Instrument Ainsworth rubber dam punch is used to place holes in rubber dam material to permit the passage of the dam over the crowns of the teeth. The handles are squeezed together and the plunger (punch) creates a hole in the rubber dam material. The instrument punches with a rotating metal table (disk) with six holes, typically designed of varying sizes and a tapered, sharp – pointed plunger. The instrument should be centered in the cutting hole so the edges of the holes are not at risk of being chipped by the plunger tip when the plunger is closed. Otherwise, the cutting quality of the punch will be ruined, as evidenced by incomplete cut holes. These holes tear easily when stretched during application over the retainer or tooth.