Analysis of Oral Microbial Dysbiosis Associated With Early Childhood Caries

Abstract Background: "Core microbes" play a key role in the development of caries and lead to microflora disorders. Our goal was to detect the core microbes associated with the microbial flora imbalance in early childhood caries (ECC). Methods: Fifteen caries-free children and fifteen high-caries (DMFT≥10) children aged 4-6 years old were recruited according to the diagnostic criteria of caries suggested by the WHO. The 16S rRNA genes from plaque samples loaded in saliva were amplified by PCR, and the PCR products were sequenced by the Illumina Miseq platform. The sequencing results were analyzed by professional software to determine the composition and structure of the saliva microorganisms. Results: There were statistically significant differences between the groups regarding the relative abundance of S. mutans (Wilcoxon rank-sum test, P<0.05). No significant difference was found between the groups regarding other species or functional genes. Conclusion: Neither unique microbes leading to early caries in deciduous teeth nor characteristics of a microbial community with a disordered structure were found. Some microorganisms related to dental caries in young children were found, but whether these microbes were truly related or were false positives requires further verification.