Evaluation On Fluoride Releasing And Recharging Abilities Of Nano Fluoirde-containing High Strength Composite

AIM:Objective To measure the fluoride releasing and recharging abilities ofNano fluorine containing high strength composite and to find the most effectivefluoride recharging method in vitro experiments.METHODS:The three experimental groups contained three Nano fluorinecontaining high strength composites(10%,20%,30%) were set up and the glassionomer cement(GIC,Fuji IX) was considered as positive control group.Thesematerials were made into special style(5mm diameter and2mm depth) and then wereplaced into deionized water (DW).The initial fluoride ion release of five sampleswhich were randomly selected from each group was measured every day using afluoride-ion specific electrode, and the process lasted for one month. Thennon-fluoride-releasing composites(Tetric N-Ceram,Universal type,Neofil,SpectrumTPH) were considered as negative control group, and were also prepared respectivelyfor18samples. Each specimen of the eight restorative materials was subjected to sixdifferent treatments to simulate a fluoride recharge:Duraphat,FLUORX FluorProtector,Copal Fluoride Varnish,Fluoride Foam TypeA,Fluoride Foam typeC,1%NaFsolution. After topical fluoride treatment, each specimen was submitted to fluoridere-release tests. The data were analyzed using ANOVA.RESULTS:During the initial period for each group, the fluoride release waspeaked at the first day, decreased rapidly at the second day, and then kept relativelystable at the5th~30th day. The overall cumulative amount of fluoride release: FujiIX>30%fluoride-containing composite>20%fluoride-containing composite>10%fluoride-containing composite. The difference was significant (P <0.05) among eachgroup expect the10%and20%fluoride-containing composite. After topical fluoridetreatment, the amount of fluoride ion re-released of FujiIX was higher than the othercomposites(P＜0.01). The amount of fluoride ion re-released of30%fluoride-containing composite was higher than the other non-fluoride-releasingcomposite(P＜0.05). The overall cumulative fluoride ion re-release after Fluoride Foam Type A treatment was higher than other treatments(P＜0.05).CONCLUSIONS: Nano fluorine containing high strength composite has thepotential for releasing and recharging fluoride and the ability of fluoride ion releasingand recharging for30%fluoride-containing composite is the most strongest. Inaddition, Fluoride Foam type A is more effective in recharging fluoride than theothers.