The intimate association between oral and gut microbiome: Does it affect systemic health? A scoping review

It is known that oral bacteria may be found in other organs and systems, which raises the hypothesis that this microbiome can contribute to the development of systemic diseases. As the gut is an organ that is part of the digestive system, it is believed that bacteria present in the mouth can also colonize it, causing dysbiosis and consequently triggering or aggravating chronic diseases, such as type 2 diabetes mellitus (type 2 DM), obesity (OB), hypertension (HT) or even colorectal cancer (CRC). This scoping review aims to map the literature on evidence of bacterial translocation from oral to gut microbiome and its possible impact on systemic health by triggering or worsening non-communicable diseases. A comprehensive search strategy will be developed and adapted to five databases (Embase, LILACS, Medline, Scopus, and Web of Science) to find all evidence associated with the research question: “What is the evidence already known about the leaking from the oral microbiome to the gut microbiome that could be associated with chronic diseases such as type 2 diabetes, arterial hypertension, obesity, colorectal cancer, bowel disease, or any other non-communicable diseases?”. Additionally, sources of unpublished studies or grey literature, such as Google Scholar and ProQuest Dissertation and Thesis, will be searched. Two reviewers will individually select titles and abstracts that fulfill the eligibility criteria. After that, the selected papers will be read in full. A third reviewer will be consulted for a final decision in case of disagreement. The JBI Manual for Evidence Synthesis will guide this scoping review development. The protocol development will be based on the PRISMA-P checklist, as there are no specific guidelines for scoping reviews. Results will be reported using the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guideline.