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.

PURPOSE:The oral cavity is an important entry point for SARS-CoV-2 infection. This study tested whether four commercially available mouthrinses and dentifrices have in vitro virucidal activity against SARS-CoV-2 (=4 log10 reduction in viral titer). MATERIALS AND METHODS:One part of stock SARS-CoV-2 virus plus one part 0.3 g/l bovine serum albumin were mixed with eight parts of test product solution. After 30 s for the rinses, or 60 s for the dentifrices, the mixture was quenched in an appropriate neutralizer, serially diluted, and inoculated onto Vero E6 cells to determine viral titer. Triplicate runs were performed for each test condition with appropriate controls for test product cytotoxicity, viral interference, and neutralizer effectiveness. Test products included: 1.5% hydrogen peroxide (H2O2) rinse; 0.07% cetylpyridinium chloride (CPC) rinse; 0.454% stannous fluoride (SnF2) dentifrice A; and 0.454% SnF2 dentifrice B. RESULTS:?The 1.5% H2O2 rinse, 0.07% CPC rinse, SnF2 dentifrice A, and SnF2 dentifrice B all produced > 4 log10 reduction in SARS-CoV-2 titer. CONCLUSION:All four test products displayed potent virucidal activity in vitro. Clinical studies are warranted to determine what role, if any, these oral care products might play in preventing transmission of SARS-CoV-2 or in the management of patients currently diagnosed with COVID-19 illness.

Biofilm model systems are used to study biofilm growth and predict the effects of anti-biofilm interventions within the human oral cavity. Many in vitro biofilm model systems use a confocal laser scanning microscope (CLSM) in conjunction with image analysis tools to study biofilms. The aim of this study was to evaluate an in-house developed image analysis software program that we call BAIT (Biofilm Architecture Inference Tool) to quantify the architecture of oral multi-species biofilms following anti-biofilm interventions using a microfluidic biofilm system. Differences in architecture were compared between untreated biofilms and those treated with water (negative control), sodium gluconate ('placebo') or stannous fluoride (SnF2). The microfluidic system was inoculated with pooled human saliva and biofilms were developed over 22 h in filter-sterilized 25% pooled human saliva. During this period, biofilms were treated with water, sodium gluconate, or SnF2 (1000, 3439 or 10 000 p.p.m. Sn2+) 8 and 18 h post-inoculation. After 22 h of growth, biofilms were stained with LIVE/DEAD stain, and imaged by CLSM. BAIT was used to calculate biofilm biovolume, total number of objects, surface area, fluffiness, connectivity, convex hull porosity and viability. Image analysis showed oral biofilm architecture was significantly altered by 3439 and 10 000 p.p.m. Sn2+ treatment regimens, resulting in decreased biovolume, surface area, number of objects and connectivity, while fluffiness increased (P< 0.01). In conclusion, BAIT was shown to be able to measure the changes in biofilm architecture and detects possible antimicrobial and anti-biofilm effects of candidate agents.