Recruitment of a clinical field trial population: reasons for nonparticipation

Open-ended telephone interviews were conducted with 294 families who refused participation in a school-based program of professionally applied topical fluoride. While the program was conducted in a flouride-deficient community, the level of topical fluoride contact in the homes of the nonparticipants was high. The traditional antifluoridationist reasons for nonparticipation were not expressed with frequency. Instead, the most frequent reason for returning a negative consent form was that the child was already receiving topical flouride applications from the family dentist. The second most frequent reason was that the child did not wish to participate. Many of the reasons given for nonparticipation were not cogent, suggesting that if the parents had been more informed about the nature of the project and about fluoride in general their responses might have been positive.