[The effects of fluoride-containing trace element agents on the growth of mutants of S. mutans].

To compare the influence of 6 trace element agents containing fluoride versus 6 trace element agents not containing fluoride on the growth of mutants of S. mutans and detect the interaction between fluoride and trace elements. Six trace element agents containing fluoride [SnF2, ZnF2, SrF2, LaF2, (NH3)2MoF8, NaF] and 6 trace element agents not containing fluoride [SnCl2, SrCl2, LaCl2, ZnAc2, (NH3)2MoO4, NaCl] were selected. The continuous anaerobic cultivating technique and the absorbency of bacteria liquid and the count of bacteria were used to assess the effects of different agents on the growth of S. mutans. NaF, SnF2, SnCl2, ZnF2, ZnAc2, (NH3)2MoF8 and (NH3)2MoO4 were found to have strong inhibition effects on the growth of mutant of S. mutans(P < 0.01). SnF2 had more stronger inhibition effects than SnCl2; ZnF2 had more stronger inhibition effects than ZnAc2, no significant differences were seen between (NH3)2MoF8 and (NH3)2MoO4. SnF2 and ZnF2 had most potent inhibition effects(P < 0.01). No significant differences were observed between SrF2, SrCl2, LaCl2, LaF2, NaCl and the control groups(P > 0.05). The agents containing fluoride and trace elements, such as stannum and zinc had the effects of prohibiting the growth of mutant of S. mutans, As far as caries prevention is concerned, the agents containing both fluoride and trace elements are more effective than mono-fluoride, the potential mechanism may be the synergistic action between fluoride and trace elements.