Measurement of fluorescence in human teeth using time-resolved microfluorometry. Changes of fluorescence characteristics by aging.

Human teeth fluoresce as a result of illumination by UV-light. The fluorescence characteristics of human teeth were investigated with respect to aging using microscope fluorometry. To measure nanoscecond decay features of a tooth's fluorescence, a microscope fluorometer equipped with an air-discharge pulsed lamp was devised. The fluorescence intensity and fluorescence decay curve were found to be age dependent in dentin tissue; the fluorescence intensity increased and the fluorescence decay time decreased with increasing human age. Ancient teeth showed more intense fluorescence with a shorter decay time than that of the modern teeth. This may result from a gradual maturation of fluorescent cross-linked collagen, which increases with age.