Nanostructure of healthy and caries-affected human teeth.

Spatially resolved small-angle x-ray scattering based on synchrotron radiation combines the quantitative assessment of nanometer-sized components using scattering with the real-space imaging by means of scanning. The method enables us to study the effect of caries-induced damages on the inorganic and organic nanoscopic components in human teeth. We demonstrate for several 200- to 500-μm-thin tooth slices that the bacterial processes dissolve the ceramic components in enamel and dentin, but the dentinal collagen network remains practically unaffected with respect to its abundance and orientation in early stages of caries and in parts of extended carious lesions. Consequently, we speculate that future caries treatments can be developed reversing the effect of bacterial attacks by means of suitable remineralization of the dentin. FROM THE CLINICAL EDITOR: In this groundbreaking study of caries pathology using synchrotron-based X-ray scattering, the authors demonstrated that while bacterial processes do dissolve the ceramic components in enamel and dentin; however, the dentinal collagen network remains unaffected, enabling the development of future caries treatments that re-mineralize the dentin.