Effects of beverage colorants and accelerated aging on the color stability of indirect resin composites

Background/purpose: Discoloration of resin-based restorations is considered a common obstacle in restorative dentistry. Several studies assessed the color stability of direct resin composites; however, little is known regarding indirect/laboratory composite resins (ICRs). The purpose of this study was to investigate the color stability of two ICRs (Gradia, Gradia, GC Dental Products) and (SR-Adoro, SR Adoro, Ivoclar Vivadent) compared to a feldspathic porcelain (Ceramco II, DENTSPLY Ceramco) following immersion in different beverages or subjected to accelerated aging. Materials and methods: Using a machine-made metal mold, 20 disc samples (10 mm in diameter and 2 mm thick) were fabricated from each proposed material. Discs were randomly divided into four groups. The baseline measurements of CIELAB metric parameters were performed on all specimens with a spectrophotometer. Three groups then underwent an immersion process in different media (coffee, tea, and cola) for 2 weeks. The last group was subjected to UV aging for 300 hours. The color coordinates and their corresponding color changes (Delta E) were measured. Results: The greatest color changes were seen in the coffee solution (Delta E = 13.34 for SR-Adoro and Delta E = 16.01 for Gradia), while tea was responsible for the greatest color change in porcelain (Delta E = 4.21). The UV aging test caused the lowest discoloration effects on all three samples (Delta E = 3.42 for SR-Adoro, Delta E = 3.01 for Gradia, and Delta E = 1.29 for Ceramco II). Conclusion: Under the limitations of this in vitro study, the color stability of commonly used ICRs appeared to be significantly affected by the staining materials used. Standardized methodologies like the one described in this paper may be very reliable for assessing clinical properties of ICR materials. Copyright (c) 2012, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.