Effects of a sodium fluoride solution and a varnish with different fluoride concentrations on enamel remineralization in vitro

To study the efficacy of sodium fluoride varnishes and a NaF solution in remineralization of enamel, 120 slabs of non-carious human enamel enamel were presoftened for 6 h and randomly divided into six groups. The slabs were stored in synthetic saliva for 9 days, except for a daily 30-min immersion in 0.1 M lactic acid-NaOH buffer. During the 9-day period, one group of the slabs received no treatment, and the rest were treated once or three times with 2.3% or 1.1% sodium fluoride varnish Duraphat, or nine times with a 0.1% NaF solution. Finally, the slabs were demineralized for 1 h, and the amount of dissolved Ca and F was determined. Microhardness of enamel was determined initially, after presoftening, after the 9-day period, and after the 1-h demineralization. All fluoride treatments prevented enamel softening almost completely during the 9 days, but the control slabs softened markedly. Fluoride varnishes were more effective than NaF solution. Three applications of 2.3% Duraphat were slightly more effective than any of the other varnish treatments, but one treatment with 2.3% varnish was not more effective than treatments with 1.1% varnish. Enamel treated three times with 1.1% varnish showed the greatest acid resistance during the 1-h demineralization. The results suggest that the efficacy of the varnish was not proportional to the fluoride concentration but rather to the number of applications. Fluoride uptake by enamel was greatest with the most concentrated varnish. Enamel solubility was not, however, directly proportional to the fluoride content of enamel.     

成膜基质对氟化物涂膜抑制釉质早期龋的效果

目的:比较含不同成膜基质的氟化物涂膜抑制釉质早期龋的效果。方法:将制备的90个釉质试样块随机分成6组,分别应用以5种成膜基质(珂巴树脂、渗透型丙烯酸树脂、甲基丙烯酸乙酯共聚树脂、聚合松香、聚乙烯醇缩丁醛)配制的氟涂膜材料和Duraphat氟涂膜进行处理。采用荧光显微镜和显微硬度计测定各组釉质试样块在pH循环前后的荧光值和硬度值的变化;并通过偏光显微镜观察其脱矿深度。结果:pH循环后各组釉质试样块的荧光值和硬度值均较pH循环前明显降低,其中渗透型丙烯酸组与其他组相比,荧光损失率和硬度值变化率最小,与其他各组相比差异均有统计学意义(P<0.05);偏光显微镜观察显示:各组釉质表面均无实质性缺损,渗透型丙烯酸组釉质脱矿深度最浅。结论:氟化物涂膜具有明显的抑制釉质脱矿的作用,含渗透型丙烯酸树脂的氟涂膜效果最好。     

Fluoride varnishes containing sodium trimetaphosphate reduce enamel demineralization in vitro

Objective: This study evaluated the effects of fluoride varnishes containing sodium trimetaphosphate (TMP) on bovine enamel demineralization in vitro.

Material and methods: Enamel bovine discs were randomly assigned into six groups (n?=?20/group): placebo, 2.5% NaF, 2.5% NaF/5% TMP, 5% NaF, 5% NaF/5% TMP, and a commercial formulation (Duraphat, 5% NaF). Varnishes were applied on all enamel discs and kept for 6?h. Loosely and firmly bound fluoride formed on/in enamel after treatment were analyzed in 10 discs from each group. The other 10 discs were subjected to a pH-cycling regimen for 7 days, and analyzed for surface (SH) and cross-sectional hardness (ΔKHN), as well as for loosely and firmly bound fluoride in/on enamel. Data were analyzed by analysis of variance (ANOVA) followed by Student–Newman–Keuls’ test (p?Results: The lowest SH change and ΔKHN were observed for the 5%NaF/5%TMP varnish, which was significantly different from all the other groups. Both fluoridated varnishes containing TMP promoted significantly lower SH change and ΔKHN when compared with their counterparts without TMP. Loosely and firmly bound fluoride was significantly lower in groups treated with varnishes containing TMP.

Conclusion: TMP and fluoride added to varnishes have a synergistic effect against enamel demineralization in vitro.     

In vitro fluoride uptake, distribution and retention by human enamel after 1- and 24-hour application of various topical fluoride agents

The in vitro fluoride acquisition by human enamel after a 1-hour and 24-hour application of APF, Duraphat (a resin varnish) or Fluor Protector (a polyurethane varnish) and subjection to various procedures was determined. Fluoride acquisition was the greatest in teeth treated with Fluor Protector and the least in APF-treated teeth. Fluoride uptake and distribution were increased by prolonging the contact time between the varnishes and enamel, and fluoride retention was decreased after subsequent exposure to synthetic saliva.     

