Which factor does NOT contribute to the longevity of high copper amalgam?

High copper amalgam is known for its enhanced longevity and durability compared to lower copper amalgams, and several factors contribute to this trait. The correct answer indicates that increased surface roughness does not contribute to the longevity of high copper amalgam.

In fact, increased surface roughness is generally detrimental to the longevity of dental materials. A rough surface can lead to the accumulation of plaque and bacteria, which may contribute to secondary caries and decay around fillings. It can also impact the smoothness and polish of the dental restoration, potentially affecting patient comfort and aesthetics.

On the other hand, factors such as increased compressive strength, high tensile strength, and increased corrosion resistance are vital for the performance of high copper amalgam. High compressive strength allows the material to withstand the forces of chewing without deforming or breaking. High tensile strength also ensures that the material can resist forces that could pull it apart. Increased corrosion resistance is critical as it helps prevent degradation of the amalgam over time due to exposure to oral fluid and bacteria, thereby maintaining its structural integrity and preventing leakage or breakdown.

Thus, increased surface roughness is not a factor that contributes positively to the longevity of high copper amalgam, making it the correct choice in this context.