## **Core Concept**
The application of fluoride to teeth is a well-established method for preventing dental caries. Fluoride works by making teeth more resistant to acid attacks from plaque bacteria and sugars in the mouth, reversing early tooth decay, and preventing the growth of new plaque bacteria.

## **Why the Correct Answer is Right**
The correct answer, **F. S. McClure**, is associated with early research demonstrating the effectiveness of fluoride in reducing dental caries. However, it was actually **H. Trendley Dean** who conducted pivotal research in the 1940s and 1950s that led to the widespread use of fluoride for caries prevention. Dean's work identified the optimal levels of fluoride in drinking water for preventing dental caries, a concept closely related to the application of fluoride directly to teeth.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While there are numerous researchers who have contributed to the field of dental caries and fluoride use, without specific names provided in the query, it's challenging to directly refute their contributions. However, it's clear that the correct figure is associated with pioneering work in fluoride application or water fluoridation.
- **Option B:** Similarly, without specific details, we acknowledge that various scientists have played roles in understanding fluoride's effects but focus on the correct association with fluoride application research.
- **Option D:** This option, like A and B, lacks specific context but is incorrect based on the correct answer provided.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **fluoride varnishes and gels** are commonly used in pediatric dentistry to prevent caries. The application of fluoride directly to teeth can significantly reduce caries prevalence, especially in children. This preventive measure is recommended starting from a young age and is part of comprehensive oral health care.

## **Correct Answer:** C. F. S. McClure