Hemostatic, gingival retraction pastes were created to eliminate the need for retraction cord and stop any bleeding. While they have been reasonably successful as hemostatics, their gingival retraction capabilities are quite limited to say the least.
That’s why virtually all these products come with a supply of hard, packing foam-like retraction caps in two sizes. You are supposed to place one of them over your prep and then have the patient bite into it, thus presumably forcing the paste deeper into the sulcus. We have never been very impressed with these caps — they never seem to fit a prep closely enough to enhance retraction — and trying to get a patient to bite into it for anterior preps is a non-starter. A better technique would be to fabricate your provisional before taking the impression and using the provisional to push the paste deeper into the sulcus.
Some of these materials are available in low and high viscosity, but all of them contain a hemostatic, typically 15% aluminum chloride in a clay-like paste.
To use, you are supposed to inject the paste into the sulcus you trying to open, but this is easier said than done. The best you will probably achieve is extruding a rope of material immediately coronal to the sulcus and then utilize the aforementioned retraction cap or provisional to try to push it into the sulcus. This is why you probably won’t want to throw out your cord just yet.
Note: These pastes require a fairly forceful water spray to remove them.