Avaliação in vitro da fluorescência de resinas compostas após envelhecimento natural

Abstract

The purpose of this study was to evaluate in vitro the variation of fluorescent composite resins, after 90 days of natural aging, and compare the fluorescent resin composites' spectrum with enamel and human dentin. There were made 20 enamel specimens (5,0mmx0,30mmX0,03mm) and 20 dentin specimens (5,0mmx1,0mm) from third healthy human molars and 5 specimens (10,0mmx2,0mm) for each one of the resin's composites from brands such as, Z350XT/3M ESPE, Opallis/FGM and Empress Direct/Ivoclar-Vivadent, in shades EA2, DA2 and achromatic enamel. The fluorescence was measured by the PerkinElmer LS 55 spectrometer fluorometer, with the excitation of 395 nm for the longitudinal evaluation of the composite resins with 375, 395 and 410 nm for the comparison of the enamel and human dentin, with the reading of the emission from 400 to 900 nm, and the analyzed data by the graphic program Origin 8.0. The percentage variation between evaluation times was subjected to the test t of student, with the level of significance of 5%. After 90 days, the resins Z350XT showed an increase in fluorescence, while the resins Opallis and Empress Direct showed a decrease in relation to the initial time, with greater variation ocurring in the first 30 days, where the intensity of the fluorensce of all composite resins, with the exception of Opallis-EA2 varied significantly with relation to the initial time (p-value<0,05). The spectrum of fluorescence from the 3 brands of composite resins, on 3 excitations were similar, with a maximum peak of emission at 450 nm, however the spectrum of enamel and dentin varied, showing fluorescence emission peaks at longer wavelengths than the composite resin, with highter excitation. The composite resins' fluorescence proved to be unstable during the period analyzed and with emission's behavior different from the enamel and human dentin.