Which bacterium is associated with Periodontitis?

Porphyromonas gingivalis is the bacterium most commonly associated with periodontitis. This organism is a key pathogen in periodontal disease due to its virulence factors that enable it to invade tissues and evade the host's immune response. It plays a critical role in the progression of periodontitis by producing various enzymes and toxins that contribute to tissue destruction and inflammation. This bacterium has been extensively studied and is recognized for its contribution to the complex microbial environment found in periodontal pockets, leading to the breakdown of periodontal tissue and ultimately tooth loss if untreated.

The other bacteria mentioned, while they may be involved in oral health and disease, do not primarily drive the pathological process of periodontitis in the same way that Porphyromonas gingivalis does. Streptococcus mutans is primarily associated with dental caries rather than periodontal disease. Actinomyces viscosus and Treponema denticola can be part of the oral microbial community, but they are not as strongly linked to periodontitis as Porphyromonas gingivalis.