Fluorescence assessment of composite resins and dental tissues: direct method

Objectives: Evaluate the fluorescence intensity (FI) of different composite-resins (CR) and compare it to dental tissues FI. Methods: CR were used to make ten discs (2mm/depth and 4mm/diameter) of each brand, divided into groups: For the groups: Z (Filtek-Z350/3MEspe); ES (Esthet-X/Dentsply); A (Amelogen-Plus/Ultradent) and DVS (Durafill- VS/Heraeus-Kulzer), shade enamel A2 was used (2mm). For the other groups, the following compositions were used: OES (Esthet-X) opaque-OA (1mm) + enamel-A2 (1mm); ODVSI (Charisma-Opal/Durafill-VSI), opaque-OM (1mm) + translucent (1mm); and DVSI (Durafill- VSI) translucent (2mm). The dental tissues specimens were obtained from human anterior teeth cut on mesiodistal approach, to supply samples of enamel, dentin and enamel/dentin (2mm). The direct measurement of the specimens FI was made by the optic fiber coupled to a spectrometer (Ocean Optics USB 4000). The FI was registered in graphs (Origin 8.0 program). Data were submitted to statistical analysis with Dunnet's test, Kruskall-Wallis and ANOVA 0.5%. Results: Light absorptions of the CR were obtained in the spectral range from 250 to 450nm, and the dental tissues were between 250-300nm. CR were excited at 398nm and exhibited emission's maxima around 485nm. The FI values for all the resins showed significant statistical differences among themselves in arbitrary-unities(a.u.); except for the groups Z and DVS. Group DVSI had the highest values of FI (13539a.u.), followed by ODVS(10440a.u.), ES(3946a.u.), OES(3841a.u.), A(3540a.u.), Z and DVS(1146a.u.). FI values for the CR were statistically different from the dental tissues ones (E=1380a.u.; D=6262a.u.; E/D=3251a.u.). The opaque interfered in the FI and the groups Z and DVSA demonstrated the closest FI values to dental enamel. Conclusions: The FI of the CR evaluated showed significant differences among themselves and when compared to dental tissues. Direct spectrofluorimetric method represents a tool for choosing the composite resin fluorescence. Supported by FAPESP 2010/50834-7.