Background: Fluorescence is the absorption of light by a substance and the spontaneous emission of light in a longer wavelength within 10(-8) seconds of activation.
Purpose: The purpose of this study was to determine the differences in fluorescence among layered resin composites with a color-measuring spectrophotometer.
Materials and methods: Spectral reflectance and color of five brands of resin composites were measured over a white standard tile according to the Commission Internationale de l'Eclairage (CIE) CIELAB color scale relative to the standard illuminant D65. Human dentin was used as a control; five specimens were made for each group and each specimen was measured three times. An ultraviolet (UV) filter was inserted or removed to exclude or include the UV component of illumination. From the spectral reflectance values, subtraction spectrum by the inclusion and exclusion of the UV component was calculated.
Results: Dentin showed a fluorescence peak around 440 to 450 nm. Three of the five resin composites showed fluorescence peaks, and the peak wavelength was 440 to 450 nm. Peak height and peak area varied by the composite. Changes in color (DeltaE*(ab)) caused by the UV component were 1.58 to 2.35, and Deltab* values were from -2.20 to -1.49 in composites that showed fluorescence peaks.