FT‐Raman investigation of human dental enamel surfaces

FT‐Raman spectra of human enamel surfaces from sound, affected (with 1 cavity) and highly affected (with at least 3 cavities) tooth samples were analyzed by principal component analysis (PCA). Major differences between the unaffected and affected tooth samples seem to arise from the structural changes along the c ‐axis of hydroxyapatite, the chief crystalline component of human dental enamel. Based on Fisher index calculations, the most discriminative value was obtained for the intensity of the only Raman active ν 2 PO 4 3− (E 1 ) symmetric deformation mode at 428 cm −1 . Moreover, these changes can be observed through the whole tooth enamel surface, establishing a predisposition to caries correlated to chemical and structural composition of tooth enamel. No spectral changes regarding the CO 3 2− substitution were detected by both nondestructive FT‐Raman and FTIR (Fourier transform infrared) spectroscopy of the powdered teeth samples. Copyright © 2009 John Wiley & Sons, Ltd.