The Experimental Study Of Anticaries Effect Given By Trace Element Agents Containing Fluoride

It has been half a century for us using fluoride to prevent dental caries. The notable anticaries effect of fluoride has been universally accepted. However, the unstandard long-term use of fluoride at high concentration can leads to the appearance of fluoride-resistant bacterial and chronic fluorosis. Therefore, it's necessary to seek more effective and safe anticaries agents.It was discovered that some trace elements such as zinc, stannum, lanthanum, strontium, molybdenum were with anticaries effect in 1940s. In addition, there was synergistic action between fluoride and some trace elements, such as stannum. Nowadays, the anticaries effect of trace element agents contain fluoride has been thought highly of for the purpose to improve agents' anticaries activity and to inhibit the growth of fluoride-resistant bacterial. However the mechanisms of trace elements preventing dental caries are not clear. In the experiments, we studied the effects on the growth of S.mutans, the activity of GTP, the acidic production of S.mutans and the demineralized of enamel, given by five trace element agents containing fluoride [NaF , ZnF2 LaF3 , SrF2 , SnF2 ,(NH4)2MoO2F4]. Furthermore their anticaries effect was also compared with sodium fluoride.There were two parts in the experiment:Patrt I: The effects on S.mutans given by trace element agents containing fluorideUsing anaerobic cultivating technique, S.mutans ATCC25175 was cultivate in BHI and TYC culture which contained NaF, ZnF2, LaF3, SrF2, SnF2 and (NH4)2MoO2F4. The counts of S.mutans was counted, the activity of glucosyltransferase (GTF) and actate dehydrogenase (LDH) were measured with Somogyi technique and dinitrobenzene, the pH values of culture before and after culture were measurated.The results showed that the growth and metabolism of S.mutans ATCC25175 could be inhibited by NaF, ZnF2,LaF3, SrF2 , SnF2 and (NH4)2MoO2F4, and the inhibiting effect of SnF2 was strongestPart II: The influence of trace element agents containing fluoride on demineralization of enamelEnamel pretreated with NaF, ZnF2 LaF3 SrF2 , SnF2 and (NH4)2MoO2F4 was etched with lactate buffer, the concentration of calcium ion in buffer was measured, microconsistency of enamel before and after etched was checked, enamel surface was observed with SEM. The results showed that demineralization of enamel could be inhibited by NaF, ZnF2> LaF3, SrF2, SnF2 (NH4)2MoO2F4, and the inhibiting effect SnF2 was strongest when using observed.The results of present study showed that trace element agents could inhibit the occure of dental caries. And the inhibiting effect of SnF2 and ZnF2 were stronger than NaF. These results could give us help in finding more efficient anticaries agent.