The laying back of the free gingivae to expose the gingival margin of a preparation using mechanical, chemical, or electrical methods. Gingival retraction cord is an absorbent string usually impregnated with a haemostatic agent such as aluminium chloride, ferric chloride, or ferric sulphate, which is gently inserted into the gingival crevice (sulcus) to provide mechanical tissue displacement. Gingival retraction cord containing epinephrine is contraindicated in patients with cardiac arrhythmias; viscous gels or pastes may be used as an alternative to cord. Electro-cautery and pulsed Nd:YAG laser irradiation have been used to achieve gingival retraction.
Abdel Gabbar F., Aboulazm S. F. Comparative study on gingival retraction using mechano-chemical procedure and pulsed Nd = YAG laser irradiation. Egypt Dent J 1995;41(1):1001–6.