Abstract
Introduction: The oral microbiota has shown important actions in the physical and mental health of human beings. Oral diseases related to oral dysbiosis are studied, as well as systemic degenerative inflammatory diseases. Objective: It was to present and discuss the main considerations and results of clinical studies on the interrelationship between gut microbiota and oral health for systemic homeostasis. Methods: The PRISMA Guidelines were followed. The search was conducted from January to February 2026 across the Web of Science, Scopus, Embase, PubMed, ScienceDirect, SciELO, and Google Scholar databases. The quality of the studies was assessed using the GRADE instrument, and the risk of bias was evaluated according to the Cochrane instrument. Results and Conclusion: According to the GRADE instrument, most studies presented homogeneous results, with X2=67.5% > 50%. A total of 112 articles were found and submitted for eligibility analysis, with 18 final studies selected to compose the results of this systematic review. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 35 studies with a high risk of bias and 21 studies that did not meet GRADE and AMSTAR-2 standards. It was concluded that there are distinct causal relationships between the microbiota and acute and chronic gingivitis. Oral microbiota dysbiosis not only induces local inflammation and exacerbates inflammation associated with metabolic diseases, but can also trigger systemic inflammation, leading to metabolic and neuropsychiatric disorders. Clinical studies have shown the effectiveness of anti-inflammatory treatments of the gut and oral microbiota in reducing periodontal disease and cognitive decline. The integration of advanced microbiome analysis and neuroimaging techniques may help to elucidate the mechanisms linking gut health, systemic inflammation, and cognitive function.