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PubMed1994

Fluoride pharmacokinetics in infancy.

Fluoride pharmacokinetic data are presented for infants given a fluoride supplement. Seventeen infants participated in a total of 20 studies. On one day, 0.013 mmol (0.25 mg) fluoride was given as a supplement (fluoride supplement study), and on another day a placebo was given (control study). Samples of plasma and urine were collected for 5 h and analyzed for fluoride. During control studies fluoride intake averaged 0.15 mumol/kg (2.9 micrograms/kg), and plasma fluoride concentrations ranged from 0.05 to 0.11 mumol/L (10 to 20 micrograms/L). In nine instances, the quantity of fluoride excreted in the urine was more than twice that consumed. When the fluoride supplement was given, total fluoride intake averaged 1.93 mumol/kg (36.6 micrograms/kg). Plasma peak concentration was reached by 30 min in 14 studies and by 60 min in six studies. Mean plasma peak fluoride concentration was 3.3 mumol/L (63 ng/mL). Area under the plasma concentration curve averaged 236 nmol.m-1 x min (4479 ng.mL-1 x min) and was not related to the dose of fluoride. The rate of urinary excretion was significantly correlated with rate of urinary flow. When the dose of fluoride was expressed per unit of body weight, fluoride retention was strongly related to the dose. Retention of the fluoride absorbed from the fluoride dose ranged from 75.4 to 87.6%. Plasma clearance averaged 6.8 mL.kg-1 x min-1 and decreased significantly with age. Net fractional clearance (renal clearance of the fluoride dose/GFR) averaged 56.7%, which was significantly greater than the 29% observed during the control studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Caries↗
PubMed1995

Short-term fluoride release/uptake of glass ionomer restoratives.

OBJECTIVES: The short-term fluoride release/uptake of four glass ionomer restoratives was measured and compared to the fluoride release after exposure to three commercial fluoride gels. METHODS: Materials tested were: 1) Ketac-Fil (ESPE GmbH); 2) Ketac-Silver (ESPE GmbH); 3) Photac-Fil (ESPE GmbH); and 4) Fuji II LC (GC Corp.). Twenty discs of each material were fabricated and stored in deionized water at 37 degrees C. Initial fluoride release was measured at 24 h intervals for 7 d, and 24 h intervals at the end of each week for 5 wk. After 6 wk, samples were divided into groups and each group was treated for 6 min with one of the following commercial fluoride gels: acidulated phosphate fluoride (APF), neutral sodium fluoride (NaF), and stannous fluoride (SnF2). Control specimens were placed in deionized water. After exposure, fluoride measurements were carried out at 24 h intervals for 7 d, and 24 h intervals at the end of 2 wk. Fluoride exposure was repeated, and measurements were again recorded over 3 wk. RESULTS: Initial fluoride release by all materials was highest during the first 24 h and decreased sharply over the first week. After exposure to APF, fluoride release increased significantly for all materials. Exposure to NaF also resulted in increased fluoride release for all materials although it was not as high as the increase recorded after exposure to APF. Exposure to SnF2 did not result in significant fluoride release by any material. SIGNIFICANCE: The results of this study suggest that certain fluoride gels may replenish fluoride within some glass ionomers and thus prolong their cariostatic potential.

Acidulated Phosphate Fluoride↗
PubMed2003

Fluoride release from NaF- and AmF-impregnated toothpicks and dental flosses in vitro and in vivo.

The aim of this study was to determine the fluoride release from toothpicks and dental flosses in vitro and in vivo, and to evaluate various approximal administration methods. In vitro, a total of 23 commercially available toothpicks and dental flosses and 3 prototypes impregnated with sodium fluoride (NaF), amine fluoride (AmF) or a combination of these two were tested. Fluoride release was determined for up to 24 h using an ion-specific electrode. A large variation was found between the products; most fluoride being released after 30 min. Generally speaking, toothpicks produced higher values than flosses. In vivo, the fluoride concentration in both treated and non-treated approximal areas was evaluated after using 2 different types of toothpicks and 4 dental flosses and after different application methods--such as a fluoride gel and fluoride solution. The mean fluoride concentration in oral fluid was up to 10 times higher at the treated sites than at the non-treated sites. Use of a fresh toothpick or a fresh piece of dental floss in each approximal space resulted in higher values compared with using one and the same toothpick/floss for the whole dentition. An interdental brush dipped in 0.2% NaF gel and a mouthrinse with 0.2% NaF resulted in elevated fluoride concentrations at the same level as when multiple toothpicks were used. To conclude, there are large variations in the fluoride release from various brands of fluoridated toothpicks and dental flosses. Treatment with a fluoridated toothpick or a dental floss can be expected to give elevated fluoride concentrations in the approximal area up to 60 min. Another interesting method for administering fluoride in the approximal area is to use an interdental brush dipped in fluoride gel.

