Abstract: Objective To evaluate the effect of pit and fissure sealant on preventing caries of the first permanent molars in children aged at 8 years old. Methods 805 children were examined and 2 190 first permanent molars were treated with pit and fissure sealant (experimental group), while 245 children with 947 first permanent molars were served as control group. The retention status of pit and fissure sealant was observed in the experimental group with 3-year follow-up, and the caries rates of the first permanent molars were observed between the two groups. Results Pit and fissure sealant retention rates of experimental group during the 3-year follow-up were 78.35%, 69.56% and 69.31%, respectively. The caries rates of the first permanent molars in the experimental group were 9.45%, 9.91% and 10.87% with the mean DMFT of 0.10, 0.11 and 0.12 after 1, 2 and 3 years, respectively, when those in the control group were 14.29%, 17.26%, 18.95% with the mean DMFT of 0.15, 0.20 and 0.21, respectively. There were significant differences in the caries rates in all three years and in the mean DMFT in the 2nd and 3rd years between the experimental group and the control group. Conclusion Pit and fissure sealant can play an effective role in the prevention of dental caries of first permanent molars.

Key words: pit and fissure sealant, first permanent molar, Sealant preservation rate., Caries prevalence, dmft