Evaluation of the effect of various types of fluoride varnishes on color stability of a composite resin

BACKGROUND and AIM: Fluoride varnish as an extrinsic factor may cause discoloration in tooth-colored restorative materials. This research compared the impact of different fluoride varnishes on color change of a composite restorative material. METHODS: This laboratory experimental study was conducted on 40 specimens of flowable composite resin were divided into four groups based on the brand of applied varnishes (Durashield, Nupro, Fluorilaque, and Profluoride varnishes) (n = 10). Color measuring (ΔE) was performed using the easy shade device and according to Commission Internationale de l’Eclairage (CIE) L*a*b* system at three times: 24 hours after immersing in artificial salvia (baseline), 24 hours after fluoride varnishes application and after brushing. The amount of color changes was calculated for all of the specimens as follows: ΔE1 (difference between fluoride application-base line), ΔE2 (difference between brushing-fluoride application), and ΔE3 (difference between brushing-base line). P < 0.05 was considered as significant. Statistical analysis was performed by one-way ANOVA and post-hoc Tukey. RESULTS: The maximum and minimum color changes after applying varnishes were observed by Nupro and Profluoride, respectively. A significant difference was observed between ΔE 1 values of all types of studied varnishes (P < 0.01) except Durashield and Fluorilaque (P = 0.35). After brushing, no significant difference was shown between color change of stained specimens due to Durashield, Fluorilaque, and Nupro. There was no significant difference between ΔE 3 values of Durashield and Fluorilaque. CONCLUSION: Trends of color change after using all studied varnishes were clinically acceptable (ΔE < 3.3). Durashield, Nupro, Fluorilaque, and Profluoride varnishes can be used without adversely affecting the color of flowable composite resin.