The oral microbiota constitutes a complex and dynamic microbial ecosystem within the human body and is increasingly recognised as an important contributor to systemic health beyond the oral cavity. Dysbiosis of the oral microbiota has been associated with a broad spectrum of cardiovascular diseases (CVDs), including atherosclerosis, coronary artery disease, heart failure and hypertension. Growing evidence supports several interconnected mechanistic pathways linking oral microbial imbalance to cardiovascular pathology. These include translocation of oral bacteria into the bloodstream during transient bacteremia, activation of systemic inflammatory and immune responses, and the production of microbial metabolites such as trimethylamine-N-oxide, short-chain fatty acids, nitric oxide and hydrogen sulfide, which can influence vascular tone, endothelial function and atherogenesis. In addition, disruption of nitrate-reducing oral commensals may impair nitric oxide bioavailability, contributing to endothelial dysfunction. This review summarises current evidence on the composition and functional roles of the oral microbiome in cardiovascular disease, highlights key microbial taxa implicated in cardiovascular risk, and discusses recent diagnostic and research advances, including sequencing and metabolomic approaches. Potential preventive and therapeutic implications, such as oral hygiene optimisation and microbiome-modulating strategies, are also considered. Although causality has not been fully established, the oral microbiota represents a promising and biologically plausible target for future cardiovascular research and risk stratification strategies.
