A 40 year old male patient came for a routine dental checkup. Intra-oral examination reveals multiple teeth restored with silver amalgam restoration and glass ionomer base. The compressive strength of the base used in this patient is:

**Core Concept**
Glass ionomer cement (GIC) is a type of dental restorative material used as a base or luting agent. It is a mixture of glass powder and liquid polyacrylic acid that sets by an acid-base reaction. The physical properties of GIC, such as compressive strength, are influenced by factors like powder-to-liquid ratio and setting time.

**Why the Correct Answer is Right**
The compressive strength of GIC is relatively low compared to other dental materials like composite resin or ceramic. However, it is suitable for use as a base material due to its adhesive properties and ability to release fluoride ions, which help prevent secondary caries. The compressive strength of GIC typically ranges from 50 to 200 MPa, depending on the type and composition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not provide a specific value for the compressive strength of GIC.
**Option B:** This option is incorrect as it provides a value that is too high for the compressive strength of GIC.
**Option C:** This option is incorrect as it provides a value that is too low for the compressive strength of GIC.

**Clinical Pearl / High-Yield Fact**
GIC is a popular choice for use as a base material in dentistry due to its adhesive properties and ability to release fluoride ions. However, it is not suitable for use as a final restoration due to its relatively low compressive strength.

**Correct Answer:** C.

✓ Correct Answer: C. 120 MPa