What are rubber dam punches?

A dam punch cuts a hole in the dam sheet sized to the tooth being isolated, using a rotating table that offers several diameters — small for anteriors, larger for molars. The cut has to be clean and complete: a partial punch leaves a tag that tears under tension and lets saliva into the field, which defeats the isolation entirely.

How the rubber dam punches range is organised

Ainsworth:

Rotating table punch.

Ivory:

Rotating table punch.

Choosing the right rubber dam punche

Keep the punch sharp and the plate undamaged. If holes are tearing rather than cutting cleanly, the pin has usually been driven against the plate off-centre at some point and the cutting edge is burred — that is a punch to replace, not to persevere with.