[S5-4] Metabolic function of oral biofilm involved in oral and systemic health
The oral biofilm has diverse metabolic functions. Saccharolytic bacteria on the teeth surface metabolize food-derived carbohydrates, produce acids, demineralize the tooth surface, and cause dental caries. Asaccharolytic bacteria on periodontal tissues metabolize host-derived proteins/amino acids, and produce ammonia, sulfur compounds, short-chain fatty acids, and cause periodontal diseases. Carbohydrate and protein/amino acid metabolisms are essential major metabolic systems for obtaining energy for bacteria. On the other hand, the oral biofilm has minor metabolic systems that are not related to bacterial survival, but are related to systemic health. Oral Veillonella, Actinomyces, Neisseria, and Rothia species reduce nitrates in vegetables to nitrites. Nitrites not only inhibit the growth and metabolism of caries- and periodontal disease-associated bacteria, but they are also transported throughout the body through the blood, where their vasodilating action improves circulatory function and normalizes blood pressure. In addition, oral Streptococcus and Neisseria species oxidize ethanol in alcoholic beverages to acetaldehyde, a carcinogen that has been suggested to cause oral/gastrointestinal cancers. In this presentation, we review the diverse metabolic functions of the oral biofilm and discuss the relationship between oral and systemic health through these metabolic functions.