The caries experience and the plaque and gingival conditions of 14-year-old children participating in fortnightly fluoride (0.2 % NaF) mouth rinsing (88 subjects) were compared with observations in children performing supervised toothbrushing with a fluoride (0.5 % NaF) solution 4-5 times per year (n = 90). Most of the children, 84 and 90% respectively, had participated in these programs for the previous 6 years. Caries was assessed only on radiographs. The mean number of decayed surfaces was 5.8 (s.d. = 4.1, n = 88) and 5.4 (s.d. = 4.1, n = 90). The mean numbers of decayed and filled surfaces were 19.3 +/- 9.2 and 27.9 +/- 10.2 for subjects with rinsing or brushing. This significant difference could not be ascribed to sex, social class, years of residence in the towns, number of dentists performing the previous treatments, toothbrushing habits, use of fluorides at home, or amount of plaque. All children had gingivitis. There were no differences in the mean number of Plaque Index score 2 or the number of Gingival Index score 2 between the children with the different preventive programs. The girls' oral hygiene was better than the boys', but the gingival conditions were the same. Sex, social class, and toothbrushing techniques tended to have a slight influence on the amount of plaque.