Oral histories: a simple method of assigning chronological age to isotopic values from human dentine collagen

Abstract

Background: Stable isotope ratios of carbon (δ¹³C) and nitrogen (δ¹⁵N) in bone and dentine collagen have been used for over 30 years to estimate palaeodiet, subsistence strategy, breastfeeding duration and migration within burial populations. Recent developments in dentine microsampling allow improved temporal resolution for dietary patterns.

Aim: A simple method is proposed which could be applied to human teeth to estimate chronological age represented by dentine microsamples in the direction of tooth growth, allowing comparison of dietary patterns between individuals and populations. The method is tested using profiles from permanent and deciduous teeth of two individuals.

Subjects and methods: Using a diagrammatic representation of dentine development by approximate age for each human tooth (based on the Queen Mary University of London Atlas), this study estimated the age represented by each dentine section. Two case studies are shown: comparison of M1 and M2 from a 19th century individual from London, England, and identification of an unknown tooth from an Iron Age female adult from Scotland.

Results and conclusions: The isotopic profiles demonstrate that variations in consecutively-forming teeth can be aligned using this method to extend the dietary history of an individual or identify an unknown tooth by matching the profiles.

• Age assignment
• carbon and nitrogen isotope ratios
• incremental analysis
• palaeodiet

Acknowledgements

The authors would like to thank Museum of London Archaeology and Steven Birch and Martin Wildgoose for access to the samples shown in this study. Grateful thanks to Jacqueline Towers and Andy Gledhill, University of Bradford for their advice and comments on the diagrams. We are indebted to the helpful comments of the reviewers.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

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