A "microbial Pompeii" has been found on the teeth of 1,000-year-old human skeletons. Just as volcanic ash entombed the citizens of the ancient Roman city, dental plaque preserved bacteria and food particles on the teeth from a medieval cemetery in Germany.
"One thing that is clear about the population we studied is that they didn't brush their teeth very often, if at all," said study leader Christina Warinner, an anthropologist at the University of Zurich in Switzerland and the University of Oklahoma in Norman. The study was published Monday in Nature Genetics. [5 Surprising Ways to Banish Bad Breath]
Dental plaque is a dentist's worst enemy, but it turns out to be a great time capsule for preserving the bacteria (or "microbiome") and bits of food on the teeth of humans long after they die. Sticky material trapped particles of food and other debris, and over time, the calcium phosphate in saliva — the same mineral found in bones and teeth — caused the plaque to calcify into tartar, also known as calculus.
"We knew that calculus preserved microscopic particles of food and other debris, but the level of preservation of biomolecules is remarkable — a microbiome entombed and preserved in a mineral matrix, a microbial Pompeii," another member of the research team, Matthew Collins of the University of York, said in a statement.
DNA from food particles found in the plaque matched pork, mutton, the type of wheat used for bread and vegetables such as cabbage. The researchers also found starch granules that matched cereals and the pea/bean family. "It's much the same thing you would find at a German restaurant today," Warinner said.
A few individuals had surprisingly healthy teeth, but most of the older adults had lost most or all of their teeth due to wearing, decay or dental disease. The microbe species were remarkably similar to those found in modern mouths, including the species that cause gum disease.