Interconnections between the Oral and Gut Microbiomes: Reversal of Microbial Dysbiosis and the Balance between Systemic Health and Disease

The human microbiota represents a complex array of microbial species that influence the balance between the health and pathology of their surrounding environment. These microorganisms impart important biological benefits to their host, such as immune regulation and resistance to pathogen colonization. Dysbiosis of microbial communities in the gut and mouth precede many oral and systemic diseases such as cancer, autoimmune-related conditions, and inflammatory states, and can involve the breakdown of innate barriers, immune dysregulation, pro-inflammatory signaling, and molecular mimicry. Emerging evidence suggests that periodontitis-associated pathogens can translocate to distant sites to elicit severe local and systemic pathologies, which necessitates research into future therapies. Fecal microbiota transplantation, probiotics, prebiotics, and synbiotics represent current modes of treatment to reverse microbial dysbiosis through the introduction of health-related bacterial species and substrates. Furthermore, the emerging field of precision medicine has been shown to be an effective method in modulating host immune response through targeting molecular biomarkers and inflammatory mediators. Although connections between the human microbiome, immune system, and systemic disease are becoming more apparent, the complex interplay and future innovations in treatment modalities will become elucidated through continued research and cross-disciplinary collaboration.