The Model Study Of The Normal Occludion Population Of XinJiang Kazak Adolescent

Objective:It is very important to establish the norms with deviation of the crown width,interarch tooth size ratiosof XinJiang Kazak adolescent with nomal occlusion,which helps to determine malocclusion and its further development.This reserch is to analyse the difference between different regions or nationalitives,to provide the most accurate and easy basis in orthodontic diagnosis and treatment for Xinjiang Kazak peoples.Methods:100 XinJiang Kazak students who were from thirteen to eighteen years old without orthodontic history were randomly collected in. All samples came from Alatai region in XinJiang.All teeth must be free of visible malform,aberration,and fully erupted.Impressions were taken ,and measurements were made,parallel to the occlusal plane at the greatest mesiodistal width of each tooth on dental cast with caliper(0.02 mm ).Each tooth was measured twice and the average of the two readings was taken as the dimension for that individual tooth.Mesiodistal crown diameters were statistically analyzed with t-tist and linear regression, using the SPSS(Statistics Package for Social Science)11.0 computer package.Results:It was found that mesiodistal crown diameters had significantly statistical difference in gender. Hence the mesiodistal crown diameters were assessed and invesigated separately for the male and female.The mesiodistal crown dimeters of XinJiang Kazak has significance with that of Xi'an Han nationality and Guangxi Zhuangzuautonomous region.There were great difference in Pont'index and Bolton'analysis in different groups.The cirrelation analysis of interarch tooth size reveal that there were significant positive relationships between upper anterior teech group and lower anterior teeth group,upper over-all teeth group and lower's.The correlation coefficients were 0.503 for upper anteriors and lower anteriors,0.596 for upper over-all teeth and lower's,0.332 for TMU2-2 and UW3-3.The correlation cofficients had signifficantly statistical diffence.Conclusion:Racial variation exists in the aspect of teeth crown and tooth size ratios,norms of eath region and nationality have to established to match the need of clinical treatment.There were distinguishing characteristics in arch dimensions in Xinjiang Kazak adolescents and these ethnic differences should be condidered during orthodontic treatment.