Color stability of orthodontic esthetic archwires- A comparative in vitro study

Objective: To study and evaluate effect of various food products on color stability of orthodontic esthetic archwires at different time period. Materials and Methods: A total of 120 coated esthetic archwires (Teflon and Epoxy Resin) were investigated. They were divided into 4 groups and 8 subgroups. Cumulative discoloring effect of staining agents (aerated drink artificial orange, colgate plax mouth wash, and red wine) and control group in distilled water were analyzed for a period of 21 days and the solution was changed every 7th day. Samples were analyzed with spectrophotometer to obtain the L*, a*, and b* (lightness, red-green, and yellow-blue) color readings. Using these values total color change (ΔE*) at each level was also calculated. A general linear model (ANOVA and Tukey's Post Hoc) test was used for statistical comparisons. Results: Significant differences were observed in ΔE value of teflon and epoxy resin coated esthetic archwires between the staining agent and the control groups (p≤.0001). Among the teflon coated esthetic archwires the ΔE value for Artificial orange (aerated drink) (5.61±0.30) was highest indicating that artificial orange discolored the wires most in the inter group followed by the red wine (5.44±0.25), and colgate plax mouthwash (1.31±0.15) the least. Among the epoxy resin coated esthetic archwires the ΔE value for red wine (4.52±0.30) was highest indicating that wires in the red wine discolored most. The colgate plax mouthwash (3.54±0.15) and the artificial orange (3.42±0.14) almost stain same. On overall comparision teflon coated and epoxy resin coated, the mean ΔE value was statically significant in all the experimental groups. But the epoxy resin coated esthetic archwires were less stained as compare to Teflon coated wires (p value <0.001**). Conclusion: Both teflon coated and epoxy resin coated archwires showed changes in colour when exposed to staining agent. In the present study the epoxy resin coated archwires were more color stable than the teflon coated wires.