Relevance. The prevalence of caries in permanent teeth of 6-year-old children in Russia reaches 13%. In view of tooth enamel mineralization completion within a few years after the eruption, the role of primary prevention is especially significant. Fissure sealing is one of the preventive measures. At the same time, the effectiveness of dental caries prevention in children within the first year after tooth eruption reaches sufficiently high rates.Material and methods. The study involved 58 children. The experimental group included 30 children (105 teeth) who had the fissures sealed by air abrasion with additional water supply using a "Rondoflex plus 360" handpiece ("KaVo", Germany). The control group included 28 children (89 teeth) who underwent standard non-invasive sealing. Sealing effectiveness was assessed in 3, 6, 12, 18, and 24 months using the E.M. Melnichenko formula modified by the authors. Statistical data were represented by percentage; the χ2 test identified inter-group differences.Results. The experimental group showed the best sealant retention (up to 76.19% after 24 months). In the control group, the percentage of retained sealant was 48.31% by the end of the follow-up period. After 1 and 2 years, the total sealant loss was 11.24% and 22.48%, respectively. This fact may be associated with the failure of the sealant adhesion to the tooth enamel under the influence of a constant chewing load.Conclusion. Analyzing two-year follow-up results, we found that caries developed in 3.81% of cases in the main group, and the control group revealed caries in 12.37%. Thus, the effectiveness of fissure sealing using air abrasion with additional water supply is 63.4% higher compared to the non-invasive technique (χ2 =16.638, p<0.001).