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Dental Fluorosis Timing — MFDS Part 1 MCQ

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EasyHuman DiseaseDental Fluorosis TimingMFDS Part 1

Dental fluorosis develops when excessive fluoride is ingested at which stage of tooth development?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: BDuring pre-eruptive enamel formation

The correct answer is B. Dental fluorosis is a developmental enamel defect caused by excessive systemic fluoride exposure while enamel is forming before eruption. The fluoride disturbs ameloblast function and enamel mineralisation, producing diffuse opacities and, in more severe cases, porosity, pitting and secondary staining. Susceptibility depends on which crowns are calcifying: current UK guidance highlights ingestion below 3 years for permanent incisors and below 6 years for premolars. Post-eruptive exposure cannot produce developmental fluorosis because crown formation is already complete. Eruption, root dentine formation and cementum formation are therefore not the causative stages for enamel fluorosis.

Reference: Department of Health and Social Care, NHS England and UK partners. Delivering Better Oral Health, Chapter 9: Fluoride, section 'Fluorides and the risk of dental fluorosis', updated 2025. https://www.gov.uk/government/publications/delivering-better-oral-health-an-evidence-based-toolkit-for-prevention/chapter-9-fluoride