Question

Cusp capping is considered when the extension of the cavity preparation reaches which of the following?

• A. More than half of the primary groove to the central groove
• B. More than two-thirds or half of the primary groove to the central groove
• C. More than half of the secondary groove to the central groove
• D. Extension is limited to the marginal ridge only

Hint:

If a cavity undermines more than half to two-thirds of a cusp, consider cusp capping to prevent fracture.

Answer 1

The Correct Option is B

To solve this question, we need to understand the concept of cusp capping in Conservative Dentistry and Endodontics. Cusp capping is a technique used during cavity preparation to preserve tooth structure and restore the functional form of a tooth.

When a cavity preparation involves a significant extension in the occlusal surface, it compromises the structural integrity of the tooth cusps. Cusp capping becomes necessary in order to prevent fracture of these weakened cusps.

The question asks when cusp capping is considered necessary based on the extension of the cavity preparation. Let's analyze each option:

1. **More than half of the primary groove to the central groove:** This implies a moderate extension but not enough to critically weaken the tooth cusp.
2. **More than two-thirds or half of the primary groove to the central groove:** This option indicates a significant extension that involves a major part of the tooth's occlusal surface towards the central groove, which compromises the cusp strength and justifies the need for cusp capping.
3. **More than half of the secondary groove to the central groove:** The focus here is on the secondary groove, which typically has less significance for cusp structural integrity compared to the primary groove.
4. **Extension is limited to the marginal ridge only:** This indicates minimal extension and does not warrant cusp capping.

From the analysis, we conclude that when the cavity preparation extends more than two-thirds or half of the primary groove to the central groove, it significantly affects the tooth's strength. Hence, cusp capping is necessary to protect the tooth from fracture.

Therefore, the correct answer is:

More than two-thirds or half of the primary groove to the central groove