Structural changes at dental tissue interfaces characterized by energy‐dispersive resonant inelastic X‐ray scattering and FTIR techniques

Abstract

Energy-dispersive inelastic X-ray scattering (EDIXS) and Fourier transform infrared spectroscopy (FTIR) were used to study hard dental tissues like dentine, enamel, and cementum in several human dental pieces of adult individuals. Analysis of linear paths crossing different interfaces were carried out. These different techniques provide specific information that allows a combined interpretation of the results as well as a comparison of performances of both methodologies. The EDIXS analysis was focused on the calcium absorption edge because this major element has a fundamental role in the formation of the calcium phosphate structure. Regarding FTIR, the investigation focused on the study of ν1, ν3, and ν4 vibrational modes of hydroxyapatite. The ν1, ν3, and ν4 vibrational modes of hydroxyapatite are related to the vibrations of the phosphate (PO43-) ion. Specifically, ν1 corresponds to the symmetric stretching vibration, ν3 is the asymmetric stretching vibration, and ν4 is the bending vibration of the phosphate ion. The results allowed us to infer a correlation between the variations observed in EDIXS and the ν3 vibrational mode measured with FTIR. This correlation between inelastic X-ray scattering and FTIR spectroscopy offers a more comprehensive characterization of hydroxyapatite parameters. Furthermore, it establishes a complementary technique for the structural characterization of dental tissues.