Adult↗
PubMed2000

Decision-making for national programs of community fluoride use.

Every community, region or country with a high or rising prevalence of dental caries should implement a caries-preventive program that automatically brings the benefits of systemic and topically applied fluoride to the entire population. The fluoridation of community water supplies or salt fulfills the requirements of providing safe, effective protection from dental caries at reasonable cost. The use of dietary fluoride supplements or fluoridated milk does not meet the requirements of a comprehensive national or community program because compliance is poor or only selected age groups are targeted. Water fluoridation is ideal for countries, regions or communities with many central water supplies or where salt production or distribution is not centralized or easy to control. Water fluoridation also has advantages where many areas exist with natural water fluoride concentrations at optimal or greater than optimal concentrations. Salt fluoridation is ideal for countries or regions with few, potable central water supplies in which salt production and distribution are centralized and easily controlled. Concentrations of fluoride for water fluoridation range from 0.5 to 1.2 parts per million (ppm) parts of water depending on climate and dietary practices. The concentration for fluoridation of salt is approximately 200 to 250 mg fluoride per kg of salt, also depending on dietary practices. Properly fluoridated salt should produce levels of urinary fluoride excretion similar to those found in communities with fluoridated water. Benefits of the two methods are similar. Salt fluoridation may be done more cheaply.

Community Dentistry↗
PubMed1993

Inhibitory effect of fluoride on insulin receptor autophosphorylation and tyrosine kinase activity.

Fluoride is a nucleophilic reagent which has been reported to inhibit a variety of different enzymes such as esterases, asymmetrical hydrolases and phosphatases. In this report, we demonstrate that fluoride inhibits tyrosine kinase activity of insulin receptors partially purified from rat skeletal muscle and human placenta. Fluoride inhibited in a similar dose-dependent manner both beta-subunit autophosphorylation and tyrosine kinase activity for exogenous substrates. This inhibitory effect of fluoride was not due to the formation of complexes with aluminum and took place in the absence of modifications of insulin-binding properties of the insulin receptor. Fluoride did not complete with the binding site for ATP or Mn2+. Fluoride also inhibited the autophosphorylation and tyrosine kinase activity of receptors for insulin-like growth factor I from human placenta. Addition of fluoride to the pre-phosphorylated insulin receptor produced a slow (time range of minutes) inhibition of receptor kinase activity. Furthermore, fluoride inhibited tyrosine kinase activity in the absence of changes in the phosphorylation of prephosphorylated insulin receptors, and the sensitivity to fluoride was similar to the sensitivity of the unphosphorylated insulin receptor. The effect of fluoride-on tyrosine kinase activity was markedly decreased when insulin receptors were preincubated with the copolymer of glutamate/tyrosine. Prior exposure of receptors to free tyrosine or phosphotyrosine also prevented the inhibitory effect of fluoride. However, the protective effect of tyrosine or phosphotyrosine was maximal at low concentrations, suggesting the interaction of these compounds with the receptor itself rather than with fluoride. These data suggest: (i) that fluoride interacts directly and slowly with the insulin receptor, which causes inhibition of its phosphotransferase activity; (ii) that the binding site of fluoride is not structurally modified by receptor phosphorylation; and (iii) based on the fact that fluoride inhibits phosphotransferase activity in the absence of alterations in the binding of ATP, Mn2+ or insulin, we speculate that fluoride binding might affect the transfer of phosphate from ATP to the tyrosine residues of the beta-subunit of the insulin receptor and to the tyrosine residues of exogenous substrates.

Adenosine Triphosphate↗
PubMedDate not supplied

Prediction of caries in pre-school children in relation to fluoride exposure.

