Identifying Intentional Tooth Blackening: Analytical Evidence and Cultural Reconstruction in Northern Vietnam

Yue Zhang1*, Yu-shiang Wang2, Viet Nguyen3, Yoshiyuki Iizuka2, and Hsiao-chun Hunh4

Tooth blackening has been widely documented in textual accounts across Southeast Asia, particularly in Vietnam. However, its identification in archaeological contexts remains methodologically challenging, as dietary staining can obscure intentional surface modification. This study applies non- destructive techniques, specifically scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), to examine blackened teeth recovered from the Dong Son Iron Age site of Dong Xa in northern Vietnam, dated to approximately 2000 BP. Elemental analysis reveals elevated concentrations of iron (Fe) and sulphur (S) on the enamel surface. When evaluated alongside ethnographic documentation of traditional blackening procedures and experimental reference samples, these compositional signatures strongly suggest the deliberate application of iron-based compounds, possibly in combination with botanical agents, consistent with historically recorded practices. Based on these findings, this research demonstrates how micro-analytical technologies cany detect embodied cultural practices and reconstruct technological traditions otherwise invisible in the archaeological record. By situating the evidence within the broader Dong Son cultural sphere and Southeast Asia, the persistence of dental blackening from the Iron Age through later historical documentation and living memory highlights a longue durée expression of embodied identity.