Variation in elemental intensities among teeth and between pre‐ and postnatal regions of enamel

Abstract

Microspatial analyses of the trace element composition of dental enamel are made possible using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Fine spatial resolution, multielement capabilities, and minimal sample destruction make this technique particularly well-suited for documenting the distribution of elements in sequentially calcifying layers of enamel. Because deciduous enamel forms from week 13 in utero up to 9 months postnatally (thereafter essentially becoming inert), the application of LA-ICP-MS allows for the retrospective measurement of prenatal and early postnatal trace-element uptake during a critical period of child development. In this study, we compared intra- and intertooth intensities of 25Mg, 57Fe, 66Zn, 68Zn, 88Sr, 138Ba, and 208Pb via LA-ICP-MS of 38 exfoliated deciduous incisors and canines donated by 36 participants in the Solís Valley Mexico Nutrition Collaborative Research Support Program (NCRSP). Pre- and postnatal comparisons within teeth showed significant increases (P < 0.001) and greater variation in the abundance of all isotopes in postnatal enamel, with the exception of a decrease in 25Mg (P < 0.001) and constant values for 88Sr (P = 0.681). Conversely, comparisons by tooth type and mouth quadrant revealed few significant differences between teeth of the same individual. We argue that more variation in the trace element composition of teeth occurs across developmental areas within a tooth than among different teeth of the same person. This study further demonstrates that sequentially calcifying areas of enamel have different chemical concentrations. The results support the use of microspatial analyses of enamel for understanding changes in nutrition, pollution, and residence.

Reconstruction of human exposure to heavy metals using synchrotron radiation microbeams in prehistoric and modern humans

“…The mean of relative concentrations by five-time scanning was taken as a relative concentration for a given heavy metal for a given tooth. The relative concentrations of Pb, Hg, Cu and Zn were standardized by dividing the value of the peak areas of a given element by the peak area of Ca in the sample because of its similarity of behavior to that of heavy metals [13]. The coefficients of variations were within 20% for this analysis.…”

“…In the past, several methodologies have been applied to analysis of heavy metals in the teeth [6][7][8][9][10][11][12][13][14][15]. Recently, XRF analysis using synchrotron radiation (SR) microbeams (SRXRF) has been applied to the analyses of tooth enamel [10][11][12].…”

Determinants of childhood lead exposure in the postleaded petrol era: The Tooth Fairy cohort from Newcastle upon Tyne

“…The neonatal line was clearly visible in all sections, allowing identification of pre-and post-natally formed enamel and dentine for sampling. 21,23,24 To investigate tooth lead levels, the individual dental phases (pre and post-natal enamel and dentine) were analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) at the School of Earth and Environment, University of Leeds. Analytical details are provided in full elsewhere.…”

Tracing fetal and childhood exposure to lead using isotope analysis of deciduous teeth

“…Advances in instrumental analysis, most notably laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), now permit the acquisition of elemental and isotope data at high spatial resolution (less than 100µm) without the need for sample digestion. Of those papers detailing the concentration of Pb in dental tissues by LA-ICP-MS, we refer to Arora et al (2004Arora et al ( , 2006Arora et al ( , 2014; Dolphin et al (2005) ;Hare et al (2011);Humphrey et al (2008a); Kang et al (2004); Shepherd et al (2012). These papers raise the interesting question "If the micro-technology exists to measure the isotopic abundance of elements in very small samples, why are there so few publications relating to the isotope composition of Pb in children's teeth?"…”