regression relationship with S-N, N-ANS,ANS-PNS (P≤0.05); Madepartial correlation analysis of ANS-Me and S-N, N-ANS, ANS-PNS with " N-ANS,ANS-PNS "," S-N, ANS-PNS "," S-N, N-ANS " as control variables, the resultswere still significant correlation between ANS-Me and N-ANS (P≤0.05), andANS-Me and S-N, ANS-PNS showed no significant correlation (P>0.05).(3) LA(surface angle) had significant linear correlation and linear regression correlationwith craniofacial measurement angle CA (central angle) and∠N-S-ANS (P≤0.05);Made partial correlation analysis of LA angle respectively to CA angle and theangle N-S-ANS with CA angle and∠N-S-ANS angle as control variables, the LAangle and CA angle still existed significant correlation (r=0.850, p=0.000), and theLA angle and the angle N-S-ANS angle showed no significant correlation (r=0.143,p=0.304).(4) Multiple linear regression analysis, the regression equation regressionequation ANS-Me in male group was Y=0.661*N-ANS+30.070, and there wassignificant (P=0.010), the coefficient of determination R~2=0.235,in female group,the regression equation was Y=0.694*N-ANS+27.472and also had statisticallysignificant (P=0.002), the determination coefficient R~2=0.302of regressionequation for male group LA; the regression equation was Y=0.968X+1.417and hadstatistical significance (P=0.000), the coefficient of determination R~2=0.955,infemale group, the regression equation was Y=0.972X+1.582and had statisticalsignificance (P=0.000), determination coefficient R~2=0.929.Conclusion:(1) The research results showed they had significant correlationbetween ANS-Me and N-ANS of youth with normal occlusion in Jiangxi area; theN-ANS could be used as a reference index in determining occlusal verticaldimension; there was no obvious correlation between the S-N, ANS-PNS andocclusal vertical distance of the same objects, which was no obvious guidingsignificance in determining the occlusal vertical dimension for clinical.(2) the LAangle and CA angle of youth with normal occlusion in Jiangxi area had significantcorrelation,CA angle could be used as clinical reference index in order to measureocclusal vertical dimension, but the N-S-ANS angle and the occlusion verticaldistance had no correlation, which was not used to determine the occlusalvertical dimension for clinical.(3) Multiple regression analysis showed when N-ANS or CA two factors were used to predicte OVD had higher forecastingaccuracy.