Color stability of gingiva-colored restorative materials: an in vitro study

The aim of this research was to determine the color stability of 3 gingival shades of dental restorative materials, Amaris Gingiva, Beautiful II Gingiva, and PermaFlo Pink, compared to a tooth-colored nanohybrid composite, Filtek Z250. Twenty-five specimens of each composite were fabricated in polytetrafluoroethylene-coated stainless steel molds and polished using a 4-step polishing regimen. The specimens were randomly assigned to groups for immersion in 1 of 5 solutions (n = 5): distilled water (control), red wine, tea, coffee, or curry (curry powder [containing turmeric] in a solution with distilled water). A desktop spectrophotometer was used to perform color measurements within the Commission Internationale de l'Eclairage L*a*b* color space, and mean overall color (E*) was calculated for each group before and after immersion for 7 days. The mean E* values of each composite before and after immersion were compared using paired t tests at the P < 0.05 level of significance. For all of the tested restorative materials, immersion in a solution of curry produced the greatest increase in mean E* values (P < 0.0001), with E* increasing 32-fold for Amaris Gingiva specimens, 27-fold for Beautiful II Gingiva, 34-fold for PermaFlo Pink, and 2-fold for Filtek Z250. There were smaller, but still significant, increases in E* for Amaris Gingiva, Beautiful II Gingiva, and PermaFlo Pink when immersed in coffee (P < 0.05). Curry caused the greatest change in E* values for all of the tested restorative materials, indicating that curry seasonings based on turmeric can cause unacceptable color change in all of the tested materials and such change can happen in a relatively short time. Coffee also has the potential to cause unacceptable color change in gingival shades of composite materials.