Metagenomic Study Of Supragingival Plaque Microorganisms In Deciduous Dental Caries Of 5-year-old Children In Qingdao

OBJECTIVE: The purpose of this study was to study the microbial community structure and functional characteristics of supragingival plaque in 5-year-old children with severe decay and health in urban and rural areas of Qingdao,and to analyze the microbial etiological mechanism of dental caries.And select potential caries-related microbial factors and establish a caries prediction model to provide new ideas for the prevention and diagnosis of dental caries in the local.METHODS: In this study,63 samples of supragingival plaque were collected from5-year-old children in Qingdao.According to the number of dental caries,(dmfs)was divided into 32 children with severe caries(high caries group,dmfs ≥ 6)and 31 children with oral health(healthy group,dmfs = 0).According to different geographical locations,the samples were divided into urban group(n = 32)and rural group(n = 31).Among them,there were 17 cases in urban caries group,15 cases in rural caries group,15 cases in urban healthy group and 16 cases in rural healthy group.The DNA genome was extracted from63 samples,16 s r RNA V3-V4 region was amplified and sequenced at both ends.We compared the effects of health status and biogeography on the microbial community of supragingival plaque.The microbial diversity,frame of the biotic community and configuration of supragingival plaque from different health status and geographical location were analyzed,and the microorganisms related to severe caries and health of young children with different geographical location were screened.Observe the correlation between dmfs and species-level microorganisms,use network analysis to observe the correlation of microorganisms related to dental caries,use ROC curve to establish dental caries prediction model,and further analyze the functional characteristics of microorganisms in supragingival plaque from the point of view of functional metabolism.RESULTS: There were significant differences in species diversity index(Shannon and Simpson)and microbial community structure between severe caries children and healthy children(P < 0.05).The effect of health status on the microbial community structure of supragingival plaque was greater than that of geographical location,but there were also differences in the microbial structure of supragingival plaque from different geographical locations(P < 0.05).The highly expressed health-related microorganisms in the healthy group and the suspected cariogenic microorganisms in the high caries group were identified,such as Prevotella,Leptotrichia,TM7,Selenomonas.Among them,the cariogenic microorganisms in urban were Prevotella,TM7,Selenomonas,while there were no significant cariogenic microorganisms in rural.On the whole,the relative abundance of Streptococcus,Actinobaculum,kingella in urban was lower than that in rural,and the relative abundance of Gemella and TM7 in urban samples was higher than that in rural samples.In the part,Actinobaculum and kingella only in urban samples were lower than those in rural,while Neisseria and Gemella were higher than those in rural.In the caries group,the genera of Streptococcus and kingella in urban samples were lower than those in rural,while the genera of Gemella were higher than those in rural.Network analysis showed that caries-related microorganisms were positively correlated;dmfs was positively correlated with Prevotella,TM7,Selenomonas.ROC curve model showed that specieslevel species had higher predictive value,and Prevotella could be used as a predictive marker of dental caries.Compared with caries group,carbohydrate metabolism and amino acid metabolism were grew in healthy group;but compared with urban caries and healthy group,carbohydrate metabolism and amino acid metabolism were improved in rural caries and healthy group,respectively.CONCLUSION: 1.Oral status is important factors that determine the distribution of microbiome,and geographical factors have an important effect on the distribution of microbiome in normal children.2.There are differences in the microbial diversity and structure of supragingival plaque between 5-year-old children with high caries and healthy children in Qingdao.The structure of the microbial map of healthy children’s plaque is more conservative in children with higher dental caries.3.There are significant differences in the microbial composition of supragingival plaque between 5-year-old children with high caries and healthy children in Qingdao.There are significant changes in the relative abundance of bacterial components such as Prevotella in the two populations,which may participate as biological factors or represent the imbalance of the flora in the occurrence and development of caries.4.Using the change characteristics of oral microbiome as biological indicators,combined with machine learning methods,a universal dental caries model that can be used to detect the oral health status of hosts from urban and rural sources is established to screen high-risk populations of dental caries and individual oral cavity Health monitoring provides a theoretical and practical basis.