Diversity of the Oral Microbiome and Dental Health and Disease

The oral microbiome is extremely diverse, and consists of potentially over 1000 different microorganisms, including viruses, protozoa, fungi, archaea, and bacteria. In conditions of oral health, biofilms are in a state of microbial homeostasis, with the vast majority of the microbiota being commensal or mutualistic in nature. In conditions of oral disease, the composition, quantity, and stability of the oral microbiota become disrupted. Factors that influence microbial composition include genetics, host defenses, microbial interactions, receptors used for attachment, acidogenicity, and salivary flow. The interplay of these factors determines the balance between oral health and disease, and when microbial homeostasis becomes disrupted, oral diseases including dental caries, endodontic disease, and periodontal disease may occur. As the aims of this review article, we will discuss the microorganisms that have been identified as the key players in dental caries, endodontic disease and periodontal disease, and propose as a hypothesis that microbial homeostasis and imbalance will have an impact on oral health and disease. Identifying the factors that influence oral health and disease may help develop preventive and therapeutic strategies for dental care provided by oral health practitioners.