The Influence Of Film-forming Materials On The Property Of Fluoride Varnishes

Fluoride varnish is an effective antcaries material that can prolong the contact time between fluorion and enamel, those basic of antcaries is the fluoride releasing of the fluoride varnishes and uptake characteristic of the enamel treated with fluoride varnishes.Object:To study the influence of film-forming materials of fluoride varnishes on the fluoride releasing of the fluoride varnishes and uptake characteristic of the enamel treated with fluoride varnishes and provide the selection basis of film-forming materials for the development of new fluoride varnish.Methods:(1) Five fluoride varnishes containing the same fluoride and one film-forming material (osmotic acrylic resin, Copal resin, polymerized rosin, polyvinyl butyral,ethylmethacrylate copolymer resins respectively) were prepared. Each fluoride varnish was painted onto 35 plastic slices (12mm×12mm×0.4mm), which were immersed in deionized water after drying. After 4h,8h,24h,48h,72h,96h and 120h, slices of each fluoride varnish were removed and the water were tested for fluoride content with a fluoride-ion selective electrode,The fluoride release rates of each fluoride varnishes were calculated.(2) Enamel blocks were got from fresh bovine teeth to make test rods.using cotton swabs and acetone to wipe off the varnishes after treated with fluoride varnishes for 24 hours.The calcium fluoride precipitated in the surface of enamel were dissolved using 1.0mol KOH solution.The fluoride concentration was measured with a fluoride-ion selective electrode and the mount of the KOH-soluble fluoride per unit area on the surface of enamel was calculated (μg/cm2).Obtain samples of surface enamel by the trace sampling technique.After dissolved by perchloric acid solution, the fluoride concentration was measured and then the mount of the structurally bound fluoride (μg/cm3) was calculated.Combined with the nature of the film-forming materials, discussed the relationship between film-forming materials and the performance of the fluoride varnishes.Results:(1) The five laboratory fluoride varnishes show different fluoride releasing modes.Within 24 hours after immersed in water, the fluoride varnish containing osmotic acrylic resin as film-forming material was able to rapidly release fluoride ions, and the fluoride varnish containing Copal resin as film-forming material relatively had an increasing trend which release fluoride consistently. The fluoride release rates of the other three fluoride varnishes were lower.(2) The mount of KOH solube fluoride of the enamel surface treated by 5 different fluoride varnishes with different film-forming materials were significant differences (p<0.05).So did the mount of structurally bound fluoride(50μm and 100μm).(3) The fluoride releasing and uptake properties of the fluoride varnish containing osmotic acrylic resin as film-forming material was close to that of Bifluoride12.(4) The fluoride-releasing rate of the fluoride varnishe containing low concentration fluoride has been higher than the fluoride varnishe containing hign concentration fluoride(p<0.05).Conclusions:The film-forming materials not only affect the fluoride-releaing characteristic of the fluoride varnishes, but also have great effect on the fluoride-uptake characteristic of the enamel treated with fluoride varnishes. Osmotic acrylic resin is more suitable for the preparation of fluoride varnish as film-forming materials.The fluoride varnish containing low concentration fluoride was more beneficial to the release of fluoride.