New amalgams show

• A. Microleakage
• B. High strength
• C. Low cost
• D. Fast setting

Answer: (A)

Microleakage is about the seal at the margin between the tooth and the restoration. Amalgam restorations don’t bond to tooth structure; they rely on mechanical retention and develop tiny gaps at the margins due to setting changes, wear, and the mismatch between metal and tooth for temperature changes. Even newer amalgams, designed for better strength and quicker setting, can’t completely eliminate these marginal gaps, so fluid and bacteria can still move between tooth and restoration over time. This microscopic leakage is a key biocompatibility concern because it can contribute to secondary caries, dentin sensitivity, and pulpal irritation if bacteria reach sensitive tissues. While high strength, fast setting, and low cost are important material attributes, they don’t directly address the issue of maintaining a tight marginal seal, which is why microleakage is the best answer.