Fig. 1

Structure of the longitudinal clinical intervention study. A After a 1-week washout period, individuals brushed their teeth twice per day for a period of 3 months with a 1450-ppm fluoride dentifrice and six additional months with a 1.5% arginine + 1450 ppm fluoride dentifrice. Dental plaque samples were collected longitudinally at post-washout (marked as “Baseline” in the figure) and after the two treatment periods (arrows). DNA and RNA were extracted from the plaque samples and separately sequenced on an Illumina platform. The corresponding metagenome (MTG) and metatranscriptome (MTT) were analyzed to determine the bacterial composition, gene content, and gene expression of the overall dental plaque community. In addition, the 16S rRNA gene was amplified in the DNA samples and sequenced separately through Illumina Miseq sequencing. B Number of dental plaque samples analyzed in the current manuscript for the two arms of the study, i.e., caries-active (CA) and caries-free (CF) individuals at the three time points. Numbers in the table represent the final number of samples included in the analysis after excluding patients that abandoned the study and samples with low number of reads. MTG, metagenomic (i.e., DNA) dataset; MTT, metatranscriptomic (i.e., RNA) dataset; 16S (i.e., amplified DNA) dataset