Synchrotron radiation-based phase-contrast microtomography of human dental calculus allows nondestructive analysis of inclusions: implications for archeological samples

Purpose: Dental calculus forms on teeth during the life of an individual and its investigation can yield information about diet, health status, and environmental pollution. Currently, the analytical techniques used to visualize the internal structure of human dental calculus and entrapped inclusions are limited and require destructive sampling, which cannot always be justified. Approach: We used propagation phase-contrast synchrotron radiation micro-computed tomography (PPC-SR-mu CT) to non-destructively examine the internal organization of dental calculus, including its microstructure and entrapped inclusions, on both modern and archeological samples. Results: The virtual histological exploration of the samples shows that PPC-SR-mu CT is a powerful approach to visualize the internal organization of dental calculus. We identified several important features, including previously undetected negative imprints of enamel and dentine growth markers (perikymata and periradicular bands, respectively), the non-contiguous structure of calculus layers with multiple voids, and entrapped plant remains. Conclusions: PPC-SR-mu CT is an effective technique to explore dental calculus structural organization, and is especially powerful for enabling the identification of inclusions. The non-destructive nature of synchrotron tomography helps protect samples for future research. However, the irregular layers and frequent voids reveal a high heterogeneity and variability within calculus, with implications for research focusing on inclusions. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License.

Automated summary

Research on dental calculus can provide insights into diet, health, and environmental pollution. The use of PPC-SR-mu CT technique allows for non-destructive examination of its internal organization, revealing important features and the high heterogeneity and variability within calculus.