Comparison Of Epidemiology And Plaque Microorganisms Of Early Childhood Caries Between Han And Uygur Children

Objective: To compare the prevalence of early childhood caries and risky factors between Han and Uygur children from three to five years old in Xinjiang,and to analyze the characteristics of plaque microbial community and their succession after treatment in severe early childhood caires by high-throughput sequencing technology,in order to provide reference for comprehensive prevention and control of dental caries.Methods: According to the Basic Method of Oral Health Survey from world health organization and the Third National Oral Health Epidemiological Survey Program,a multi-stage random stratified cluster sampling method was applied in this study.According to the regional and population distribution statistics of Xinjiang Uygur Autonomous Region,1727 Han and Uygur children aged from three to five years old from 26 kindergartens in Kashgar City and Yining City as the central city of Kashgar area and Yili Kazakh Autonomous Prefecture with the largest proportion of population in southern and Northern Xinjiang,were selected for questionnaire survey and oral examination.The prevalence,the mean dmft value,filling rate and distribution of dental caries were recorded,and logistic regression analysis was based on various of factors such as social environment,economic status,diet,oral hygiene habits and oral health behavior.Supragingival plaque of deciduous molars was collected from children with severe early childhood caires and healthy controls.The composition and diversity of microbial community were analyzed by Illumina high throughput sequencing technique.At the same time,dental filling therapy and oral health care guidance were provided to the children with severe early childhood caires.Follow-up was conducted one year later.The changes of plaque microbial community and their correlation were analyzed by the same site and method.SPSS21.0 software was used for data collection and statistical analysis.All tests were two-tailed with a significance level of 0.05.Results: 1)The prevalence of early childhood caires(ECC)was 78.2% and the prevalence of severe early childhood caires(SECC)was 41.2% of 1727 children.There was no significant difference in ethnic distribution that the prevalence of ECC and SECC between Han children(78.7%,42.6%)and Uygur children(77.9%,40.1%).Considering the comparison between both ethnical groups,different results of the prevalence of ECC for both Han and Uygur Children during different age do present statistical evidences.The prevalence of ECC and SECC in the five-year-old group was higher.The prevalence of SECC among Han children living urban was significantly higher than that in rural areas(52.3%).The prevalence of ECC among Uygur children in different regions was significantly different,and the prevalence of ECC in Yining was higher(84.7%).2)The caries rate of deciduous molars and maxillary central incisors were the highest,and there were differences in ethnic distribution.Uygur children had higher caries rate of deciduous molars,while Han children had higher caries rate of deciduous anterior teeth.3)The filling rate of dental caries was 1.72%.The filling rate of Han children was higher than that of Uygur children,and that of urban children was higher than that of rural children(P<0.001).4)Age,urban life,low education level of mothers,breast-feeding,caretaker with cavities,frequent eating before sleep,and less dental specialist treatment were risky factors of ECC and SECC in Han children.Age,Yining life,low-income families,caretaker with cavities,frequent pre-sleep eating,high-frequency sugary diet,late or non-brushing of teeth,and less dental specialist treatment were risky factors of ECC and SECC in Uygur children.5)A total of 3219033 high-quality sequences clustered into 18928 operational taxonomic units(OTUs)at 97%,representing 443 independent species belonging to 117 genera,58 families,30 orders,20 classes,and 11 phyla.Diversity index showed that the composition and diversity of plaque microflora were different between the two ethnic groups.The diversity of plaque microflora in oral health group was higher than that in SECC group.6)Actinomyces,Aggregatibacter,Haemophilus and Terrahaemo-philus are the dominant bacteria of Han children with SECC.Streptococcus and Veillonella are the dominant bacteria of Uygur children with SECC.7)Actinomyces spp.and Terrahaemophilus aromaticivorans are the core bacteria related to Han children with SECC.Veillonella dispar,Streptococcus sinensis,Selenomonas dianae and Actinomyces spp.are the core bacteria related to Ugyur children with SECC.8)In SECC group,the abundance of Leptotrichia shahii,Prevotella spp.,Alloprevotella tannerae,Selenomonas sputigena in Uygur children group were significantly higher than that in Han children group,while the abundance of Actinomyces gerencseriae,Actinomyces johnsonii,Actinomyces massiliensis,Neisseria elongate,Kingella oralis,Kingella denitrificans in Han children group was significantly higher than that in Uygur children group.9)One year after the treatment,the abundances of microbes in children with SECC showed an obvious trend of health.But the flora abundance of secondary caries children was similar or more than that of pre-therapy.Conclusion: 1)The prevalence of ECC and SECC among Han and Uygur children ageing from three to five years old in Xinjiang is high and the filling rate is low.2)There was no significant difference in the prevalence of ECC and SECC between Han and Uygur children,but the influence of related risky factors on ECC is different among different ethnical groups.3)The composition and diversity of supragingival plaque flora between Han and Uygur children have significant differences in caries status and ethnic groups.4)Decent oral hygiene control and filling therapy can lead to a healthy succession of plaque microflora.