School-based Fluoride Varnish Programs in Different Caries-risk Areas

Objectives: To evaluate a 3-year school-based fluoride varnish (FV) (Duraphat 2.23% F) programme, with different application frequencies performed in high, medium and low caries risk areas on the Swedish west-coast. Out of 854 randomly selected 13-year-olds, 758 (89%) fullfilled the trial, which was carried out between 1998 and 2001. Method: Using a simple mobile unit, two dental nurses visited the schools and treated the adolescents with FV at different intervals: 1) twice a year at 6-month intervals, 2) three times a year within one week, 3) 8 times per year during the semesters with 1-month intervals and 4) no FV treatment (control). All participants visited regularly their dental clinic and were supposed to use F toothpaste daily at home. Radiographic caries recordings were performed using Gröndahls index. Results: The mean ± S.D. enamel caries increment on the approximal surfaces in the high caries risk area was 0.89 ± 1.50 in group 1, 1.37 ± 1.90 in group 2, 0.54 ± 1.26 in group 3 and 2.85 ± 3.36 in group 4 (p<0.05 for groups 1-3 vs. group 4). Similar statistical differences regarding enamel approximal caries were found in the medium, but not in the low caries risk area. Regarding new dentine caries increment on approximal surfaces, there were only significant differences between groups 1-3 vs. group 4 in the high caries risk area. Conclusion: This 3-year caries trial, including 758 adolescents, showed that a school-based fluoride varnish programme affected the caries incidence on the approximal surfaces in high and medium, but not in low caries risk area. The frequency of application of the varnish did not seem to play a significant role. This study was supported by County Council Västra Götaland Region and Patentmedelsfonden.