| Background:Childhood dental caries is the most common disease in children worldwide,affecting 541 million children worldwide and leading to a heavy medical and economic burden.Dental caries can not only threaten the local oral health of children,but also affect the physical and mental health of children in severe cases.How to prevent and manage dental caries has become an important issue in the field of stomatology.Although previous culture-based studies have focused on Streptococcus mutans,the results of sequencing-based studies on the key oral bacteria for dental caries are often inconsistent.Therefore,the subgroup differences of oral bacteria need to be elucidated.Objective:In this paper,the health status of dental caries in children was investigated to explore the influencing factors of dental caries.High-throughput sequencing of supragingival plaque and non-irritating saliva samples from children with caries was performed to identify the caries-associated key bacteria in children of different locations,ages and genders.Methods:1.A total of 4828 questionnaires were collected from children aged 3-8 years in Pingshan District of Shenzhen.SPSS 25.0 was used to analyze the caries status with different oral hygiene behaviors and dietary habits,especially in different age and sex groups.2.Supragingival plaque samples and unstimulated saliva samples from 102 children with dental caries were subjected to 16S rRNA gene sequencing,and detailed oral examinations were recorded.QIIME,DADA2,LEfSe,MaAsLin2 and other analysis methods were used to analyze the influence of different sampling sites on the key caries-related bacteria,and further explored the key bacteria in different age subgroups.Results:1.The prevalence of dental caries in children in this area is increasing with age,and the mean dmft is also increasing.In this survey,the prevalence of caries was not significantly different between boys and girls.Lifestyle factors,such as eat after brushing teeth at night and start brushing the baby’s teeth later,with a statistically significant strong positive correlation with caries risk in children(P<0.05).2.The diversity of microbial communities in supragingival plaque was significantly different from that in unstimulated saliva,and the distribution of microbial communities in supragingival plaque was more evenness than that in saliva.Saccharibacteria was the most correlated species with caries severity in both supragingival plaque and unstimulated saliva samples from children with caries.Acinetobacter was the key bacteria in supragingival plaque group.While Actinomycetales and Clostridiales were the key bacteria for caries in saliva group.3.Beta diversity analysis showed that age was significantly associated with the severity of caries,but there was no correlation between gender in either Alpha or Beta diversity.Two and fifteen species were found in plaque to be associated with the severity of dental caries in preschool children and school-age children,respectively.However,Saccharibacteria was the only bacteria associated with the severity of dental caries in both groups.Conclusion:1.This study confirmed that materia alba,caregiver caries,late start of brushing teeth and eating after brushing teeth were the most critical risk factors for dental caries in local children aged 3-8 years.2.There were significant differences between preschool and school age children in the key bacteria related to caries,among which Saccharibacteria was the only consistent key bacteria,suggesting that it may have important research value.3.The relationship between oral flora and caries may have population heterogeneity,so it is necessary to consider the specific population characteristics in future research and transformation. |
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