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 nu(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 (C) 2009 John Wiley & Sons, Ltd.