engleski

The Detection of Carious Lesion Porphyrins Using Violet Laser Induced Fluorescence

Objectives: The aim of the study was to establish spectral regions for laser excitation of protoporphyrin IX (PP), coproporphyrin (CP) and uroporphyrin (UP) solutions under different pH conditions. The second aim was to compare laser induced fluorescence (LIF) spectra of PP, CP and UP solutions with various pH to the fluorescence of natural carious lesion and the results of other studies. Materials and methods: Absorption spectra of PP, CP and UP solutions with pH values in range from 0.6-13.0 were taken on a Varian model spectrophotometer. According to the peak absorption of the porphyrins used, laser at 405 nm (10 mW) was selected for LIF measurements of PP, CP and UP solutions, as well as the natural carious lesion. Results: Depending on the pH value, the LIF of the PP, CP and UP solutions exhibited the red shift toward higher wavelengths. Using excitation at 405 nm laser wavelength, fluorescence bands peaking at 601 nm and 655 nm of the acidic PP solution were observed. Conclusions: Violet LIF peaks of porphyrin solutions measured in vitro are similar to the wavelengths of a real carious lesion and fluorescence band peaks of natural teeth known from literature. However, the fluorescence of tested porphyrins does not completely explain the fluorescence spectra of dental caries and further studies are needed. pH seems to have an important influence on the light absorption and emission of porphyrins.

porphyrins ; coproporphyrins ; uroporphyrins ; dental caries ; spectrometry ; fluorescence

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