As stated previously, in a relatively intact arch it is easier to isolate several anterior teeth. Dental floss should be used first to verify that the contacts are clear and that the rubber dam will pass through. The rubber sheet is held against the teeth and the centre point marked of those teeth to be isolated. Holes are punched at these points, and the rubber dam is then applied to the teeth. Taking a leading edge of rubber through the contact knifing through makes application relatively simple, or dental floss may be used to draw the rubber through a difficult contact. Once in place the selected wedges are applied.