Abstract: Objectives To study the characteristics of salivary microflora in the children with severe early childhood caries by metaproteomic technique. Methods We collected non-stimulating saliva from the children with severe early childhood caries and with free caries. All the salivary proteins were extracted and zymolysised into polypeptides for mass spectrometry analysis so as to analyze the characteristics of microbial community in childhood. Results The salivary microflora in the children with free caries originated from 19 phylums, or 1216 species. The high abundant oral microbiota are the 5 phylums of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria and the 11 species of Neisseria lactamica, Streptococcus pneumoniae, Neisseria sicca, Haemophilus parainfluenzae, Neisseria meningitis, Haemophilus influenzae, Neisseria flavescens, Neisseria gonorrhoeae, Kingella kingae, Neisseria mucosa, Neisseria polysaccharea. The salivary microflora in the children with severe early childhood caries originated from 24 phylums, or 1698 species. The high abundant oral microbiota are the 5 phylums of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Cyanobacteria and the 4 species of Streptococcus pneumoniae, Neisseria lactamica, Neisseria sicca, Haemophilus influenzae. Conclusions Metaproteomics can be used to analyze the composition of oral saliva microbial community. The structure of saliva microflora in children with severe dental caries is more complicated than that in the children with free caries, which may be related to the dental caries and dysbiosis of the oral microecology.

Key words: Severe early childhood caries, Slivary, Metaproteomics, Microbial community