Oral Health: The Need for Both Conventional Microbial and Molecular Characterization

Taxonomic profiling and functional characterization of the healthy human oral bacterial microbiome from the north Indian urban sub-population

Poor oral health has broad consequences that can be seen at personal as well as societal levels, especially in developing countries like India. We have limited information on the healthy oral cavity's inhabitant microorganisms that play a crucial role in overall oral health. In a comprehensive culture-independent approach, the bacterial composition of healthy human oral cavities was determined from a sub-population of northern India. During this study, 20 mouthwash-derived metagenomes were explored for identifying bacterial diversity using the 16S rRNA hypervariable V3 region with the MiSeq Illumina platform. On the taxonomy assignment of operational taxonomic units (OTUs), 20 assigned phyla and 162 genera were recovered among the participants. The mean relative abundance revealed that Streptococcus was the dominant genera among the participants. However, at inter-individual analysis, Neisseria and Haemophilus exhibited first-order dominance among five and three healthy individuals, respectively. Correlation studies indicate that Streptococcus shares a strong relationship with Rothia, Corynebacterium, Prevotella, and Veillonella, whereas it was negatively correlated with Neisseria, Aggregatibacter, Porphyromonas, and Fusobacteria like Gram-negative bacteria. Bacterial diversity showed insignificant differences at the level of age and gender within and between the participants. The results support several of the major findings of previous reports on the healthy oral microbiome of the Indian population, however, the present investigation further illustrates that demographic region leaves an impact on overall bacterial composition. The study will assist in a better understanding of the oral microbiome from region-specific Indian population that was otherwise highly under-represented.

Ribeiro AP, Offenbacher S, Loewy ZG. Anti-Inflammatory Effects of Vitamin E in Response to Candida albicans

Oral mucositis, inflammation, and ulceration that occur in the oral cavity can manifest in significant pain. A formulation was designed to investigate the potential of vitamin E to ameliorate inflammation resulting from Candida albicans in cell-based systems. Human gingival fibroblasts and THP1 cells were stimulated with heat killed C. albicans and Porphyromonas gingivalis LPS (agonists). Unstimulated cells were included as controls. Cells were also simultaneously treated with a novel denture adhesive formulation that contains vitamin E (antagonist). The experimental conditions included cells exposed to the experimental formulation or the vehicle for 2 h for mRNA extraction and analysis, and cells left for 24 h under those experimental conditions for analysis of protein expression by ELISA. ssAffymetrix expression microarray pathway analyses demonstrated that the tested formulation exhibited a statistically significant (p < 0.05) inhibition of the following key inflammatory pathways: TLR 6, IL-1 signaling (IRAK, A20), NF-kappaB, IL-6 signaling (gp130, JK2 and GRB2), TNF signaling (TNF receptor) and Arachidonic acid metabolism (PLA2). Quantitative PCR array analysis confirmed the downregulation of key inflammatory genes when cells under adhesive treatment were challenged with heat killed C. albicans. PGE2 secretion was inhibited by the tested formulation only on THP1 cells after 24 h stimulation with C. albicans. These results suggest that the active formulation containing vitamin E acetate can modulate inflammatory responses, through anti-inflammatory actions as indicated by in vitro experimental conditions.

Inhibitory activity of a green and black tea blend on Streptococcus mutans

Through the years, tea consumption has been associated with good health, and some publications are related to oral health. The bioactive components of green tea are thought to be able to influence the process of caries formation through inhibition of proliferation of the streptococcal agent, interference with the process of bacterial adhesion to tooth enamel, and inhibition of glucosyl transferase and amylase; however, little is known about black tea and oral health. The aim of the present in-vitro study was to determine the inhibitory activity of a novel, patent-pending and proprietary blend of green and black tea aqueous extracts on Streptococcus mutans, a bacterium widely associated with plaque development and tooth decay. A minimum inhibitory concentration (MIC) of 12.5 mg/mL and a minimum bactericidal concentration (MBC) of 12.5 mg/mL was established against S. mutans, meaning that at concentrations of 12.5 mg/mL and higher, the proprietary tea blend is effective against the growth of S. mutans. This MIC concentration is lower than the ones reported in the literature for alcoholic black tea and green tea extracts tested separately. As a promising natural ingredient for oral health, this finding is a good indicator for the use of this proprietary blend of black and green tea water extracts.