Assessing fluoride concentration uniformity and fluoride release from three varnishes

BACKGROUND: The authors investigated the fluoride content uniformity of three commercial fluoride varnishes, as well as their fluoride-release behaviors. METHODS: The authors examined 20 doses from each of two tubes of Duraphat (Colgate-Palmolive Co., New York) and Duraflor (Pharmascience Inc., Montreal), and 20 doses of individually packaged 0.25-milliliter and 0.40-mL units of CavityShield (OMNII Oral Pharmaceuticals, West Palm Beach, Fla.). Part of the dose was dissolved in chloroform, followed by fluoride extraction with distilled water. The authors painted the remaining varnish from five predetermined doses from each group onto plastic substrates for examination of fluoride release. Fluoride concentrations in the solutions were measured with a fluoride-selective ion electrode. RESULTS: One-way analysis of variance showed statistically significant differences between varnish groups. The fluoride content was more uniform in Duraphat and CavityShield than it was in Duraflor. The fluoride release profiles in terms of percentage of total fluoride released over time were different among different groups of varnishes and were similar among samples from the same test group. The authors found that Duraflor released consistently more fluoride in artificial saliva than did the other two varnishes. CONCLUSIONS: Fluoride content can vary between doses dispensed from the same tube. Uniformity also varies between different varnishes and affects the retention of fluoride in the varnish. CLINICAL IMPLICATIONS: Clinicians should be aware that the nonuniform appearance of fluoride varnish as squeezed out of the tube could indicate separation of ingredients, resulting in variation of fluoride content.     

两种氟防龋涂膜材料的释氟性及抗脱矿能力的研究

目的 比较两种氟防龋涂膜材料的释氟性及其提高釉质的抗脱矿能力。方法 将两种市售的FQ氟涂膜和多乐氟涂膜分别涂覆于20 mm×20 mm的方形聚酯塑料载片表面，每个聚酯塑料载片浸于20mL去离子水中，分别于浸水后3 h、6 h、12 h及24 h测定氟离子浓度，计算释氟率；扫描电镜观察氟涂膜表面形貌。制备5 mm×5 mm×3 mm的牛切牙釉质块，自凝树脂包埋后表面打磨抛光，测定初始表面显微硬度(SMH0)，在釉质块表面涂覆氟涂膜，浸水12 h，然后去除氟涂膜，对釉质块进行pH循环脱矿，7天后测定釉质块表面显微硬度(SMH1)，计算脱矿后釉质表面显微硬度下降率，设立阳性对照和阴性对照。结果 FQ氟涂膜和多乐氟3 h、6 h、12 h、24 h释氟率分别为(2.73±0.27)%、(3.19±0.05)%、(3.58±0.19)%、(3.63±0.08)%和(0.16±0.02)%、(0.34±0.03)%、(0.43±0.03)%、(0.48±0.03)%；经过pH循环脱矿后，应用过氟涂膜的釉质表面显微硬度下降率显著低于未用氟涂膜的釉质（85.95±3.50）%,FQ氟涂膜和多乐氟的硬度...     

Evaluation of fluoride release from experimental TiF4 and NaF varnishes in vitro

Fluoride varnishes play an important role in the prevention of dental caries, promoting the inhibition of demineralization and the increase of remineralization.

Objective

This study aimed to analyze the amount of fluoride released into water and artificial saliva from experimental TiF₄ and NaF varnishes, with different concentrations, for 12 h.

Material and Methods

Fluoride varnishes were applied on acrylic blocks and then immersed in 10 ml of deionized water and artificial saliva in polystyrene bottles. The acrylic blocks were divided in seven groups (n=10): 1.55% TiF₄ varnish (0.95% F, pH 1.0); 3.10% TiF₄ varnish (1.90% F, pH 1.0); 3.10% and 4% TiF₄ varnish (2.45% F, pH 1.0); 2.10% NaF varnish (0.95% F, pH 5.0); 4.20% NaF varnish (1.90% F, pH 5.0); 5.42% NaF varnish (2.45% F, pH 5.0) and control (no treatment, n=5). The fluoride release was analyzed after 1/2, 1, 3, 6, 9 and 12 h of exposure. The analysis was performed using an ion-specific electrode coupled to a potentiometer. Two-way ANOVA and Bonferroni''s test were applied for the statistical analysis (p<0.05).

Results

TiF₄ varnishes released larger amounts of fluoride than NaF varnishes during the first 1/2 h, regardless of their concentration; 4% TiF₄ varnish released more fluoride than NaF varnishes for the first 6 h. The peak of fluoride release occurred at 3 h. There was a better dose-response relationship among the varnishes exposed to water than to artificial saliva.

Conclusions

The 3.10% and 4% TiF₄ -based varnishes have greater ability to release fluoride into water and artificial saliva compared to NaF varnish; however, more studies must be conducted to elucidate the mechanism of action of TiF₄ varnish on tooth surface.     

Studies of fluoride varnishes in Finland.

