Ancient Vietnamese Beauty Ritual: Tooth Blackening Dates Back 2,000 Years

Daily Health

25/03/2026

A groundbreaking study has revealed that the striking beauty practice of tooth blackening in Vietnam is far older than previously thought, with evidence now pointing to its origins at least 2,000 years ago. This discovery transforms a distinctive cultural custom from speculation into concrete proof of ancient identity, aesthetic preferences, and sophisticated chemical knowledge.

Key Takeaways

Archaeological evidence from northern Vietnam indicates tooth blackening was practiced as early as the Iron Age, approximately 2,000 years ago.
The practice involved a deliberate application of an iron-rich paste, distinct from natural staining or betel chewing.
The technique likely utilized tannins from plants combined with iron salts, creating a durable black pigment.
This ancient custom persisted for centuries, signifying social status, adulthood, and cultural identity.

Unearthing Ancient Practices

Excavations at Dong Xa in northern Vietnam yielded skeletal remains with teeth coated in a dark layer, too uniform to be accidental staining. Archaeologist Yue Zhang from the Australian National University analyzed these remains, confirming the coating as intentional tooth blackening. The findings include teeth from the Iron Age and a more recent sample from around 400 years ago, demonstrating the practice's longevity across Vietnamese history.

Distinguishing From Other Causes

While betel chewing is known to cause dark teeth, earlier Vietnamese betel stains were reddish-brown, unlike the dense black observed at Dong Xa. Chemical analysis of the burial sites also ruled out random soil exposure as the cause, as it wouldn't produce the consistent iron-sulfur signal found on the teeth. This led researchers to conclude that the blackening was a deliberate cosmetic treatment.

The Chemistry of Black Teeth

The enduring color was likely achieved by mixing tannins, natural plant compounds that bind readily with metals, into a paste. When heated extracts reacted with iron salts, they formed intensely dark iron compounds. Exposure to air then solidified the pigment into a durable black coating. This chemical process is similar to that used in medieval inks and textiles, highlighting the custom's scientific basis.

A Laborious and Meaningful Ritual

The tooth blackening process in Vietnam was elaborate, sometimes extending over 20 days. It involved roughening the tooth surface, applying plant extracts, acids, and binders over several nights, and polishing with ash or coconut tar for a refined finish. The significant time, effort, and discomfort involved suggest the practice conveyed commitment and social standing, not just appearance.

Cultural Significance and Continuity

Across Asia, tooth blackening has historically signified beauty, the transition to adulthood, and social differentiation. The Dong Xa findings provide strong evidence that this living custom has deep historical roots in Vietnam. The practice's appearance coincided with the increased availability of iron, which was crucial for creating the necessary chemical reactions for the dye. The persistence of this custom for centuries, evidenced by the 400-year-old burial, underscores its importance as a marker of cultural continuity rather than a fleeting trend. This ancient bodily adornment now stands alongside other artifacts like bronze drums and old texts as direct evidence of the significant social weight carried by personal style in ancient Vietnam.

Future Research

While the current study analyzed only three archaeological teeth due to preservation challenges, the methods used allow for further examination of existing collections. Future research aims to analyze more samples from Vietnam and neighboring regions to understand the geographical spread and evolution of this practice and its underlying chemistry.

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