PAKISTAN: Archaeologists have unearthed the oldest known evidence of dentistry. Working in a neolithic graveyard in what is now Pakistan, Roberto Macchiarelli, of the University of Poitiers in France, and his colleagues found 11 human teeth that had holes carefully drilled in them.
The teeth are 7,500 to 9,000 years old - thousands of years older than any previous evidence of dentistry.
Detailed microscopic examination of the teeth, from nine individuals, showed clearly that the conical, cylindrical and trapezoidal holes must have been made by some kind of drill.
One person had three drilled teeth, and another had a tooth that was drilled twice. Because the holes were in molars, deep inside the mouth, it is unlikely they were drilled for decorative or ceremonial reasons, the researchers said. Four teeth showed signs of decay, "indicating that the intervention in some cases could have been therapeutic or palliative", the researchers wrote in the April 6th issue of the journal Nature.
"Some type of filling may have been placed in the cavity; however, no evidence survives to confirm this," they wrote.
The scientists created a drill using a bow and drill heads modelled on those they found, and they used it to drill holes in samples of human teeth.
"Presumably the know-how originally developed by skilled artisans for bead production was successfully transferred to drilling of teeth in a form of proto-dentistry," they wrote.