Microbiome in Early Childhood Caries: Caries Severity-Dependent Insights.

Introduction: Children with early childhood caries (ECC) show different caries severities and susceptibility in different tooth types and location in the oral cavity. The study aimed to investigate differences in the oral microbiome in ECC subjects stratified according to the severity of caries and between more and less caries-prone teeth within the same subjects.

Methods: Supragingival plaque from the upper and lower anterior regions in the oral cavity of subjects were collected in 3 groups of increasing caries severity: G1 - molar (M) caries only; G2 - molar and upper anterior (UA) caries; and G3 - M + UA + lower anterior (LA) caries followed by microbiome analysis.

Results: Alpha-diversity analyses showed inter- but no intra-individual statistically significant differences between the UA and LA (p < 0.001, LA > UA) and a significant difference between the microbiome of the three caries groups (p < 0.001). There were significant beta-diversity differences between G1 and G2 (p < 0.05) and in the composition and diversity among the three groups (p < 0.001). Actinomyces, Saccharibacteria_genera_inserta_sedis, and Eikenella had increased differential abundance in G1 versus G3 and Fusobacterium was less abundant in G2 compared to the other groups.

Conclusions: There were clear distinct differences in tooth-site-specific and caries-severity microbiome diversity patterns and bacterial abundance profiles in S-ECC children.