**Core Concept**
Vitremer is a type of glass-ionomer cement (GIC) used in dentistry. It is a mixture of glass powder and liquid, which reacts to form a hard, durable, and fluoride-releasing restorative material.

**Why the Correct Answer is Right**
Vitremer is a glass-ionomer cement (GIC) that contains a mixture of fluoroaluminosilicate glass powder and an aqueous acidulated phosphate fluoride (APF) solution. The reaction between the glass powder and the liquid forms a complex of calcium, aluminum, and fluoride ions, which releases fluoride ions over time. This property makes Vitremer an effective restorative material for preventing secondary caries and promoting tooth remineralization.

**Why Each Wrong Option is Incorrect**
**Option A:** Not applicable, as this is a placeholder.
**Option B:** Incorrect, as there are other types of glass-ionomer cements available, such as Fuji II, but Vitremer is a specific product.
**Option C:** Incorrect, as this option is not a type of glass-ionomer cement.

**Clinical Pearl / High-Yield Fact**
Vitremer is a popular choice for pediatric restorations due to its ease of use, aesthetics, and ability to release fluoride ions, which helps prevent caries in children.

**Correct Answer: D. Vitremer is a type of glass-ionomer cement (GIC) used in dentistry.**