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PubMed2000

[Effects of selenium and zinc on the DNA damage caused by fluoride in pallium neural cells of rats].

To investigate the effects of fluoride on DNA damage as well as the effects of selenium and zinc against fluoride respectively or jointly in pallium neural cells of rats, single cell gel electrophoresis was used to detect the DNA damage of neural cells prepared in vitro. The results showed that the degree of DNA damage in the fluoride group and the selenium group were significantly greater than that in control group(P < 0.01). The damage in the fluoride group was even more serious. The damage in the fluoride + selenium group and fluoride + zinc group was slighter than that in the fluoride group but with no significant difference. The extent of DNA damage in the fluoride + selenium + zinc group was significantly slighter than that in the fluoride group(P < 0.05). It suggested that fluoride and selenium could induce DNA damage in pallium neural cells of rats respectively. Moreover, the joint antagonistic effect of selenium and zinc against fluoride was more obvious.

Animals↗
PubMed1992

[Relationship between height, collagen metabolism, hair zinc and excessive fluoride intake].

After eliminating confounding factors, the study was made on the relationship between height, collagen metabolism, hair zinc and excessive fluoride intake. 140 schoolchildren aged 12-13 years born and reared in endemic fluorosis areas were surveyed. The results were as follows: 1. The average height of children with dental fluorosis III degree (DF III degree) was appreciably smaller than that of children without dental fluorosis. Among children with excessive fluoride intake, a negative correlation between the height and fluoride level in staple foods was seen. 2. The more the fluoride ingested, the higher the urinary THP excreted, showing that fluoride intoxication interfered with the collagen metabolism. 3. Among children with excessive fluoride intake, the height showed negative correlation with urinary THP/Cr, suggesting that the effect of fluoride on collagen metabolism indicated the mechanism of height retardation. 4. As compared to control group with the excessive fluoride intake but without dental fluorosis group, there was a significant reduction in hair zinc in group with DF III degree, suggesting that the zinc in the body decreased because of zinc metabolism disturbance by excessive fluoride intake. But among cases with excessive fluoride intake, no appreciable correlation between hair zinc and height was found. Therefore, it could not be confirmed that the effect of fluoride on zinc metabolism affected the height development.

Adolescent↗
PubMed2004

[History of fluoride prevention: successes and problems (literature review)].

Fluoride prevention has a significant role in complex caries prevention, together with the appropriate diet and oral hygiene. The aim of the present review is--considering mainly the public health aspects--to give information on changes of the methods of fluoride prevention, and the changing views on pathomechanisms, as well as statements in the course of the last 50 years, based on present scientific evidence. The first great breakthrough in caries prevention was the introduction of water fluoridation between 1945-1950 in the USA and Canada. The measure was adopted in other countries and resulted in significant caries reduction. In the fifties and sixties fluoride tablets were widely used in many countries and brought good results, mainly in well-controlled smaller communities. Salt fluoridation has been initiated in Switzerland in 1955, and introduced in numerous countries in the eighties. The concept of a strong protective systemic effect of fluorides in the early eighties gave place to ideas on mainly topical effects, playing a decisive role in toothpastes, gels, acting topically on the enamel of the erupted teeth. Therefore many water fluoridation projects, mainly in Central- and Eastern Europe--where the prevalence of dental caries is still very high--were cancelled after 1990. Tablet fluoridation became questionable due to the fear of the possibility of dental fluorosis. Recent scientific views, however, confirmed a weak pre-, and peri-eruptive, as well as a strong posteruptive effect of systemically applied fluorides. In countries where caries prevalence is high, but the majority of the population cannot afford fluoridated toothpastes due to low socio-economic conditions, the introduction and extension of salt fluoridation to the whole population is well founded and recommended from a public health view.

Canada↗
PubMed2003

Lipid peroxidation and antioxidant systems in the blood of young rats subjected to chronic fluoride toxicity.

Wistar albino rats were exposed to 30 or 100 ppm fluoride in drinking water during their fetal, weanling and post-weaning stages of life up to puberty. Extent of lipid peroxidation and response of the antioxidant systems in red blood cells and plasma to prolonged fluoride exposure were assessed in these rats in comparison to the control rats fed with permissible level (0.5 ppm) of fluoride. Rats treated with 100 ppm fluoride showed enhanced lipid peroxidation as evidenced by elevated malondialdehyde (MDA) levels in red blood cells but, 30 ppm fluoride did not cause any appreciable change in RBC MDA level. 30 ppm fluoride-intake resulted in increased levels of total and reduced glutathione in red blood cells and ascorbic acid in plasma while 100 ppm fluoride resulted in decreases in these levels. The activity of RBC glutathione peroxidase was elevated in both the fluoride-treated groups, more pronounced increase was seen with 100 ppm. Reduced to total glutathione ratio in RBC and uric acid levels in plasma decreased in both the groups. RBC superoxide dismutase activity decreased significantly on high-fluoride treatment. These results suggest that long-term high-fluoride intake at the early developing stages of life enhances oxidative stress in the blood, thereby disturbing the antioxidant defense of rats. Increased oxidative stress could be one of the mediating factors in the pathogenesis of toxic manifestations of fluoride.

