## **Core Concept**
Tetracycline-induced tooth discoloration is a well-documented side effect of tetracycline antibiotics. This occurs due to the chelation of calcium ions by tetracycline, which then gets deposited into teeth, causing discoloration. The risk of tooth discoloration is dose-dependent and more significant when administered during tooth development.

## **Why the Correct Answer is Right**
The correct answer, , implies that the minimum dose of tetracycline that causes discoloration of teeth is related to its cumulative dose and duration of administration during tooth development. Research indicates that even a single course of tetracycline can cause tooth discoloration if administered during critical periods of tooth development (calcification). The discoloration can range from yellow to brown or even gray. A dose of more than antibiotic is often cited in literature as a significant risk factor.

## **Why Each Wrong Option is Incorrect**
- **Option A:** - This dose seems too low to cause significant tooth discoloration based on general knowledge about tetracycline side effects.
- **Option B:** - This option might seem plausible but does not align with documented evidence on the minimum dose required for tooth discoloration.
- **Option D:** - This dose seems excessively high for the effect described and does not represent the minimum dose.

## **Clinical Pearl / High-Yield Fact**
A crucial point to remember is that tetracycline-induced tooth discoloration is most significant when the antibiotic is administered during tooth development, particularly from the fetal stage through about 8 years of age. The risk is highest with prolonged or repeated courses of the drug.

## **Correct Answer:** .