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

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.

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.

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.

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.