1984 Volume 34 Issue 5 Pages 548-555
Previous studies showed that fluoride mouth-rinsing (F.M.R.) is an effective carious reduction procedure in vitro and in vivo. The purpose of this study was to examine the effect of F.M.R. solutions at various pH and fluoride concentrations on powdered enamel by means of chemical analysis and X-ray diffractometry. The F.M.R. solutions used were acidulated phosphate sodium fluoride solution (pH 5.0, APF), Miranol solution (pH 5.0, BMD Co.) and neutral sodium fluoride solution (pH 7.0, NaF), 100, 250, and 500ppmF-, respectively. Powdered enamel was treated with the various fluoride solutions for 30 minutes at 37°C, followed by washing with distilled water.
The fluoride uptake into enamel was determined with the combination fluoride selective electrode coupled to an ion meter by McCann. Acid resistance was evaluated by measuring calucium released into acetate buffer (pH 4.0) for 3 minutes with an atomic absorption spectrophotometer. X-ray diffraction analysis was performed with an automatic recording X-ray diffractometer to observe the crystallinity and identify the reaction products.
The amount of fluoride uptake from APF and Miranol was larger than that from NaF. Especially 500ppmF- of APF revealed a clear increment of fluoride uptake. The fluoride uptake from Miranol was about 2.3 times higher than that from NaF (pH 7.0), but there was no clear difference of fluoride uptake in the powdered enamel treated with Miranol. Acid resistance and crystallinity were relative to fluoride uptake in the powdered enamel.
Consequently both fluoride uptake and acid resistance were greater with acidulated F.M.R. solutions than neutral F.M.R. solution. In addition, it is suggested that the repeated application of F.M.R solution have a cariostatic effect in spite of low fluoride concentration.