Prevention of rat fissure caries by sodium fluoride varnish (Duraphat) with different fluoride concentrations

125 Osborne-Mendel rats were weaned at 22-23 days, inoculated with Streptococcus sobrinus and fed a cariogenic diet for 40 days. The control group received no treatment; the study groups received applications of Duraphat containing 2.3, 1.1, or 0.6% fluoride or a placebo varnish on days 21-23. The placebo varnish had no effect on caries. Fissure caries was significantly reduced by the 2.3 and 1.1% fluoride varnishes, whereas the caries reduction found after treatment with the 0.6% fluoride varnish was not statistically significant. These results suggest that reducing the fluoride content of Duraphat by half does not significantly reduce its caries-preventive effect, but the progress of caries seems to be somewhat slower with the 2.3% fluoride varnish.     

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.     

Effect of a combination of fluoride dentifrice and varnish on enamel surface rehardening and fluoride uptake in vitro

The purpose of this study was to evaluate the effect of combining fluoride dentifrice (FD) and varnish (FV) on in vitro enamel surface rehardening and on fluoride uptake under a pH-cycling regimen. Seventy-eight bovine enamel blocks with early lesions were used and 52 were divided into four treatment groups: (a) placebo non-fluoridated dentifrice (PD); (b); FD (1100 p.p.m. F as NaF); (c); FV (Duraphat) + PD; and (d) FV + FD. The FV was applied to enamel blocks of groups FV + PD and FV + FD before the pH-cycling regimen, and all of them were submitted to dentifrice during cycling. Surface enamel microhardness was determined on the dental blocks before and after demineralization, and after the pH-cycling regimen. The percentage of surface microhardness recovery (%SMHR) was calculated. Fluoride in the blocks was also determined, after removing three layers of enamel. The highest values of percentage SMHR were observed for the FD group. The greatest fluoride uptake was found in the FD and FV + FD groups, but the difference between them was not statistically significant. It was found that the frequent use of fluoride dentifrice resulted in greater benefit in enamel surface rehardening, with a similar effect on fluoride uptake, when compared with its combination with a single fluoride varnish application.     

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...     

Caries inhibiting effect of ammonium fluoride varnish in vitro

The reaction of incorporation of fluoride into tooth enamel from NH4F varnish, and Duaphat were measured using SEMq2 in vitro. Level of enamel uptake of fluoride was highest in teeth treated with NH4F varnish. Average depth of fluoride penetrated into enamel was more than 80 microns from the two varnishes. Prolonged coating duration from 24 hours to 1 week did not increase uptake and penetration of fluoride from both varnishes. The NH4F varnish was found to be superior to Duraphat in terms of inhibiting artificial caries lesion formation (P less than 0.001).     

The role of 'CaF2-like' material in topical fluoridation of enamel in situ

In this paper the role and importance of 'CaF2-like' material deposited on enamel (Fon) by means of an APF gel and the varnishes Duraphat and Fluor Protector are described and discussed. The amount of Fon, determined by KOH extraction, is a measure of the amount of CaF2-like material on the enamel surface. Fluoride in the enamel (Fin), determined by etching, is the amount of F- bound in the solid enamel. Fon and Fin data are presented after various F- treatments and after wearing enamel slabs in dentures for a period of 1 week. The results of this work show that if we compare the three fluoridating agents, APF gel, Duraphat varnish, and Fluor Protector varnish in situ, only Fluor Protector shows a measurable amount of Fon after 1 week. The amounts of Fon acquired by the enamel surface (one application) rank as APF gel approximately Duraphat much less than Fluor Protector. Most likely, Fon in situ leaches away through the pellicle, with an apparent diffusion coefficient of about 10(-6) cm2.sec-1. The Fin data show that after APF gel or Duraphat treatment a substantial amount of Fin leaches away during 1 week in situ; the Fin values of Fluor Protector do not change. The efficiency of the fluoridating agents is most likely determined by the application period and fluoride availability. For APF gel, Duraphat, and Fluor Protector about 5%, 1%, and 44% of the available fluoride participates in the fluoridation process. CaF2-like globules are known to precipitate after gel or varnish treatment on the enamel surfaces and can be dissolved in KOH solution.(ABSTRACT TRUNCATED AT 250 WORDS)     

A 2-year report on caries prevention by fluoride varnishes in a community with fluoridated water

