"Approximately 600 different species of bacteria have been identified from the human mouth, although any one person may have only a third of this number.
The majority of these species are compatible with oral health, but a minority have been shown to be associated with diseases,
such as tooth decay and periodontal disease.
Forty-four percent of these species have been cultured and named by microbiologists.
Another 11 percent have been cultured, but are not yet named.
Forty-five percent have not yet been cultured and are known from molecular studies that recognize the DNA fingerprints of these uncultivated species.
Investigators are currently examining the link between certain oral bacteria and systemic diseases
such as cardiovascular disease, stroke, and preterm delivery",