A patient is bothered by the appearance of teeth #12 and #13, which show cervical white-to-brown decalcified areas. Which developmental defect is MOST consistent?

Correct answer: C. Enamel hypocalcification (a qualitative defect with normal enamel thickness)

• A. Tetracycline staining is generalized and banded, corresponding to the period of drug exposure, and is intrinsic yellow-to-grey rather than localized cervical decalcification.
• B. Amelogenesis imperfecta is HEREDITARY and affects the ENTIRE dentition, both dentitions, in a generalized pattern.
• C. CORRECT. HYPOCALCIFICATION is a QUALITATIVE defect: enamel matrix is laid down to normal thickness but is inadequately mineralized, producing opaque white, yellow, or brown areas that are soft and porous and pick up extrinsic stain. When limited to a few teeth in a specific region it reflects a LOCAL insult or a systemic insult confined to a narrow window of amelogenesis. Contrast this with HYPOPLASIA, which is a QUANTITATIVE defect — reduced enamel thickness with pits and grooves.
• D. Fluorosis is symmetric and generalized across teeth that formed at the same time — the stem describes only two adjacent teeth.

Note: Hypocalcification = right amount of enamel, wrong quality. Hypoplasia = right quality, not enough enamel.