Effect of fiber reinforcement on color stability of composite resins

Aim: The aim of this in vitro study was to determine the effect of fiber reinforcement on the color changes of two different composite resins. Materials and Methods: A silorane-based composite (Filtek Silorane, A2 shade) and a methacrylate-based composite (Valux Plus, A2 shade) were used in this study. Three groups of samples (control group with no reinforcements, polyethylene fiber [Ribbond THM]-reinforced composite, and glass fiber [everStick® Net]-reinforced composite groups) were prepared from each composite (n = 8). The color change was calculated between baseline and 1 day (DE1) and between baseline, 7 days (DE2), and 21 days (DE3) with a spectrophotometer. The data were analyzed by ANOVA, Duncan's multiple-range tests and independent sample t-test. Results: Statistical analysis of variance presented the statistically significance difference between composite, fiber, and time for DE (P < 0.05). The Ribbond reinforced composite showed a similar color change to the control group (ΔE = 3.69), while the everStick reinforced composite showed the largest total color change (ΔE = 4.13). It was determined that the time is an effective factor on the color stability of reinforced composites (P < 0.05). Conclusion: The addition of fiber may lead to color change in composite resins. The amount of change may differ depending on the structural properties of the composite resin or the fiber and time.