**Question:** Type I gypsum product is also called

A. Plaster of Paris
B. Plaster of Paris (POP)
C. Calcium sulfate dihydrate
D. Plaster of London

**Core Concept:**

Type I gypsum products are a class of materials primarily used in medicine and dentistry for making casts, splints, and prostheses. The term "Type I" distinguishes them from Type II gypsum products, which are used in construction and other industries. The basic component of Type I gypsum products is calcium sulfate hemihydrate (gypsum). Calcium sulfate dihydrate and calcium sulfate hemihydrate are two different forms of calcium sulfate, which can be dehydrated to obtain gypsum products.

**Why the Correct Answer is Right:**

Type I gypsum products, specifically Plaster of Paris (POP), are composed of calcium sulfate hemihydrate, which is a form of calcium sulfate. When water is added to POP, it reacts with the hemihydrate to form calcium sulfate dihydrate, the solid form of gypsum. This hydration process is essential for the setting and hardening of the plaster casts, splints, or prostheses.

**Why Each Wrong Option is Incorrect:**

A. Plaster of London is not a correct term for Type I gypsum products. Plaster of Paris is the correct term for Type I gypsum products.

B. Although Plaster of Paris is a correct term for Type I gypsum products, stating it as an answer along with the reason why it is right provides redundant information. The correct answer should only include Plaster of Paris.

C. Calcium sulfate dihydrate is the solid form of gypsum, not a term for Type I gypsum products. The correct term for Type I gypsum products is Plaster of Paris.

**Clinical Pearl:**

Plaster of Paris (POP) is the correct term for Type I gypsum products, which are essential for various medical applications such as making casts, splints, and prostheses. Understanding the hydration process involving calcium sulfate hemihydrate and water is crucial for using POP effectively in clinical practice.