The tooth exposome in children's health research

Abstract

Purpose of review: The exposome concept proposes a comprehensive assessment of environmental exposures from the prenatal period onwards. However, determining exposure timing, especially over the prenatal period, is a major challenge in environmental epidemiologic studies.

Recent findings: For decades, teeth have been used to estimate long-term cumulative exposure to metals. Recently developed high-dimensional analytical methods, which combine sophisticated histological and chemical analysis to precisely sample tooth layers that correspond to specific life stages, have the potential to reconstruct the exposome in the second and third trimesters of prenatal development and during early childhood.

Summary: A retrospective temporal exposomic approach that precisely measures exposure intensity 'and timing' during prenatal and early childhood development would substantially aid epidemiologic investigations, particularly case-control studies of rare health outcomes.

Figure 1

Components of the exposome measureable using tooth matrix biomarkers. (a) Metallomics: elemental bio-imaging of teeth using laser ablation-based mass spectrometry provides detailed spatial distribution of multiple metals across enamel and dentine. (b) Dietary transitions: recently developed biomarkers using barium signatures distinguish breast milk intake (between dashed lines) from introduction of infant formula (below black dashed line). (c) Targeted and untargeted organics analysis in teeth reveals exposure to multi-class organic chemicals within (2^nd versus 3^rd trimester) and between (Child A versus Child B) children. QTOFMS was operated in a dual electrospray ionization mode (positive and negative modes). Study design and results are presented in Andra et al [12]. Abbreviations for the chemicals on Y-axis: BPA, bisphenol A; MMP, mono-methyl phthalate; MEP, mono-ethyl phthalate; MBP, mono-nbutyl phthalate; MBzP, mono-benzyl phthalate; MEHP, mono-2-ethylhexyl phthalate; NIC, nicotine; COT, cotinine; HCOT, hydroxycotinine; BAP; bisphenol AP; BPF, bisphenol F; MP, methyl paraben; PP, propyl paraben; BP, butyl paraben; PFOA, pentadecafluorooctanoic acid; PFOS, perfluorooctanesulfonic acid; and DMP, dimethylphosphate. (d) Uncovering historical exposure to external stressors: Raman spectroscopic analysis of macaque tooth dentine shows signatures that correspond to various medical events.