Purpose: To investigate and compare the effects of a dental cream containing complexes of casein phosphoprotein-amorphous calcium phosphate (CPP-ACP) and fluoride mouthwashes on the regression of white spot lesions (WSL). Materials and Methods: The study group consisted of 26 healthy adolescents (mean age 14.6 years) exhibiting 60 teeth with 152 visible WSL sites on incisors and canines immediately after debonding of fixed orthodontic appliances. After bracket removal, professional tooth cleaning and drying, a visual scoring (0-4) and laser fluorescence (LF) readings were carried out. The patients were randomly assigned to two different treatment protocols with the aim of remineralising the lesions: A) daily topical applications of a dental cream containing CPP-ACP (Topacal) for 3 months followed by a 3-month period of daily toothbrushing with fluoridated dentifrice, or B) daily 0.05% sodium fluoride mouthwash combined with fluoridated dentifrice for 6 months. The registrations were repeated after 1, 3, 6 and 12 months and follow-up data were compared with baseline with aid of chi-square and paired t-tests. Results: A significant improvement of the clinical WSL-scores was found over time in both groups, but there was a statistically significant difference (p0.01) concerning the number of sites that totally disappeared after 12 months in favour of the CPP-ACP regime, 63% compared with 25% respectively. The clinical registrations were mirrored by a statistically significant decrease (p0.05) in the LF readings at the 6- and 12-month follow-ups compared with baseline. No significant differences were displayed between the groups. Conclusions: Clinical scoring and LF assessment suggested that both regimens could promote regression of WSL after debonding of fixed orthodontic appliances. The visual evaluation suggested an aesthetically more favourable outcome of the amorphous calcium phosphate treatments. Schlagwörter: lesion regression, milk derivate, orthodontics, sodium fluoride mouthwash, white spot lesions