Subgingival microorganisms and bacterial virulence factors in periodontitis.

Considerable information has come forth in recent years on the pathogenic organisms in human periodontitis and the sequence of events by which they produce periodontal disease. Important periodontopathogens include Bacteroides gingivalis, Bacteroides intermedius and Actinobacillus actinomycetemcomitans. Virulence factors of B. gingivalis and B. intermedius may mainly involve enzymes with potential to interfere with host defenses and to disintegrate periodontal tissues. Pathogenic properties of A. actinomycetemcomitans appear predominantly to be exerted by leukotoxin and other noxious products.