Minimum dose of tetracycline which will show tooth discoloration and enamel hypoplasia:
**Core Concept**
The question is based on the pharmacological principle of tetracycline's effect on teeth, specifically the minimum dose required to cause tooth discoloration and enamel hypoplasia. Tetracycline is a broad-spectrum antibiotic that can bind to calcium ions in developing teeth, leading to discoloration and other dental abnormalities.
**Why the Correct Answer is Right**
The correct answer is related to the dosage of tetracycline that exceeds the safety threshold for dental development. Tetracycline can cause tooth discoloration and enamel hypoplasia when administered during tooth development, which typically occurs in utero and up to 8 years of age.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is too low to cause significant tooth discoloration and enamel hypoplasia.
**Option B:** This option is also incorrect as the minimum dose for tooth discoloration is higher.
**Option D:** This option is incorrect as the dose is not the minimum required for tooth discoloration and enamel hypoplasia.
**Clinical Pearl / High-Yield Fact**
Tetracycline-induced tooth discoloration is a classic example of a drug's teratogenic effect. It's essential to avoid tetracycline use in pregnant women and children under 8 years old to prevent dental abnormalities.
**Correct Answer:** C. 20mg/kg/day