Abstract: Objective To evaluate the remineralization of initial enamel caries on primary teeth by three children′s nonfluoride toothpastes.Methods 50 artificial caries models were created from primary teeth,which were then randomly distributed into 5 groups,namely bioactive glass group,Shuanghuanglian group,xylitol group,NaF group,and deionized water group.The specimens were subjected to a PHcycling regime for 7 days.Surface enamel microhardness was measured by microhardness tester,and morphologic changes of enamel carious lesions were detected by polarized light microscopy.Results Surface microhardness of bioactive glass group was significantly higher after remineralization (P<0.05),but not as much as that of NaF group (P<0.05).Meanwhile,microhardness didn′t improve in xylitol group,Shuanghuanglian group or deionized water group (P<0.05).Polarized light microscopy showed the depth of demineralization lesion obviously reduced in both bioactive glass group and NaF group.Conclusions Bioactive glass children′s toothpastes can obviously promote the remineralization of initial enamel caries on primary teeth,but the remineralization ability is inferior to that of NaF toothpastes.Besides,Shuanghuanglian children′s toothpastes and xylitol children′s toothpastes demonstrate no ability of remineralization in this research.

Key words: initial enamel caries, remineralization, primary teeth, bioactive glass, shuanghuanglian, xylitol