When discussing the bacteria associated with periodontal diseases, which association is false?

The assertion regarding the red complex is indeed inaccurate. The definition of the red complex refers specifically to a group of bacteria that are strongly linked to periodontitis, which includes Porphyromonas gingivalis and Treponema denticola, alongside Tanerella forsythia, rather than Fusobacterium nucleatum. While Fusobacterium nucleatum is certainly associated with periodontal disease and plays an important role in the formation of dental plaque, it is classified as part of a different group known as the orange complex.

In contrast, the associations made in the other three statements are well-established. Pregnancy gingivitis is indeed associated with Prevotella intermedia, which has been shown to increase during pregnancy due to hormonal changes. Chronic periodontitis is characterized by a shift toward a microbial community that includes more anaerobic, Gram-negative, motile organisms as the disease progresses. Lastly, aggressive periodontitis is heavily linked with Aggregatibacter actinomycetemcomitans (Aa), which is known for its pathogenicity in this form of periodontal disease. Understanding these relationships is crucial for diagnosing and treating periodontal diseases effectively.