The metagenome and metabolome signatures of dental biofilms associated with severe dental fluorosis

Objective: To explore the plaque biofilm microbiome associated with severe dental fluorosis (SF), and to describe its metagenome and metabolome. Methods: Sixteen plaque biofilm samples were collected from eight 6- to 15-year-old Thai children with SF and eight age-matched, caries-free and controls. Biofilms were analyzed using shotgun metagenomic sequencing, followed by bioinformatics evaluation. Results: Taxonomic profiling of biofilms from SF and controls identified a total of 12 phyla and 354 species. While alpha diversity was similar between the groups, beta diversity analysis ( = 0.0010) indicated distinct microbial community structures. LEfSe highlighted key discriminatory taxa: five health-associated species ( and ) were enriched in controls, while , known for fluoride-sensitive esterase production, was significantly elevated in SF. Functionally, eight metabolic pathways were altered; three of these (phosphatidylcholine acyl editing, anhydromuropeptides recycling II, ubiquinol-7 biosynthesis), hypothesized to support activity, were upregulated in the SF group. Conclusion: SF is associated with a significant shift in the biofilm microbiota, characterized by enrichment of and a reduction in health-associated taxa. Altered metabolic pathways supporting provide mechanistic insights into its role as a candidate biomarker for fluorosis, warranting further investigation.