Effect of residual mercury content on creep in dental amalgams.

For most of the tested amalgams, the increased mercury content caused by delayed compaction increases the flow or creep. The amalgams that had high creep values when packed early were decidedly affected by the increase in mercury content caused by delay in compaction. Amalgams made with Dispersalloy, Tytin, Sybraloy, and New True Dentalloy are not as sensitive to the mercury content as are some of the others tested. Tests for creep may be related more to clinical practice if they are performed on specimens compacted three minutes after trituration rather than on specimens compacted immediately (a half minute) after trituration. In clinical practice, small amounts of amalgam should be mixed and used immediately after trituration. If the delay between trituration and compaction is longer than three minutes, additional mixes are required. We therefore conclude that, in making a large amalgam restoration, many small mixes have superior results over one large mix.