Which item is used to stabilize finishing discs during polishing?

• A. Amalgam well
• B. Mandrel and pop on sandpaper disc
• C. Celluloid strip
• D. Amalgam carver

Answer: (B)

Stability during polishing comes from mounting the abrasive disc on a mandrel with a pop-on attachment. The mandrel provides a rigid shaft that fits in the handpiece, while the pop-on disc locks securely to it, keeping the abrasive surface flat, centered, and firmly attached as you polish. This reduces wobble, allows even pressure, and helps control heat, yielding a smoother, more predictable finish. The other items serve different purposes: an amalgam well holds amalgam for carving, a celluloid strip acts as a matrix, and an amalgam carver shapes amalgam.