Inflamed gums! They hurt and bleed when you brush, and they contribute to tooth decay and loss of teeth. Now new research, announced today by the National Institute of Dental and Craniofacial Research, points to an “evil genius” of bacterial species that hides in the cleft between teeth and gums and causes periodontitis (gum disease).
Normally bacteria reside in the so-called “subgingival space” between gums and teeth and make no trouble. The body’s white blood cells keep these bacteria in check, gobbling and destroying them, if they threaten to multiply and grow out of hand. Thus a benign equilibrium is maintained between the white cells and the microbes. But one bacterial species, Porphyromonas gingivalis, exploits this live-and-let-live opportunity to stir up trouble.
According to the NIH statement, P. gingivalis do not expand their numbers. Rather they remain at low levels, hiding in the subgingival space, and secrete chemical messengers that interfere with the normal functions of the white cells. The interfering chemicals impair the white cells’ capacity to kill bacteria, and consequently, the normal bacteria start to multiply and inflammation results. It is a state in which the white cells are continually revved up and fighting off bacterial growth.
Meanwhile, as the periodontal inflammation spreads, P. gingivalis enjoys a great meal, feasting on the detritus of disintegrated cells and destroyed bacteria that are generated by the fight. The inflammation also leads to tooth decay and loss of teeth.
Researchers at universities in Louisville, KY, Seattle, Philadelphia, London and Tokyo worked out the role P. gingivalis in periodontitis by experimenting on mice. Richard Darveau, one of the researchers, said this about the discovery:
There is one key word that explains everything: homeostasis. Periodontal health is a matter of maintaining homeostasis, or equilibrium, among the bacterial inhabitants of the subgingival space and innate immunity cells. P. gingivalis is a master at disrupting homeostasis. Although this bacterium certainly is not the only cause of periodontitis, it stands out as a major culprit.
If further research shows P. gingivalis contributes to periodontitis in human beings via the same mechanism as in mice, then it should be possible to block the disruptive action of the chemical messengers the bacteria secrete, perhaps using drugs that can be applied to affected teeth, the NIH statement suggested.
The issue has importance beyond oral health, because gum inflammation due to periodontitis increases the risk of heart disease and strokes substantially. Ever since I learned of this connection a number of years ago, I’ve taken pains to clean my teeth and mouth thoroughly twice a day. I use a combination of brushing, several rinses with mouthwash, and cleaning between teeth with soft picks. Despite the effort, I still occasionally develop sore, bleeding gums in one part of my mouth or another. So, I look forward to further progress in this area of research.