Whiteness Evaluation After Violet LED and Argon Plasma Bleaching

Objectives: To evaluate color and whiteness index of teeth submitted to bleaching with violet LED (VL) light and non-thermal argon plasma (NTAP) combined with hydrogen (HP) or carbamide peroxide (CP) agents.
Methods: Bovine crowns were divided into (n=10) VL, VL/HP, VL/CP, NTAP, NTAP/HP, NTAP/CP, HP, CP and C (control) groups. Color change (CIELAB-ΔE_ab, CIEDE2000-ΔE₀₀) and whiteness index (ΔW_D) were calculated considering measurements performed before (baseline) and 14 days elapsed from the last bleaching application. ΔE_ab, ΔE₀₀ and ΔW_D were analyzed by two-way ANOVA and Tukey test (a=5%).
Results: VL significantly increased color change of CP (p=0.023), but only according with ΔE_ab. Whiteness index was similar among HP groups, but VL/CP promoted ΔW_D higher than NTAP/CP (p=0.001) and CP (p=0.016). VL alone exhibited ΔW_D significantly higher than NTAP and C (p<0.001). VL and NTAP exhibited perceptible bleaching according to ΔE_ab,ΔE₀₀ andΔW_D, but presented lower color and whiteness change values than HP- and CP- treated groups (p<0.05).

Conclusions: Violet LED applied alone or combined with CP was capable of increasing color change and whiteness index of teeth, while NTAP did not promote or increased the efficacy of bleaching gels.