Prevalence of pathogens in periodontal lesions and blood vessels

Objective: despite the cumulative evidence which supports a causal association between periodontitis and atherosclerosis or its sequelae, the nature of the relationship remains unclear. The aim of our study was to screen atherosclerotic plaques and healthy blood vessels for periodontal pathogens, and compared the results with clinical and bacteriological findings. Methods: twenty-two patients undergoing cardiac artery bypass graft surgery were studied. Eleven patients had moderate generalised chronic periodontitis and eleven patients had severe generalised chronic periodontitis. The day before vascular surgery the patients had a thorough periodontal examination, and bacteriological samples were taken from diseased sites. Atheromatous plaques and samples of vessels used for bypass grafting (internal mammary arteries and saphenous veins ) were harvested during surgery. A modified checkerboard DNA-DNA hybridisation procedure was used to screen periodontal and vascular samples for 20 selected bacterial species. Results: periodontal and vascular samples from the severe periodontitis group contained a higher mean number of bacterial species than the moderate periodontitis group. The microbial profiles of colonized vessel samples were very similar, independently of the vessel type. In the severe periodontitis group, healthy internal mammary artery and saphenous vein grafts were more frequently colonized than atheromatous plaques. Conclusions: the presence of periodontal pathogens in atherosclerotic plaque does not necessarily signify a causal link between periodontitis and atherosclerosis, as the same bacteria are found in apparently healthy vessels.