Stain on Dentin after Silver Diammine Fluoride and Potassium Iodide

Method: Rectangular dentin blocks from root trunks of extracted permanent molars were cut into four blocks each. All blocks were coated with clear varnish except one flat surface of similar size. The 4 dentin blocks from the same tooth were allocated into four different groups randomly. Gp1- Artificial caries lesions (≈200µm deep) created (BHI broth, multi-species cariogenic bacteria, 10 days) + SDF; Gp2-Artificial caries lesion created + SDF + KI; Gp3- immersed in sterilized BHI broth (10 days)  + SDF; Gp4- immersed in sterilized BHI broth (10 days) + SDF + KI. Color of the dentin blocks was recorded using PANTONE color sheets and was coded into 1-Light yellow (PANTONE code: 12-0704-TPX/11-0907-TPX); 2-Yellow (1205U/7401U); 3-Light brown/Greyish (4635U/402U); 4-Dark brown/Black (4625U/BlackU) for comparison.

Result: All dentin blocks (each group n=20) had similar color at baseline (coded 1). After intervention, all dentin blocks in Gp1 and Gp3 while no block in Gp2 and Gp4 were coded 4. A total number (proportion) of 5 (25%), 13 (65%), and 2 (10%) of the blocks in Gp2 was coded into 1, 2, and 3 respectively. The corresponding values for blocks in Gp4 were 3 (15%), 13 (65%), and 4 (20%) respectively. Pairwise comparison of Friedman’s two-way ANOVA showed that the rank of color coding of dentin blocks receiving SDF+KI was significantly lower than those receiving SDF alone regardless of the lesion/sound status of the dentin surfaces (Gp2 vs. Gp1 and Gp4 vs. Gp3, p<0.001).

Conclusion: The blackening effect of topical application of SDF solution on dentin surfaces can be reduced by an immediate application of KI solution following it.