The bacterium Streptococcus gordonii induces tooth decay, announced researchers at the American Association for Dental Research’s annual meeting in March. It is the second bacterium found to do so, S. mutans being the other.
In a previous study, researchers from the University of Connecticut and the State University of New York at Buffalo had suggested that S. gordonii could cause caries, but they did not know how much or under what conditions.
Their current research confirms that S. gordonii causes caries in animals, but that it is less virulent than S. mutans.
To assess the cariogenicity of sucrose and high-fructose corn sweetener, researchers inoculated rats with S. gordonii or S. mutans; control rats remain uninoculated. The rats were given drinking water supplemented with 10 percent sucrose, 10 percent high-fructose corn sweetener, or 10 percent maltodextrin (a caloric digestible complex carbohydrate) and an artificial sweetener.
Researchers found that uninoculated rats had fewer cavities than the inoculated rats. The S. mutans–infected rats developed the highest caries levels if they drank the water and sucrose mixture. In S. gordonii–infected rats, caries levels were not as high as in S. mutans–infected rats, and there was no clear distinction between the effects of sucrose and high-fructose corn sweetener.
"These results suggest that S. gordonii must be considered a possible human decay-causing bacterium," said lead researcher Dr. Jason M. Tanzer of the University of Connecticut. "They also suggest that sucrose and high-fructose corn sweetener appear equally supportive of decay induced by the weaker decay-causing S. gordonii, in contrast to the more virulent S. mutans."
