AbstractThe present study set out to determine whether or not a mass media periodontal campaign had any effect upon preventive knowledge and behavior related to periodontal diseases. The campaign was denoted “The year against periodontal disease”, and launched by the Norwegian Dental Association. The empirical basis stemmed from nationwide interview surveys in February 1981 (prior to the campaign). 1982 (after the campaign), 1983, and 1985. Knowledge of how to prevent periodontal diseases and behavior in terms of daily use of dental floss and toothpicks increased from 1981 to 1985. However, the only campaign message which seemed to have reached the public was the most simple knowledge message: “Periodontal diseases are prevented by improved brushing”, and had been reinforced among those who had made a dental visit recently. However, behavioral changes which could be ascribed to the campaign did not seem to have occurred. This is consistent with empirical results from other mass media campaigns in health ed