FLICKR, NATIONAL MUSEUM OF HEALTH AND MEDICINEThe late zoologist Charles Atwood Kofoid couldn’t possibly have known that he and his colleagues had begun to chip away at the human oral microbiome when, in 1929, they described in the Journal of the American Dental Association “animal parasites of the mouth and their relation to dental disease.” Scientists studying periodontal diseases have for decades realized that certain pathogenic bacteria contribute to inflammation and the eventual destruction of tissues within the oral cavity. But now it’s recognized that the mouth is populated with commensal microbes, too, and that these typically benign bacteria can contribute to a person’s health beyond their gums, tongue, and teeth.
“The whole world passes through the oral cavity,” said Purnima Kumar, an assistant professor of periodontology at the Ohio State University College of Dentistry. This makes investigating the microbial communities present in the mouth a challenge. “When we collect a sample we don’t know if it’s just something that’s passing by, or if it’s truly a member of the community,” she explained.
In addition to recognizing transient mouth microbes, researchers must distinguish between the distinct bacterial communities within the mouth: the microbes found on the tongue differ from those found on the roof of the mouth, those within the biofilms that coat the teeth and gums, and those elsewhere in the oral cavity, said microbiologist Floyd Dewhirst from The Forsyth Institute in Cambridge, Massachusetts. In ...
