[Effect of retraction materials on the blood supply of marginal gingiva]

Effect of knitted cord and retraction medicaments applied to achieve gingival displacement prior to taking impression has been studied on the blood supply of marginal gingiva of volunteers using laser Doppler flowmetry. Immediately after application of #00 cord saturated with 0.9% saline, 25% AlCl3 or 15.5% Fe2(SO4)3 solutions, significant decrease of blood perfusion was registered. Removal of cords containing medicaments resulted in prompt gingival hyperemia. However, vasoconstriction observed as a consequence of cord application saturated with 0.1% epinephrine proved to be long-lasting and persisted even in the 20th min of cord removal. In conclusion our results suggest that the reduced perfusion of marginal gingiva is evoked by the mechanical compression of retraction cord. At the time of making impression, which procedure in clinical practice is due immediately after cord removal, the blood flow of marginal gingiva is elevated. Permanent hypoperfusion can be achieved only by the means of cord impregnated with 0.1% epinephrine.