Method: a randomized, examiner and patient-blind, placebo-controlled, parallel-group design, clinical trial, comprising 12 to 48 month-old children, 100 in the test group (Duraphat,Colgate, fluoride varnish) and 100 in the control group (placebo varnish) was conducted in a public health care center in Rio de Janeiro, Brazil. Two trained pediatric dentists performed the clinical exams (Kappa=0.85) at baseline and every six months. Dental caries was recorded at the D2 (cavitated enamel lesion) and D3 (dentine lesion) levels using the International Caries Diagnosis and Assessment System (ICDAS II).
Result: At baseline, mean age of the participants was 29 months (SD 10.4) and mean dmfs was 0.8(SD 1.9). Most of them brushed their teeth with a fluoridated toothpaste (80%) and consumed fluoridated tap water (97%). After 24 months of follow-up, 89 and 92 children of the test and the control groups were analyzed, respectively. Thirty-two (42.7%) children in the test group and 43 (57.3%) children in the control group presented new dentinal caries lesions (Chi-square test, P= 0.14), showing a relative risk reduction of 23% (95%CI:-9.5;45.9).The mean caries increment differences between the test and control groups were -0.8 (95%CI:-2.0;0.4) at the D2 level and -0.7 (95%CI:-1.9;0.4) at the D3 level.
Conclusion: Twice-yearly professional application of fluoride varnish during two years in 12 to 48 month-old children who lived in a fluoridated area and used fluoridated toothpaste did not result in a significant decrease in caries incidence.