The oral cavity is a specialized ecological niche of the human body and forms a continuum with the digestive and respiratory system. The vastly diverse endogenous microbiota of the oral cavity is collectively referred to as the "oral microbiome". It has been, and continues to be, explored by numerous cultivation or culture-independent methods, yielding more that 600 individual taxa (1) . They show tropism for different microhabitats, but may also show differential associations with oral health or disease. Commensal oral microbiota live in a symbiotic relationship with the host, which is crucial for the maintenance of oral health (2) . Yet, disruption of this tight relationship by various factors will result in dysbiosis, allowing for the survival and establishment of a more virulent pathobiotic polymicrobial community that may impair the efficient immune response (3, 4) . Clinically, these events could manifest as an oral infectious diseases.