Stone Age dentists treated cavities with tar

New analysis helps confirm that some form of dentistry has existed for roughly 14,000 years

Computer reconstructions of two human teeth, seen from above. Some 13,000 years old, they show cavities. Marks on the inner walls of each cavity were made by a pointed stone tool used to remove infected tissue, researchers now propose.

S. BENAZZI

Ouch! And eww! Two teeth from a person who lived in what’s now northern Italy between 13,000 and 12,740 years ago show signs of Stone Age dentistry. And the good doctor, back then, didn’t drill and fill cavities. That dentist scraped them out. Then he (or she) coated them with bitumen. It’s a natural, tarry form of crude oil. (Folks back then used the same sticky goop to attach stone tools to handles.)

The newly studied teeth bore signs of someone having removed infected soft, inner tissue. That’s what a research team led by Gregorio Oxilia and Stefano Benazzi concludes. These biological anthropologists work at the University of Bologna in Italy.

An earlier study found evidence that farmers up to 9,000 years ago may have used stone tools to drill out dental cavities. But the newly described dentistry is far, far older than that. This suggests that ways to remove tooth decay clearly developed long before farmed foods rich in starch and sugars made cavities more common. The Bologna team described its new findings online March 27. They appear in the American Journal of Physical Anthropology.

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Two front teeth from a person who lived around 13,000 years ago in what’s now northern Italy. Each show examples of treated tooth decay. Teeth shown from the side (top) and looking down on the chewing surface (bottom).S. BENAZZI

Two years ago, Oxilia and Benazzi’s team reported that a pointed stone tool had apparently been used to remove decayed tissue from a tooth. It came from a man who had been buried some 14,000 years ago in what is now Italy.

Says Benazzi, these Italian finds are the only known examples of dentistry by Stone Age people who foraged for food. By that he means these folk were not farmers. They would have hunted animals for meat and gathered nuts, roots and berries. This toothy evidence, he adds, may point to “a broader trend, or tradition” of early dentistry among late Stone Age hunter-gatherers in what is now Italy.

Early people may have regularly used their front teeth to grip wood, hides and other material. It’s possible that some also altered the shape of their teeth for cultural reasons. Such practices could have led to tooth damage. But none of these explanations of the tooth treatments appear as likely as dentistry, says Isabelle De Groote. She’s a paleoanthropologist at Liverpool John Moores University in England.

About 20 years ago, researchers excavated a site in Italy called Riparo Fredian. It yielded mainly teeth from six people. These included the two front teeth described in the new study. Microscopic study of decayed tissue in these teeth turned up scrape marks and flaking. These marks were likely made by someone who used a pointed stone implement to widen cavities before removing infected tissue. Sound painful? It probably was, Benazzi says.

Chemical and microscopic analysis of dark bits of material on cavity walls turned out to be bitumen, plant fibers and some possible hairs. Placing bitumen over treated tissue might have protected it against further infection, Benazzi speculates.

An ancient scrape-and-coat treatment for tooth decay developed from a much older practice of using pointed pieces of stone or wood as toothpicks, he suspects. Members of the human genus, Homo, may have wielded toothpicks as early as 1.77 million years ago.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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