'Microbial Pompeii' Found in Ancient Skeletons' Plaque Samples

Bacteria and microscopic food particles entombed in plaque on teeth of skeletons is a "microbial Pompeii" that has preserved a record of oral health from more than 1,000 years ago, scientists said.

Writing in the journal Nature Genetics, the researchers report this ancient oral health record reveales that, despite major changes in human diet, periodontal disease is caused by the same bacteria now as it was then, and that opportunistic pathogens were abundant in the mouths of ancient humans.

By analyzing the plaque, also referred to as dental calculus, an international team of 32 scientists from 12 institutions were able to identify dietary components trapped in oral cavities that would have otherwise deteriorated from the archaeological record.

"We knew that [dental] 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," said Matthew Collins, a study author from the University of York.

"As we learn more about the evolution of this microbiome in response to migration and changes in diet, health and medicine, I can imagine a future in which most archaeologists regard calculus as more interesting than the teeth themselves," Collins said.

Christian von Mering, a study author from the SIB Swiss Institute of Bioinformatics, called dental calculus "a window into the past" that may turn out to be one of the best-preserved records of microbes in humans.

The researchers said their discovery has wide-reaching implications for the understanding of how human oral microbes evolved, as well as the origins of periodontal diseases, which attack the gums and bone around the teeth.

"Dental calculus acts both as a long-term reservoir of the oral microbiome and as a trap for dietary and environmental debris. This allows us to investigate health and disease, as well as reconstruct aspects of an individual's life history and activities. Never before have we been able to retrieve so much information from one small sample," said research leader Christina Warinner.

The researchers said this work could lead to new insights on periodontal diseases, which are common in humans, domestic pets and animals in zoos. Periodontal disease, however, is not common in wild animals, which suggests that it is a disease that results from the modern lifestyle, the researchers said.

"The study of ancient microbiomes helps us understand the evolutionary history of human health and disease," said Frank Rühli, a senior author of the study and Head of the Centre for Evolutionary Medicine at the University of Zürich. "It informs modern medicine."