A back molar found in a Siberian cave is believed to be the oldest evidence of dental treatment. About 59,000 years ago, someone carefully drilled a cavity in the tooth to ease a toothache.
It was a Neanderthal who had done it. The tooth, Chagyrskaya 64, is a lower left second molar recovered from Chagyrskaya Cave in the Russian Altai Mountains. A huge, odd-shaped cavity extends to the almost complete occlusal floor of the tooth crown, reaching well into the pulp chamber.
The researchers report in the May 13 issue of PLOS One that this concavity cannot be explained by decay, wear, or geological processes alone. Rather, it was made with a small, pointed stone tool to treat severe dental decay.
Researchers have long been interested in Neanderthal medical knowledge. Evidence shows they looked after sick, injured, and older members of their groups, and may have used healing plants. But it’s still unclear whether this was planned medical care or more like instinctive self‑healing, similar to what some non‑human primates do.
Before this finding, the oldest known example of an invasive dental procedure belonged to a 14,000-year-old Homo sapiens individual from Ripari Villabruna in northeastern Italy. Now, researchers have pushed this record back to Chagyrskaya 64, extending the finding by more than 40,000 years and ascribing it to Neanderthals rather than anatomically modern humans.
“What amazed me was how intuitively the person who owned this tooth understood exactly where the pain was coming from and realized that its source could be removed,” said Alisa Zubova, an anthropologist at the Peter the Great Museum of Anthropology and Ethnography in St. Petersburg and one of the study’s lead authors, told Tech Explorist.
“We have never encountered anything like this before, neither among Neanderthals nor among modern humans from much later periods.”
Chagyrskaya Cave, southwestern Siberia, Russia. a. cave location map (created in ArcGIS software, using open data from https://www.usgs.gov/products/maps accessed on December 15, 2021); b. stratigraphic sequence with Chagyrskaya 64 molar discovery location indicated in orange; c. general view of the cave; d. discovery location of the Chagyrskaya 64 molar in situ in Layer 6c/2.
Credit: Zubova et al., 2026, PLOS One
Ancient DNA reveals the first Neanderthal family
Housed in the northwestern Altai foothills of southwestern Siberia, Chagyrskaya Cave contains the largest collection of Neanderthal fossils in northern Asia. The site was occupied by a wave of population that spread just before 70,000 and 60,000 years ago from Central and Eastern Europe. The molar was then extracted from the base of one of the cave’s most intact sedimentary layers, dating to approximately 59,000 years ago.
A large central concavity measures 4.2 mm in length, 2.8 mm in width, and has a maximum depth of 2.6 mm. It is located on the molar’s occlusal surface and consists of three interconnected, partially overlapping depressions. Micro-CT analysis showed that this concavity covers the whole pulp chamber volume. It also has transverse expansion in the mid-crown area.
Results of CT-scan of the Chagyrskaya 64 molar. Morphology of the concavity is shown in five projections, from left to right: mesial (1) distal (2, 3), disto-buccal (4), buccal (5).
Credit: Zubova et al., 2026, PLOS One
Dentine beneath cracks showed clear signs of demineralization characteristic of advanced caries; on a standard scale, this would be assessed as grade 4–5, indicating that the decay had progressed through the enamel and into dentine. Interestingly, severe damage was absent in another molar from the same location, which belonged to a Neanderthal from around the same time period.
A harder question arises: was that hollow deliberately made, or could something natural explain it? It is extremely smooth and rounded, which is too much of a precision for an acute freak accident to have been at work here; trauma usually produces sharp, jagged edges that are fractured at the interface between bone and soft tissue.
Solely ordinary wear was excluded as well, since whilst extreme tooth wear can sometimes expose the pulp, it does not create a cavity which broadens towards the surface, such as what is seen here. In addition, geological processes are not capable of producing such deep and precise voids in dental tissues.
To test their idea, the researchers didn’t stop at the ancient tooth. They picked up modern human molars and set to work with jasper drills, the same kind of stone tools found in the cave sediments. They recreated a mouth‑like setting, water and all, and began carefully boring into the teeth.
Their results were astounding: thinly linear scratches finely etched into the walls of dentine, resembling those observed within a Neanderthal molar. This unique pattern could not be obtained solely through scraping. Notably, each experiment was completed in less than an hour, illustrating how quickly obsessing on a narrow focus can sculpt relief from pain.
“Treating a carious tooth is not just feeding or guarding someone,” said Ksenia Kolobova, director of the study and archaeologist at the Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences.
“It requires diagnosing the source of pain, selecting an appropriate tool, performing a painful, invasive action, and persisting despite the patient’s discomfort. That is active, targeted medical intervention.”
An unremarkable, trivial detail is two scratches from a toothpick on the same molar, fine, linear marks left by a continuously pushing narrow object between teeth at the crown bases. These scratches correspond with a typical behavior seen among ancient human populations, including multiple species of Homo.
Several toothpicking and invasive drilling marks were found on the same tooth, suggesting at least two distinct types of dental care, either received or performed by the owner. This combination has never been seen in a Neanderthal tooth before.
Raman spectroscopy was performed on 14 areas of the tooth surface, searching tosearching for plant material, wax, or resin that might have been stuffed into the pit after treatment. Thus, no such residues were observed, though the authors caution that their absence cannot be taken as proof of a vacuum, because organic materials are known to deteriorate over just 1 myr.
The neural implications of this finding are much larger than in your practice. Doing the drilling required using and manipulating the fingers in concert, however, to maintain fine motor control while enduring a long period of concentration, even as it physically hurt. Archeological evidence from Chagyrskaya Neanderthals also suggests they were more aware of pain than modern humans, making their resolve to undergo or conduct such a procedure even more sobering.
“I can say that what struck me, and continues to strike me, is what an incredibly strong-willed person this Neanderthal must have been,” said Lydia Zotkina, a traceologist at the Institute of Archaeology and Ethnography and the study’s other lead author.
“He must have surely understood that although the pain of the procedure was greater than the pain of the inflammation, it was only temporary and had to be endured.”
Dental caries is rare in Neanderthals; fewer than 10 confirmed cases have been documented from sites including Palomas, Bau de l’Aubesier, De Nadale, and Kebara. The researchers note that a second tooth from the same Chagyrskaya population, belonging to a Neanderthal child aged nine to eleven, also shows carious lesions, suggesting that at least some members of this group carried the bacteria responsible.
Deadly human diseases may have caused the Neanderthal extinction
Whether the treatment of Chagyrskaya 64 reflected a known technique passed between group members or the intuitive act of an unusually perceptive individual cannot yet be determined.
Further studies include examining dental calculus from the Chagyrskaya population for traces of medicinal plant use, and examining Neanderthal skeletal collections worldwide for similar subtle marks that may have been overlooked.
As Zubova put it, “This is the first time we have encountered a case where the right idea for treating a disease arrived about 60,000 years ahead of its time.”
Journal Reference
Zubova, A. V., Zotkina, L. V., Olsen, J. W., Kulkov, A. M., Moiseyev, V. G., Malyutina, A. A., Davydov, R. V., Markin, S. V., Maksimovskiy, E. A., Chistyakov, P. V., Krivoshapkin, A. I., & Kolobova, K. A. (2026). Earliest evidence for invasive mitigation of dental caries by Neanderthals. PLOS ONE, 21(5), e0347662. DOI: 10.1371/journal.pone.0347662