Researchers studying the ruins of Çatalhöyük in central Turkey have discovered evidence that residents once wore human teeth as jewelry.

A group of archaeologists discovered three preserved human teeth while on a dig at the Neolithic proto-city, a UNESCO world heritage site.

The teeth date back to approximately 6500 BC and two showed signs of having been ground into a conical shape using a microdrill, then drilled so they could be placed on a string and used as jewelry.

Researchers in the ancient Turkish city of Çatalhöyük found three human teeth, two of which showed signs of having been used in jewelry

Researchers believed the teeth came from middle-aged adults and were removed after death, according to a Forbes contributor report.

“These material choices – and their rarity overall – suggest a deeper symbolic value,” says University of Copenhagen researcher Scott D. Haddow.

Haddow and his colleagues say this is the first documented case of human teeth artificially modified by grinding and drilling to turn them into decorative objects.

While previous research has shown the use of animal teeth as decorative objects, adult teeth might have a special cultural significance among the inhabitants of Çatalhöyük.

This summer, another team of researchers documented how dental issues were common in Çatalhöyük, which was inhabited between 7100 BC and 5500 BC.

The group of researchers believe their samples are the earliest example of artificially modified human teeth in the region

The local population were sheep herders and lived on a grain-heavy diet that led to a high prevalence of dental problems.

10 to 13 percent of the adult remains had dental cavities, something researchers which archaeologists attribute to grain-based diets.

Previous research has shown that dental issues were common in the city, caused by a grain-heavy diet that might have lent teeth extra symbolic value

At its peak, Çatalhöyük had a population of around 8,000 people, who lived ‘in very crowded conditions, with trash pits and animal pens right next to some of their homes,’ according to Clark Spencer Larsen, an anthropologist from Ohio State University.

‘So there is a whole host of sanitation issues that could contribute to the spread of infectious diseases.’

Based on differences in bone samples, researchers suggest that over time the city residents were forced to go farther outside the city to find grazing land, new plots of land for farming, and firewood.

Çatalhöyük is one of the earliest examples of dense urban living, with more than 8,000 residents living in tightly packed quarters

With crowding and resources slowly growing scarce, the population showed signs of internal strife.

‘We found an increase in cranial injuries during the Middle period, when the population was largest and most dense,’ Larsen said.

‘An argument could be made that overcrowding led to elevated stress and conflict within the community.’

Çatalhöyük was ultimately abandoned around 5950 BC, after climate change and depleted resources made it an inhospitable

When the climate began warming in the region over the course of several hundred years, the city began losing population as crop yields and resources grew scarce before it was ultimately abandoned in 5950 BC.

‘Çatalhöyük was one of the first proto-urban communities in the world and the residents experienced what happens when you put many people together in a small area for an extended time,’ Larsen said.

‘It set the stage for where we are today and the challenges we face in urban living.’