Which statement accurately summarizes the SDF application protocol?

• A. Isolate the tooth with cotton rolls, moisten the lesion with the smallest amount of SDF using a microbrush, and avoid touching intra- or extraoral soft tissues
• B. Isolate the tooth with a rubber dam, moisten the lesion with a large amount of SDF, and rinse after application
• C. Do not isolate the tooth; apply SDF directly to the lesion and surrounding tissues
• D. Apply SDF to multiple teeth without isolation and do not use a microbrush

Answer: (A)

Proper SDF application relies on precise, localized delivery with solid tissue protection. Isolating the tooth with cotton rolls helps keep the field dry and free from saliva, which can dilute or interfere with the medicament and increase the chance of staining other tissues. Using a microbrush to apply only a small amount of SDF directly to the carious lesion ensures targeted treatment without oversaturation, which reduces unnecessary spread to adjacent soft tissues. Avoiding contact with intra- or extraoral soft tissues prevents unintended staining and irritation. Rinsing after application or treating multiple teeth without isolation would compromise effectiveness and precision, which is why those approaches aren’t used.