Objective To observe the effect of fluoride drop orfluoride ion infiltration on demineralization of the first permanent molar of children.Methods 45 children applied by fluoride drop over 3 years in Chengdu and 40 controls were selected. 45 children applied by fluoride ion infiltration more than 3 years in Xiamen and 40 controlswere selected in this study. Demineraliza- tion of the different sites of the first permanentmolarwas evaluated byKaVo DIAGNOdent. The effect of FD and FII in toddler pe- riod on demineralization of the first permanent molarwas evaluated.Results Early demineralization of the first permanent molar in children without fluoride drop were more severe than that of children with fluoride drop in toddle period(P0·05).Conclusion Fluoride drop in toddle period can help the remineralization of newly erupted first permanent molar of children. There is no effect of fluoride ion infiltration on demineralization of newly erupted first permanent molar of chil- dren.
