Stone Age dentists treated cavities with tar | Science News for Students

Stone Age dentists treated cavities with tar

New analysis helps confirm that some form of dentistry has existed for roughly 14,000 years
May 5, 2017 — 7:10 am EST
stone age dentistry

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.


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.

more ancient dentistry
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).

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.

Power Words

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biological anthropology     (also bioanthropology) The study of human origins (and culture) that focuses on the evolution of hominids and other primates based on their biology and how it might explain how their bodies adapted to their environment. Scientists who work in this field are known as biological anthropologists.

bitumen     A natural type of especially heavy, dense petroleum. This type of heavy crude oil must be diluted before it can flow through pipelines.

cavity      (in dentistry) A tiny hole in a tooth that develops over time. Cavities are more likely to happen when a person eats a lot of sugar or does not brush and floss regularly. Dentists refer to these as caries.

chemical     A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical can also be used as an adjective to describe properties of materials that are the result of various reactions between different compounds.

decay     The process (also called “rotting”) by which a dead plant or animal gradually breaks down as it is consumed by bacteria and other microbes

fiber     Something whose shape resembles a thread or filament of some kind. (in nutrition) Components of many fibrous plant-based foods. These so-called non-digestible fibers tend to come from cellulose, lignin, and pectin — all plant constituents that resist breakdown by the body’s digestive enzymes.

genus     (plural: genera) A group of closely related species. For example, the genus Canis — which is Latin for “dog” — includes all domestic breeds of dog and their closest wild relatives, including wolves, coyotes, jackals and dingoes.

Homo     A genus of species that includes modern humans (Homo sapiens). All had large brains and used tools. This genus is believed to have first evolved in Africa and over time its members continued to evolve and radiate throughout the rest of the world.

hunter-gatherer    A cultural group that feeds itself through hunting, fishing and gathering wild produce (such as nuts, seeds, fruits, leaves, roots and other edible plant parts). They can be somewhat nomadic and do not rely on agriculture for their food.

infection     A disease that can spread from one organism to another. It’s usually caused by some sort of germ.

intervention     A planned effort to prevent or treat a disease or other condition relating to health or well-being.

journal     (in science) A publication in which scientists share their research findings with the public. Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. 

microscopic     An adjective for things too small to be seen by the unaided eye. It takes a microscope to view objects this small, such as bacteria or other one-celled organisms.

nut     (in biology) The edible seed of a plant, which is usually encased in a hard protective shell.

paleoanthropologist     A scientist who studies ancient humans and hominid biology and the behavior and how hominids evolved. This field is based on the analysis of fossils, remnants, artifacts or markings created or used by these individuals.

physical anthropology     The type of anthropology, or study of humankind, that deals with how humans have gradually changed over time. It includes how their look or structures might have varied.

starch     A soft white chemical made by all green plants. It’s a relatively long molecule made from linking together a lot of smaller, identical building blocks — all of them glucose, a simple sugar. 

Stone Age     A prehistoric period when weapons and tools were made of stone or of materials such as bone, wood or horn. This period lasted millions of years and came to an end around 10,000 to 12,000 years ago.

tissue     Any of the distinct types of material, comprised of cells, which make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.

tool     An object that a person or other animal makes or obtains and then uses to carry out some purpose such as reaching food, defending itself or grooming.


Journal: G. Oxilia et al. The dawn of dentistry in the late upper Paleolithic: An early case of pathological intervention at Riparo FredianAmerican Journal of Physical Anthropology. Published online March 27, 2017. doi:10.1002/ajpa.23216.

Journal: G. Oxilia et al. Earliest evidence of dental caries manipulation in the Late Upper PalaeolithicScientific Reports. Published online July 16, 2015. doi:10.1038/srep12150.