Public Health · patient case question
Which property is most relevant to the effectiveness of a fluoride product?
Patient case: Fluoride, preparation design, syphilis and patient communication
Scenario: Five short items.
Show answer and explanation
Correct answer: B. The bioavailability of free fluoride ion
- A. Viscosity affects handling and how well a varnish stays put, but it is not what determines the anticaries effect.
- B. Correct. Only free, ionisable fluoride can enter the tooth surface and drive remineralisation. Formulations in which fluoride is bound by incompatible abrasives deliver far less benefit than their stated concentration suggests.
- C. Colour stability is a cosmetic property of varnishes with no bearing on efficacy.
- D. Flavouring improves acceptance, especially in children, but contributes nothing to the mechanism.
Note: ⚑ The recall listed 'bioavailability' and 'substantivity' as the two competing options and did not mark a key. Both are defensible: bioavailability governs how much active fluoride is delivered, while substantivity — prolonged retention and slow release — is the reason varnish outperforms a rinse. Expect either to be arguable; discuss in the group.