Autofluorescence in human dentine in relation to age, tooth type and temperature measured by nanosecond time-resolved fluorescence microscopy.

Stationary and dynamic characteristics of autofluorescence in human dentine were examined with a nanosecond time-resolved fluorescence microphotometer. With ageing, the intensity of the fluorescence increased whereas the decay time decreased. There were no differences in fluorescence intensity, decay time or spectral profile among tooth types taken from the same individuals or from individuals of the same age. Fluorescence intensity was enhanced after the application of heat (37 and 50 degrees C), but remained unchanged when specimens were kept at 4 degrees C. These results suggest that the increase in fluorescence intensity was partially due to a temperature-dependent physicochemical mechanism.