Determination of plasma catecholamines in dogs after experimental gingival retraction with epinephrine-impregnated cord

Blood catecholamine levels were determined by high-performance liquid chromatography after placement of the cord around two teeth in a random sequence of the following treatments: (1) untreated cord to intact gingival crevice (C), (2) epinephrine cord to intact crevice (E1), and (3) epinephrine cord to a crevice disrupted with a tapered diamond bur to simulate a subgingival procedure such as in crown preparation (E2). Each cord was left in place for 30 min while blood was drawn from the external jugular vein at 0, 5, 10, 20 and 30 min, and at 10 and 30 min after removal of the cord. Catecholamine values were compared to baseline (time 0) measurements. Treatment C resulted in no significant change in blood catecholamines. Treatment E1 caused a significant increase (p less than 0.01) in blood epinephrine levels, reaching a 641 per cent increase at 30 min. Treatment E2 produced a highly significant increase (p less than 0.001) in blood epinephrine with a greater than 5000 per cent increase 10 min after cord removal. Norepinephrine and dopamine levels were not significantly altered by any of the treatments.