Application of low-wavenumber Raman spectroscopy to the analysis of human teeth

Low-wavenumber Raman spectroscopy is demonstrated for its potential to analyse mineralization abnormalities in human teeth. Four different dental samples were analysed in this study, denoted as healthy control, mild hypomineralization, enamel caries, and AI (severely degraded due to Amelogenesis imperfecta). All specimens were imaged using principal component analysis. The spectra from low- wavenumber and midwavenumber regions were simultaneously collected allowing for direct comparison between the two regions. This approach provided a method to characterize structural and chemical variation within samples. Structurally different hydroxyapatite was found to be present in the surface and bulk of the enamel. The thin outer layer of the enamel contained the most structurally ordered mineral. The obtained Raman images enabled characterization and comparison of lesion domains as well as relative hydroxyapatite abundances across all dental samples.