Dental tissues affected at 14 weeks in utero (during first trimester) by tetracycline administration — which tissues are primarily at risk?

Correct answer: C. Deciduous teeth undergoing mineralization (primarily dentin)

• A. Permanent tooth buds are at risk from later tetracycline exposure (birth to age 8), not at 14 weeks gestational.
• B. Correct. At 14 weeks intra utero (first trimester, ~week 14), primary deciduous teeth are in their mineralization stage. Tetracycline binds to calcium in calcifying tissues, causing permanent yellow-brown staining primarily in dentin. The dentin is most affected since it mineralizes first. Effects depend on the timing, dose, and duration of tetracycline exposure.
• C. Primary teeth are the primary concern at this gestational age — permanent teeth don't mineralize until after birth.
• D. Only specific primary tooth tissues are forming at 14 weeks — the effect is broader than incisors alone.