Determination of strontium concentration in a primary molar tooth using X-ray fluorescence measurements and a two-dimensional K-shell XRF model*

The concentration of strontium (Sr) and other elements were linked to the dental health of both primary and permanent teeth. Sr concentration was shown to be influenced by the child’s environment and an indicator of dietary habits. Sr was also shown to decrease enamel’s demineralization.  X-ray fluorescence (XRF) is a nondestructive technique extensively used over the past few decades to measure elemental concentrations and distributions in tissues. A linear raster XRF scan (30 s and 0.2 mm step size) of a primary molar tooth was performed using the microbeam from an integrated x-ray tube and polycapillary x-ray lens unit (FWHM = 1.7 mm) and an orthogonally-positioned silicon-drift x-ray detector. Sr concentration was determined using a two-dimensional K-shell XRF model and the measured Sr Kα and Sr Kβ signals. The model computed relative Sr Kα and Sr Kβ signals accounting for x-ray attenuation of incident polyenergetic x-rays and emergent XRF photons in an elliptical uniform sample. Sr concentrations were calculated to be (0.7 ± 0.2) mg/g for the Kα signal and (4.5 ± 1.8) mg/g for the Kβ signal under the assumption that Sr x-rays originated solely from the tooth’s dentin tissue. Future analysis will include the enamel and dentin layers of the tooth.