BOB HIRSHON (host):
Prehistoric dental plaque. I’m Bob Hirshon and this is Science Update.
Most of us consider dental plaque a plague, because it leads to tooth decay and gingivitis. But scientists at the University of Adelaide’s Center for Ancient DNA are thankful for plaque. Scraped from ancient teeth from prehistoric humans, plaque provides a DNA record of the bacteria that lived in human mouths thousands of years ago. In the journal Nature Genetics, they report that people back then had many more varieties of bacteria living in their mouths, and that diversity kept harmful bacteria at bay. They say that today’s diet of processed flour and sugar encourages the growth of mostly harmful bacteria, leading to far more tooth decay.
In other dental news, a study in the journal General Dentistry suggests that bacteria-killing mouthwashes substantially reduce cavities and gum disease, by reducing levels of harmful bacteria. I’m Bob Hirshon, for AAAS, the science society.