A Comparative Study On Sagittal And Vertical Characteristics Of Class Ⅲ Malocclusion In Mixed Dentition Between Uygurs And Hans In Urumqi

Objectives: To study the sagittal and vertical characteristics and differences of the the Uygurs and Hans’ cranial face in the mixed dentition of Class Ⅲ malocclusion in Urumqi area.Method: From February 2014 to December 2018,60 patients with Class Ⅲand mean mandibular plane angle malocclusion were enrolled by inclusion/ exclusion criteria from the Department of Orthodontics,the Fifth affiliated Hospital of Xinjiang Medical University.The cephalogram of the subjects was measured by winceph7.0software and the data were statistically analyzed by spss 22.0.Results: In the sagittal bony index,The male APDI,Beta and NP-FH in the Uygur group were all lower than that of the female,and there was a significant difference(p <0.05).There was no significant difference in sagittal direction between male and female in Han group(p > 0.05).In the comparison between Uygur and Han males,there was a statistical difference(P < 0.05)in the index of SNA,ANB,NA-PA and A-B facial angle.The difference of NP-FH between the Uygur and Han female groups was statistically significant(p <0.05).The results of dental index comparison showed that there was no significant difference(p > 0.05)between Han male and female groups.There was significant difference in U1-L1 and U1-NA angle between Uygur male and female(p < 0.01).There were statistical differences in U1-NA angle,U1-NA distance and L1-NB distance between Uygurs and Hans’ male(p < 0 05).Between Uygur and Hans’ female groups,only U1-L1 had a statistically significant difference(p <0.05).In the vertical index,the results of Uygur male and female comparison showed that there were significant differences(p < 0 05)in the OP-FH angle,total facial height(N-Me)and the lower facial height(Ans-Me).There were significant differences(p < 0 05)in MP-FH,y-axis angle and OP-FH value between male and female of Han groups.In the comparison between Uygur and Han males,there wasonly statistical difference(p < 0.05)on Ans-Me.The difference of MP-FH and y-axis angle between Uygurs and Hans’ female was statistically significant(p < 0.05).Conclusion: In Urumqi area,the sagittal and vertical growth and development characteristics of craniofacial region of class III malocclusion with mean mandibular plane angle in mixed dentition were different in different genders and groups in Urumqi area.