Evaluation of Composite Resin Color and Microhardness in Different Solutions

This study evaluated the effect of acidic and alcohol-containing liquids on the color and surface microhardness of a micro-hybrid composite

Method:

Seventy two composite discs (10mm diameter, 2mm height) were randomly divided into nine groups (n=8/gp): control (C); Artificial Saliva (AS; Roxane Laboratories, Inc, Columbus, Ohio); Biotene (B; GlaxoSmithKline Consumer Healthcare L.P. Moon Twp, PA); passion fruit juice (PFJ); orange juice (OJ); Sprite (Spr); Coca-cola (Co); white wine (WW); red wine (RW). The cured surface was polished to a gloss with Sof-Lex discs. Each treatment group was immersed into its respective solution for twenty-eight days (37°C). The Vickers microhardness (Leco Corporation, Michigan, USA) and color assessment (SpectroShade Micro Dental, MHT S. P. A., VIA Milano, Italy) were performed at the end of the exposure time and compared to the control group. The data were analyzed by mixed model ANOVA.

Result:

There was a significant decrease in microhardness of the composite discs (25-30%) in all groups compared to the control group. Co and OJ showed a smaller decrease in microhardness than AS and B groups, while Spr, PFJ, RW, and WW showed the greatest decrease. The shade changes among the groups were the greatest/the darkest for RW and Co groups; however, all groups except for the control group showed discoloration discernible to a human eye. 

Conclusion:

White wine and red wine solutions caused the largest decrease in microhardness of micro-hybrid composites, suggesting a correlation of alcohol content with composite softening. On a green-magenta scale, RW stained the composite the greatest.