Tooth biomarkers to characterize the temporal dynamics of the fetal and early-life exposome

[Display omitted] •Tooth dentin extracts were profiled with untargeted chemical analysis.•390 metabolites and exogenous exposures were annotated in tooth extracts.•Over 250 metabolite features discriminated the prenatal and postnatal tooth fractions.•Unique metabolite features were found in the prenatal tooth fraction.•Tooth exposome provides retrospective measurements of fetal and early life exposures. Teeth have unique histology that make this biomatrix a time-capsule for retrospective exposure analysis of fetal and early life. However, most analytic methods require pulverizing the whole tooth, which eliminates exposure timing information. Further, the range of chemicals and endogenous exposures that can be measured in teeth has yet to be fully characterized. We performed untargeted metabolomics on micro-dissected layers from naturally shed deciduous teeth. Using four liquid-chromatography high-resolution mass spectrometry analytical modes, we profiled small molecules (