Application of pit and fissure resin sealant has been widely used as a caries preventive measure, particularly in pediatric dental practice. A light cured fluoride slow releasing sealant (Teethmate-F) which contains about 1wt% fluoride ions, provides not only mechanical protection of caries susceptible pits and fissures, but also enhances the acid-resistanse of the adjacent area of the surface enamel, by supplying fluoride ions slowly released from the sealant by hydrolysis. The sealant was applied to 50 permanent molars and premolars of 25 children and evaluated clinically regarding the rates of sealant retention as well as the caries prevention in these teeth after 1-year-3-month observation. The retention rates of this sealant was 78.0%, whereas the rates of the detected carious lesion was 2.0%.