INHIBITORY EFFECT ON STREPTOCOCCUS-MUTANS BY FLUORIDE TREATED CONVENTIONAL AND RESIN-REINFORCED GLASS-IONOMER CEMENTS

The aim of the present study was to study the effect of fluoride gel t reatment on fluoride release and inhibition of acid production of Stre ptococcus mutans by different glass ionomer cements. Test slabs of fou r glass ionomer materials were fitted into the bottom of a test tube. A layer of S. mutans cells was centrifuged onto the test slabs, and th e specimens were incubated for 4 h in 1.7% sucrose solution. Incubatio ns were made using fresh: aged (29 d), aged and F-treated (1.25% F-geI ), and aged, F-treated and aged samples (n=15 per group). After each i ncubation, pH and F contents of the fluid phase were determined, The f reshly mixed glass ionomer samples released large amounts of fluoride, and the pH fall in the fluid phase was significantly inhibited. For a ged samples, the fluoride release decreased strongly and no inhibitory effect on acid production by S. mutans was seen. After application of fluoride gel, fluoride release and inhibitory effect were significant ly higher than initially for all glass ionomer cements. In conclusion, all glass ionomer cements were able to take up fluoride and subsequen tly release it, which resulted in reestablishment of their antibacteri al effect. The patterns of fluoride release and antibacterial action w ere virtually the same for conventional and resin-reinforced glass ion omer cements.