Color changes of esthetic elastomeric ligatures evaluated with the Commission Internationale d'Éclairage color system

Objective: The aim of this study was to assess and compare color changes in esthetic elastomeric ligatures after 30 days in situ using a spectrophotometer and the Commission Internationale d'Éclairage (CIE) color system.

Materials and methods: The sample comprised elastomeric ligatures of four color groups (n = 42): blue pearl (BP); colorless; white pearl (WP); and pearl. Four samples from each group were allocated in for quadrants of seven patients in a split-mouth model. Color measurements were performed with a spectrophotometer in the elastomeric ligatures as received (T0) and after 30 days in situ (T1). Variables L*, a*, and b* were compared between times (T1-T0) with Wilcoxon paired ranks; color changes were compared between groups with Kruskal-Wallis test; Dunn's test was used for multiple comparisons. Spearman's correlation was applied between CIELAB and CIEDE2000 calculations.

Results: All groups showed color changes (T1-T0) in a* and b*, but only the Group BP had a change in L* (P < 0.01). Group C showed the greatest lightness decrease (ΔL = -2.49 ± 0.47) (P < 0.05), the smallest yellowing (Δb = 3.17 ± 0.88) (P < 0.05), and the smallest total color change (ΔE₂₀₀₀ = 3.19 ± 0.85), which had no statistical difference from Group WP (ΔE₂₀₀₀ = 3.36 ± 0.53). Correlation between ΔE_ab and ΔE₂₀₀₀ was moderate (r = 0.59; P < 0.01).

Conclusions: Esthetic elastomeric ligatures became yellowish after 30 days in situ, and there were color differences between them.