The levels of salivary mutans streptococci and caries experience were used as predictors for caries incidence in 3 groups of pre-school children from areas with different levels of natural and topical fluoride exposure. Altogether 1022 children, 4-5 years of age at baseline, were examined according to the WHO-criteria and followed for 2 years. The low fluoride group (n = 374) had a low fluoride level in the piped water and no topical fluoride applications; the F-varnish group (n = 442) had low water fluoride but semiannual topical applications of a fluoride varnish; the optimal fluoride group (n = 206) had an optimal level of fluoride in the drinking water and semiannual F-varnish applications. The number of salivary mutans streptococci was estimated and scored at baseline with the Strip mutans chair-side method. The sampling procedure was repeated in 337 children of the low fluoride group 3 weeks after baseline. In comparison with the low fluoride group, caries incidence was 30% and 60% lower in the F-varnish and the optimal fluoride group respectively. The caries predictive ability decreased with increasing fluoride exposure. The sum of sensitivity and specificity decreased from 151% (65% + 86%) in the low fluoride group to 131% (40% + 91%) in the optimal fluoride group. The positive predictive value was highest (62%) in the low fluoride group. Repeated salivary samplings at baseline did not improve the caries predictive power. The results suggest that the overall fluoride exposure should be taken into account when caries risk assessment strategies for preschool children are developed and implemented.

Child, Preschool↗
PubMed2001

Effect of topical fluoride on retention of pit and fissure sealants.

PURPOSE: The purpose of this study was to evaluate the clinical effect of topical fluoride on retention of light-cured (CLC) and self-cured (CSC) pit and fissure sealants. METHODS: CLC and CSC sealants were placed in vivo on opposite sides of the arch before and after fluoride treatment. A total of 122 sealants were placed on virgin permanent molars and premolars of 16 dental hygiene students enrolled in a two-year program. Sealant retention in both fluoridated and non-fluoridated teeth was evaluated at 6, 12, and 18 month intervals. RESULTS: Overall sealant retention for both fluoridated and non-fluoridated teeth at 6, 12 and 18 months was 68%, 48%, and 49%, respectively. There was a significant difference (p < 0.001) when fluoridated vs. non-fluoridated teeth were compared. Retention was greater on the fluoridated teeth, with respect to the sealant material (CLC-fluoride). Significant differences (p < 0.001) were found when CLC-fluoride and CLC-no fluoride treatment groups were compared. However, no significant differences were found in retention when CSC-fluoride and CSC-no fluoride groups were compared, or when CLC was compared to CSC irrespective of fluoridation. Significant differences (p < 0.0001) were found when sealant retention on molars was compared to premolars--retention of sealants was greater on premolars. CONCLUSION: This study suggests that sealant retention may not be adversely affected by a topical fluoride treatment applied immediately prior to placement.

Acidulated Phosphate Fluoride↗
PubMed2001

Current concept on the anticaries fluoride mechanism of the action.

The paper discusses a possible new concept of the role of fluoride and its mechanism of action in caries prevention. In the past fluoride inhibition of caries was ascribed to reduced solubility due to incorporation of fluoride (F) into the enamel minerals (firmly bound fluoride or fluorapatite). Based on the new findings, it appears that fluoride, either released into or present in the fluid phase bathing the hard tissue, is more important for the reduction of caries development and progression. There is convincing evidence that fluoride has a major effect on demineralization and remineralization of dental hard tissue and that it interferes with acid production from cariogenic bacteria. The provision of dissolved fluoride is the key to successful therapy. The source of this fluoride could either be fluorapatite or calcium fluoride (CaF2) (like) precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. The precipitates of calcium fluoride do not dissolve quickly as was initially believed. Calcium fluoride coating at neutral pH by pellicle proteins and phosphate is the main reason for this. The dissolution of the fluoride from calcium fluoride is pH dependent. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. These are subsequently incorporated into the enamel as hydroxyfluorapatite or fluorapatite.

Calcium Fluoride↗
PubMed1975

Studies on intermittent fluoride administration.

