Dental enamel caries (early) diagnosis and mapping by laser Raman spectral imaging

A method for estimating the extent of tooth caries and providing imaging information based on Raman Spectral Imaging is suggested. This non-destructive optical method is able to characterize and differentiate between normal enamel tooth surface, and initial and advanced tooth caries. Images and corresponding spectra were acquired from various tooth sites, and it was demonstrated that normal, white opaque, brown discoloured, and pitted tooth surfaces all have different distinct spectral features which characterize the different degrees of dental caries. Spectral analysis allows for detection of early changes in the surfaces of carious teeth, and the associated mapping capability allows for morphological characterization. It was found that the emission at 960cm-1, which corresponds to PO stretching in the hydroxyapatite bond, is the most significant and can be used for diagnosis of caries. The emissions at 1070cm-1 and at 590cm-1 can also be applied, but are less accurate. The results suggest that this technique may be further developed and applied for clinical diagnosis of initial and more advanced demineralization processes of the enamel tooth surfaces.