Plaque Bacteria: Ecology, Pathogenesis, and Control
The human mouth contains an abundance of micro organisms. These oral bacteria have certain characteristics in common. For example, all possess surface molecules and the concomitant capacity for cell to cell interaction. This contributes to their ability to form dental plaque. Plaque is a protective bacterial film which naturally accumulates on teeth. It has a number of beneficial effects. Excessive plaque formation, however, may also contribute to diseases such as gingivitis and peridontitis. Therefore, bacterial proliferation in the mouth requires some form of control. Various means can be employed to maintain microbial populations at levels compatible with health. Currently, antimicrobial agents are used. Perhaps in the future additional methods will evolve.
Thus far, 37 genera of bacteria have been identified within the human oral cavity (2:3247). The researchers, Kolenbrander and London (1993), have examined certain characteristics which the members of this diverse population have in common.
Most of the bacteria, for example, exhibit the property of intergeneic coaggregation. This coaggregation is characterized by "direct and viability independent cell to cell recognition" (2:3247). It results through the formation of bacterial adhesins on the cells' outer membrane or cell wall (2:3247). These adhesins enable the cells to simultaneously participate in different interactions with their partner cells.
Coaggregation tends to be specific. In fact, the partnerships can sometimes even be site specific.
The interactions, however, also may be either intra , inter , or multigeneric. Kolenbrander and London, for instance, found that 90% of their A. naeslundii, S. gordonii, Streptococcus mitis, Streptococcus oralis, and Streptococcus sanguis cultures coaggregated (2:3247). These they identified as early tooth colonizers. All were found to addition...