Microbial profiling of dental plaque in caries-active and caries-free children: A cross-sectional 16S rRNA gene sequencing study.

OBJECTIVES: Advances in deoxyribonucleic acid (DNA) sequencing and bioinformatics have improved understanding of caries- and health-associated oral microbiomes. This preliminary study investigated differences in dental plaque microbiota between caries-active (CA) and caries-free (CF) Indian children using 16S rRNA gene sequencing. MATERIALS AND METHODS: Twenty-five children were enrolled (20 CA, 5 CF), and 30 supragingival plaque samples were collected: 20 from CA lesions, 5 from clinically sound CF surfaces (CFS) in CA children, and 5 from CF (healthy control) children. DNA was extracted and the V3-V4 regions of the 16S rRNA gene were sequenced using the Illumina platform. Bioinformatic analyses included operational taxonomic unit clustering and alpha and beta diversity assessment. RESULTS: No significant differences in alpha or beta diversity were observed among groups ( P > 0.05), indicating comparable overall richness and evenness. Streptococcus mutans , traditionally considered a primary cariogenic pathogen, was absent in 65% of CA subjects. Seventeen genera were detected exclusively in plaque samples from CA surfaces including Bifidobacterium , Scardovia , Lactobacillus , Peptoanaerobacter , Propionibacterium , Streptobacillus , Desulfobulbus , and several previously uncultured taxa. In contrast, some taxa, including Corynebacterium matruchotii , Capnocytophaga gingivalis , Campylobacter gracilis , and Selenomonas noxia , were more commonly associated with samples from CFS. CONCLUSIONS: The findings indicate compositional differences in plaque microbiota between CA and CF children and support the concept that dental caries is a polymicrobial, dysbiosis-driven disease rather than the result of a single pathogen. Further large-scale studies incorporating functional analyses are required to clarify the ecological and clinical significance of these microbial patterns.