Abstract
Dental caries and periodontitis, two major conditions encountered in the field of dentistry, are regarded as infectious diseases caused by specific oral bacterial species. These species are known to not only show pathogenicity in the oral cavity, but can also invade the bloodstream as a result of invasive treatments, such as tooth extraction. Although bacteremia is generally transient in healthy individuals,a complex composed of platelets, fibrin, and bacteria on the endothelium of the heart can lead to the onset of infective endocarditis in individuals with certain kinds of heart disorders. In addition, the bacteremia is considered to be frequently caused by daily oral hygiene procedures in addition to invasive treatments, which led us to consider that an oral bacterial invasion of the bloodstream occurs more often than expected. If such invasion occurs frequently, it is reasonable to speculate that oral bacteria are able to migrate to other tissues and organs via the bloodstream, and cause a variety of systemic diseases. The association of periodontitis with various kinds of systemic diseases is known.We have conducted numerous analyses of the virulence of various strains of Streptococcus mutans for bacteremia, and their effects on cardiovascular and cerebrovascular tissues. Those studies have provided abundant information and knowledge of bacterial features, which we intend to apply to future studies of other species. For example, our results have shown that strains with alterations of cell surface antigens are highly virulent. Based on our findings, additional investigations of a variety of different oral bacterial species are now being performed.
