A Comparative Study of Heat and Self-Cured Acrylic Resins on Color Stability of 5 Brands of Denture Teeth

Background: Denture teeth play a critical role in overall aesthetic outcomes of removable complete dentures, and long-term maintenance of these outcomes depends on the color stability of the prosthetic teeth. The characteristics of denture base resins play a significant role in prosthetic clinical performance and aesthetics. Objectives: The purpose of this study was to assess the effect of two flasking materials on the color stability of five brands of denture teeth that were immersed in commonly consumed beverages. Materials and Methods: In the present study 560 denture teeth (20 series) were invested with heat- and cold-cured acrylic resin. All the specimens were thermo cycled between 4°C and 60°C, with 60 Seconds dwell times for 1000 cycles. Subsequently, the specimens in each group were divided into four subgroups based on the immersion medium: coffee, tea, cola, or distilled water. Digital images of the teeth were taken before immersion and 30 days after immersion. The color samples were measured using the CIE L* a * b * system, and color differences (∆E) were calculated. The data were evaluated by 3-way ANOVA and the Tukey HSD test. Results: There were significant differences in color change between the cold-cured acrylic resins and the heat-cured acrylic resins, with a reduced amount of discoloration in the heat-cured group (∆E = 10.12 ± 3.93, P = 0.001). The solutions showed significantly different amounts of discoloration on the teeth; distilled water had the least effect (∆E = 8.49 ± 2.62, P = 0.001) and coffee had the maximum discoloration (∆E = 14.14 ± 7.77, P = 0.001). A Tukey test showed that there was no significant difference between each brand of denture teeth. Conclusions: Coffee caused the most color changes in the examined resin denture teeth. Tea and cola left less staining on the teeth, and distilled water caused the least discoloration. Generally, investing by heat- and cold-cured acrylic resins can significantly affect the color stability of resin denture teeth; however, heat-cured acrylic resins had fewer color changes.