Silicon (option A) is not the mineral used to reduce cavity. The correct answer is Fluorite (option B), which is used to reduce cavity.

Explanation:

Fluorite, also known as calcium fluoride, is a mineral that is commonly used to reduce cavity formation. It is a natural source of fluoride, an essential mineral that helps in preventing tooth decay.

Fluoride is known for its ability to strengthen tooth enamel, the outer layer of the teeth, making it more resistant to acid attacks from bacteria and food. When the enamel is strong, it is less likely to develop cavities.

Here is why Fluorite is used to reduce cavity:

- Fluoride ions in fluorite can replace hydroxyl ions in tooth enamel, creating a stronger compound called fluorapatite. This fluorapatite is more resistant to acid attacks and prevents the demineralization of the enamel.

- Fluoride also promotes remineralization, which is the process of replenishing minerals in the teeth. When the enamel is demineralized due to acid attacks, fluoride helps in attracting minerals like calcium and phosphate back into the enamel, making it stronger and less prone to cavities.

- Fluoride can also inhibit the growth of bacteria that cause tooth decay. It disrupts the metabolism of these bacteria, preventing them from producing acids that erode the enamel.

- Fluoride can also reduce the amount of acid produced by bacteria in the mouth. This acid can wear down the enamel and lead to cavities. By reducing acid production, fluoride helps in maintaining a healthier oral environment.

- Fluoride treatments, such as fluoride varnishes or fluoride mouth rinses, are often recommended by dentists to provide an extra layer of protection against cavities. These treatments deliver a concentrated dose of fluoride to the teeth, further strengthening the enamel and preventing cavity formation.

In conclusion, while silicon is a mineral that has various industrial uses, it is not used to reduce cavity formation. Fluorite, on the other hand, is a mineral that contains fluoride and is widely used in oral health products and treatments to prevent tooth decay and reduce cavity formation.