ABSTRACT
PURPOSE: The purpose of this study was to measure the color of low viscosity bulk-fill resin with a capping layer and to compare it with the color of microhybrid composite resin. MATERIALS AND METHODS: A low viscosity bulk-fill resin (SDR) and microhybrid composite resin of shade A2 (A2) or A3 (A3) were fabricated to 4 mm thickness and light cured for 20 seconds. CIE L*a*b* values of the resin specimens were measured with a colorimeter. Then shade A2 and A3 microhybrid composite resin was capped over low viscosity bulk-fill resins in 2 mm thickness (SA2, SA3). The resin specimens were light cured for 20 seconds and the color was measured and analyzed (n = 10). Color differences (DeltaE) between SA2 and A2, SA3 and A3 were also calculated. RESULTS: L* value was highest in SDR followed by SA2 and SA3. L* value of A2 and A3 was the lowest. a* value was lowest in SDR followed by SA2 and SA3, and A2 and A3 was the highest. b* value was lowest in SDR followed by A2 and SA2, and A3 and SA3 was the highest. DeltaE between A2 and SA2 (DeltaE = 3.4), and that between A3 and SA3 (DeltaE = 3.1) was lower than the perceptible color difference threshold of DeltaE = 3.7. CONCLUSION: DeltaE between low viscosity bulk-fill resin with a capping layer and microhybrid resin was lower than the perceptible color difference threshold.