Abstract

The growth of direct veneer solutions has led to new inventions in nanocomposite materials. However, the major concern of composite material is its discoloration characteristic, which cannot be tolerated in veneer restorations. The aim of this in-vitro experiment was to compare the color stability (ΔE) of nanohybrid composite materials: flowable nanocomposite (G genial Universal Flo from GC Japan) with prefabricated composite resin veneer (Componeer from Coltene: Altstätten, Switzerland). Thirty-four samples of GUF (A2) and PCRV (bleach shade) were prepared. Samples were immersed in instant coffee for 24 hours in four weeks, and were measured between weeks. GUF was pre-treated with photosynthesis using LED Halogen light (light intensity 1200-2000mw/ cm3) for 40 seconds. Then polishing and finishing GUF samples used aluminum oxide discs (Sof-Lex; 3M ESPE). Both samples were analyzed for their color changes using CIE L*a*b* system with a spectrophotometer (CM-5, Konica Minolta, Osaka, Japan). The results of the Independent T-test statistically showed a significant difference (p<0.05) from the average value of color stability in every week between Componeer and GUF The one-way ANOVA statistical test showed a significant difference (p<0.05) from the average value of color stability of both PRCV Componeer and GUF groups between weeks 1, 2, 3, and 4. After four weeks, GUF group veneer system revealed a better performance in color stability (ΔE = 5,331 ± 0,707) in comparison to prefabricated veneer groups (ΔE = 16,408 ± 2,183) with p value<0.05. In summary, GUF has less discoloration in comparison to PRCV Componeer.