The effects of the supplementation of equal amounts of fluoride given at different frequencies on caries inhibition and on fluoride uptake and retention by the molar surfaces were investigated in 3 rat caries tests. In the first experiment fluoride was supplemented to the drinking water, in the second it was incorporated in the cariogenic diet and in the third it was applied topically. In the first caries test fluoride was administered in the drinking water either continuously at concentrations of 20, 40 and 60 ppm F or at the double concentrations of 40, 80 and 120 ppm F every second day for 10 days prior to a cariogenic period of 21 days. At the end of the 10-day fluoride administration period the fluoride concentration in the molar surfaces (F-M) were closely correlated to the fluoride concentrations of the drinking solutions and to the intake by the animals. The molar surface disolution rates (S-M) were significantly lower in all fluoride groups than in the control groups but were not correlated to the F-M. At the end of the subsequent 21-day cariogenic period the S-M were not significantly lower in the fluoride than in the control groups. The F-M, significantly higher in the fluoride than in the control groups, were in the former groups not significantly different from each other. Irrespectively of the fluoride administration schedule, the caries incidences were equally lower in all fluoride groups than in the control groups. In the second caries test NaF and Na2PO2F were incorporated in the cariogenic diet and given to the rats at the same daily dose but at frequencies of 12, 18 and 36 times. The concentrations tested were 225, 150 and 75 ppm F. There were no significant differences between NaF and Na2PO3F in caries inhibitions, F-M and S-M. The frequency of fluoride administration had no significant effects on the parameters investigated. In the third caries test NaF and Na2PO3F were applied topically once, twice or thrice daily during a 20-day cariogenic period at concentrations of 4500, 2250 and 1500 ppm F respectively. While NaF and Na2PO3F were equally effective in inhibiting caries, NaF was more effective than Na2PO3F in enriching the F-M and in reducing S-M. Again the frequency of fluoride application had no significant effects. Because of the lack of influence of the frequency of fluoride supplementation on caries inhibition and the lack of correlation between caries reductions and F-M and S-M it was concluded from the caries tests that in the rat the interference of fluoride with the bacterial metabolism through its continous presence at the plaque-enamel interface rather than the reduction of enamel solubility and the promotion of enamel remineralization seems to be its most important cariostatic mechanism. A second series of experiments investigated the effects of the daily intragastric administration to pregnant rats of either 3.5 mg F once daily or 1...

Animals↗
PubMed2006

Pit and fissure sealants versus fluoride varnishes for preventing dental decay in children and adolescents.

BACKGROUND: The majority of the detected increment in dental caries is confined to pit and fissure surfaces of first molars. Application of pit and fissure sealants and topical fluorides are widely used procedures in the prevention of decay, and their effectiveness in caries prevention has been proved by systematic reviews. OBJECTIVES: The objective of this study was to compare the effectiveness of pit and fissure sealants with fluoride varnishes in the prevention of dental decay on occlusal surfaces. SEARCH STRATEGY: Electronic searching was performed on the following databases: the Cochrane Oral Health Group's Trials Register (last update November 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2005, Issue 4), MEDLINE (from 1966 to December 2005), EMBASE (from 1974 to November 2004), SIGLE (from 1976 to December 2004), SCISEARCH, CAplus, INSPEC, JICST-EPLUS, NTIS, PASCAL (last update December 2004), DARE, NHS EED and HTA (last update November 2005). Reference lists from articles that fulfilled the inclusion criteria in this review and from review articles based on the search of MEDLINE were searched for additional relevant articles. Conference abstracts published as books or journals and handsearched by the Cochrane Oral Health Group were also included. SELECTION CRITERIA: The inclusion criteria for study selection were: random or quasi-random allocation study design; sealants versus fluoride varnish or sealants and fluoride varnish combination versus fluoride varnish alone; included studies included caries documentation on occlusal surfaces of permanent molars and the subjects were under 20 years of age. Both parallel and split-mouth study designs were accepted. The primary outcome of interest was the increment in the numbers of carious occlusal surfaces of premolars and molars. A study was excluded if sealants and fluoride varnish were not compared with each other. DATA COLLECTION AND ANALYSIS: Two review authors carried out the baseline searches, selecting the papers on the basis of the title, keywords and abstract and making decisions about the eligibility and data extractions. The same review authors assessed the methodological quality of all included studies: for example, the allocation concealment, blinding, and completeness of follow up. Authors of the studies were contacted for additional information. Risk ratios (RR) as effect estimates were calculated for the differences in whether surfaces were carious or not in the treatment groups, along with the appropriate standard errors and 95% confidence intervals (CI). No data could be combined or meta-analyses undertaken due to the clinical and methodological diversity between study designs. MAIN RESULTS: Four studies were eligible for inclusion in the review. Three of the four studies compared the effectiveness of sealants with fluoride varnish application, and one study compared the effectiveness of sealants and fluoride varnish combination with fluoride varnish alone. Results of two studies revealed the effectiveness of pit and fissure sealants to be statistically significantly higher than an application of fluoride varnish every 6 months in preventing occlusal decays of first molars at 23 months (RR 0.74, 95% CI 0.58 to 0.95) and at 9 years follow up (RR 0.48, 95% CI 0.29 to 0.79). One of these studies was classed as at low risk of bias, one of moderate to high risk. One small study at moderate to high risk of bias failed to find a statistically significant difference between sealants and fluoride varnishes. One study of low risk of bias found a statistically significant difference in favour of the sealants and fluoride varnish combination compared with merely fluoride varnish at 24 months follow up with RR 0.36 (95% CI 0.21 to 0.61). The age of children in the included studies was 5 to 9 years. Allocation concealment was classified adequate in two of these four studies. AUTHORS' CONCLUSIONS: There was some evidence of the superiority of pit and fissure sealants over fluoride varnish application in the prevention of occlusal decays. However, it remained unclear to what extent there is difference between the effectiveness of pit and fissure sealants and fluoride varnishes. Therefore, more high quality research is needed. No recommendations for the clinical practice could be given and the benefit of pit and fissure sealants and fluoride varnishes should be considered locally and individually.

