**Core Concept**
In 1960, the American Dental Association (ADA) approved the first fluoride toothpaste, marking a significant milestone in the prevention of dental caries. This approval was based on the recognition of fluoride's role in strengthening tooth enamel and preventing tooth decay.

**Why the Correct Answer is Right**
The introduction of fluoride toothpaste was a result of extensive research demonstrating its efficacy in reducing the incidence of dental caries. Fluoride works by promoting the deposition of calcium and phosphate ions into tooth enamel, thereby increasing its hardness and resistance to acid attacks. This process, known as fluorapatite formation, is mediated by the presence of fluoride ions in the toothpaste.

**Why Each Wrong Option is Incorrect**
**Option A:** The development of fluoride toothpaste was not a result of the discovery of a new fluoride compound, but rather the adaptation of existing fluoride compounds for use in a toothpaste formulation.
**Option B:** Although the ADA did approve fluoride toothpaste in 1960, it was not the first year of fluoride toothpaste approval, as some countries had already approved similar products.
**Option C:** The approval of fluoride toothpaste was not limited to a specific type of fluoride compound, as various forms of fluoride, including sodium fluoride, were used in early toothpaste formulations.

**Clinical Pearl / High-Yield Fact**
The ADA's approval of fluoride toothpaste in 1960 marked a significant shift in the prevention of dental caries, with the widespread use of fluoride toothpaste contributing to a substantial decline in the incidence of dental caries in the following decades.

**Correct Answer:** **C**.