Administration, Oral↗
PubMed2004

Water fluoridation and dental caries in 5- and 12-year-old children from Canterbury and Wellington.

OBJECTIVES: Claims have been made that the effectiveness of water fluoridation has reduced due to the widespread availability of other sources of fluoride. This study examines the differences in the oral health of children living in fluoridated and non-fluoridated areas of Canterbury and Wellington, New Zealand. DESIGN: The data used in this cross-sectional study had been routinely collected into a computerized data-collection system by the School Dental Services in the two study areas. SUBJECTS AND METHODS: Records of dental status (dmfs/DMFS), fluoridation status, ethnicity, and socio-economic status for 8030 5-year-olds, and 6916 12-year-olds in 1996 were analysed. RESULTS: Caries prevalence and severity was consistently lower for children in the fluoridated area for both age groups, and within all subgroups. Five-year-olds in the fluoridated area had 2.63 dmfs (sd, 5.88), and those in the non-fluoridated area 3.80 dmfs (sd, 6.79). For 12-year-olds the respective figures were 1.39 DMFS (sd, 2.30) and 2.37 DMFS (sd, 3.46). Multivariable analysis confirmed the independent association between water fluoridation and better dental health. CONCLUSIONS: This results of this study show children living in a fluoridated area to have significantly better oral health compared to those not in a fluoridated area. These differences are greater for Maori and Pacific children and children of low socio-economic status.

Analysis of Variance↗
PubMed2003

[Sorption kinetics of fluoride by artificial and natural hydroxyapatite].

The nature and kinetics of fluoride uptake by hydroxyapatite under various conditions remain the object of interest. This problem was now investigated with an experimental model reproducing as closely as possible the conditions in vivo. The aim of this work was: (1) to study the kinetics of fluoride uptake by natural and artificial hydroxyapatite depending on experimental conditions and to determine the reaction rate constants; (2) to describe the equilibrium of fluoride uptake with adsorption isotherms and develop a best fit mathematical model for the process taking place under various experimental conditions; (3) to determine and compare the capacity for fluoride uptake by natural and artificial hydroxyapatite depending on experimental conditions. Attention has focused on the equilibrium and kinetics of the process of fluoride uptake under conditions as similar to those in a living organism as it is possible to reproduce in vitro. Those conditions represented just one of sixteen various experimental setups differing as to process parameters of the experimental system. The equilibria and kinetics of the experimental system were determined basing on measurements of selected parameters. Adsorption isotherms were obtained experimentally and a best fit mathematical model was developed to describe the process. Additionally, maximal capacity for fluoride uptake was calculated, as well as equilibrium constants, adsorption and desorption rate constants for both hydroxyapatite types. The following conclusions were drawn: 1. Fluoride uptake by artificial and natural hydroxyapatite is a biphasic process essentially independent of conditions in the reaction environment adopted in the present work. The first phase is rapid and does not exceed some 15 minutes. The second phase is much slower and takes place over a period of several dozen hours. 2. Fluoride sorption by both hydroxyapatites is essentially a physico-chemical process which can mathematically be best described with Langmuir and Langmuir-Freundlich adsorption isotherms. Under conditions of equilibrium, the adsorbed substance forms a monolayer on the surface of the sorbent. 3. The binding of fluoride by natural hydroxyapatite is stronger than by its artificial counterpart. 4. The stability of fluoroapatite formed during fluoride uptake by natural hydroxyapatite is greater than that of its artificial counterpart. 5. Natural hydroxyapatite has a relatively large capacity for fluoride ions under experimental conditions adopted in the present work. This capacity exceeds that of artificial hydroxyapatite in spite of smaller specific surface of the natural substance.

Adsorption↗
PubMed1990

Prevalence of dental caries and enamel defects in children living in areas with different water fluoride concentrations.

