Anita Radini, archaeologist at University of York in England spends much time looking at Tartar. Really old tartar.
Tartar or plaque – this bacterial film that feels like sweaters on the teeth – contains a wealth of information about what has happened in his daily life long-dead individuals. Radini has seen all sorts of things included: leftovers, textile fibers, DNA, pollen, bacteria and even wings of small insects.
Some years ago, however, when he examined the plaque of a nun from medieval Germany. Radini saw something completely new: particles in bright blue. She showed Christina Warinner, another dental specialist, who was shocked.
[ Like the Science Times page on Facebook. | Sign up for the Science Times newsletter. ]
The scientists have assembled a multidisciplinary team of scientists and have set themselves the goal of elucidating the origins of this blue dust. The results, described in a paper published Wednesday in Science Advances, far exceeded the team's expectations.
It turned out that the particles of ultramarine pigments, the finest and most expensive blue dyes, consist of lapis lazuli stone from Afghanistan. The German nun with the pigment in his teeth – B78, as it is called in archeological literature – was probably a painter and writer of religious texts. The researchers must have been highly qualified to be entrusted with such a rare powder.
The statement confirms the conventional assumption that medieval European women did not have much to do with the production of religious texts. "Imagine someone copying a medieval book – if you imagine anything, you'll imagine a monk, not a nun," said Alison Beach, a historian at Ohio State University and author of the study.
The skeleton of B78 dates from 997 to 1162 AD. The nun was probably 45 to 60 years old when she died, and was buried in an unmarked grave near a nunnery in Dalheim, Germany. Historians know little about the place, as it was almost completely destroyed by fire in the 14th century.
Dr. Radini first noticed blue trails as she dipped a sample of B78 tartar into a faint acidic solution. Scientists use this method to dissolve calcified tartar to examine remaining food, pollen or other particles.
Most scientists would have gone away and allowed the solution to dissolve overnight. But Dr. Radini paused and looked for a while to make sure the process was going well. Under the microscope she was surprised to see blue particles falling from the matrix of the tartar. In the morning the color had disappeared.
Mineral pigments tend to lose their color in acids, so Radini needed to find a way to extract and preserve the blue pigment. The method that worked best was to place the plate in a bath of ultrapure water and use high-frequency sound waves to break the matrix.
Through a series of experiments, the team identified the particles. Monica Tromp, a microscopist at the Max Planck Institute for the History of Science, showed by scanning electron microscopy that the pigment contains all the chemical elements of lapis lazuli. Roland Kröger, a physicist at the University of York, used spectroscopy to confirm the structure of two minerals, lazurite and phlogopite, which are found only in lapis lazuli. That was "a smoking weapon," Warinner said.
At that time, the blue pigment was "more valuable or valuable than the gold used for manuscripts," Dr. Only five percent of the lapis lazuli used in the production process are converted to pigment, and the material would have had to travel thousands of miles from trade routes to Europe.
The pigment probably landed on the woman's teeth using her mouth to mold her brush. The researchers found that ultramarine was present throughout the B78 tooth plaque, suggesting that she had painted many books in her lifetime.
"We seek to find sources that reflect the lives of women in the Middle Ages and are not influenced by the experiences or opinions of men about the lives of women," said Dr. Beach. "Well, we have direct evidence of what this woman did in everyday life – all because they did not brush their teeth."
"I have a new relationship with my sonicare now."