**Core Concept**
The question tests the understanding of dental materials and their properties, specifically the abrasivity of conventional glazed dental porcelain compared to gold on tooth enamel. This concept is crucial in **dentistry** as it affects the choice of restorative materials and their potential impact on oral health.

**Why the Correct Answer is Right**
Conventional glazed dental porcelain is approximately 7 times as abrasive as gold to tooth enamel. This is because porcelain, despite being glazed, has a **microscopic roughness** that can still cause wear on opposing natural teeth, whereas gold is a softer, more **ductile material** that tends to wear itself rather than the opposing tooth enamel.

**Why Each Wrong Option is Incorrect**
**Option A:** This option underestimates the abrasivity of porcelain compared to gold.
**Option B:** This option overestimates the difference in abrasivity.
**Option D:** This option significantly overestimates the abrasivity difference.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the choice of dental restorative material can significantly impact the longevity and health of the tooth and surrounding tissues. Understanding the properties of these materials, including their abrasivity, is essential for **dental restoration** decisions.

**Correct Answer:** C. 7 times as abrasive as gold to tooth enamel