Effectiveness of the semi-annual aplication of fluoride varnish on reducing caries incidence in prescholars: results after 18 months

The aim of this work was to evaluate whether, after 18 months of follow up, the semiannually application of the fluoride varnish in preschool children, reduce the incidence of caries in the deciduous dentition. The possible adverse effects and the acceptance of the intervention have also been investigated. Study design: controlled clinic trial, randomized, double-blind, with the use of placebo. Two hundred children between 12 to 48 months, recruited in one public healthy unity, have been included in the research. A hundred children have been allocated in the test group (fluoride varnish Duraphat®, Colgate Oral Pharmaceuticals, New York, NY, USA) and a hundred in the control group (placebo varnish, Colgate Oral Pharmaceuticals, New York, NY, USA). Clincial examinations, followed by semiannual applications of varnish in the test and control groups were performed by two pediatric dentists trained (Kappa=0,85) that have utilized the International Caries Detection and Assessment System II (ICDAS II) to register the index def-s under levels of detection d1 (active lesion in enamel non cavitated, lesion in enamel cavitated and lesion in dentin) and d3 (lesion in dentin). It has been also identified, the ocurrence of adverse effects and other complaints by means of telephon interviews with parents 7 to 10 days after varnish application of the first varnish application. After 18 months of follow up, 85 children of the test group and 92 of the control group were examined. The difference between the mean caries increment, in the test and control groups, were -0,9 (CI95%: -2,4;0,4) in d1 level and -0,8 (CI95%:-1,9;0,2) in d3 level. The risk of developing new carious lesions in dentin was 30% (RR=0,70; CI 95%:0,49;0,99) less in the children in test group compared to controls. 183 parents were interviewed about adverse effects and acceptance of the intervention. There was a complain about the one children that felt burning in mouth after placebo application and a parent felt troubled about the yellowish teeth right after fluoride varnish application. In conclusion, the semiannual application of fluoride varnish in the deciduous teeth of preschool children reduces the risk of developing caries lesions in dentin. Besides, the intervention is safe and well accepted by children and parents.