More Bacteria Present Than Previously Thought.

• Position: Research into oral bacteria - Brief Article

The human mouth is awash with bacteria. Mostly neighborly bugs, they live on teeth and gums, helping to digest food and ward off attack by less-friendly, disease-causing bacteria that can steal their way in. According to researchers at Stanford (Calif.) University, there are more of these oral inhabitants than previously thought. Using a combination of old and new scientific methods to study a scraping of plaque from a healthy human mouth, they found evidence of 37 bacteria that microbiologists had never before recorded. Some were closely related to types that scientists are familiar with, but others were very different. Knowing more about the bacteria that reside in a normal, healthy mouth may help physicians understand changes in the bacterial population that can lead to gingivitis, periodontitis, and tooth decay.

"Our data suggest that a significant proportion of the resident human bacterial flora remain poorly characterized, even within this well-studied and familiar microbial environment," notes David Relman, assistant professor of medicine and of microbiology and immunology at Stanford. He indicates that the subgingival crevice--the deep gum pocket cradling each tooth--has been repeatedly scrutinized in the search for microbes. Even though almost 500 bacterial strains have been identified already, he believes this may be only a fraction of the bacteria living in this oral groove.

Oral bacteria have traditionally been studied by taking a scraping or sample from inside the mouth, growing the...