## **Core Concept**
The question tests knowledge on the concentration of stannous fluoride used in topical fluoride applications, which is a crucial aspect of preventive dentistry. Stannous fluoride is used for its cariostatic and desensitizing properties. Understanding the specific concentrations of fluoride agents is essential for their effective and safe use.

## **Why the Correct Answer is Right**
The correct concentration of stannous fluoride used in topical applications is **. This concentration is effective for preventing dental caries and is commonly used in professional fluoride treatments. Stannous fluoride works by inhibiting the growth of bacteria that cause dental caries and also helps in reducing tooth sensitivity. The specific concentration of** is supported by dental research for its efficacy and safety.

## **Why Each Wrong Option is Incorrect**
* **Option A:** - This concentration is too low to be effective for a topical fluoride treatment.
* **Option B:** - While closer, this is not the standard concentration used for stannous fluoride in topical applications.
* **Option D:** - This concentration seems excessively high and not typically recommended for stannous fluoride applications due to potential toxicity and side effects.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that stannous fluoride has both anticaries and desensitizing properties, making it a valuable agent in dental preventive care. However, it's also known for causing tooth staining, which is a significant consideration in its application. The standard concentration of **is critical for balancing efficacy and minimizing side effects.

## **Correct Answer:** .