Effect of Potassium Iodide, Bleaching, and Microabrasion on the Colour of Silver Diamine Fluoride Stained Remineralised Caries Lesions

Purpose: This study aimed to investigate the effect of potassium iodide (KI), bleaching, and microabrasion on the colour of caries-like lesions treated with silver diamine fluoride (SDF).
Materials and Methods: Enamel specimens were demineralised and then randomised into six groups (n = 15): G1, demineralised; G2, remineralised with 38% SDF to create stained remineralised caries-like lesions (s-RCLs); G3, s-RCLs + KI; G4, s-RCLs + KI + at-home bleaching protocol (15% carbamide peroxide (CP), 4 h/d×7); G5, s-RCLs + KI + microabrasion (6.6% hydrochloric acid); G6, s-RCLs + KI + microabrasion and at-home bleaching protocol. Colour was measured spectrophotometrically at baseline, after demineralisation, and after the treatments. Outcomes were analysed using ANOVA followed by Tukey’s test (α = 0.05).
Results: The increased colour change after demineralisation (ΔE ≥ 6.7) indicated the creation of white spot lesions. G2 (ΔE = 12.3) and G3 (ΔE = 11.1) were significantly discoloured (P ≤ 0.0039), with no significant difference between them, and significantly darker (P 0.0001) than G1 (ΔE = 0.4) and G5 (ΔE = 4.4). G2 was significantly (P ≤ 0.0325) darker than G1, G4, G5, and G6 (ΔE = 0.4, 8.1, 4.4, 7.9), respectively.
Conclusion: While KI did not reduce SDF staining, microabrasion offered limited aesthetic improvement. However, 15% CP demonstrated greater efficacy in partially improving the colour outcome of SDF-stained lesions. Keywords: arrested caries, bleaching, carbamide peroxide, microabrasion, silver diamine fluoride