If amalgam is contaminated with moisture, the most uncommon result is which of the following?

Contamination of amalgam with moisture can lead to a variety of issues during and after the placement of the material. Among these potential problems, the formation of blisters, postoperative pain, and a decrease in compressive strength are all relatively common outcomes observed in clinical practice when moisture interferes with the proper setting of amalgam.

Blister formation occurs due to the reaction of water with the components of the amalgam, leading to gas trapping and subsequent blistering on the surface. Postoperative pain may arise as a result of inadequate bonding or the moisture affecting the setting process, which can create sensitivity in the tooth. Lower compressive strength is a direct consequence of the moisture, as it inhibits the amalgam from achieving its ideal properties and full strength.

In contrast, secondary caries is not a typical direct result of moisture contamination during amalgam placement. While improper placement or failure to adequately seal margins can certainly lead to secondary caries over time, the initial contamination with moisture does not directly cause caries formation. Instead, secondary caries are often linked to other factors such as inadequate restoration margins or the oral environment after the amalgam has set, making it the least common immediate outcome of moisture contamination among the options presented.