Influence of a series of organic and chemical substances on the translucency of resin composites

The objective of this study was to investigate the changes in the translucency of resin composites following a series of immersion treatments in organic and chemical substances. Color of resin composites was measured according to the CIELAB color scale relative to the standard illuminant D65 over a white and a black background. Translucency parameter (TP) of resin composites was calculated at baseline, and after sequential immersion: Step 1, porcine liver esterase (a substitute for a salivary esterase); Step 2, organic substances (mucin and serum) and phosphate-buffered saline (PBS) as a control; Step 3, chemical alteration agents chlorhexidine (CH) and carbamide peroxide (CP); and Step 4, 2% methylene blue. Porcine liver esterase caused small changes in TP (DeltaTP = -0.5 to 0.2). After Step 2, DeltaTP values of three groups were similar in the range of -0.7 to 1.2. After Step 3, DeltaTP values of all groups were small in the range of -1.5 to 2.2. After Step 4, DeltaTP values were high and differences that varied by the resin composite and the immersion protocol were clearly observed (DeltaTP = -13.4 to -2.5). Changes in TP were mainly influenced by resin composite. After Step 4, mucin and serum groups showed generally small changes in TP compared to PBS group. It is a possibility that the high changes in TP after immersion in methylene blue is an indication of dye absorption which might be an indication of the degree of resin composite degradation.