Salivary fibrinolytic activity before and after oral surgery estimated on different types of fibrin.

Mixed saliva was collected from 25 healthy young people from who mandibular impacted molars were to be removed. Collection of saliva was repeated immediately after operation and 5 days later. Fibrinolytic activity measured by the fibrin plate method employing four different solutions of fibrinogen: (1) bovine plasmino-gen-rich fibrinogen; (2) bovine fibrinogen with human bata-plasminogen; (3) bovine plasminogen-free fibrinogen; and (4) human fibrinogen. After 20 hours of incubation the fibrinolytic activiey was measured. The preoperative samples all showed activator activity, whereas plasmin activity seldom was detectable. The measured activity was significantly higher on the human fibrin plates than on any of the other plates. No difference was detected between the fibrin made of solutions (1) and (2), indicating that the possible presence of streptokinase in saliva is unimportant for the quantitative fibrinolytic activity Immediately after surgery the activity had decreased or disappeared on the bovine fibrin plates. Five days after operation, fibrinolytic activity had not returned to the normal preoperative level. The findings show that salivary fibrinolytic activity after oral surgery is usally controlled by the fibrinolytic inhibitors present in plasma and in the exudate of the oral ulcer.