During SDF application, how should the carious lesion be moistened?

• A. With the smallest amount of SDF solution possible using a microbrush
• B. With a large amount of SDF solution
• C. With water
• D. With saliva

Answer: (A)

Delivering a high local concentration of the active ions directly to the carious tissue is the goal, with minimal dilution and precise control. Using the smallest amount of SDF, applied with a microbrush, keeps the solution on the lesion long enough to act without overflowing onto surrounding tissues or diluting with saliva or water. This focused application maximizes arrest potential while reducing staining or irritation of adjacent areas. Water or saliva would dilute the solution and lower effectiveness, and applying a large amount can lead to pooling and unintended contact with surrounding tissues.