Lactic Acid Bacteria in the Human Oral Cavity: Assessing Metabolic Functions Relevant to Oral Health and Disease.

Many perceive lactic acid bacteria as beneficial for health. They are recognized for preventing abnormal fermentation and spoilage of ingested foods by producing lactic acid, which aids in gut acidification. Moreover, lactic acid bacteria are extensively employed in food science. In contrast, lactic acid bacteria in the oral cavity are often perceived as pathogenic factors contributing to the development of dental caries. As a consequence, substantial research has been conducted in oral and dental sciences to explore lactic acid bacteria and the oral microbiome. This research primarily involves analyzing bacterial flora, investigating metabolic activities such as acid production, and investigating metabolic regulation within the oral environment. The oral cavity serves as the gateway to the digestive tract and respiratory system, characterized by a constantly fluctuating environment that significantly impacts the metabolic activity of lactic acid bacteria. Hence, when investigating oral lactic acid bacteria, it is crucial to adopt research plans and methodologies that account for these metabolic environment changes. In this section, we present some of the methods employed in our study.