A 59,000-Year-Old Cavity Could Rewrite The History Of Dentistry

A Neanderthal Had a Cavity and Likely Tried to Do Something About It

About 59,000 years ago, somewhere in what is now Siberia, a Neanderthal was dealing with a painful, rotting tooth. What happened next, according to a new study, is something researchers had not previously documented in Neanderthals: evidence that this ancient human relative likely tried to treat it.

Researchers analyzing a Neanderthal molar found in Chagyrskaya Cave in the Altai Mountains of southwestern Russia say the tooth bears marks of a deliberate attempt to drill into a decayed area, likely carried out using a small, pointed stone tool. Their findings appear in PLOS ONE. If the interpretation holds up, it would be the earliest known example of invasive dental treatment by any human species, pushing the history of dentistry back tens of thousands of years.

At the heart of the find is one of the biggest debates in the science of human origins: just how intelligent were Neanderthals? Were they reacting to pain by instinct, the way animals do? Or were they capable of reasoning through a problem and acting on a solution?

Neanderthal Dentistry Traced to a Siberian Cave

Chagyrskaya Cave has long been one of the richest sites in the world for Neanderthal remains. Located in the foothills of the northwestern Altai Mountains, the cave holds the largest collection of Neanderthal fossils in North Asia, with more than 70 fossil fragments recovered there, including 26 teeth. Genetic evidence links these Neanderthals more closely to late European Neanderthals than to other ancient humans found nearby.

The tooth at the center of this study, catalogued as Chagyrskaya 64, is a lower second molar from an adult. When scientists examined its surface, they found a large, irregularly shaped hole carved into what would have been the chewing surface, deep enough to reach the innermost chamber of the tooth, the soft, nerve-rich core. A scan of the tooth’s interior revealed signs of significant decay caused by bacteria breaking down carbohydrates and releasing acids that eat away at dental tissue. In other words, this tooth had a serious cavity. And then, the researchers argue, someone likely went in after it.

Decay, Not Damage, Explains the Hole in the Neanderthal Molar

Before claiming the hole was made on purpose, the team had to rule out every other possible cause. Normal wear and tear? Seven other molars from the same cave showed nothing like it. A fracture? Dental breaks typically leave sharp, jagged edges; the edges of this hole were smooth and rounded, a sign the modification happened while the individual was still alive. Natural chemical processes? No known geological mechanism, the researchers say, could carve a deep hole into dense dental tissue, and the sediment layer where the tooth was found showed virtually no disturbance.

That left one explanation: a person made it. Based on the pattern of tiny scratches on the interior walls, scratches running in a circular pattern consistent with a rotating or drilling motion, the authors argue the procedure was likely carried out with a small, pointed stone tool.

Experiments Show How Neanderthal Cavity Treatment Could Have Worked

To test whether this was physically possible, the team ran experiments using small stone tools made from jasper, a hard rock found near Chagyrskaya Cave. Because Neanderthal teeth are irreplaceable specimens that cannot be subjected to experimental drilling, the tests were done on modern human teeth, with water added to simulate the moisture of a living mouth.

Two methods were tried: scraping and rotating the tool like a hand-powered drill. Scraping produced only shallow marks. Rotation worked far more effectively, breaking through to the inner chamber in under an hour in some cases; one experiment took just over five minutes to produce an initial depression.

When researchers compared those results with the ancient tooth under microscopes, the similarities were clear. Scratch patterns, hole shape, and smooth, worn edges all matched. A chemical analysis of the tooth’s surface did not detect evidence of a filling material, so whether anything was packed into the cavity afterward remains an open question.

The tooth also showed grooves from what appears to be repeated toothpick use, a sign the individual was already managing oral discomfort before the more intensive procedure.

What a Single Fossil Tooth May Reveal About Neanderthal Intelligence

Using a toothpick, or chewing on a plant to soothe pain, is something other primates have been observed doing. Researchers have long struggled to separate those automatic responses from the sort of conscious, planned problem-solving associated with modern human intelligence.

What the authors argue sets this tooth apart is the apparent sequence of choices involved. Based on the trace evidence, they believe someone may have identified the painful tooth, selected an appropriate tool, and carried out a controlled procedure to remove damaged tissue. Evidence of two distinct types of manipulation, each requiring different tools or techniques, further suggests that whoever did this was adapting their approach as they went.

As the paper puts it, these patterns “bring Neanderthal behavior closer to modern humans and differentiate that behavior from the instinctive actions of other primates.”

For a long time, the story of intentional dental care has begun with early modern humans. This tooth, worn down and carefully worked roughly 59,000 years ago, raises the possibility that story may need to start earlier.

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