Impact of storage media and temperature on color stability of tooth-colored CAD/CAM materials for final restorations

Abstract

Background: This in-vitro study examined the impact of storage solution, storage duration, and storage temperature on discoloration of three tooth-colored CAD/CAM materials for final restorations. Methods: Specimens ( N = 288; n = 96 per material) with a thickness of 1 ± 0.03 mm of the following CAD/CAM materials were fabricated: resin composite (Lava Ultimate, 3M), polymer-infiltrated ceramic (VITA Enamic, VITA Zahnfabrik), and leucite ceramic (IPS Empress CAD, Ivoclar Vivadent). After baseline measurement, specimens were stored in red wine, curry solution, cress solution, and distilled water at 37°C or 55°C. The discoloration was measured using a spectrophotometer (Lambda 35 Perkin Elmer, Perkin Elmer Inc.) after 1 and 7 days storage. Data were analyzed using four-way ANOVA followed by the Scheffé post-hoc test and partial eta squared ( η P ²) test ( p < 0.05). Results: The highest influence on ∆ E was exerted by storage duration ( η P ² = 0.295, p < 0.001), followed by storage solution ( η P ² = 0.171, p < 0.001), CAD/CAM material ( η P ² = 0.049, p < 0.001), and storage temperature ( η P ² = 0.033, p < 0.001). Specimens stored for 7 days in staining solutions showed more discoloration than those stored for just 1 day. Higher ∆ E values were achieved for specimens stored in curry solution, followed by red wine, cress solution, and distilled water. Resin composite Lava Ultimate showed larger ∆ E values compared with the resin hybrid ceramic VITA Enamic and leucite ceramic IPS Empress CAD. Specimens stored at 37°C showed significantly less discoloration than those stored at 55°C. Conclusions: The degree of coloration of the materials depends on food and temperature and was most pronounced with Lava Ultimate.