Color changes induced by light curing of resin composites

Abstract

Introduction: Color changes that occur after the light-activation of resin composites should be understood. Objective: To evaluated the influence of light-curing devices on the color of resin composites immediately after light-activation and after one-week, at 37ºC, into water storage. Material and methods: Three A2-shade composites (Z100, Z250, and Z350), and four light-curing devices (three halogens and one LED) were evaluated. Seventy-five cylindrical specimens were light-activated for 20s. CIE-Lab color was analyzed using a spectrophotometer. Color changes between uncured and immediately light-activated materials (∆E 1 ), and between immediately light-activated and one-week-37˚C-water-stored materials (∆E 2 ) were obtained. Data were evaluated by two-way Anova, followed by Tukey test (α = 0.05). Results: For ∆E 1 , composites (p = 0.0008), lights (p = 0.015), and the interaction (p = 0.017) were significant. Z100 showed the smallest value (3.08 ± 1.73). The halogen 210 mW/cm 2 device showed the smallest ∆E 1 (3.09 ± 1.25), while the LED 200mW/cm 2 showed the highest value (4.94 ± 2.37). For ∆E 2 , composites (p = 0.00016), lights (p < 0.0001), and the interaction effect (p = 0.0002) were significant. Z350 showed the smallest value (2.24 ± 1.17). The halogen 400mW/cm 2 device showed the smallest ∆E 2 (2.15 ± 2.15), while the halogen device 525mW/cm

<p>The Effects of Irradiance on Translucency and Surface Gloss of Different Bulk-Fill Composite Resins: An in vitro Study</p>

“…The Filtek One bulk fill was affected by the curing light intensity, with the higher light intensity resulting in a higher TP value. This was an agreement with the results of a study by Mondelli et al 17 which evaluated the changes in optical appearance in resin-based composites after light curing. The material color showed a significant change after light curing; this can be explained by the change in translucency while the material is being cured, a process called photobleaching; after light activation, photoinitiators break their chromophore groups, which diminishes their yellow color.…”