Oral Microbiota: A Dynamic Ecosystem in Health and Disease- An Expert Review

The oral cavity harbors a highly diverse microbiota, second only to the gut, comprising bacteria, fungi, viruses, archaea, and protozoa. These microorganisms colonize specific niches like the tongue, teeth, and gingival crevices, forming complex biofilms that contribute to oral and systemic health. In a balanced state, the oral microbiota supports immune modulation, inhibits pathogenic colonization, and aids in nitrate metabolism. However, dysbiosis—triggered by poor hygiene, high-sugar diets, smoking, or systemic diseases—disrupts this balance and contributes to conditions such as dental caries, gingivitis, periodontitis, oral candidiasis, and peri-implantitis. Moreover, several oral pathogens have been implicated in systemic diseases including cardiovascular disease, diabetes mellitus, and adverse pregnancy outcomes. Fusobacterium nucleatum, for instance, is linked to colorectal cancer progression. Advances in high-throughput sequencing have expanded our understanding of microbial composition and function, offering novel insights into diagnostics and therapy. Current strategies now include the use of probiotics, prebiotics, and targeted antimicrobial therapies alongside traditional plaque control. Innovative approaches like microbiome transplantation and phage therapy are also emerging. This review synthesizes the role of oral microbiota in health and disease, emphasizing its diagnostic value and therapeutic potential. Targeted modulation of the oral microbiome may significantly enhance both oral and systemic healthcare outcomes.