Thermal behavior of dental enamel and geologic apatite: An infrared spectroscopic study

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Erscheinungsjahr:
2003
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Beschreibung:
  • Teeth and bones consist of an apatite-type structure and such biogenic apatites usually occur innano-crystalline form. Because of the small particle size in biological tissues, local structural detailsof biogenic apatite have still not been resolved in detail. Comparison of the phonon spectra of enamelapatite with those of inorganically formed apatite was carried out to improve our understanding ofthe vibrational behavior of biogenic apatite. In situ mid-infrared absorption spectra of dental enameland geologic fluorapatite were recorded from 300 K to ca. 750 K. Lattice vibration modes werestudied at low temperature in the infrared region of 150 to 650 cm–1. The IR excitations indicate thatgeologic apatite undergoes heavier thermal changes than enamel apatite at temperatures between 60K and 300 K. In situ high-temperature IR spectra confirm the different thermal evolution of dentalenamel and geologic fluorapatite. The P-O overtones or combinational vibrations and hydrous spe-cies of enamel apatite show two different thermal regions below and above 600 K. The thermalbehavior in the region below 600 K corresponds to the loss of adsorbed and part of the lattice water,combined with an increase of structural OH groups. In the second thermal region (above 600 K), thesimilarity of thermal response of dental enamel to that of the geologic apatite from 300 K suggeststhe existence of a highly ordered system. This result may be explained by the dehydration and atomicrearrangements in the channels of enamel apatite structure below 600 K.
Lizenz:
  • info:eu-repo/semantics/closedAccess
Quellsystem:
Forschungsinformationssystem der UHH

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oai:www.edit.fis.uni-hamburg.de:publications/1b8a3dd0-130f-4dfa-8e9e-e9790420f392