Which of the following is a gypsum product?

Plaster is the correct answer because it is a specific type of gypsum product derived from gypsum rock when it is heated to form calcium sulfate hemihydrate. This process, known as calcination, results in a powder that can be mixed with water to create a workable paste. When it hardens, it forms a solid, durable material commonly used in dental applications for creating molds, casts, and models due to its ability to capture fine details.

In contrast, cement, while similar in appearance, is produced through a different process involving limestone and clay, and does not fall under the category of gypsum products. Plastic and wax, while used in various dental applications, are synthetic materials that do not involve gypsum in their composition at all. Their properties and uses significantly differ from those of plaster, reinforcing why plaster is recognized specifically as a gypsum product.