[Dissertations 25 years after date 12. Classification and virulence of black-pigmented bacteria in relation to periodontitis]

Bacteria in dental plaque play an essential role in the origin and development of periodontitis. In the seventies of the last century it became clear that black-pigmented bacteria of the genus Bacteroides play a vital role in this process. These bacteria are currently known as Porphyromonas gingivalis and Prevotella intermedia. In a PhD dissertation 25 years ago it was shown by DNA analysis that this group of bacteria is very heterogeneous, and that different species exist, which are associated with different oral infections. Because Porphyromonas gingivalis plays an important role in periodontitis, this bacterium has been investigated extensively during the last decades. The entire genome is now known at the DNA level. In addition, transmission between spouses has been shown to be possible, although it does not always cause periodontal disease. It is not yet possible to conclude if for patients with Porphyromonas gingivalis a different antibiotic policy should be used compared to patients without this bacterium.