Potassium iodide: Does it reduce silver diamine fluoride induced tooth staining?


Although almost completely preventable dental caries remains a significant public health challenge. A number of studies and reviews have shown that silver diamine fluoride (SDF) has significant ant-caries activity. However, it does produce a pronounced and permanent black staining. It has been suggested that the application of a saturated solution of potassium iodide (KI) immediately after SDF prevents staining and a number of studies have been reported.

The aim of this review was to assess whether using potassium iodide (KI) immediately after application of silver diamine fluoride (SDF) significantly reduces tooth staining.


Searches were conducted in the Scopus, Ovid, PubMed,Google Scholar and SIGLE databases. All original research articles, irrespective of study design prospective, retrospective and randomised controlled clinical trials on patients with caries or in-vitro studies involving teeth treated with KI after SDF were considered.  Three reviewers independently extracted data and assessed risk of bias. A narrative summary was presented.


  • 6 studies were included, 5 of which were in-vitro.
  • 5 studies reported stain reduction in the teeth treated with application of KI to carious tooth structure following the application of SDF.
  • 1 study reported no significant beneficial effect on reducing staining, when compared to SDF alone.
  • 1 in-vivo case report reported some staining after six months, even with SDF + KI treatment.


The authors concluded: –

Although some studies reported a positive effect, insufficient evidence exists supporting a tangible clinical benefit of SDF + KI treatment on the tooth staining, mainly due to methodical variations within the current literature.


While the authors have searched a good range of databases for this review only one of the studies identified was conducted in a clinical setting. This clinical study was a small case report involving just 5 teeth in a single patient. The remaining 5 included studies were all of an in-vitro design being undertaken on either extracted teeth (4 studies) or decalcified dentine slices (1 study). So, while these studies did demonstrate some reduction in staining it does not mean that these findings can be extrapolated to the clinical situation.  In total only 195 teeth were used in the 6 studies with just 75 being treated with SDF and KI.

At present there is little clinically relevant evidence for the effectiveness of KI in reducing staining caused by SDF. Additional high quality well-reported studies of appropriate size are required if the effectiveness of KI is to be properly evaluated.


Primary Paper

Roberts A, Bradley J, Merkley S, Pachal T, Gopal JV, Sharma D. Does potassium iodide application following silver diamine fluoride reduce staining of tooth? A systematic review [published online ahead of print, 2020 Jan 3]. Aust Dent J. 2020;10.1111/adj.12743. doi:10.1111/adj.12743

Review protocol on PROSPERO

Other references

Dental Elf – 17th Jul 2019

Silver diamine fluoride for caries management?


Dental Elf – Silver Diamine Fluoride Blogs




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