Sr diffusion from fillings into the tooth dentine biocomposite: nano-imaging and nano-XRF/XRD tomography for mapping chemical changes around

Sr-containing dental filling materials such as glass-ionomer cement are widely used for tooth restorations. Already weeks after placement long-range passive diffusion of Sr ions into the mineralized dentine matrix is detected. We examine to what extent this diffusion alters the properties of dentine and its resistance to degradation. Because dentine contains µm diameter tubules and is rich in mineral crystals of Ca and P, we need high resolution/energy nanoprobe to be able to identify Sr deposits. We propose to map the micro-chemistry of dentine using high flux nm sized beams, coupled with PCE nano-CT imaging. Nano-XRF in combination with XRD will reveal Sr in relation to the tubules and will disclose changes in the mineralized fibers and apatite nanocrystals lattice parameters. The high-resolution imaging capacities of ID16B are needed to identify diffusion paths of Sr in dentine facilitating the assessment of the clinical use of Sr leaching out of dental filling materials.