Comparison of color stability of two types of denture base resins in various food colorant solutions: An in vitro study

Abstract

Background: Heat cured Polymethylmethacrylate (PMMA) and Lucitone are the most commonly used denture base resins but their discoloration results in esthetic problems. There is evidence that these resins get discolored on contact with coloring solutions due to sorption but very few studies report on the effect with food colorants. Hence, this study was conducted to evaluate and measure the effect of these food colorants on the denture base resins. Purpose: The color stability of two commercially available denture base acrylic resins (Trevalon & Lucitone) was studied in vitro. Materials and Methods : The specimens were exposed to solution of artificial saliva (control), mixture of artificial saliva and coffee solution and mixture of artificial saliva and turmeric solution. The color measurements were made at baseline (before immersion) and after 30 and 60 days of exposure to staining solutions and color characteristics compared with a white standard using a computer controlled spectrophotometer. Finally, the color stability was quantitatively measured again and color differences (∆E) were calculated. Results: The results of discoloration were analyzed with ANOVA, and it indicated that all factors (time, material, and staining solution), and all possible interactions among them, were found to be statistically significant (p<0.05). For the observations made in 30 & 60 days intervals, the specimens that exhibited the least color change were in the artificial saliva (0.92) solution. The greatest color changes observed according to the National Bureau of Standards unit system were Lucitone (8.72) in turmeric solution, Lucitone (7.76) in coffee solution, Lucitone (1.86) in saliva solution. The changes in the other acrylic resin (PMMA) in the 3 solutions were slight and at trace level. Conclusions: All materials tested were acceptable from the standpoint of color stability for long term exposure to these food colorants. Trevalon ® (PMMA), demonstrated maximum color stability as compared to Lucitone FRS and discoloration increased proportionally with immersion period.