A big issue when trying to prepare a tooth is when the tissue is cut or bleeding when tying to get an impression. Here’s a technique from Dr. Lee Ann Brady that eliminated most of the tissue damage during the preparation of the tooth.
Step 1 – During the gross reduction of the tooth and leave the margin position of the preparation equigingival, or just supragingival avoiding the tissue.
Step 2 – Next place your first cord. Dr. Brady recommends using size zero cord from Dux Dental called UniBraid because of the rigidity of the cord. That will help it stay where you place it, help it hold its dimensions and it doesn’t stretch. Place the cord around the circumference of the tooth, and cut it so there is no overlap or tails visible. Choosing gingival retraction cord is by clinician personal preference. Cord types and properties can vary and some may be less desirable. There’s a wide range of cord options (non-impregnated and chemically impregnated cords) and manufacturers. Tip: Always wear latex-free gloves when handling gingival retraction to avoid contamination.
Step 3 – This first cord acts to retract and move the tissue away from the margin of the preparation. You should be able to go back and drop your margin without cutting the tissue.
Step 4 – Conclude the prep and do all of your polishing and refinement. At this point you can now focus on retraction for impression taking.
Article Source: http://www.oralhealthgroup.com/news/gingival-retraction-using-paste-systems/1002122009/