Combined effects of staining substances on resin composites before and after surface sealant application

The objective was to measure the combined effect of mucin, chlorhexidine and tea solution on the staining of four dental resin composites, and to determine the effect of surface sealant on staining. One side of cured resin composite specimens of 10 mm in diameter and 2 mm in thickness were polished with 600-grit silicon carbide paper. One group of specimens (n = 5) was treated with a surface sealant [BisCover, Bisco, USA; SS ( surface sealant) group], and the other group was not ( NO group; control). Specimens were sequentially immersed in the following substances: Mucin in phosphate buffered saline (PBS); chlorhexidine; tea solution; and ultrasonic cleaning and then immersion in PBS. Color was measured on a reflection spectrophotometer. Changes in color (Delta E*(ab)) and color parameters, such as hue, chroma and value, after immersion in tea solution and subsequent cleaning were analyzed by repeated measures, analysis of variance at the 0.05 level of significance. The range of Delta E*(ab) values after immersion in tea solution was 11.4 - 21.1 for NO group and 10.5 - 19.6 for SS group, and that after cleaning was 2.4 - 10.0 for NO group and 2.7 - 8.3 for SS group. After staining, CIE L* value ( lightness) decreased, and CIE a* and b* values increased. Color changes of resin composites were not acceptable after sequential immersion treatment (Delta E* (ab) > 3.3). The changes in color and color parameters of sealant applied group were not significantly different from those of control group except for a few combinations of color parameters and resin composites.