Human Tooth Enamel: A Raman Polarized Approach

Abstract

Despite numerous studies of human biominerals, some problems still remain concerning the relationship between their composition and their structure. For a better understanding of this problem, full spectra of the internal vibrations of human tooth enamel crystallites were obtained through polarized Raman microspectrometry and these are published for the first time. The micro-Raman technique is nondestructive and enables micrometric-scale examination of all the samples with a minimum of artifacts. The spectra show some variation from the predicted bands and many similarities with fluorapatite spectra. The mineral part of enamel is initiated in an organic environment and contains carbonate ions. Despite the carbonation, the crystal structure is preserved. Based on these results, a new description of the structure of apatite crystal is proposed. A box of Ca2+ ions surrounds and isolates the PO43– ions from one another, decreasing the influence of substitutions.

Polarization in Raman spectroscopy helps explain bone brittleness in genetic mouse models

“…Notable differences in RS intensity between orthogonal bone orientations [ Fig. 3(e)] occur mostly at locations previously reported by the Penel group 8,26 to be sensitive to polarization: ν3 phosphate (1045 cm −1 ), amide III δðNHÞ band (1273 cm −1 ), 44 and amide I (1668 cm −1 ). The most striking differences occur at peak shoulders and would, therefore, be overlooked by many standard analyses.…”

“…5 However, RS is traditionally limited to biochemical content without directly assessing matrix organization. Recently, the link inherent between polarization of the Raman phenomenon and structural organization of crystals and birefringent molecules 6,7 has been extended to tissue, 8 specifically the collagen matrix. 9,10 Polarization RS may overcome the traditional structural limitations and improve the ability of RS to explore the underlying mechanisms that influence fracture resistance.…”

“…However, traditional peak ratios only report a small portion of the known spectral changes that occur with polarization as previously characterized by others. 8,18,[25][26][27] Moreover, limiting analysis to established peak ratios may overlook crucial aspects of complex toughness phenotypes if they manifest as subtle peak widening or shifting.…”

Dental Enamel Irradiated with Infrared Diode Laser and Photo-Absorbing Cream: Part 2—EDX Study

“…This therapy was applied after a cariogenic challenge followed by a second cariogenic challenge. We previously reported on the findings of a structural analysis of samples in which we identified specific light-induced molecular vibrations 36,37 and investigated the vibrational modes of organic and inorganic components. 38 …”

Structural, Elemental and Molecular Characterization of Normal And Osteoarthritic Human Articular Cartilage

“…Raman analysis is sensitive to molecular orientation, and discerning between orientation and compositional contribution is crucial as bone is comprised of mineralized collagen fibres with alternating orientation within successive lamellae. The capability of Raman microspectroscopic analysis to distinguish between structural and chemical changes in bone were reported, by exploiting the dual influence of composition and structure with in the sample on the Raman signal [13,14].…”