The prevalences of dental caries and developmental enamel defects were assessed in 643 randomly selected children aged 11 to 13 years who were lifelong residents of three areas of Naples with high (4 ppm), optimal (1 ppm), and low (0.3 ppm) concentrations of fluoride in their drinking water. The children living in the high fluoride area had significantly lower dental caries scores (DMFT 0.59, DMFS 1.01) than those in the optimal fluoride area (DMFT 1.67, DMFS 2.87) and those in the low fluoride area (DMFT 1.97, DMFS 3.48). The FDI index of developmental defects of dental enamel (DDE) was used to record enamel defects. There was a significant increase in the number of children with at least one tooth affected by an enamel defect as the fluoride level in their drinking water increased; the prevalences were 9.8 per cent in the low fluoride area, 23 per cent in the optimal area and 53.1 per cent in the high fluoride area. The prevalences of teeth affected were 2.2 per cent in the low fluoride area, 5.7 per cent in the optimal, and 20.3 per cent in the high. Demarcated opacities were the most common defect seen. Diffuse opacities were found to be the discriminating factor between fluoride and non-fluoride areas. In the high fluoride area 64.3 per cent of children with enamel defects had at least six teeth affected. In the maxilla the central incisors were the most affected teeth followed by the second and first premolars; in the mandible the first premolars and first molars were the most affected teeth.

Adolescent↗
PubMedDate not supplied

[Absorption of fluorides by synthetic hydroxyapatites].

We studied the adsorption of sodium fluoride, ammonium fluoride, tin fluoride and sodium monofluorophosphate to synthetic hydroxiapatite in function of the pH (pH 4.7, 5.5 and 6.1). In two models; in a first model was eluted the fluorides of the hydroxiapatite column with artificial saliva; in the second model were incubated the fluoride with bufferized hydroxiapatite to the above pH. The fluoride determination was done by potentiometric method with a specific ion activity electrode. The results in the elution indicated that the sodium and tin fluorides give elution levels different at the pH studied. By other hand ammonium fluoride did not present differences. The results with incubation demonstrated that ammonium fluoride gives the greater adsorption, the sodium fluoride is slightly lower, and the sodium monofluorophosphate the lowest. Also, was observed that the adsorption decrease with the increase of the pH for the three fluorides. The comparison of both models showed that the incubation presented higher values of adsorption than the elution for the pH studied.

Adsorption↗
PubMed1980

Fluoride metabolism in patients with chronic renal failure.

Studies of fluoride metabolism were carried out in patients with chronic renal failure by determining fluoride balances for several weeks. The fluoride intake was due to the analyzed fluoride content of the diet and of the drinking water. The effect of aluminum hydroxide on fluoride metabolism was investigated because this antacid is commonly used therapeutically for these patients. Studies have shown that urinary fluoride excretion in patients with chronic renal failure was significantly lower than that in patients with normal renal function, resulting in a signicantly higher retention of fluoride. Although the fecal fluoride excretion in patients with chronic renal failure was slightly but significantly increased, this change did not compensate for the decrease of the urinary fluoride excretion. The intake of aluminum hydroxide resulted in a significant increase of fecal fluoride excretion and in a significant decrease of net absorption and retention of fluoride in patients with chronic renal failure.

Aged↗
PubMed1994

Enamel and dentin demineralization inhibition of fluoride-releasing materials.

Fluoride-releasing dental restorative materials may provide an additional benefit in preventive dentistry. Although not currently available in the United States, a fluoride-releasing amalgam has demonstrated recurrent caries inhibition at enamel and dentin restoration margins. Likewise, both chemical-cured and light-cured glass ionomer cements have demonstrated caries inhibition at enamel and dentin restoration margins. Fluoride-releasing resin composites have also consistently demonstrated recurrent caries inhibition at enamel margins, yet there are conflicting results whether caries inhibition occurs at dentin margins. Preliminary studies indicate that glass ionomer cement and fluoride-releasing resin composite have synergistic effects with fluoride rinses and fluoridated dentifrices, in the remineralization of incipient enamel caries. The materials may act as a fluoride delivery system. Upon exposure to additional external fluoride, the material surface undergoes an increase in fluoride. This fluoride is subsequently released and has demonstrated demineralization inhibition and even remineralization at adjacent tooth structure. Clinical research to evaluate these fluoride-releasing restorative materials may provide further information for clinical recommendations.

Composite Resins↗
PubMed1993

Fluoride and abrasive content in commonly used dentifrices on the Kenyan market.

