Relationship between Duration of Fluoride Exposure in School-Based Fluoride Mouthrinsing and Effects on Prevention and Control of Dental Caries.

The objective of this paper was to assess the effects of school-based fluoride mouthrinsing (S-FMR: weekly using 0.2% NaF solution) in two groups of school children with different periods of exposure to S-FMR in elementary school. Subjects were the S-FMR group consisted of 599 children, participated for six years. The control group consisted of 282 children, participated for less than one year in the sixth year of elementary school. From the results of the present survey, the caries reduction rate of S-FMR in the permanent teeth was 36.6% for DMFT and 42.8% for DMFS, and person rates with DMF, DMFT, DMFS, and CO (questionable caries under observation) were inhibited in both boys and girls. Girls in the control group showed clearly higher values for all parameters of dental caries because of earlier teeth eruption; however, no gender differences were observed in the S-FMR group. As caries prevalence in the first molars accounted for about 85% regardless of participation to S-FMR, and first molar caries were more common in the mandible than in the maxilla, consideration should be given to preventive measures against pit-and-fissure-caries in addition to S-FMR.