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Oldest dental filling found in a Stone Age tooth

Colin Barras

You may not want to try this at home. A simple wax cap that was applied to a broken tooth 6500 years ago is the oldest dental filling on record. It adds to evidence that Neolithic communities had a surprisingly sophisticated knowledge of dentistry.

The recipient of the treatment was most likely a 24 to 30-year-old man, living in what is now Slovenia. His fossilised jawbone was found early last century near the village of Lonche. At the time, the find – one of the oldest human bones ever found in the region – was described, catalogued and filed away in a museum in nearby Trieste, Italy.

Some chippings with round and smooth edges are present on the occlusal buccal margin of tooth

“The jawbone remained in the museum for 101 years without anybody noticing anything strange,” says Claudio Tuniz at the International Centre for Theoretical Physics in Trieste. That was until Tuniz and his colleague Federico Bernardini happened to use the specimen to test new X-ray imaging equipment, and spotted some unusual material attached to a canine.

They constructed a high-resolution 3D picture of the tooth, which revealed a long vertical crack, and an area of enamel that had worn away to create a large cavity in which the dentine was exposed. The unusual material formed a thin cap that perfectly filled the cavity and the upper part of the crack.

Residues of beeswax cover the edges of the vertical crack

Infrared spectroscopy identified the material as beeswax, and radiocarbon dating found it and the tooth to be both around 6500 years old. This suggests the beeswax may have been used to plug the cracked and worn tooth while its owner was still alive, which would make it the oldest example of a dental filling ever found – predating gold prostheses used in Imperial Rome.

“We knew that we had hit the jackpot,” says Tuniz.

Flint dentist drills

Although it’s difficult to rule out the possibility that the beeswax was added for another purpose – perhaps as part of a funeral ritual – and that the tooth cracked as it dried out in the cave, Tuniz and Bernardini think this is unlikely. They point out that the placing of the wax suggests it was purposely added to seal the exposed dentine.

Previous finds also suggest that Neolithic humans were competent dentists. In 2001, David Frayer at the University of Kansas in Lawrence and his colleagues found drill holes – probably made by a flint tip – in 11 human molars from a 7500 to 9000-year-old graveyard in Pakistan. Four of the drilled teeth showed signs of decay, but none carried a dental filling.

Some enamel fragments are lost in the edges of the vertical cracks

“It is always difficult to make sense of manipulations of skeletons or teeth,” says Frayer. “But I think [Tuniz and Bernardini’s team] have made the best argument possible for the beeswax being used as a dental filling.”

“Beeswax would make sense as a filling material for a number of reasons,” says Stephen Buckley at the University of York, UK, who was part of a team that recently found evidence, from an analysis of teeth, that Neanderthals practised medicine. “The melting point of the wax is low, so it’s easily melted, yet it solidifies to fit the gap when cooled to room temperature.”

He adds that beeswax can contain honey and propolis, both of which have antibacterial and anti-inflammatory properties. “I used beeswax for a major project on Egyptian mummification, and it was very useful – hence its employment by the Egyptian embalmers,” he says.

“The more we learn about prehistoric populations the more we appreciate their sophisticated ways,” says Frayer. “They did so many interesting things, now being unlocked by careful observation and advanced technology.”

Journal reference: PLoS One, DOI: 10.1371/journal.pone.0044904