Effect of different artificial aging protocolson fluorescence of resin composites

ABSTRACT This study evaluated the effect of different artificial aging on fluorescence of resin composites. Forty-five cylindrical specimens (6mm in diameter and 1mm thick) were made of each resin composite: IPS Empress Direct, Filtek™ Z350 XT, and Durafill. A baseline measurement of fluorescence by the direct method using the fluorescence spectrophotometer RF-5301 PC was performed. After, resin specimens were divided into 3 groups according to artificial aging protocol to be submitted: (1) aging by mechanical brushing: 30,000 cycles were performed, with fluorescence measurements after 10,000, 20,000 and 30,000 cycles; (2) chemical aging by ethanol: the samples were immersed in ethanol for 15 days, with measurements after 5, 10 and 15 days of immersion; (3) light aging: resin specimens were subjected to UV radiation for 216h with fluorescence readings after 72, 144, 216h. Data were submitted to one-way repeated measures ANOVA and Tukey’s test (α=0.05). Baseline fluorescence of the tested resins was ranked in this ascending order: Durafill < Filtek Z350 XT < IPS Empress Direct. Simulated toothbrushing and ethanol immersion reduced fluorescence, except for Z350 XT. For light exposition, fluorescence was reduced after 100h for Empress Direct and Durafill, while a reduction after 100h and 200h was detected for Z350 XT. Artificial aging protocols influenced the fluorescence and that this phenomenon is material dependent. In general, the fluorescence is reduced with aging.