Color stability of mineral trioxide aggregate and calcium enriched mixture cement

Aim: To assess the effect of light irradiation and different immersion media on discoloration of white mineral trioxide aggregate (WMTA) and calcium enriched mixture (CEM) cement at different time intervals. Methods: Enamel sections of 12 teeth were removed and six cavities were prepared in each tooth. The cavities were filled randomly either with WMTA or CEM and covered with transparent sealant. Half the specimens were irradiated for 160 sec (eight exposures of 20 sec each) and the remaining were irradiated for 40 sec (two exposures of 20 sec each); digital images were taken after each exposure. The teeth were stored in phosphate buffer saline, oxygen-rich medium and glycerin (n = 4). Digital images were obtained after 1, 3, 7, 14, and 28 days. Commission Internationale de I'E'clairage (CIE) color space system and Photoshop CS5 software were used to evaluate the discoloration. The color change (Delta E) and lightness (Delta L) values was analyzed using repeated measures ANOVA and Tukey's Tukey's honest significant difference (HSD) test. Results: The materials tested showed significant discoloration over time (WMT > CEM; P < 0.001). Delta E increased significantly while Delta L decreased in three media over time (P < 0.001). Greater duration of light curing caused a significant decrease in Delta L and Delta E values in both materials (WMTA > CEM; P < 0.001). Conclusion: Color stability of WMTA was inferior to CEM samples after exposure to different duration of irradiation and media over time.