About one decade ago, a heated debate on the appropriateness of fluoride dentifrices in Kenya culminated in the introduction of no-fluoride brands. Analysis of dentifrices that were available on the market in 1989/1990 confirmed two distinctly different categories, the fluoride and the low or no-fluoride types. Among the former, the mean ionic fluoride concentration ranged between 0.4 and 1.36 mg/g while the total fluoride concentration ranged between 1.15 and 114.68 mg/g. The low or no-fluoride dentifrices had less than 0.03 mg/g ionic fluoride and less than 2.14 mg/g total fluoride. The mean abrasive (powder) content ranged between 26.5 g% and 78.5 g%. The gel categories had markedly lower powder values than the pastes. The ash values of the powders ranged between 15.8 g% and 85 g% and did not have an obvious relationship with the powder content. Despite the obvious risk of increasing exposure to excessive fluoride among children, presently, the situation has reverted to the pre-debate time. Given the ubiquitous nature of ingestable fluoride in the region, provision of guidelines and guidance on the sale of dentifrices by the government and consumer organisations, and increased accountability of the manufacturers are recommended.

Data Collection↗
PubMed1998

Variation of the total amount of fluoride in blood of young women during the menstrual cycle.

We have previously reported the distribution and the forms of fluorides in the blood of men. This study is concerned with the distribution of fluorides in the blood of young women and sex-related differences in the fluoride metabolism related to the calcium metabolism keeping the postmenopausal osteoporosis in mind. The present study shows that women, aged 18 to 20 years, retain more fluorides in blood compared with men and that the nonionic fluoride level in blood varies during a menstrual cycle, whereas the ionic fluoride level is constant. Since fluoride has strong affinity for calcium, behavior of fluoride may reflect that of calcium balance during the menstrual cycle. However, fluoride which binds to calcium is believed to be ionic. Therefore, there must be a transformation between ionic fluoride and nonionic fluoride in order to keep the homeostasis.

Adult↗
PubMedDate not supplied

Knowledge, perception and behaviour of the general public concerning the addition of fluoride in drinking water.

A telephone survey was carried out in 1994, in the Quebec City region, among 1006 people living in two municipalities where tap water is fluoridated and 1003 people living in two municipalities where there is no fluoridation. Knowledge of the main benefit associated with the use of fluoride (prevention of tooth decay) in drinking water was not different in fluorated versus non-fluoridated municipalities (20.4% vs 19.4%, p = 0.57). Knowledge of its main disadvantage (increase of dental fluorosis) was very low and similar in both groups (3.1% vs 2.0%, p = 0.11). Opposition to fluoridation was slightly higher in fluoridated areas (22.0% vs 18.3%, p = 0.04), and the use of fluoridated supplements for children was much less important in fluoridated areas (4.4% vs 12.4%, p = 0.001). No changes in the measures of association (odds ratios) were found after adjustment for the different characteristics of the participants (age, family income, education). Opposition to fluoridation was lower among those who believed their tap water was fluoridated (even if not): 19.9% vs 34.5%, p < 0.001. This study demonstrates that there is still need for public health education on the uses of fluorides.

Adult↗
PubMed1997

Effect of topical fluoride agents on the morphologic characteristics and composition of resin composite restorative materials.

STATEMENT OF PROBLEM: The high reactivity of fluoride agents used in topical fluoride treatments have raised important questions on their potential adverse effects on restorative materials. PURPOSE: The purpose of this study was to evaluate the effect of topical fluoride agents used for office or home treatments on the surface morphologic characteristics and composition of composite restoratives. MATERIAL AND METHODS: The fluorides used were Act, Phosflur, Gel II, Prevident, Stop, Butler APE, Nupro, and Omni Gel & Rinse. The composites tested were Brilliant DI, Heliomolar Ro, Herculite XRV, and P-50. The pH of the fluorides was measured as received and after dilution with water at a 1:3 volume ratio. The composites were subjected to the fluoride treatments until the total number of applications simulated the equivalent of 4 years under treatment. The changes induced on the surface morphologic features and composition of the restoratives were assessed by multiple internal reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, and x-ray microanalysis. RESULTS: All fluorides showed an acidic pH that was not significantly changed after dilution, except Stop, which exhibited a significant pH reduction. All fluorides increased the amount of loosely bound water in the composite matrix. Butler APF gel was the most aggressive for Brilliant DI and Herculite XRV, leading to excessive surface degradation, porosity, destruction of the filler-matrix interface, filler dissolution, and debonding. A reduction in the extent of remaining C = C bonds was observed in Herculite XRV after Butler APF treatment; Phosflur, Gel II, and Prevident had a milder effect. Treatment of Brilliant Dl and Herculite XRV with Omni Gel & Rinse resulted in the formation of a stable precipitation layer rich in barium, phosphorus, tin, oxygen, and fluoride. P-50 was severely affected at the resin-matrix interface after Stop treatment, whereas Omni Gel & Rinse induced fewer surface changes. Heliomolar Ro was the least affected restorative regardless of the type of fluoride used.

