What are the systemic mechanisms of fluoride?

• A. Reducing enamel solubility through incorporation into its structure during tooth development
• B. Inhibiting plaque formation
• C. Increasing enamel porosity
• D. Decreasing tooth eruption

Answer: (A)

Systemic fluoride works by becoming part of developing teeth. When fluoride is ingested, it becomes incorporated into the tooth mineral, forming fluorapatite in place of some hydroxyapatite. This fluorapatite is less soluble in acid, so the enamel is more resistant to demineralization and better able to remineralize when challenged by acid. Because this protection is built into the tooth during formation, teeth formed in the presence of fluoride retain higher resistance throughout life.

Other options don’t reflect a systemic effect on the tooth mineral. Reducing plaque formation is more about topical or antimicrobial actions, not incorporation into tooth structure. Increasing enamel porosity would weaken enamel rather than strengthen it. Decreasing tooth eruption is not a consequence of fluoride exposure.