Purpose: The aim of this study was to evaluate the efficacy of three topical fluoride treatments to arrest initial root carious lesions. Materials and Methods: Forty patients participated in a randomised study. Of the 60 root carious lesions that were included, 20 were randomised for treatment with the Carisolv® chemo-mechanical technique and the Duraphat (2.23% F) fluoride varnish, 20 with Duraphat alone and 20 with stannous fluoride solution (8%). The lesions were treated at baseline and after three and six months; a clinical evaluation was carried out on these occasions and after 1 year. Results: All but four lesions were categorised as arrested caries during the 1-year follow-up period: 18 in the Carisolv/Duraphat group and 19 each in the Duraphat and the stannous fluoride groups, respectively. There was a minor reduction in the mean size of the lesions of around 0.1 to 0.2 mm height and width and a moderate change in colour from a lighter to a darker appearance. No obvious differences were found between the groups. The mean percentage of mutans streptococci in plaque from all lesions was 3.5% at baseline, and it decreased to 1.8% during the year. The decrease was, however, not statistically significant, and no significant differences were found between the groups. Conclusions: It can be concluded that the frequent topical application of fluoride could be a successful treatment for incipient root carious lesions, irrespective of the type of fluoride treatment used. Schlagwörter: chemo-mechanical caries removal, clinical trial, fluoride varnish, root caries, stannous fluoride