The major component of zinc phosphate cement is:
**Core Concept**
Zinc phosphate cement is a widely used dental restorative material, and understanding its composition is crucial for dental professionals. It is a type of glass-ionomer cement that is known for its durability and resistance to wear.
**Why the Correct Answer is Right**
The major component of zinc phosphate cement is actually zinc oxide, which reacts with phosphoric acid to form a glass-like matrix. This reaction is facilitated by the presence of phosphoric acid, which acts as a catalyst. The zinc oxide and phosphoric acid react in a specific ratio to form a strong and durable cement. The presence of zinc oxide is essential for the cement's mechanical properties and durability.
**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because while zinc oxide is a component of zinc phosphate cement, it is not the major component. The major component is actually a combination of zinc oxide and phosphoric acid.
* **Option B:** Incorrect because this option is incomplete and does not accurately describe the composition of zinc phosphate cement.
* **Option C:** Incorrect because this option is also incomplete and does not accurately describe the composition of zinc phosphate cement.
**Clinical Pearl / High-Yield Fact**
A key characteristic of zinc phosphate cement is its ability to form a strong and durable bond with tooth structure. This is due to the presence of zinc oxide, which reacts with the tooth's hydroxyapatite to form a stable bond.
**Correct Answer: A. Zinc oxide.**