Which statement describes fluoride's effect on enamel solubility?

• A. It increases solubility
• B. It reduces solubility through incorporation into tooth structure during development
• C. It has no effect
• D. It solubilizes enamel crystals

Answer: (B)

Fluoride reduces enamel solubility by becoming part of the tooth's mineral structure, especially during development. When developing enamel takes up fluoride, some hydroxyl groups in the original hydroxyapatite lattice are replaced to form fluorapatite. This fluoridated crystal is more resistant to acid dissolution, so the enamel becomes less soluble under acidic conditions. In short, fluoride’s incorporation into the forming tooth structure creates a mineral that's harder to dissolve, which is why the statement about reducing solubility through incorporation during development is the best description.