When should the mercury rich layer of amalgam, known as plash, be removed?

The correct timing for removing the mercury-rich layer, or plash, from amalgam is during the carving process. This is crucial because, during carving, the amalgam is shaped and contoured to the appropriate occlusal form. The removal of the plash at this stage ensures that the restoration will have optimal mechanical properties and a smooth surface for better occlusal function.

In this context, leaving the plash intact until finishing and polishing could lead to a weak restoration, as the excess mercury can affect the overall integrity of the amalgam. By removing it during carving, the dental assistant helps facilitate better bonding of the amalgam particles and improves the overall quality of the dental restoration.

After carving, finishing and polishing contribute to the final smoothness of the restoration but are not the ideal stages for the removal of the plash, as the material is typically set and less manageable at that point. Addressing the plash during carving allows for a more efficient and effective preparation of the restoration before it is hardened and finalized.