Adolescent↗
PubMed1995

Pretreatment with low doses of norethindrone potentiates the osteogenic effects of fluoride on human osteosarcoma cells.

We recently reported that picomolar doses of norethindrone (NET), a synthetic analog of 19-nortestosterone, significantly stimulated human TE85 osteosarcoma cell proliferation, differentiation, and activity in vitro. In the present study, we investigated the possibility that NET interacts with another osteogenic agent, i.e., fluoride, to stimulate human TE85 osteosarcoma cell proliferation, differentiation, and activities. Bone cell proliferation was measured by the stimulation in [3H]thymidine incorporation. Differentiation was monitored by the increase in alkaline phosphatase-specific activity. Osteoblastic activity was assessed by the stimulations in collagen synthesis and in osteocalcin secretion (in the presence of 1 nM 1,25-dihydroxyvitamin D3). When the human TE85 cells were incubated with mitogenic doses of NET and fluoride concurrently, the stimulatory effects of the two agents on these parameters exhibited no significant interaction. The enhancing effect of NET on the osteogenic effect of fluoride was not due to a shift of the fluoride dose response curve. Pretreatment with NET for 24 h followed by a treatment with a mitogenic dose (i.e., 100 microM) of fluoride for an additional 24 h significantly and synergistically potentiated the effects of fluoride on the [3H]thymidine incorporation, alkaline phosphatase-specific activity, collagen synthesis, and osteocalcin secretion, compared with those with the subsequent vehicle (0.05% ethanol) treatments. In contrast, pretreatment with fluoride for 24 h before the addition of NET for 24 h did not produce significant synergistic stimulations in the test parameters. Pretreatment of TE85 cells with the same doses of dihydrotestosterone or progesterone prior to treatment with fluoride under the same conditions did not induce synergistic potentiation of fluoride in [3H]thymidine incorporation, suggesting that the synergistic interaction with fluoride is probably not a common property of anabolic sex steroids. In summary, we found that: (1) the osteogenic effects of fluoride and NET were additive when cells were treated with both agents concurrently; (2) a 24-h pretreatment with picomolar doses of NET potentiated the osteogenic actions of fluoride in human TE85 osteosarcoma cells; and (3) pretreatment with NET produced a subsequent fluoride response that was synergistic. In conclusion, these findings led us to speculate that the osteogenic actions of NET and fluoride act through different mechanisms, and that NET at low doses has a permissive effect on the osteogenic effects of fluoride, and as such NET may be used in concert with fluoride to increase osteoblast proliferation, differentiation, and activity.

Alkaline Phosphatase↗
PubMed1993

A mathematical model for fluoride uptake by the skeleton.

