Various ingredients are utilized to inhibit the growth of harmful bacteria associated with cavities, gum disease, and bad breath. However, the precise mechanisms by which these ingredients affect the oral microbiome have not been fully understood at the molecular level. To elucidate the molecular mechanisms, a high-throughput bacterial transcriptomics study was conducted, and the gene expression profiles of six common oral bacteria, including two Gram-positive bacteria (Actinomyces viscosus, Streptococcus mutans) and four Gram-negative bacteria (Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, and Prevotella pallens), were analyzed. The bacteria were exposed to nine common ingredients in toothpaste and mouthwash at different concentrations (stannous fluoride, stannous chloride, arginine bicarbonate, cetylpyridinium chloride, sodium monofluorophosphate, sodium fluoride, potassium nitrate, zinc phosphate, and hydrogen peroxide). Across 78 ingredient–microorganism pairs with 360 treatment–control combinations, significant and reproducible ingredient-based transcriptional response profiles were observed, providing valuable insights into the effects of these ingredients on the oral microbiome at the molecular level. This research shows that oral care product ingredients applied at biologically relevant concentrations manifest differential effects on the transcriptomics of bacterial genes in a variety of oral periodontal pathogenic bacteria. Stannous fluoride, stannous chloride, and cetylpyridinium chloride showed the most robust efficacy in inhibiting the growth or gene expression of various bacteria and pathogenic pathways. Combining multiple ingredients targeting different mechanisms might be more efficient than single ingredients in complex oral microbiomes.

This research analyzed metabolomic and proteomic differences between participants with gingivitis (>20 bleeding sites) and generally healthy participants (≤3 bleeding sites) at baseline and 4 weeks post stannous fluoride (SnF₂) dentifrice treatment. Sixty-two metabolites were different (p < 0.05) between groups at baseline. Forty cytokines were analyzed using immunoassays and a group of proinflammatory cytokines (IL-1α, IL-1β, TNF-α, SAA, ICAM-1, VCAM-1) was elevated in participants with gingivitis (p < 0.1) versus healthy gingiva at baseline, with C-reactive protein (p < 0.05) being significantly elevated. Proteomic analysis carried out in baseline oral lavage revealed four of the top hits (p < 0.0004) were central-metabolism-related: aldolase A, triosephosphate isomerase, lactate dehydrogenase, and malate dehydrogenase. Enzymatic assays confirmed the proteomic finding that malate dehydrogenase and triosephosphate isomerase activities were elevated in gingivitis samples; SnF₂ dentifrice treatment reduced their activity. Collectively, 20 proteins with the lowest p-values in oral lavage appeared to be indicative of periodontal health, potentially forming the basis to cluster samples into healthy and unhealthy groups. A TLR-ATP biosensor model was established and demonstrated that microbial virulence factors induced the observed changes in oral lavage. Combined findings suggest gingivitis involves upregulation of host cell bioenergetic processes involving enzymatic activity in the glycolysis and citric acid cycle pathways.

This research examined the effects of daily application of an oral hygiene regimen on the subgingival microbiome over 24 months. Generally healthy adults (107 enrolled, 87 completed) with early periodontitis used a home-care regimen (stannous fluoride paste, cetylpyridinium chloride rinse, power toothbrush, and floss) or usual care (control). Subgingival plaque samples were analyzed enzymatically for bacterial toxins. TLR ligands were measured using TLR-SEAP and TLR-ATP assays. Proinflammatory cytokines and metalloproteinases were quantified via immunoassays. Subgingival DNA was sequenced using a shotgun approach to assess microbial diversity. Increasing levels of bacteria, toxins, TLR activation, inflammatory cytokines, and MMPs were observed for periodontitis versus gingivitis and gingivitis versus healthy sites. The regimen significantly reduced levels of the critical proinflammatory cytokine IL-1β, as well as MMP-1 and MMP-9, at 24 months. By month 6, TLR ligands within subgingival plaques decreased. The abundance of pathogenic bacteria correlated with levels of virulence factors, proinflammatory cytokines, MMPs, and severity of clinical measures. Two distinct constellations of pathogenic bacteria were identified. Gingival sites were categorized into responders and non-responders per clinical symptoms and biomarkers. The regimen yielded more responder sites (70%) versus the control (47%), p = 0.0002914. The regimen reduced pathogenic bacteria, IL-1β, MMP1, and MMP-9, paralleling clinical reductions in periodontal disease.