Evaluation of salivary microbiota from an ecological perspective

A variety of bacteria densely colonize the human oral cavity not as individuals, but as members of an indigenous microbiota that exhibit extensive intracellular interactions. To prevent the onset of oral diseases caused by the members of this microbiota, regulation of the total oral microbiota, including the surrounding bacterial environment, is required. In this review, we highlight current knowledge on the global composition of the salivary bacterial population associated with oral conditions through a molecular ecological approach using the 16S rRNA gene. The salivary bacterial populations of Japanese subjects were commonly dominated by bacterial genera such as Streptococcus, Prevotella, and Neisseria, and their relative abundances differed according to the specific periodontal condition of the patient. This suggests that manipulation of the predominant oral microbiota may assist in the maintenance of periodontal health. A broad view of the relationship of oral health with oral microbes would provide novel insights into oral health and disease.