59,000-Year-Old Neanderthal Molar Shows Evidence of Possible Caries Manipulation

A Neanderthal adult lower molar named Chagyrskaya 64, found deep in sediment in 2016 at the bottom of the cave's occupational layers in Chagyrskaya Cave in the Altai Mountains of Russia, contains a large rounded hole occupying almost all of its chewing surface that was artificially created.

The Chagyrskaya 64 tooth dates to approximately 59,000 years ago. Micro-CT scans showed demineralization of the enamel and dentin typical of caries that had reached deep into the pulp.

Microscopic analysis and experimental archaeology on modern teeth showed that traces inside the Chagyrskaya 64 cavity are compatible only with the rotational movement of a thin-tipped stone tool drill. The drilling reached the pulp and removed infected tissues. The contours of the cavity are smooth and polished, indicating the patient survived the procedure and continued to chew with the tooth.

A groove attributable to regular tooth picking was found on the side of the Chagyrskaya 64 tooth. Chagyrskaya Cave has been undergoing excavations since 2007 and has yielded more than 70 fossils of Neanderthals who occupied the site between around 59,000 and 49,000 years ago. The molar was found in isolation and not attached to a skeleton.

U.S. researchers was published in the journal PLOS ONE on Wednesday. Spectroscopy showed no residue of beeswax, tar, or other filling materials in the Chagyrskaya 64 cavity. Two cases of caries were found in Chagyrskaya, including one untreated cavity on a deciduous tooth.

Caries was relatively rare among Stone Age hominins, with less than ten cases identified amongst Neanderthal teeth recovered by archaeologists. Rates of tooth decay started to climb in the Neolithic when the carb-rich diet introduced by farming favored the growth of caries-causing bacteria. Grooves attributable to toothpick use have been found on fossils belonging to Homo habilis.