Abstract
The auto-fluorescence characteristics of human teeth change with age. AGEs (advanced glycation endproducts), which are a crosslink of collagen, are considered to be involved in the mechanisms that cause the fluorescence characteristics to change. Although fluorescence intensity is a well-examined index of aging, it has inherent limitations. In contrast, fluorescence lifetime is useful for the evaluation because it can be reviewed quantitatively. Therefore, we mapped the distribution of fluorescence lifetime of teeth in relation to the formation and aging of teeth. The fluorescence decay profile of teeth was measured by time-correlated single photon counting, and lifetime was calculated from the fitting curve of the decay profile in a two-component exponential function. As a result, the distribution of fluorescent lifetime in dentin corresponded to tooth development; fluorescent lifetime of the crown dentin was shorter than that of the root dentin. Furthermore, the fluorescence lifetime decreased as human age increased. Because these changes in fluorescent lifetime are attributed to the accumulation of AGEs, whose fluorescence lifetime is short, our mapping of fluorescent life visualizes the formation and aging of teeth.
