Micro-punches versus micro-slices for serial sampling of human dentine: Striking a balance between improved temporal resolution and measuring additional isotope systems

Rationale The last decade has seen a dramatic increase in the application of serial sampling of human dentine in archaeology. Rapid development in the field has provided many improvements in the methodology, in terms of both time resolution as well as the ability to integrate more isotope systems in the analysis. This study provides a comparison of two common sampling approaches, allowing researchers to select the most suitable approach for addressing specific research questions. Methods Two common approaches for sequential sampling of human dentine (micro-punches and micro-slices) are compared in terms of viability and efficacy. Using archaeological deciduous second molars and permanent first molars, this study demonstrates how the two approaches capture aspects of the weaning process in different ways. In addition, different aspects related to the extraction protocols, such as the thickness of the central slide and the solubilisation step, are also evaluated. Results While both approaches show similar intra-tooth isotopic patterns, the micro-punches approach is preferable for research that requires a very fine temporal resolution, while the micro-slices approach is best for research where delta S-34 values are needed, or when the samples are poorly preserved. In addition, the solubilisation step has a large effect on collagen yield, and, to a lesser extent, on isotopic compositions. Therefore, it is important to ensure that only samples that have undergone the same pre-treatment protocol are directly compared. Conclusions We present the pros and cons of the two micro-sampling approaches and offer possible mitigation strategies to address some of the most important issues related to each approach.

Automated summary

This study compares two common sampling approaches for sequential sampling of human dentine and provides guidance for selecting the most suitable approach for specific research questions. The results show that the micro-punches approach is preferable for studies requiring fine temporal resolution, while the micro-slices approach is best for research requiring specific values or with poorly preserved samples.