In the SDF application protocol, what is used to isolate the tooth?

• A. Cotton rolls
• B. Rubber dam
• C. No isolation
• D. Gauze and tape

Answer: (A)

Maintaining a dry field is essential for SDF effectiveness. The liquid needs to stay on the carious lesion long enough to interact with the tooth structure, and saliva can dilute or wash it away, reducing its arresting action. Cotton rolls provide a quick, simple way to absorb moisture and allow easy air-drying of the tooth surface around the lesion, giving you a dry, accessible site for the application. While a rubber dam offers superior isolation in other procedures, it is often impractical for SDF because it can complicate placement and access to small or multiple lesions, and it's not necessary to achieve the required dryness. Gauze and tape offer some drying but are less reliable and less convenient than cotton rolls. No isolation leaves the surface constantly exposed to saliva, which compromises the treatment. So, the best approach is to use cotton rolls to keep the tooth dry during SDF application.