Influence of Tea, Coffee, and Turmeric Solutions on the Color Stability of Denture Base Acrylic Resins and Silicone Soft Lining Material: An In Vitro Study

Background and objectives With the continuous presence of microflora, saliva, and frequent intake of coloured food, the colour stability of any aesthetic material may become compromised. Hence, the present study was conducted to evaluate the influence of tea, coffee, and turmeric solutions on the colour stability of commercially available heat-cured and autopolymerizing denture base acrylic resins as well as a soft lining material. Methods Twenty-four rectangular samples measuring 20 mm × 15 mm × 2 mm were prepared for each type of test material. The samples were divided into four groups of six and immersed in different staining solutions, then stored in an incubator at 37°C for 30 days. Colorimetric measurements were taken on the 1st, 7th, and 30th days using an ultraviolet-visible-near infrared (UV-VIS-NIR) spectrophotometer and reported according to the Commission Internationale de L'Eclairage (CIE) Lab system. Data were statistically analyzed using ANOVA, followed by the Tukey honestly significant difference (HSD) test. Comparisons between time intervals were performed using the paired t-test. Results In the heat-cure acrylic group, significant colour changes were caused by tea and coffee solution after days 7 and 30 (P < 0.001*) and by turmeric solution at all three time intervals. In the autopolymerizing acrylic group, significant colour changes were observed in turmeric and coffee solutions after days 7 and 30 and in tea solution after day 1 (P < 0.001*). For Molloplast-B, significant colour changes were seen in tea after day 7 (P < 0.001*) and in coffee and turmeric solutions at all three time intervals. Interpretation and conclusion Within the limitations of this study, it was concluded that significant colour shifts occurred in all three materials over time. The staining becomes more intense with time, except for autopolymerizing acrylic in tea and heat-cure acrylic in coffee. All the mean colour shifts were clinically acceptable, except for heat-cure acrylic in tea after 30 days.