ABSTRACT
This chapter explains the anatomy and physiology of the oral cavity, the oral cavity as a microbial habitat, the nature of the microbial communities inhabiting different regions of the oral cavity and what microbes get up to in the oral cavity. It describes the role of the oral microbiota in human health and well-being, diseases caused by the oral microbiota, dysbiosis of the oral microbiota and manipulation of the oral microbiota. Approximately 90% of saliva is produced by the salivary glands, which are located outside of the oral cavity, while the rest is produced by the buccal glands, which are present in the oral mucosa. In regions other than the gingival crevice, saliva is the main determinant of pH in the oral cavity. The pH of saliva varies with its rate of secretion and resting saliva is more acidic (pH 6.5–6.9) than stimulated saliva (pH 7.0–7.5).
