Laser-induced autofluorescence spectroscopy of dental caries

We studied spectral autofluorescence characteristics of dental caries. A wi de range of carious lesions revealed characteristic emission of endogenous fluorophores with strong fluorescence bands in the red spectral region when excited with 407 nm line radiation of a krypton ion laser. Healthy hard de ntal tissue exhibited no emission bands in the red. The fluorescence spectr a, fluorescence excitation spectra as well as the reflectance spectra of ca rious lesions were found to be typical for fluorescent porphyrins, mainly p rotoporphyrin IX. A possible source of these porphyrins within carious tiss ues is bacterial biosynthesis. Non-invasive sensitive in vivo caries detect ion by means of appropriate excitation sources and porphyrin fluorescence d etectors should be possible.