Periodontal disease has a two-way relationship with systemic health conditions. It can influence systemic health while certain systemic conditions can also increase susceptibility to periodontal disease. Periodontal disease is associated with increased risk of cardiovascular disease, cerebrovascular accidents, diabetes and other conditions. Potential mechanisms include direct effects of periodontal pathogens, host inflammatory responses, common risk factors and genetic predispositions. Periodontitis may enhance atherosclerosis through direct bacterial effects, increased inflammatory markers, platelet aggregation and other indirect host responses.