Despite the artificial fluoridation of drinking water in Kuopio, part of the children have high caries incidence. We therefore started our studies on fluoride varnishes in 1977 in an attempt to find a feasible means of applying fluoride topically in children at high risk of caries. In our first trial, the sodium fluoride varnish Duraphat was found to be effective in preventing caries, but the effectiveness of the silane fluoride varnish Fluor Protector could not be unequivocally established, despite the fact that Fluor Protector deposited markedly more fluoride in enamel than Duraphat. In a second study in children in a low-fluoride area, use of Duraphat was found to be more effective than fortnightly fluoride rinses or Fluor Protector. Increasing the frequency of application from two to four times a year did not increase the effectiveness of Duraphat even in highly caries-prone children in a 2-year trial. On the basis of peak values of fluoride in parotid saliva after application, use of either fluoride varnishes was considered safe. Although the fluoride content of the enamel remained elevated for at least two years after discontinuation of treatment with both varnishes, the caries preventive effect did not continue after the applications were stopped. This shows that increasing the fluoride content of enamel is not the main mechanism by which fluoride varnishes prevent caries, and that the applications need to be continued as long as caries is a problem.     

Evaluation of fluoride release from an orthodontic bonding system.

Decalcification around brackets is sometimes observed after orthodontic treatment. Fluoride-releasing orthodontic adhesives have been developed in an attempt to reduce the frequency and severity of decalcification. This study evaluated, in vitro, a light-activated, fluoride-releasing composite resin adhesive, FluorEver OBA. The findings indicate that FluorEver OBA released small concentrations of fluoride ions over time. A mean of 2.6 ppm was released on day 1, decreasing to a mean of 0.42 ppm by day 2 and to 0.04 ppm by day 43. The clinical implications of these findings are discussed.     

中子活化法测定氟保护漆体内释放的临床研究

目的利用中子活化分析法测定氟保护漆应用前、后牙釉质中氟含量的变化。方法选择15例患者,以临床同一患者将要拔除的2颗下颌乳中切牙为研究对象,1颗拔除作为对照,另1颗涂布口腔专用氟保护漆24h后再拔除,测定2颗牙牙釉质中氟的含量,进行统计学分析。结果试验组氟化物的含量为(142.78±42.25)μg/g,对照组为(119.62±38.62)μg/g。试验组中氟的含量大于对照组,差异有统计学意义(P<0.05)。结论氟保护漆的应用能有效增加牙齿硬组织中氟的含量。     

Treating hypersensitivity with fluoride varnishes

Dentinal hypersensitivity results when stimulation causes the fluid in open dentinal tubules to undergo pressure changes, which activates mechanoreceptor nerves and results in pain. Treatment with fluoride varnish forms a protective layer of calcium fluoride that prevents this fluid flow, thereby reducing dentinal sensitivity.     

A new look at fluoride varnishes

Fluoride varnishes have been available for over 30 years but there may be clinicians and dental public health practitioners who are unaware of the true level of effectiveness they provide in caries control. Under the headings of effectiveness, ease of application and safety the available evidence is digested and summarized to inform the reader about the indications, method of use and alternative options for caries control.     

Localized fluoride release from fluorine-carrying polyphosphonates.

Fluoride release from fluorine-carrying copolymers of vinylphosphonate induced by calcium apatite and tooth enamel has been investigated. Fluoride ions were determined potentiometrically in the study of calcium hydroxyapatite, and Auger spectroscopy was used to study the fluoride release to enamel. The adsorbed copolymer of vinylphosphonic acid and vinylphosphonyl thiofluoride was shown to release fluoride to calcium hydroxyapatite and to enamel. The oxygen analog has shown a similar behavior with calcium hydroxyapatite, but not with tooth enamel. The results suggest a potential application of such copolymers as caries preventive agents which combine the effects of polyphosphonates and of fluoride ions.     

Fluoride release from varnishes in two in vitro protocols

BACKGROUND: The authors conducted a study to evaluate fluoride released from fluoride varnishes that had been applied with two different protocols. Fluoride release information for these two approaches may allow clinicians to vary application intervals to better meet the needs of their patients. METHODS: The authors painted enamel slabs from exfoliated primary molar teeth either in a single application (five samples) or three times within a single week (five samples) with fluoride varnish (Duraphat, Colgate-Palmolive, New York). The samples were immersed in buffered calcium phosphate solution (pH 6) to simulate the oral environment; the amount of fluoride released was measured during a span of six months. RESULTS: The total release of fluoride was significantly higher in the three-application regimen (34.9 micromoles) than in the single application (23.7 micromol). The rate of release was slower using the three-application regimen. Thus, applying fluoride-release varnish three times in a single week produced greater and longer release of fluoride than did one application. CLINICAL IMPLICATIONS: Massed application of fluoride varnish during a single period during the year may be as effective as spaced single applications. This method can be a good alternative to delivering fluoride varnish to high-caries-risk patients who are mobile or difficult to recall.