When an archaeologist looks at an ancient skull with dark black teeth, the first question is not about beauty, but about the cause: Is this color the result of a disease? A chemical reaction with the soil? Or the remains of plants that were chewed? However, a recent study published in early 2026 turned this question upside down, after it scientifically proved that black teeth at an archaeological site in northern Vietnam were neither accidental nor natural, but rather a deliberate cultural practice in which iron was used as the main ingredient in a compound pigment.
The study, which appeared in the peer-reviewed journal Archaeological and Anthropological Sciences, examined human remains from the Dong Xa site in the Red River Delta of northern Vietnam, an Iron Age site associated with the Dong Son culture known for its material wealth and metallurgical traditions.At this site, black teeth were found uniformly and clearly on a number of skeletons dating back about 2,000 years. But the surprise was not the presence of the color itself, but the "analysis of what it is and its chemical composition."
The main challenge for the researchers was to distinguish between "natural pigmentation" and "intentional pigmentation." It is known that chewing certain plants such as fufu can leave a dark trace, and iron-rich soil can stain teeth after burial. It was not enough to rely on visual inspection, so the team turned to precise techniques such as scanning electron microscopy and portable X-ray analysis to examine the elements present on the enamel's surface.
The results showed high levels of iron and sulfur in the black layer, indicating the use of iron compounds in the pigment mixture. The researchers didn't stop there, and reproduced a mixture inspired by historical recipes for tooth coloring in Southeast Asia, based on iron salts and plant materials rich in tannins.When this mixture was experimentally applied to modern teeth, almost the same chemical signature emerged. This match between the archaeological sample and the laboratory experiment was the decisive moment: "The blackening was not an environmental effect, but a deliberate and deliberate human action."
But why did people color their teeth black?
Historical and anthropological records indicate that tooth coloring was a well-established aesthetic practice in Vietnam until the early 20th century, with white teeth sometimes seen as undesirable or associated with animals or childhood. In contrast, glossy black was considered a sign of maturity, elegance, and social belonging. Some sources suggest that tooth coloring was practiced at puberty or before marriage, linking it to social rites of passage.
Proving that the practice existed two thousand years ago means that this tradition was not a passing phenomenon, but a deep part of cultural identity. The teeth here are not just a biological organ, but a space to show belonging, identity and taste. The use of iron compounds indicates technical knowledge of chemical reaction materials, reflecting a level of organization and artisanal expertise.
More excitingly, this discovery opens the door to re-examine other archaeological sites in the region. If there is a clear chemical fingerprint that can be traced, we may be able to map the spread of this practice across Southeast Asia, perhaps linking it to patterns of migration or cultural interaction between ancient societies.
Methodologically, the study is an example of how the natural sciences can contribute to the interpretation of social phenomena. Rather than just general cultural interpretations, the chemical analysis provided physical evidence linking matter and behavior. This brings up an important question in archaeology: To what extent can materials reveal values? How can an element like iron become a key to understanding the concept of beauty in an ancient civilization?
In the end, this discovery is not just about the color of teeth, but about how we read the body in the past. Every material artifact carries a story, but this story needs precise tools to decode it. In the case of Dong Za, iron was the thread that led researchers to understand that the "black smile" was not the result of chance, but a conscious cultural choice, reflecting a different perception of beauty and identity than we know today.
Thus, the discovery becomes more than just an archaeological find; it is a reminder that standards of beauty are not fixed across time, and that what we see as strange today may have once been a standard of taste, prestige, and belonging. Most importantly, science, when combined with culture, can bring small details-like tooth color-to life and tell us about a whole world that smiled differently.
Bibliography:
Zhang, Y., Wang, Y.S., Nguyen, F., Iizuka, Y., and Hong, H.S.(2026).A kingdom with blackened teeth 2000 years ago: Tracing the practice of tooth coloring in ancient Vietnam.Journal of Archaeological and Anthropological Sciences, 18(2).
Kilgrove, K.(2026, February 21).2000-year-old skulls reveal tooth-coloring practice in ancient Vietnam.Live Science.
Journal of Archaeology(2026, February 13).2000-year-old cosmetic practice: Tooth coloring in Iron Age Vietnam.
VIZ.org(2026, February 12).Scientists reveal the origins of tooth coloring in Vietnam during the Iron Age.
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