High-resolution X-ray microdiffraction analysis of NaOH-treated dentin

Various kinds of basic chemicals interact with dentin directly in different clinical conditions. However, owing to the lack of appropriate models and technology, it is still not known how the mineral components of dentin react to these chemicals. The technology of high-resolution X-ray microdiffraction, in combination with scanning electron microscopy, has been applied to study the microstructure and minor crystallographic changes in a longitudinal dentin section before and after chemical treatment. Phase analysis was performed; the crystal sizes at two dentin sections were calculated from the reflections (002) and (211), and the crystal orientations of reflections (222), (213) and (002) were compared before and after treatment. The results show an inhomogeneity of the microstructure in dentin between the coronal and the root regions and that they react differently to basic treatment. In particular, NaOH treatment causes a change in crystal sizes and disorder.