Measurements of Fluorescence Heterogeneity in Human Teeth Using Polarization Microfluorometry

Abstract

Human teeth fluoresce as a result of illumination by UV-light (λ_max = 450 nm). The spectral, anisotropic, and temporal heterogeneities of a tooth's fluorescence have been investigated with respect to tooth structure. A polarization microfluorometer and a time-resolved fluorometer were employed. The fluorescence intensity of the dentin increases with tooth age. On the basis of the fluorometric investigations, it appears that a complex of cross-linked collagen with hydroxyapatite is a possible fluorescing compound within the tooth tissue. Observed fluorescence anisotropy in the tooth tissue suggests heterogeneous structure of the fluorescing compound. Anisotropy distribution shows characteristic profiles which are independent of age and sex, and of type of tooth. Analysis of fluorescence decay curves suggests that such profiles are due to the characteristic arrangement of the fluorophore electric dipole, which in turn relates to tissue construction.