The Oral Microbiome and Its Bidirectional Relationship with Oral Health and Systemic Diseases: A Review of Mechanisms and Clinical Implications

Abstract

The human oral cavity, as one of the most complex microbial habitats in the body, hosts a diverse community of microorganisms, including bacteria, archaea, fungi, and viruses. The equilibrium of this ecosystem can be influenced by factors such as diet, tobacco and alcohol use, lifestyle, and medical conditions. Disruption of this balance leads to dysbiosis. This imbalance is associated with a spectrum of oral diseases, such as dental caries, periodontal diseases, candidiasis, and halitosis. Furthermore, mounting evidence underscores the association between the oral microbiome and systemic diseases, including gastrointestinal disorders, cardiovascular diseases, diabetes, autoimmune diseases, and some cancers. These links are primarily established through systemic inflammation and the translocation of microorganisms. For instance, in periodontal diseases, pathogenic bacteria can alter the immune response and contribute to the onset or exacerbation of systemic conditions. Conversely, systemic diseases like diabetes can exacerbate dysbiosis by inducing changes in the oral environment. This interactive cycle highlights the critical importance of maintaining oral microbiome homeostasis. This review article, by examining effective strategies for preserving microbial balance and oral health, emphasizes the necessity for personalized care. Among these approaches are the use of dental probiotics, xylitol, mouthwashes, fluoride, and essential oils. Specific oral probiotics can be beneficial in restoring microbial balance through mechanisms such as pathogen competition. Sugar substitutes like xylitol are effective by inhibiting the metabolism of cariogenic bacteria. Additionally, the proper use of fluoride-containing mouthwashes and toothpastes is recognized as a cornerstone of microbial plaque control. In conclusion, this review highlights the fundamental role of oral microbiome health in maintaining general well-being and provides practical strategies for the prevention and management of oral diseases. Future research, focusing on the identification of biomarkers and the development of microbiome-modifying therapies, will be a significant step towards personalized medicine in oral health. © 2025, Mazandaran University of Medical Sciences. All rights reserved.