Which condition affects the durability of dental amalgam?

The presence of voids within a dental amalgam restoration significantly affects its durability. Voids are air pockets or gaps that can occur during the mixing and placement of amalgam. When these voids are present, they compromise the structural integrity of the restoration by reducing the contact area between the amalgam particles. This can lead to a decrease in strength, making the restoration more susceptible to fracture, wear, and potential failure over time.

In contrast, while the mixing technique used, the patient's oral hygiene, and the color of the material can influence various aspects of a dental restoration, they do not directly affect the physical properties of the amalgam in the same fundamental way that the presence of voids does. An optimal mixing technique can minimize voids, and maintaining good oral hygiene is essential for the longevity of any dental restoration, but it is the actual presence of voids that critically undermines the amalgam's durability.