**Question:** Glass ionomer cement is composed of:

A. Glass particles
B. Resin matrix
C. Both glass particles and resin matrix
D. None of the above

**Core Concept:** Glass ionomer cements are a type of dental restorative material that exhibit both adhesive and restorative properties. They are used for direct restorations, luting of indirect restorations, and as a luting agent for orthodontic brackets.

**Why the Correct Answer is Right:** Glass ionomer cements are composed of both glass particles and a resin matrix. The glass particles act as a reservoir for ions, such as fluoride, which can be released into the oral environment to help prevent caries. The resin matrix provides adhesion and durability to the tooth structure.

**Why Each Wrong Option is Incorrect:**

A. **Option A (Glass particles only):** Glass particles are essential for glass ionomer cements, as they provide the ion-releasing properties. However, the resin matrix is also crucial for adhesion and durability.

B. **Option B (Resin matrix only):** While the resin matrix provides important properties, the glass particles are responsible for ion release, which is a key feature of glass ionomer cements.

C. **Option C (Neither glass particles nor resin matrix):** This option contradicts the fundamental characteristics of glass ionomer cements, which are based on both glass particles and a resin matrix.

E. **Option D (None of the above):** This answer choice is incorrect because option C correctly describes the composition of glass ionomer cements, which include both glass particles and a resin matrix.

**Clinical Pearl:** Glass ionomer cements are a valuable restorative material due to their ability to release fluoride ions, which can help prevent caries and promote adhesion to tooth structure.

**Correct Answer:** C. Both glass particles and resin matrix

---

Glass ionomer cements are a versatile dental material that combine the benefits of glass particles (ion release) and a resin matrix (adhesion and durability). The glass particles act as an ion reservoir, releasing fluoride ions that help prevent caries, while the resin matrix provides adhesion to tooth structure and durability in the oral environment. This combination of components makes glass ionomer cements an effective material for direct restorations (fillings) and luting cements for indirect restorations (crowns, veneers, etc.). Additionally, the fluoride release from glass ionomer cements can be beneficial for patients with high caries risk.