A possible relationship between periodontal diseases (PDs) and cardiovascular diseases (CVDs) has been supposed and investigated. This review of the literature focuses exclusively on published studies on current theories and models of correlation between PDs and CVDs. A literature search of clinical and observational studies, in the English language, was performed in MEDLINE/PubMed, OVID database and Cochrane Oral Health Group's Trial Register. In addition, references cited in reviewed studies were evaluated for relevant papers. Various mechanisms are described in order to explain this possible association such as a hyper-responsive inflammatory response to chronic infections in predisposed individuals, and systemic effects of periodontal microorganisms including blood platelet aggregation, atheroma formation, increase in lipid levels, activation of acute phase reaction and systemic production of proinflammatory mediators, but a ultimate relation as well as the potential mechanisms have not been defined yet. Controversial result can be related to different method or objectives of studies including different study design, exposure evaluation, outcome variables and clinical endpoints considered. This paper provides a narrative review of the epidemiological studies dealing with the potential association between PDs and cardiovascular events. A precise association between PDs and CVDs, as well as the involved mechanisms are not yet well defined. Additional large-scale longitudinal epidemiological and intervention studies are necessary to validate this association.