Scientists uncover skeleton with blue teeth

11 January 2019

The accidental discovery of blue teeth in a medieval skeleton has revealed a colourful life lead over a 1000 years ago...

The find, quite literally a hidden gem, is the first direct evidence that women were involved in the creation of religious manuscripts during medieval times in Germany.

“It was something we found by accident; we were doing this study on dental calculus, which is this amazing calcified plaque or tartar on your teeth... but what we found were these extraordinary, brilliant blue particles, that we eventually learned were lapis lazuli,” explains Professor Christina Warinner, lead scientist in the study.

Lapis lazuli is a precious stone that has been treasured for centuries. During the medieval period, a technique was developed to convert it into a vivid blue pigment. The stones would have travelled thousands of miles along ancient trade routes from the only known lapis lazuli mines at the time, which were in Afghanistan. The rarity and cost of this material meant it was reserved for those with exquisite skill and talent, meaning the skeleton, known only by her data label "B78", would have been highly trusted.

The skeleton was unearthed during the excavation of a cemetery with known ties to a religious community in Dalheim, Germany. The bones were radiocarbon dated to AD 997-1162 and identified as female, but why would there have been pigments in her mouth? One idea is that she was an artist and would have shaped her paintbrush with her lips to form a fine point, therefore introducing the pigment into the mouth. Over time, these pigments would build up, and with little flossing and dental hygiene in those days, the plaque would harden and preserved the pigment trapped within. “It’s the only part of your body that fossilises while you’re still alive” say Warinner, “it’s really a time capsule of your life”.

Sonication, a technique which uses sound waves, was used to gently free the pigments from the solid calculus. Once separated, these blue particles were compared to many blue reference pigments that were known to have existed during that time. Using energy-dispersive x-ray spectroscopy, a technique which details the elemental components of the stone, together with Raman spectroscopy, which looks at the stone structure, produced a positive match for lapis lazuli.

The findings help to disprove a common notion about the medieval era. According to Warinner, “it had been widely assumed that only people living in large cities or major centres of artistic production would have had access, and that it would have been really limited to use by male monks, and here we have a direct contradiction of that.”

Pairing archaeology and analytical chemistry in this way is enabling Warinner and her team to sink their teeth into the past in a whole new way, including revealing roles played by both sexes. “We know that we can reconstruct aspects of diet, but this is now starting to extend into professions and craft activities...”

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