RESUMO
Objective@# Assessing the effect of pit and fissure sealing on children’mandibular first molar in four years follow-up.@*Methods@#The second grade pupils of five primary schools in Guangzhou were given pit and fissure sealing, 733 teeth were performed pit and fissure sealant. The retention rate of the sealant and caries incidence of the mandibular first molar were analysed in four years follow-up. @*Results @# In four years follow-up, the retention rate of mandibular first molar was 57.16%. In terms of the caries incidence, the sealing group was 9.82%, while the unsealing group was 15.77%(χ2 = 7.045, P < 0.05). The decrease rate of caries in the sealing group was 37.73%, the caries incidence for the shallow pit and fissure group was 7.76%, no statistical differentce could be found two groups (χ2 = 0.844,P = 0.358).@*Conclusion@#Caries incidence of mandibular first molar obviously decreased 4 years later after the pit and fissure sealing.