Immediate and delayed effects of a dental health education film on periodontal knowledge, attitudes, and reported behavior of Dutch adolescents.

In a field experiment the immediate and delayed effects of a 20-min dental health film on periodontal knowledge, attitudes, and reported behavior were assessed. Subjects were 425 12-14-yr-old Dutch adolescents. There were 12 experimental classes and eight control classes, matched for type of school, class, and level of urbanization. Results showed a substantial knowledge gain for the experimental group. This effect was sustained over a period of 2 months. For six items the gain was over 40%. Results did show a marginal effect of the film for attitude scores but no effect for reported behavior, either immediate or delayed. The effect of the film on knowledge was partly determined by background variables such as type of school, level of urbanization, and subject's age. No such interaction effects were obtained for attitude and reported behavior. The conclusion must be that knowledge of dental health issues can be improved by relatively simple means, but to change attitudes and behavioral dental practices more is needed than a 20-min film.