Approximal Caries Development in Adolescents with Low to Moderate Caries Risk after Different 3-Year School-Based Supervised Fluoride Mouth Rinsing Programmes

The aim was to evaluate a 3-year randomised controlled trial of school-based fluoride mouth rinsing (FMR) on approximal caries development in 13- to 16-year-olds with low to moderate caries risk. The adolescents used F toothpaste at home and underwent prophylactic treatment at yearly check-ups at public dental clinics. Out of 788 randomly selected 13-year-olds, 622 completed the trial, carried out in 1999-2003. Supervised by a dental nurse, the subjects rinsed with a 0.2% NaF solution at different intervals. Group 1 rinsed their teeth on the first three schooldays every semester; group 2 on the first three and the last three schooldays every semester; group 3 on three consecutive days once a month during semesters; group 4 once every fortnight during semesters, and group 5 (control) did not rinse. Radiographic recording of approximal caries was performed. FMR on the three first and the three last schooldays every semester (group 2) had a prevented fraction of 59%, with approximal enamel lesions as a diagnostic threshold. Corresponding figures for groups 1, 3 and 4 were 30, 47 and 41%, respectively. The control group differed statistically from groups 2-4 for new enamel and dentin lesions and fillings (p < 0.01). Enamel lesions constituted more than 90% of the new caries lesions. Caries progression was low for all groups and no significant differences were found between groups. The main conclusion from this randomised controlled trial is that school-based FMR, as a supplement to the daily use of F toothpaste, reduces caries incidence on approximal surfaces in adolescents with low to moderate caries risk.