The benefit of semi-annual applications of sodium fluoride varnish (Duraphat) and silane fluoride varnish (Fluor Protector) was studied in 11-13 year-old children with life-long exposure to fluoridated drinking water (1-1.2 parts/10(6)). Annual clinical and radiographic examinations were made on 67 children in the Duraphat group and 71 children in the Fluor Protector group. Fluoride varnish was applied semi-annually using the half-mouth technique. At the end of 2 years, the mean overall DMFS-increments on the control side and test side of the Duraphat group were 5.0 and 3.8 (p less than 0.01), respectively, and of the Fluor Protector group 3.7 and 3.3 (NS). The caries reductions were 24% and 12%, respectively. Since there were no differences between initial mean DMFS scores of the groups, it was assumed that lower increments in the Fluor Protector group were due to Fluoride ions crossing the midline and providing protection on the control side as well. When increments in the Duraphat control side and the Fluor Protector test side were compared, the caries reduction of Fluor Protector was 35% (p less than 0.01). Fluoride varnishes provide additional benefit even when fluoride intake from drinking water is optimal.     

Effects of experimental xylitol varnishes and solutions on bovine enamel erosion in vitro

This in vitro study aimed to analyze the effects of application of xylitol varnishes and solutions to protect against enamel erosion. Twelve bovine enamel specimens were pre-treated with 5% NaF-Duraphat varnish, 10% xylitol varnish, 20% xylitol varnish, placebo varnish, 5% NaF solution, 10% xylitol solution or 20% xylitol solution. The varnishes and solutions were applied for 6 h and 1 min, respectively. Controls remained untreated (n = 12). Specimens were then subjected to erosive demineralization (Coca-Cola, 4 × 90 s/d) and remineralization (artificial saliva, 2 h) cycling for 10 days. After 5 days, the varnishes and solutions were reapplied. After reapplication, two specimens per group were analyzed by SEM. Enamel loss was measured profilometrically after the 5th and 10th days. Data were then analyzed statistically by ANOVA and Tukey's post-hoc test (n = 10, P < 0.05). After the 5th day, all varnishes and 20% xylitol solution significantly reduced the enamel loss when compared to the placebo varnish/control. After 10 days of erosive pH cycling, both xylitol varnishes and solutions significantly reduced the enamel erosion when compared with the control. However, 10% xylitol solution produced a smooth layer on eroded enamel and significantly reduced the enamel erosion when compared to the placebo varnish/control. Xylitol thus appears to be a good option to partially reduce enamel erosion.     

Enamel fluoride uptake of a novel water-based fluoride varnish

Aim of the in situ-study was to evaluate fluoride retention in sound and demineralised enamel after application of a novel water-based fluoride (0.12% F) varnish Mirafluorid (Hager and Werken, Germany) compared to the resin-based varnish (2.26% F) Duraphat (Colgate, USA). Each five enamel specimens were prepared from 60 bovine incisors. In 150 of these specimens, incipient lesions were produced with acidic hydroxyethylcellulose (pH 4.8; 72 h), 150 specimens were not demineralised. The samples were equally (n=100) allotted to three groups (A: Mirafluord, B: Duraphat, and C: control). Each 80 specimens (40 demineralised and 40 sound) were varnished with either Mirafluorid or Duraphat or remained unfluoridated (controls). The other specimens were used for measuring base-line fluoride content of the respective tooth. Each six specimens (three demineralised and three sound) were fixed in intraoral appliances worn for 5 days by 10 volunteers in three series (A-C). During the experiment, the samples were brushed twice daily with fluoridated toothpaste. KOH-soluble and structurally bound fluoride (0-30 and 31-60 microm depth) was determined immediately, 1, 3 and 5 days after fluoridation. Fluoride uptake was calculated as compared to base-line content and statistically analysed. Immediately after fluoridation, uptake of KOH-soluble and structurally bound fluoride was similar for Mirafluorid and Duraphat in both demineralised and sound enamel. However, at day 1, 3 and 5 statistically significantly higher amounts of KOH-soluble and structurally bound fluoride were found in the samples treated with Duraphat. For Mirafluorid only the uptake for KOH-soluble fluoride and structurally bound fluoride in the first enamel layer (0-30 microm) of the demineralised samples was significantly higher compared to the controls (C). It is concluded that the novel fluoride varnish Mirafluorid deposits less KOH-soluble and structurally bound fluoride on both demineralised and sound enamel compared to Duraphat under in situ-conditions.     

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.     

Effect of a fluoride varnish on demineralization adjacent to orthodontic brackets.

