Laser-induced fluorescence studies of caries model

Abstract

The goal of this study is fluorescence investigations in the process of caries growth in presence of bacteria metabolism products. Spectra of teeth, illuminated with 337 nm nitrogen laser were measured during in vitro caries formation. Spectra, obtained from sound tooth consist of one intensive peak at 480-500 nm and one secondary peak at 430-450 nm. In the process of the caries formation of the teeth we observed increase in intensity at 430-450 nm and appearance of two peaks in the red spectral region at 590-650 nm. A general decrease in the intensity of the fluorescence signal is observed, but changes in spectral shape are more significant. We observe that the peak increase at 430-450 nm is related to the tooth demineralization. Bacteria presence and their metabolism products induce fluorescence signal in the red region. These results allow consideration of caries in terms of two different processes, which lead to its formation: demineralization and metabolism products increase, which are caused by bacteria activities, and could be used to obtain a more complete picture of caries formation.