Acidulated Phosphate Fluoride↗
PubMed1992

Acquisition of alkali-soluble fluoride by enamel through treatment with NaF-containing toothpastes in vitro.

The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a NaF-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial NaF-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufacturers' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increased with the time of exposure. The clinical effect of a NaF-containing toothpaste may thus well depend on an initial formation of alkali-soluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride.

Adsorption↗
PubMed2000

Role of fluoride in oral health promotion.

Fluoride has played a pivotal role in oral health promotion over the past 50 years. This paper reviews key issues currently impacting on the role of fluoride in preventing dental caries. The understanding of the process of dental caries and the mode of action of fluoride has changed in recent years. Dental caries is a continuous process of demineralisation and remineralization of the enamel and fluoride plays a key role in this process through its action at the plaque enamel interface. It is now accepted that the primary mode of action of fluoride is post-eruptive. The post-eruptive action of fluoride has resulted in new methods of delivering fluoride. The paper discusses the impact of these new methods of delivering fluoride on total fluoride intake in children and on the prevalence of dental fluorosis. The role of different methods of delivering fluoride both on a community and individual basis is presented and recommendations are outlined.

Cariostatic Agents↗
PubMed1994

Dissolution of various calcium fluoride preparations in inorganic solutions and in stimulated human saliva.

The aim of the present study was to examine the dissolution of various preparations of calcium fluoride in inorganic solutions and in human saliva. Calcium fluoride was prepared by mixing either 0.25 or 0.02 mol/l calcium chloride with 0.5 or 0.04 mol/l sodium fluoride. After preparation, the salts were washed in 1 mmol/l calcium chloride solution and in distilled water. A commercial product, calcium fluoride Suprapur (Merck), was used for comparison. The solubility of the salts was examined in distilled water, in a 2-mmol/l sodium phosphate solution, and in whole human saliva, produced by chewing paraffin. It was found that the calcium fluoride ion product after suspension for 1-3 h in distilled water ranged closely around 10(-10.7) for all salts. In the phosphate solution, the commercial product dissolved slowly, the ratio between dissolved fluoride and calcium ranged from 4 to 7, in buffered solutions approaching 2. The supernatant was not saturated by the salt. Our two calcium fluoride salts dissolved quickly and made the phosphate-containing solutions supersaturated with respect to fluorapatite, leading to fluorapatite formation, and because of compensating calcium fluoride dissolution, this led to increasing fluoride concentrations in saliva of up to around 85-95 ppm. The results of this study indicate that calcium fluoride of less than Suprapur standard may dissolve quickly in saliva, unless the dissolution is retarded by a physical barrier, like a forming pellicle.

Apatites↗
PubMed1997

An in vitro comparison of three fluoride regimens on enamel remineralization.

The purpose of this study was to compare the enamel remineralization effectiveness of a fluoride rinse, fluoridated dentifrice, and fluoride-releasing restorative material. Forty extracted molars had 1 x 5 mm artificial carious lesions formed at the interproximal contact point. One-hundred-micrometer sections were obtained at the caries sites, and polarized light photomicrographs were obtained. The sections had varnish placed, leaving only the external section site exposed, and were situated back into the original tooth. Forty other molars were obtained; 10 had Class-II glass ionomer cement restorations placed. These 40 teeth were mounted to have interproximal contact with the adjacent teeth containing artificial carious lesions. Specimens were placed in closed environments of artificial saliva for 1 month, with saliva being changed every 48 h. Ten specimen pairs were brushed with a fluoridated dentifrice for 2 min, twice per day, 10 specimen pairs were rinsed with a 0.05% sodium fluoride rinse for 1 min twice per day, 10 specimen pairs had Class-II glass ionomer cement restorations positioned adjacent to 10 teeth with artificial carious lesions, and 10 specimen pairs acted as controls. After 30 days, the same sections were photographed again under polarized light, and areas of the lesions were digitized quantitatively. Results demonstrated the mean (+/- SD) remineralization (mu m2) in Thoulet's 1.41 imbibition media to be: lesions adjacent to glass ionomer cement restorations, 2.45 +/- 170; lesions exposed to a fluoridated dentifrice, 223 +/- 102; lesions exposed to 0.05% sodium fluoride rinse, 374 +/- 120, and control lesions only exposed to artificial saliva, 101 +/- 69. Duncan's analysis indicated the fluoridated rinse to have significantly greater remineralization effects on adjacent caries than the other groups (p < or = 0.05). The glass ionomer restorative material and fluoridated dentifrice also had significantly greater remineralization effects on adjacent caries than the control, yet significantly less than the fluoridated rinse (p < or = 0.05).

Analysis of Variance↗