Imaging‐assisted time‐resolved dentine sampling to track weaning histories

Abstract

Tooth dentine serial sampling followed by isotope analyses allows detection of shifts in an individual's diet during the periods of tooth formation, providing information on breastfeeding, weaning, and childhood nutrition. Current sampling methods, however, do not fully capture the potential resolution of dentine increments because of the difficulties caused by the conical growth pattern, and changes in growth rate during tooth development resulting in uncertain timing. Here, we present an imaging‐assisted microsampling approach that takes the biological growth pattern of dentine into account in an effort to improve temporal resolution. We used high‐resolution light microscopy images of first molar longitudinal thin sections to generate an accurate optical reference of growth pattern and formulated a new scheme to assign collected microsamples to age. This allowed us to track dietary changes over more precisely confined and shorter time periods, providing greater detail and resolution for the breastfeeding and weaning process. We applied our method to track early life dietary history in four individuals from a small cemetery in Alsace, France, dated to the early 5th century AD (the Late Antique/Migration period). Even within this short timescale, 13C/12C and 15N/14N ratio sequences suggest variability in diets and weaning periods, and hint at early maternal mobility.

Using teeth as tools: Investigating the mother–infant dyad and developmental origins of health and disease hypothesis using vitamin D deficiency

“…Utero initiation of the first permanent molar is reported in the dental literature (e.g., Avery, 2002;Butler, 1967), but this basic piece of information is not readily available in sources commonly used by medical and biological anthropologists (e.g., Beaumont & Montgomery, 2015). As a result, deciduous teeth alone are commonly used to investigate in utero matters (e.g., Czermak, Schermelleh, & Lee-Thorp, 2018;Skinner & Dupras, 1993).…”

Infant and childhood diet at the passage tomb of Alto de la Huesera (north‐central Iberia) from bone collagen and sequential dentine isotope composition

“…Beaumont et al, ; Sandberg et al, ). Collagen extraction was carried out following a modified University of Cape Town method (Sealy, Johnson, Richards, & Nehlich, ), with sequential microsampling undertaken following the method developed by Czermak, Schermelleh, and Lee‐Thorp (this issue). One complete tooth half was demineralized in 0.5 M hydrochloric acid (HCl) solution at 4 °C for ca.…”

“…2 weeks, rinsed three times with deionized water until pH neutral. The demineralized tooth half was then cut longitudinally and the posterior side was removed in order to minimize incremental growth overlapping as dentine formation is S‐shaped rather than linear and increments bend concentrically around the pulp chamber (for more details, see Czermak et al, this issue). The thin cementum layer was removed by mechanical cleaning the tooth root surface, and any identified secondary and tertiary dentine was avoided by reaming out the pulp cavity before sampling.…”

“…12 samples on average per tooth. This method is more anatomically sensitive than linear slicing (Czermak et al, this issue). Resulting dentine microsamples were labelled according to a numerical sequence of dentine segments and their approximate age assigned by comparing the dentine sections' anatomical location to the stage of dental development, following AlQahtani et al ().…”

Shifting weaning practices in Early Neolithic Cis‐Baikal, Siberia: New insights from stable isotope analysis of molar micro‐samples

“…Current research (e.g., Burt, ; Czermak, Schermelleh, & Lee‐Thorp, Forthcoming; van der Sluis, Reimer, & Lynnerup, ) to refine the ability to either improve slicing methods or use smaller dental punches may be able to further refine micro‐sampling methods soon but are not yet feasible for large comparative projects.…”