X-ray fluorescence, x-ray scattering, and x-ray attenuation measurements of a primary incisor tooth slice using a table-top microbeam system

Primary teeth are easily accessible human tissues. Measurements of their bulk and trace elemental composition can be used to study developmental health issues such as malnutrition or exposure to toxic elements. X-ray fluorescence (XRF) elemental detection is nondestructive, fast, and inexpensive. An experimental and modelling XRF method probing elemental composition of microscopic volumes (<10^-3 mm³) of a primary tooth was developed. An incisor primary tooth slice (0.63 mm x 10 mm²) was prepared and placed perpendicular to the microbeam (~0.02 mm) from a table-top integrated x-ray lens and x-ray tube. X-ray attenuation and XRF data were acquired by placing the x-ray detector in transmission and backscatter geometries, respectively. 2D XRF raster scan measurements mapped the tooth area, and linear attenuation coefficient (µ) measurements identified the resin, dentin, dentin-enamel junction, and enamel regions. Peak fitting analysis of XRF spectra in the dentin and enamel layers (3 trials x 300-s) identified the K-shell XRF peaks of five elements P, Ca, Cu, Zn, and Sr. An x-ray scatter and XRF model employed experimental data and initial elemental concentrations to compute the mass density and elemental concentrations in the dentin and enamel layers. Measured elemental concentrations and mass density values agree with literature data.