What is the main mechanism of fluoride?

• A. Inhibiting bacterial metabolism
• B. Enhancing remineralization and inhibiting demineralization
• C. Blocking plaque formation
• D. Killing oral bacteria

Answer: (B)

Fluoride works primarily by shifting the mineral balance at the tooth surface toward repair. When acids from plaque dissolve enamel, minerals like calcium and phosphate are lost. Fluoride enhances remineralization by promoting the redeposition of these minerals and forming a less soluble mineral form, fluorapatite, from the original hydroxyapatite. This makes enamel more resistant to acid and helps early lesions arrest or reverse.

While fluoride can have some antibacterial effects, the most important and consistent benefit for caries prevention is this enhancement of remineralization and inhibition of demineralization. It doesn’t block plaque formation or kill bacteria in the way the other options imply.