ABSTRACT
Objective@#To study the difference in the flora structure and gene function of dental plaque in caries-free and caries-active preschool children by 16S rRNA sequencing.@*Methods@#After oral examination of 96 preschool children aged 3-6 years, they were divided into 3 groups according to their decayed, missing and filled surface (dmfs) index: group CF with no caries (n=31), group ECC with moderate early childhood caries (n=29) and group SECC with severe early childhood caries (n=36). Dental plaques were collected, and DNA was extracted and then underwent metagenomic sequencing by Illumina HiSeq 2 500. The bacterial community structure was analyzed by Qiime. @*Results @#A total of 12 phyla, 31 classes, 31 orders, 50 families, 92 genera and 1 104 species were found in the dental plaque samples of the three groups, most of which belonged to 9 dominant genera, including Streptococcus, Veillonella, etc. The microbial diversity of the dental plaques in the three groups was similar (P > 0.05). Veillonella, Lactobacillus, Megasphaera, and Scardovia in the SECC group were significantly higher than those in the other two groups. There was a significant correlation between the decayed, missing and filled surface (dmfs) index and the genus. Bifidobacterium, Veillonella, Lactobacillus had a positive correlation with the dmfs index, while Eikenella had a negative correlation with the dmfs index. Indicator species analysis showed that Atopobium, Veillonella, Megasphaera, Scardovia, Lactobacillus and Bifidobacterium had high indicative values in the SECC group. @*Conclusion @# There are significant differences in plaque microbiota among preschool children with different caries sensitivities. Veillonella, Megasphaera, Scardovia, Lactobacillus, Bifidobacterium and Atopobium may be the indicator genera of severe early children caries.