A mathematical model was developed that predicts fluoride accumulation and clearance from the skeleton based upon fluoride bioavailability, bone remodeling rate, and the fluoride binding characteristics of bone. It was assumed that fluoride binds to bone in a nonlinear fashion such that a smaller percentage of fluoride is bound to bone if fluoride intake is increased to high levels. Bone resorption rate was assumed to be proportional to the solubility of hydroxyfluoroapatite which is inversely related to bone fluoride content. The predictions made by the model compared favorably with experimental results from fluoride uptake and clearance studies. Parametric studies done using the model showed the following: (1) fluoride can be cleared from the skeleton by bone remodeling, but fluoride clearance takes over four times longer than does fluoride uptake; and (2) fluoride uptake by the skeleton was positively associated with bone remodeling rate. However, the concentration of fluoride in newly formed bone does not decrease with reduced remodeling rates and surpasses 10,000 ppm for intakes of fluoride greater than 9 mg/day. For osteoporosis, daily dose and duration of fluoride treatment should be selected to avoid reaching a toxic cumulative bone fluoride content.

Apatites↗
PubMed1996

Dexamethasone enhances the osteogenic effects of fluoride in human TE85 osteosarcoma cells in vitro.

The in vitro osteogenic effects of fluoride have not always been consistently observed in human bone cells. The present study sought to test if dexamethasone (Dex) could potentiate the action of fluoride to increase the detectability of the stimulatory effects of fluoride on [3H]thymidine incorporation, alkaline phosphatase (ALP) specific activity, collagen synthesis, and osteocalcin secretion in human TE85 osteosarcoma cells. Neither Dex at 10(-10)-10(-6) M or fluoride at a mitogenic dose (100 microM) had any consistent stimulatory effects on thymidine incorporation. When the cells were treated with both agents simultaneously, significant and highly reproducible stimulations were observed. The mitogenic effects of the two agents were confirmed with cell number counting. Analysis of variance (ANOVA) revealed a significant interaction (P < 0.001) between fluoride and Dex on cell proliferation. The enhancing effect of Dex on [3H]thymidine incorporation was not due to a shift of the optimal dose response of fluoride. Though fluoride alone or Dex alone also had no consistent effect on ALP specific activity, the co-treatment with fluoride and Dex for 24 hours produced significant (P < 0.001, ANOVA) stimulation in ALP specific activity. Fluoride alone had no consistent effect on collagen synthesis and on 1, 25(OH)2D3-dependent osteocalcin secretion, whereas Dex treatment consistently inhibited these two osteoblastic parameters in a dose-dependent manner. However, both the collagen synthesis and osteocalcin secretion rates were significantly higher (P < 0.001 ANOVA for each) when the cells were co-treated with Dex and fluoride (100 microM) than when they were treated with Dex alone. Thus, these data indicate that the response in collagen synthesis and osteocalcin secretion to fluoride stimulation was more readily observed in the presence of Dex than in its absence. ANOVA analysis revealed that the interaction between fluoride and Dex on collagen synthesis, but not the 1,25(OH)2D3-dependent osteocalcin secretion, was significant (P < 0.02). In summary, we have demonstrated for the first time that in TE85 cells (1) Dex potentiated the effects of fluoride on cell proliferation, ALP specific activity, and collagen synthesis; (2) while Dex at 10(-7)-10(-6) M alone inhibited the collagen synthesis and at 10(-9)-10(-6) M reduced osteocalcin secretion, Dex at 10(-8)-10(-6) M significantly stimulated the proliferation of TE85 cells; and (3) Dex interacted with fluoride to increase the percentage of experiments showing an osteogenic action of fluoride. In conclusion, the in vitro osteogenic actions of fluoride in human TE85 cells are more consistently observed in the presence than in the absence of Dex.

Alkaline Phosphatase↗
PubMed2000

An in vitro study of fluoride release from a resin-modified glass ionomer cement after exposure to toothpaste slurries of different pH.

