Color Stability of Visible Light-Cured, Hard Direct Denture Reliners: An In Vitro Investigation

Purpose: Previous studies have disclosed the unsatisfactory color stability of autopolymerizing, hard direct denture reliners (HDDR). The present study investigated the color stability of the newly introduced visible light-cured and dual-cured HDDRs. Materials and Methods: Five HDDRs were evaluated after 1 hour, 1 day, 7 days, and 30 days of immersion in coffee, tea, and water. Color measurements were obtained with a tristimulus colorimeter, and color differences (AE*) were calculated. Results: After 30 days of immersion one visible light-cured material exhibited the highest AE* value (17.8). The other materials showed acceptable color stability in water and coffee. However, tea strongly affected their color. Conclusion: Reliners, staining solutions, and immersion time are significant factors that affect color stability. After 7 days of immersion, all of the materials showed perceptible color differences. Tea exhibited higher staining capacity than coffee.