**Core Concept**
Marginal leakage refers to the unwanted passage of fluids or gases through the margins of a dental restoration, such as a filling or crown. This can be exacerbated by temperature changes, which can cause the restoration material to expand and contract.

**Why the Correct Answer is Right**
The correct answer is related to the physical properties of dental restoration materials. Materials that are sensitive to temperature changes, such as those with high coefficients of thermal expansion, are more prone to marginal leakage. This is because the material expands when heated and contracts when cooled, creating gaps between the restoration and the tooth structure. For example, **amalgam** fillings have a relatively high coefficient of thermal expansion, making them more susceptible to marginal leakage due to temperature changes.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specifically relate to temperature changes. While it may be true that some dental materials are more prone to marginal leakage than others, this option does not address the specific issue of temperature sensitivity.
* **Option B:** This option is incorrect because it is a type of dental material that is actually resistant to marginal leakage due to its low coefficient of thermal expansion. **Glass-ionomer cement** is a material that is less prone to marginal leakage because it contracts when heated and expands when cooled, reducing the likelihood of gaps forming between the restoration and the tooth structure.
* **Option C:** This option is incorrect because it is a type of dental instrument used to remove decayed tooth structure, rather than a material that is prone to marginal leakage.

**Clinical Pearl / High-Yield Fact**
When selecting a dental restoration material, it is essential to consider its coefficient of thermal expansion and how it may interact with temperature changes. Materials with high coefficients of thermal expansion, such as **amalgam**, are more prone to marginal leakage and may require additional measures to prevent this issue.

**Correct Answer: D. Amalgam**