The aim of the study was to evaluate the fluoride release from an aged resin-modified glass ionomer (Vitremer) after exposure to five toothpaste slurries with different pH values. Cylindrical specimens of the material were leached in de-ionized water for 3 months and then exposed for 30 min daily for 10 days to three dentifrice slurries (20 specimens/group) containing 0.05% fluoride with pH values of 2.6, 5.7 and 8.3 and two non-fluoridated slurries with pH values of 2.5 and 5.7. A neutral NaF solution (0.05% F) was used as a control. During the 30 min exposure time, the fluoride concentration was gradually decreased in order to imitate the clinical situation. Thereafter, specimens were immersed individually in de-ionized water and the fluoride release determined. After the first day of exposure, all groups except one without fluoride (pH 5.7) showed significantly (P < 0.05) increased fluoride release. After exposure to the fluoridated toothpaste slurry with pH 5.7, significantly (P < 0.05) more fluoride was released compared to the toothpaste slurry with pH 8.3. Low pH (2.5 or 2.6) of the slurry resulted in a significantly (P < 0.05) higher fluoride release, regardless of whether it was fluoridated or not. The total amount of fluoride released after exposure to the more acidic fluoride toothpaste slurry was greater than that released from the more acidic non-fluoride toothpaste and the less acidic fluoride toothpaste. Our data indicate that the fluoride release from the resin-modified glass ionomer studied may be increased after treatment with an acidified NaF-toothpaste.

Analysis of Variance↗
PubMed1999

In vitro and in vivo fluoride release from orthodontic elastomeric ligature ties.

Clinically, demineralization of enamel around orthodontic attachments can occur after only 1 month. Fluoride incorporation into elastomeric ligature ties may provide additional protection against decalcification through fluoride release. This study compared the fluoride release of fluoride-impregnated and nonfluoride elastomeric ligature ties (Ortho Arch Company) both in vitro and in vivo. A total of 260 fluoride-impregnated and 260 nonfluoride elastomerics were evaluated in this study, 400 in vitro and 120 in vivo. For the in vivo part of the study, six patients had fluoride and nonfluoride elastomerics placed in cross-quadrant fashion in their mouths; these were removed and tested for residual fluoride release after 1 month. With the use of the potentiometric analytical method, the fluoride release of the elastomerics was determined in distilled water as the 24-hour residual release, to compare the in vitro and in vivo fluoride leached into solution. The data was analyzed with the Wilcoxon matched-pairs signed ranks test. The distilled water control yielded an F- reading of 0.03 +/- 0.01 microgram/F/mL. In the in vitro part of the study, an average of 0. 38 microgram/F/mL/elastomeric was released over the 1 month period by the fluoride-impregnated elastomerics; this decreased significantly (P <. 05) to a 24-hour residual value at 1 month of 0.02 microgram/F/mL/elastomeric ligature, which is in the same order of magnitude as the distilled water control solution. The nonfluoride ties produced a calculated 24 hour residual fluoride release of 0. 003 microgram/F/mL/elastomeric after 1 month; this is much less than the distilled water control and would not be possible to measure accurately. After 1 month in vivo, significantly greater (P >.05) amounts of 24-hour residual fluoride were apparent: F- elastomerics = 1.43 microgram/F/mL/elastomeric and nonfluoride elastomerics = 0.44 microgram/F/mL/elastomeric. Fluoride ties gained weight intra-orally. Residual, leachable fluoride was present in fluoride-impregnated and nonfluoride elastomeric ligature ties after 1 month of intraoral use, due to imbibition. The clinical efficacy of fluoride-impregnated elastomeric ligature ties to prevent decalcification in the presence of plaque needs to be investigated.

Female↗
PubMed2002

Esthetically objectionable fluorosis attributable to water fluoridation.

