Abstract
The rate of disappearance of radioactive iodide from a deep dentinal cavity has been used as a means to measure the influence of various cavity washing agents on pulpal microcirculation. Hydrogen peroxide in concentrations of 2–4% exerted a pronounced influence when it was allowed to act in deep dentinal cavities where the red colour of the pulp was barely visible through the dentin. Repetitive treatments of 3 % hydrogen peroxide of 40 sec duration caused a potentiated depression of the microcirculation. This was true when the dentinal wall between the cavity and the pulp was intact. In cases of pulp exposure the influence seemed to be much less. All other agents tested failed to influence the pulpal microcirculation as reflected by the present method.