School of Dental Medicine, University of Zagreb, Croatian Dental Society - Croatian Medical Association
Abstract
U istraživanju se željelo odrediti spektralna područja za lasersku ekscitaciju otopina protoporfirina IX (PP-a), koproporfirina (CP-a) i uroporfirina (UP-a) s različitim pH-vrijednostima. Drugi je cilj bio usporediti spektre laserski inducirane fluorescencije (LIF-a) otopina PP-a, CP-a i UP-a različitih pH-vrijednosti s fluorescencijom prirodne karijesne lezije i rezultatima ostalih istraživanja. Materijali i postupci: Apsorpcijski spektri otopina PP-a, CP-a i UP-a s pH-vrijednostima u rasponu od 0,6 do 13 izmjereni su spektrofotometrom (model Varian). Laser od 405 nm (10mW) odabran je prema najvišoj apsorpciji porfirina za mjerenja spektra laserski inducirane fluorescencije (LIF-a) PP-a, CP-a i UP-a te prirodne karijesne lezije. Rezultati: Ovisno o pH-vrijednosti, LIF-ove otopine PP-a, CP-a i UP-a pokazuju pomak prema višim valnim duljinama. U kiseloj otopini PP-a uočeni su fluorescencijski vršci na 601 nm i 655 nm nakon ekscitacije lasera na valnoj duljini od 405 nm. Zaključak: In vitro mjerenja LIF-a porfirinskih otopina ljubičastim laserom pokazuju sličnosti s valnim duljinama prave karijesne lezije i vrhovima fluorescencijskih vrpci prirodnih zuba poznatih iz literature. Ipak, fluorescencija testiranih porfirina ne objašnjava potpuno fluorescencijske spektre zubnog karijesa te su potrebna daljnja istraživanja. Čini se da pH ima važan utjecaj na svjetlosnu apsorpciju i emisiju porfirina.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
