Analysis of structural changes at interfaces of dental tissues. An EDIX and FTIR approach

J. ROBLEDO; J. J. LEANI; H. J. SÁNCHEZ; M.S. GRENÓN

Congreso; 29th Annual Users? Meeting (RAU).; 2019

In this paper we report a study of an important property of biomineralized phases, such as crystallinity, by using two different spectroscopic techniques. Crystallinity is not only important for understanding biomineralization, it is also related to the maturation and mechanisms of growth of calcium phosphates in biological surroundings [1-4]. Hard dental tissues like dentine and cementum were studied in several human dental pieces of adult individuals from the same geographic region. Cross cuts of several teeth were performed at dental root level resulting in a planar slice exposed for analysis. Two types of analyses were performed along linear paths crossing the dentine?cementum or root-dentine interfaces and also all over a surface: Energy Dispersive Inelastic X-Ray Scattering (EDIXS) [5] and Fourier-Transform Infrared spectroscopy (FTIR) [6].With EDIX, the analysis took advantage of this techniques of performing spatially resolved structural analysis and 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 study of ν1?ν3 infrared absorption bands of PO4 3? phosphates. The EDIX measurements were carried out at the IAEA end-station of the XRF beamline at the Elettra Sincrotrone Trieste, Italy and the XRF D09B beamline at the Brazilian Synchrotron Light Source (LNLS). The FTIR measurements were performed with a Bruker Equinox 55 interferometer coupled to a Bruker Hyperion 3000 microscope, on the Sinbad?IR beamline at the LNF (Laboratori Nazionali di Frascati, Italy) facility.With both techniques, the results confirm for the first time previous assumptions about the growth and maturation of dental calculi, i.e., crystallinity progresses from regions of high crystallinity to regions of lower crystallinity, and, in addition, its quantification with spatial resolution in the sample. A gradual pattern was observed in dental calculus. Another result from this study was that cementum and dentine had similar crystallinity, despite their different biological and mechanical functions.