Which statement about silver diamine fluoride is true?

• A. It is purely antimicrobial and has no effect on demineralization
• B. It turns carious areas black but does not stain sound tooth structure
• C. It reverses caries by regenerating tooth structure
• D. It is contraindicated in all patients

Answer: (B)

Silver diamine fluoride works by delivering both antimicrobial silver and fluoride to a carious lesion, so it helps stop decay and supports remineralization of demineralized dentin. The standout clinical effect you’ll see is a dark discoloration of treated carious tissue—the silver compounds give the dentin a gray to black color as the decay is arrested. Crucially, this staining is localized to the carious tissue; sound tooth structure typically does not darken with SDF application. That combination—darkening of carious areas while leaving sound tooth structure unchanged—captures the real-world behavior of the material, making the statement about black staining of carious areas without staining sound tissue the correct one. It’s not a miracle cure that regenerates tooth structure, and SDF also has antimicrobial action, but it doesn’t reverse caries by regenerating dentin. It isn’t contraindicated for all patients, though there are specific considerations (such as silver allergy) that guide its use.