An 8-year-old boy from a village where groundwater contains 2.8 mg/L of fluoride has diffuse chalky-white mottling with brown staining of the enamel of permanent teeth. The teeth are otherwise structurally sound. This finding is best explained by:

• A Excess fluoride intake after full eruption of permanent teeth
• B Fluoride excess causing skeletal fluorosis with secondary dental changes
• C Calcium deficiency leading to hypoplastic enamel
• D Excess fluoride ingestion during tooth development producing dental fluorosis ✓

Explanation

Dental fluorosis results from excessive fluoride intake during the period of enamel formation, roughly the first 8 years of life, before eruption of permanent teeth. Drinking water above about 1.5 mg/L produces mottling, while levels above 4 to 10 mg/L sustained for years produce skeletal fluorosis. Fluoride acting on already erupted enamel cannot alter its structure, which kills the key distractor.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.