Retraction cords and Astringents

Plain retraction cords provide purely mechanical gingival displacement — the braided fibre physically separates the cord tissue from the preparation margin without pharmacological effect. Impregnated cords contain haemostatic astringent agents (typically aluminium chloride 20–25% or aluminium sulphate) that constrict capillaries in the sulcular epithelium, reducing crevicular fluid and gingival bleeding during impression-taking. For healthy, non-bleeding gingiva, plain cord is sufficient; for inflamed or bleeding sulci, impregnated cord (e.g. ATRIA impregnated cord) is preferred to ensure a clean, dry impression margin.

For a posterior molar with a healthy gingival sulcus of 0.5–1 mm depth, size #0 or #1 cord provides adequate lateral and apical displacement. A two-cord technique is recommended for deep subgingival margins: first place #000 cord against the base of the sulcus to open access, then pack #1 cord above it to achieve maximum lateral deflection before removing the #000 cord and taking the impression. The first cord remains in the sulcus during impression-taking in single-cord techniques using #1.

Standard placement time is 5–8 minutes — sufficient for tissue displacement and haemostasis with impregnated cords. Extended placement beyond 10 minutes increases the risk of permanent gingival recession, particularly in biotype I (thin, scalloped) gingiva commonly found in Egyptian patients with crowded dentitions. Remove the cord slowly and parallel to the long axis of the tooth to avoid tissue tearing, then immediately blow air lightly and take the impression within 15–30 seconds before tissue rebound occurs.

Impregnated retraction cords most commonly contain aluminium chloride (AlCl&sub3; 20–25%) or aluminium sulphate, both of which precipitate serum proteins and constrict sulcular capillaries without significant systemic effects. Earlier epinephrine-impregnated cords are now rarely used in Egypt due to cardiovascular contraindications in cardiac patients. Aluminium-based agents are compatible with PVS impression materials; cords impregnated with sulphur-containing compounds must be thoroughly rinsed before PVS injection to prevent polymerisation inhibition at the marginal interface.

Yes. MedSTA supplies plain and AtriumCare impregnated retraction cords, Voco retraction paste, and Atria cord applicators in EGP, with nationwide delivery to Cairo, Giza, Alexandria, Mansoura, and all Egyptian governorates. In-stock items are dispatched same-day from MedSTA's Cairo warehouse.