Home fluoride regimens have long been used to reduce the amount of demineralization adjacent to orthodontic appliances. In the absence of patient compliance, another method of applying the fluoride must be used. The purpose of this study was to evaluate, in vitro, the ability of a fluoride varnish, Duraflor, to directly inhibit demineralization of enamel surrounding orthodontic brackets. Brackets were bonded to 36 extracted human canines and premolars with a traditional composite resin and randomly assigned to three equal groups of twelve. Group 1 served as the control with no topical application after bonding. Group 2 was treated with a single application of a nonfluoridated placebo varnish. Group 3 was treated with a single application of Duraflor. All groups were cycled in an artificial caries challenge for 1 hour two times daily for 37 days and were brushed with a medium bristled toothbrush to simulate mechanical wear of the varnish. Demineralization of enamel was evaluated in longitudinal buccolingual tooth sections using polarized light microscopy. Both average depth and area of demineralization were measured with a sonic digitizer. ANOVA (P 相似文献   

Evaluation of fluoride release from commercially available fluoride varnishes.

BACKGROUND: The authors conducted a study to evaluate the fluoride released from two fluoride varnishes: Duraphat (Colgate-Palmolive Co., New York) and Duraflor (Pharmascience Inc., Montreal). Fluoride-release information for these commercially available dental products has not been available to clinicians treating children at risk of developing dental caries. METHODS: The authors painted enamel slabs from primary molar teeth with 30 milligrams of two varnishes: nine samples received Duraphat, nine received Duraflor and five samples served as controls. The samples were immersed in buffered calcium phosphate solution (pH, 6.0) to simulate the oral environment, and the amount of fluoride released was measured weekly for six months. RESULTS: From week 4 to the end of the study, Duraphat released significantly more fluoride than Duraflor. Duraflor continued releasing fluoride until week 19, while Duraphat released fluoride until week 28. The authors found greater variability in the release of fluoride from the Duraflor samples than from the Duraphat samples. Two-thirds of the fluoride was released from both products by the end of the study. CONCLUSIONS: Both varnishes released fluoride for five to six months. However, the two products exhibited differences in their release kinetics. CLINICAL IMPLICATIONS: These findings show that either of the fluoride varnishes may maintain a high level of fluoride in plaque fluid around primary teeth over a long period, but that the availability of fluoride may vary among tubes of the same product and between the two products themselves.     

A 2-year report on caries prevention by fluoride varnishes in a community with fluoridated water

Abstract – The benefit of semi-annual applications of sodium fluoride varnish (Duraphat®) and silanc fluoride varnish (Fluor Protector®) was studied in 11-13-year-old children with life-long exposure to fluoridated drinking water (1–1.2 parts/ 10⁶). Annual clinical and radiograpic examinations were made on 67 children in the Duraphat group and 71 children in the Fluor Protcctor group. Floride varnish was applied semi-annually using the half-mouth tecnique. At the end of 2 years, the mean overall DMFS- increments on te control side and test side of the Duraphat group were 5.0 and 3.8 ( P 0.01), respectively, and of te Fluor Protector group 3.7 and 3.3 (NS). The caries redutions were 24%and 12%, respectively. Since there were no differences between initial mean DMFS scores of te groups, it was assumed that lower increments in the Fluor Protector group were due to fluoride ions crossing the midline and providing protectioon on the control side as well. When increments in the Duraphat control side and the Fluor Protector test side were compared, the caries reducation of Fluor Protector was 35% ( P <0.01). Fluoride varnishes provide additional benefit even when fluoride intake from drinking water is optimal.     

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.     

Uptake of KOH-soluble and KOH-insoluble fluoride in sound human enamel after topical application of a fluoride varnish (Duraphat) or a neutral 2% NaF solution in vitro.

The uptake of alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) and alkali-insoluble fluoride (apatitically bound fluoride) on sound human enamel from treatment with Duraphat or a neutral 2% NaF solution was investigated in vitro. Blocks from impacted third molars were used. More fluoride was deposited on the enamel from the neutral 2% NaF solution than from the Duraphat treatment. All the fluoride could be dissolved in alkali. Globules of calcium fluoride-like material were demonstrated by scanning electron microscopy. Chemical analysis showed no measurable increase in the apatitically bound fluoride (alkali-insoluble fluoride) after brief exposures. Duraphat-treated samples submerged in water after the exposure lost only about 50% of the deposited fluoride, whereas samples treated with 2% NaF are known to lose all their fluoride under similar circumstances, a condition which may be related to the favorable clinical effect of Duraphat.