Which statement is NOT a source of topical fluoride?

• A. Fluoride toothpaste
• B. Water fluoridation
• C. Fluoride varnish
• D. Dietary fluoride supplements

Answer: (D)

Topical fluoride is fluoride that acts directly on the tooth surface at the time of contact. Fluoride toothpaste and fluoride varnish deliver fluoride right to the teeth, providing the direct, localized effect that helps remineralize enamel and inhibit demineralization. Water fluoridation, while a systemic source, also increases fluoride levels in saliva, which then contacts the teeth and contributes to a topical effect in the mouth.

Dietary fluoride supplements are taken by mouth and circulate systemically, delivering fluoride through the bloodstream rather than applying it directly to the teeth. They are not applied to tooth surfaces as a topical agent, so they are not considered a topical fluoride source.