More than 3,000 years ago, communities across parts of present-day Poland cremated their dead and buried the ashes in ceramic urns. For archaeologists, these burials have long posed a problem. High temperatures alter bones and teeth, making many standard methods for estimating age at death difficult or impossible to apply.
Fragments of cremated teeth subject to histological analyses. Credit: A. Hałuszko / Hałuszko et al., Scientific Reports (2026)
A new study published in Scientific Reports shows that burned teeth still preserve microscopic features that provide useful information about the people who once carried them. Researchers examined 62 tooth roots from eight cemeteries belonging to the Lusatian Urnfield culture, a society that flourished during the Late Bronze Age and Early Iron Age, roughly between 1300 and 500 BCE.
The Lusatian Urnfield culture took its name from a burial custom shared across large areas of Central Europe. After cremation, families placed the remains of the deceased inside urns and buried them in large cemeteries. Some of these burial grounds contained hundreds or even thousands of graves. Since cremation served as the dominant funerary practice, complete skeletons rarely survive, leaving many questions about the people buried there.
The research team focused on cementum, a tissue covering the roots of teeth. As a person ages, cementum forms microscopic growth lines known as the lines of Salter. Scientists count these lines and combine the results with the known eruption age of a tooth to estimate how old a person was at death.
Researchers prepared thin cross-sections from the tooth roots and examined them under a microscope. The growth lines survived the cremation process far better than expected. Different observers produced consistent counts, suggesting the method works reliably even on heavily burned archaeological material.
The study found a clear relationship between age and several features of the cementum. Both the number of growth lines and the thickness of the cementum increased with age. When researchers combined these measurements, they obtained narrower age ranges than those produced through traditional skeletal analysis alone.
Czernikowice sites 2 and 4, Poland: Burnt human remains from Lusatian Urnfield burials. A) Cranial fragments with preserved sutures from a mature female (burial 166). B) Cracking and cortical layer separation in long-bone fragments from a possible female (grave 78). C) Uneven burning in long-bone fragments from a mature female (burial 166). D) Even burning in long-bone fragments from a probable adult male (burial Cz/18). Credit: A. Hałuszko / Hałuszko et al., Scientific Reports (2026)
The findings suggest that tooth-based methods offer a useful option for archaeological populations where bone preservation is poor. Such approaches are especially important for cremation cemeteries, where many conventional techniques provide limited results.
The team noticed another pattern while examining the samples. The width of the growth lines varied significantly between cemeteries. Differences did not appear to be linked to sex, age, or tooth type. Instead, local conditions seem to have played a role. Diet, environment, health, or other aspects of daily life may have influenced how these microscopic structures formed.
Scientists still debate exactly how the lines develop. Earlier studies often treated them as annual markers similar to tree rings. Current evidence points to a more complicated biological process. The variation observed between cemeteries adds support to this view and suggests that the lines record more than age alone.
Future research will compare cremated teeth with samples from people whose ages are already known. Such work would help refine the method and improve confidence in age estimates. Researchers also hope to test advanced imaging techniques that reduce the need to cut archaeological teeth into sections.
For now, the study shows that cremated teeth preserve far more information than once thought. Even after exposure to intense heat more than three millennia ago, microscopic traces within tooth roots still offer evidence about age and perhaps aspects of life experienced by Bronze Age communities.
Publication: Hałuszko, A., Tangl, S., Dobsak, T., & Kanz, F. (2026). Methodological validation and inter-site analysis in Late Bronze and Early Iron Age cremations using tooth cementum annulation counts. Scientific Reports. doi:10.1038/s41598-026-51841-z