Stone Age hunter-gatherers tackled their cavities with a sharp tool and tar

Stone Age dentists didn’t drill and fill cavities. They scraped and coated them.

Two teeth from a person who lived in what’s now northern Italy between 13,000 and 12,740 years ago bear signs of someone having scoured and removed infected soft, inner tissue. The treated area was then covered with bitumen, a sticky, tarlike substance Stone Age folks used to attach stone tools to handles (SN Online: 12/12/08), says a team led by biological anthropologists Gregorio Oxilia and Stefano Benazzi, both of the University of Bologna in Italy.

The find indicates that techniques for removing infected parts of teeth developed thousands of years before carbohydrate-rich farming diets made tooth decay more common, the researchers report online March 27 in the American Journal of Physical Anthropology. Farmers may have used stone tools to drill dental cavities as early as 9,000 years ago (SN: 4/8/06, p. 213).

Oxilia and Benazzi’s team reported in 2015 that a pointed stone tool had apparently been used to remove decayed tissue from a tooth that belonged to a man buried in northern Italy around 14,000 years ago.

While these Italian finds represent the only known examples of dental treatments practiced by Stone Age hunter-gatherers, “they may be part of a broader trend, or tradition, of dental interventions among late [Stone Age] foragers in Italy,” Benazzi says.

Other possible causes of tooth damage, such as regularly using the front teeth to grip wood, hides and other material or modifying tooth shapes for cultural reasons, appear less likely than dentistry, says paleoanthropologist Isabelle De Groote of Liverpool John Moores University in England.

Excavations about 20 years ago at an Italian site called Riparo Fredian yielded mainly dental remains of six people, including the two front teeth in the new study. Microscopic study of decayed tissue in these specimens revealed scrape marks and flaking, produced when someone used a pointed stone implement to widen cavities before removing diseased parts of teeth. If that sounds painful, it probably was, Benazzi says.

Chemical and microscopic analysis of dark bits of material on cavity walls identified bitumen, plant fibers and some possible hairs. Placing bitumen over treated tissue might have protected 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, Benazzi suspects. Members of the human genus, Homo, may have wielded toothpicks as early as 1.77 million years ago.