Cross Sectional Investigation Of Malocclusion In Multinational Children And Juvenile Of Urumqi

Objection: Through the sampling survey, to determine the prevalence and distribution of malocclusion in juvenile and children of Urumqi. Methods: After the stratified and cluster random sampling, 3,006 multinational elementary and middle schoolchildren aged from 7～15 years (1,437 females, 1,569 males) in Urumqi are chosen. At the standard of Angle's classification and individual normal occlusion, a full clinical examination about malocclusion was carried out in the school premises by using mouths mirrors and other tools in natural lighting, filling in the examination tables, packing up the data, and then dealing with them statistically. Results: Of 3,006 subjects, There were 1,447 malocclusion cases according to the Angle's classification, and the overall prevalence of malocclusion was 48.13%. Among them, 35.89% is in Angle'sⅠ, 5.82% in Angle'sⅡ, and only 6.36% in Angle'sⅢ. There was statistically significant difference betweenmales (48.31%) and females (42.19%) in their overall prevalence of malocclusion (P<0.05).The distribution in three different age spans from 7～9, 10～12, to 13～15, respectively in 41.63%, 47.80% and 50.58%, still having the statistically significant difference (P<0.05). The four main people(ethnics) had significant difference in statistic, prevalence respectively being 43.28%, 51.37%, 40.38% and 52.81% in the Han Nationality, the Uygur national minority, the Kazakh national minority and Hui tribe (P<0.05). But in the mixed and permanent dentition stage, there weren't statistically difference with the prevalence of 46.02%, 49.84%(P>0.05). From the malocclusion traits detected, the crowding of permanent dentition is the main malocclusion type, amounting to 36.15% in under anterior area, 24.40% in upper anterior area, and other abnormality are in turn overbite, over-jet, abnormal spacing of anterior areas, central line asymmetry, open bite of anterior teeth, and etc. Conclusions: The rate of malocclusion of the juvenile and children in Urumqi is higher. The different rate gives us a help to advance the etiology and the mechanism of malocclusion so that we can advance the efficient prevention and treat measures. The research can provide information to improve research in this way in Urumqi.