Figure 2. Backscattered electron-microscopy imaging (BSE) versus ptychographic X-ray nanoCT (PXCT) of bulk crown dentine.

Highly mineralized islands of peritubular dentine in the intertubular matrix as revealed by (a) BSE microscopy at 10 keV and (b) PXCT at 6.2 keV. The mass density range measured by PXCT is shown in g/cm³ in the colorbar of (b). The scale bar is 5 μm for both images. The full width at half maximum (FWHM) of the profile plot taken across one of the branches of the tubules is used in panel (c) to evaluate the spatial resolution as described in the main text.