Synchrotron X-ray fluorescence mapping of Ca, Sr and Zn at the neonatal line in human deciduous teeth reflects changing perinatal physiology

Abstract

Objectives: Our first objective was to review the evidence describing the appearance and microstructure of the neonatal line and to link this with known changes in neonatal physiology occurring at and around birth. A second objective was to explore ways to improve identification of the neonatal line by mapping the pre-and postnatal distribution of Ca, Sr and Zn in deciduous cuspal enamel and superimposing these maps onto transmitted light micrographs that included a clear true section of the neonatal line. Materials and Methods: We used synchrotron X-ray fluorescence to map elemental distributions in pre-and postnatal enamel and dentine. Two deciduous canines and 5 molars were scanned with an X-ray beam monochromatised to 17.0 keV at either 10.0, 2.5 or 1.0 µm resolution and 10 ms integration time. Results: Calcium maps distinguished enamel and dentine but did not clearly demarcate tissues formed pre-or postnatally. Strontium maps reflected presumed pre-and postnatal maternal serum levels and what are likely to be diet-dependent regions of Sr enrichment or depletion. Prenatal Zn maps, particularly for dentine, mirror elevated levels in the fetus and in colostrum during the first few days of life. Conclusions: The neonatal line, enamel dentine junction and surface enamel were all Zn-rich. Within the neonatal line Zn may be associated with increased crystallinity but also with caries resistance, both of which have been reported previously. Elemental mapping may improve the identification of ambiguous NNLs and so be useful in forensic and archaeological studies.

Synchrotron X-ray fluorescence imaging of strontium incorporated into the enamel and dentine of wild-shot orangutan canine teeth

“…For comparison, Shepherd et al (2012) reported much lower Sr concentrations in the deciduous dentine of 3 children of UK origin to be 38±3ppm, 65±8 ppm and 135±13 ppm respectively, the differences between them being attributable to diet and nursing history. Dean, Spiers, Garrevoet & Le Cabec (2019b) also reported Sr concentrations in deciduous enamel and dentine that ranged between 100 and 150 ppm. Sex differences in gastrointestinal Sr absorption have been reported in rats and monkeys but not in great apes and humans (Dahl, et al 2001).…”

Teeth reveal juvenile diet, health and neurotoxicant exposure retrospectively: What biological rhythms and chemical records tell us

“…Oral biologists discovered these neonatal lines by examining sections of hundreds of naturally shed deciduous teeth from children, finding similar dark lines in a comparable position in nearly all teeth. [4,48] These structures serve as natural and permanent markers of the profound physiological and nutritional transition that occurs at birth. Developments in laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS, Box 2) allow individual elemental concentrations to be measured across a tooth section from adjacent microscopic spots serially ablated in a linear progression, [49][50][51][52] which is illustrated in Figure 1, p. 399 of ref [53] .…”

“…Oral biologists discovered these neonatal lines by examining sections of hundreds of naturally shed deciduous teeth from children, finding similar dark lines in a comparable position in nearly all teeth. [ 4,48 ] These structures serve as natural and permanent markers of the profound physiological and nutritional transition that occurs at birth.…”

Multiple cutaneous fistula after titanium dental implant: A case report

“…XRF is an analytical technique used to determine the chemical composition of a given material 8 . It is based on the principle that individual atoms, when excited by a primary x‐ray source, emit a set of characteristic and specific fluorescent x‐rays that allow identification and quantification of an element, becoming an optimal technology for quantitative and qualitative analysis of a specific sample 8,9 . A large amount of Ti and less of S, Fe, and Zn within the fistulous tract were identified.…”

“…This reaction was not expected because Ti is considered to be inert and, for this reason, the most commonly used material in dental implants 12,13 . It has been demonstrated over the years that under the influence of chemical and physical factors, 9,14 corrosion occurs on the contact surface of implants, allowing an increase in primary stability and osteointegration improvement. Osteoblasts have a greater affinity for rough surfaces, favoring the differentiation of osteoblast precursor cells and consequently, the deposition of bone matrix 15 .…”