This is another piece of equipment now largely superseded. For single tooth isolation, a hole punched 2 cm diagonally from the middle of the sheet gives universal dam. The hole is simply orientated to the quadrant under treatment. For multiple isolation, it is preferable to hold the dam against the teeth to be isolated, and mark the centre of each tooth with a pen, as shown in Figure 3. The holes will then be punched in accordance with the patient s dentition and not with an arbitrary stamp.