The ability of a newly developed urethane lacquer containing silane fluoride (Fluor Protector®) to deposit fluoride in the enamel was tested in vivo using the enamel biopsy technique. The enamel fluoride concentration was measured before, 1 week after a single application or two applications of the lacquer performed with a 1-week interval, and 6 months after two applications. At the depths of 0.5 and 2.0 μm from the enamel surface, the mean fluoride levels increased by about 1,600 and 1,200 ppm (p < 0.001), respectively, after one application, and about 2,800 and 1,800 ppm (p < 0.002), respectively, after two applications. 6 months after two applications, 701 and 50% (p < 0.001) of the fluoride acquired at the two depths, respectively, seemed to be lost, indicating that a substantial part of the fluoride retained 1 week after treatment was not permanently bound in the enamel.
The formation of calcium fluoride (CaF2) was measured on sound enamel (SE) and in caries-like enamel lesions (CL) after treatment in vitro with 2% neutral NaF or Duraphat. The caries-like lesions were created by exposure to acidified gel at pH 4.5 within a 0.07-cm2 window punched in water-repellant tape. The same window area was used in series (n = 10) of SE or CL during the application of NaF for 1 or 5 min or for 18 h or Duraphat for 6 or 18 h. CaF2 was extracted with 1 M KOH for 24 h, and fluoride was determined by gas chromatography. The short-term applications of NaF produced only negligible amounts of CaF2 on SE. The amounts of CaF2 in CL after 5 min application of NaF corresponded to (mean +/- SEM) 27 +/- 2.0 micrograms F/cm2. More than half of this amount was observed after only 1 min exposure to the NaF solution. The quantities of CaF2 in CL were similar after 6 and 18 h application of Duraphat, amounting to 26 +/- 2.2 and 31 +/- 2.2 micrograms F/cm2, respectively, suggesting that the reaction was essentially terminated after 6 h. These amounts were only about one fourth of the quantity obtained after 18 h exposure to the NaF solution. Thus, the conventional 5-min treatment with NaF produced the same amount of CaF2 in CL as 6 or 18 h exposure to Duraphat.
Abstract – Fluoride concentrations were measured in whole saliva samples collected from 16 subjects at different intervals up to 60 min after chewing of various supplementary F preparations: chewable E tablets (0.21 mg F), plain F tablets (0.25 mg F) or F‐containing chewing gum (0.25 mg F). Each of the F preparations was administered in a low dose (0.21–0.23 mg F) or in a high dose (0.42–0.50 mg F). Mean resting levels of fluoride in saliva ranged from 0.03 to 0.05 parts/10 6 . Peak values averaging 15–25 parts F/10 6 in the low‐dose group and 25–40 parts F/10 6 in the high‐dose group were recorded within 5 min after intake. After 30 min, the salivary fluoride concentrations in both groups had decreased to levels below 1 part/10 6 and approached resting levels 60 min after intake. The availability of fluoride in saliva, as estimated from AUC values (areas under curves, relating fluoride concentrations to the time from 0 to 60 min), was similar with each of the preparations applied in the low dose. When used in the high dose, the chewing gum and also the plain tablets provided significantly more fluoride in saliva than the chewable tablets. The data may suggest that unflavored plain F tablets are equally suitable as a vehicle for fluoride aiming at a topical cariostatic effect as specially designed chawable tablets or chewing gum.
The release of fluoride from fluoride-containing chewing gum and the fluoride concentration in whole saliva was measured at different intervals after the start of the chewing procedures. The residual fluoride contents were 78, 32, and 6% of the initial 0.25 mg in the gum after chewing for 2, 5, and 10 min, respectively. When chewing for 10 min, the salivary fluoride increased from 0.05 to 11.7 and 15.3 parts/10(6) after 2 and 5 min, respectively, followed by a fall to 3.9 parts/10(6) after 10 min. Concentrations exceeding the preintake level were still recorded 60 min after the start of the chewing.
The formation of CaF2 was measured on sound enamel and in artificial, standardized (acidified gelatin, pH 4.5) caries-like enamel lesions after exposure to: (a) dentifrice/saliva slurries adjusted to relevant F-concentrations of approximately 100 or 8 ppm by appropriate addition of 1,000 ppm F NaF or Na monofluorophosphate (MFP) dentifrice, respectively, or (b) a mixture of saliva with a 0.2% NaF solution obtained by a usual 1-min rinse procedure or an aqueous solution of 0.2% NaF. CaF2 was determined after extraction with KOH and fluoride analysis by gas chromatography. Only negligible amounts of CaF2 were produced on sound enamel ranging from (mean +/- SEM) 0.76 +/- 0.14 micrograms F/cm2 with the 0.2% NaF solution to as little as 0.04 +/- 0.06 with the MFP dentifrice slurry. In caries-like enamel lesions, the CaF2 production with the 0.2% NaF solution/saliva mixture corresponded to 3.7 +/- 0.4 micrograms F/cm2 and corresponding amounts obtained with the dentifrice/saliva slurries were 1.5 +/- 0.19 micrograms F/cm2 with NaF, but only 0.19 +/- 0.04 with MFP. It was suggested that the deposition of CaF2 in the micropores of early lesions can be expected to be an important mechanism with F rinses, probably to some extent with NaF dentifrices, but barely with MFP dentifrices. The formation of CaF2 on sound enamel is unlikely to play a significant role in the caries-reducing effect of F rinses and F dentifrices.
The present study was designed to assess the effect of F compound and F concentration in dentifrices on fluoride in whole saliva after ordinary toothbrushing. The dentifrices tested had the same basic composition and contained NaF: 500, 1,000 or 1,500 ppm F or MFP: 1,000 or 1,500 ppm F. Whole saliva samples were collected at different times up to 120 min after brushing with controlled amounts of dentifrice. With all dentifrices tested, total F in whole saliva remained higher than controls for more than 60 min. Total F and F–– levels showed a simple relationship to the F concentration in the dentifrices. The F–– levels were initially significantly lower with the MFP than with comparable NaF preparations, but 10 min after brushing similar F–– levels were observed with the two compounds. With the MFP dentifrices the proportion of F–– to total F increased from 4% after 0.5 min to about 65% after 10 min indicating that MFP was subjected to rapid hydrolysis in the oral environment.
Abstract – The intraoral hydrolysis of monofluorophosphate (MFP) was compared in nine subjects with natural teeth and in nine edentulous subjects after a 1‐min mouthrinse with a 100 ppm MFP solution. Analyses of total F and F‐ in whole saliva samples collected up to 15 min after the rinse suggested that apatite catalyzed breakdown of MFP mediated by dental enamel contributes significantly to the intraoral hydrolysis of MFP.
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