Functional profiles of coronal and dentin caries in children.

: Dental caries results from a dysbiosis of tooth-associated biofilms and frequently extends through enamel into dentin which has a different structure and composition. : To evaluate the metatranscriptome of caries to determine the metabolic potential of caries communities compared with health. : Samples from children, caries-free (CF:  = 4) or with coronal (CC:  = 5) or dentin (DC:  = 5) caries were examined for gene expression potential. Functional profiling was performed using HUMAnN2 (HMP Unified Metabolic Analysis Network). : There was increased gene expression diversity in DC compared with CC and CF. Genes in CF included alcohol dehydrogenase from , methylenetetrahydrofolate reductase from and choline kinase from streptococci. Genes in CC mapped mainly to . Arginine deiminase in DC mapped to and . Glycerol kinase genes mapped to in all groups whereas glycerol kinase in DC were from and streptococci. Uracil-DNA glycosylase in DC mapped to and . Repressor LexA in DC mapped to and . : Functional profiling revealed enzyme activities in both caries and caries-free communities and clarified marked differences between coronal and dentin caries in bacterial composition and potential gene expression.