A patient presents with hypocalcified white spot on the buccal surface of a canine, mid-crown region. This is MOST likely:

Correct answer: A. Enamel hypocalcification (focal defect in enamel mineralization)

• A. Correct. A white spot on the buccal surface of a canine in the middle of the crown (not at the gingival margin) that has been present since tooth eruption represents enamel hypocalcification — a localized developmental defect in enamel mineralization, often from a local insult (trauma to primary predecessor, fever during development, etc.).
• B. A carious white spot lesion occurs at the gingival margin (plaque stagnation area), not the mid-crown buccal surface.
• C. Amelogenesis imperfecta is a generalized genetic condition affecting all or most teeth — not a single white spot on one tooth.
• D. Hypercalcification is not a recognized clinical entity causing white spots.