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

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.

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.

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).

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