OBJECTIVE: We compared estimates of fluorosis prevalence and risk attributable to fluoridation using an index applied to the entire dentition and to the maxillary anterior teeth. We also estimated the prevalence of perceived esthetic problems attributable to current fluoridation policy (Attributable Burden). METHODS: Fluorosis prevalence estimates were obtained from the National Survey of Oral Health in US School Children (1986-87) for the 1839 survey children aged 12 -14 years who were scored for fluorosis, had never received fluoride drops or tablets, and had lived in only one home. For each child we calculated Dean's fluorosis index, and an anterior fluorosis index (value of the highest scored maxillary anterior tooth). We used each index to calculate risk of fluorosis attributable to fluoridation by subtracting at each level of severity the prevalence of fluorosis among those living in low fluoride areas (F <or= 0.3 ppm) from the prevalence among those living in optimally fluoridated areas (0.7 ppm F <or=1.2 ppm). Findings from five published studies were used to calculate risk of perceived esthetic problem attributable to fluorosis, by severity, i.e. the difference in the mean percentage of respondents who were satisfied with the appearance of their teeth with and without fluorosis. Finally, Attributable Burden was estimated by summing the products of risk of perceived esthetic problems attributable to fluorosis and risk of fluorosis attributable to fluoridation for each level of fluorosis severity. RESULTS: Prevalence of fluorosis, very mild or greater, was 26% with Dean's Index, which was significantly higher than the 18% figure calculated with the anterior index. Using the anterior index, fluoridation was a risk factor for very mild (attributable risk = 15%) and mild fluorosis (attributable risk = 3%). Risk of fluorosis (very mild or greater) attributable to fluoridation was significantly higher when calculated from prevalence estimates using Dean's Index than estimates calculated with the anterior index (24% versus 18%). The mean values of risk of perceived esthetic problems attributable to very mild and mild fluorosis were 9% and 33%, respectively. CONCLUSION: We found that approximately 2% of US schoolchildren may experience perceived esthetic problems which could be attributed to the currently recommended levels of fluoride in drinking water. The findings further suggest that both estimates of fluorosis prevalence and risk of fluorosis attributable to fluoridation will be higher when calculated with an index applied to the entire dentition. Data were unavailable for fluoridated toothpaste and diluted formula consumption, thus the risk of fluorosis attributable to fluoridation may be overestimated if consumption was higher in fluoridated areas. The risk of perceived esthetic problems attributable to fluoridation must be weighed against its lifetime benefits and the associated costs of alternative solutions such as educating parents about appropriate toothpaste use and lowering the fluoride content of children's toothpaste.

Adolescent↗
PubMed2006

Fluoride release rate from an orthodontic sealant and its clinical implications.

The objectives were to measure the rate and amount of fluoride ions released from the sealant over a period of 17 weeks and to determine whether the fluoride-releasing sealant has a recharging ability when fluoride ions are reintroduced into the environment. Disc-shaped specimens were prepared from two types of sealants: (1) 10 discs were made using a fluoride-releasing sealant and (2) 10 discs were made of a nonfluoride adhesive primer (control). An ion analyzer was used to measure the fluoride release using a fluoride ion-specific combination electrode. The results of the repeated measure analysis (F = 7.76) indicated that the fluoride-containing sealant released fluoride ions into the solution in sustained but significantly (P = .014) decreasing rates from a high of 0.074 +/- 0.04 ppm/week/mm2 in the first week to a low of 0.015 +/- 0.017 ppm/week/mm2 at the end of the 17th week. Furthermore, the Pro Seal discs had the ability to be recharged with fluoride ions introduced from a foaming solution of acidulated phosphate fluoride. The mean fluoride release rate one week after recharging was 0.354 +/- 0.095 ppm/week/mm2 and decreased to 0.014 +/- 0.009 ppm/week/mm2 after eight weeks. The control sealant showed no significant fluoride release and was unable to absorb the fluoride ions available in the solution. The fluoride-containing sealant Pro Seal released fluoride ions in sustained but significantly decreasing amounts. The Pro Seal discs had the ability to be recharged with fluoride ions.

Cariostatic Agents↗
PubMed1999

Fluoride in the oral environment.

A predominant part of the cariostatic activity of fluoride is a function of its concentration in the fluid environment of the teeth. The fluoride exposure results in a slightly elevated steady-state level of fluoride in the oral fluids, primarily in saliva and plaque fluid. So far, however, little is known about the intra-oral fluoride concentration necessary to achieve a cariostatic effect at the site of action. Following fluoride intake, the fluoride remaining in the oral cavity is diluted by the saliva pool. The remaining fluoride may be found in several compartments in the oral cavity. It may be ionized in saliva, ionized in plaque (plaque fluid), bound in plaque, bound as calcium fluoride, bound to enamel, and bound to soft tissues. Fluoride is also distributed to the oral tissues and into the dental plaque by diffusion. It is well established that plaque, after fluoride exposure, becomes a fluoride reservoir which stores for some time and releases fluoride. The present review gives an insight into the important parameters that determine the disposition and fate of fluoride in the oral environment. To achieve in-depth understanding, and hence formulation of the optimal fluoride therapy, more information is needed to consolidate our understanding of the distribution, retention, and elimination of fluoride in the oral cavity. Such knowledge will form a better basis for providing our patients with more effective dental fluoride products and regimens.

Dental Plaque↗