Ionic Fluoride Research Articles

Effect of In-Vitro Fluoride Ion Treatment on the Mechanical Properties of Bone Tissue

Cortical bone tissue has been modeled as a short fiber reinforced composite material. It is composed of an organic matrix comprised mainly of Type I collagen reinforced by a mineral crystal similar to carbonated hydroxyapatite. We have developed an in-vitro ion treatment method to alter mechanical properties of the bone tissue using fluoride ion solutions. When bone is exposed to a high ionic strength fluoride solution, part of the bone mineral dissolves and precipitates as calcium fluoride. Changes in the mechanical properties such as, elastic modulus, ultimate stress and ultimate strain are dependent on the concentration and the pH of the treatment. Mechanical properties of fluoride treated (high ionic strength) bone tissue showed that elastic modulus, yield stress and ultimate stress are reduced in comparison to the controls. However ultimate strain increased considerably as compare to controls indicating that there might be a slippage between the bone mineral and the organic phase.

A simplified micromethod for fluoride analysis

A simplified method for the determination ionic fluoride (F −) concentrations in microvolume samples using a F −-selective electrode is described. Portions (20 μl) of a series of F − standard solutions (1000–0.4 parts/10 9 F −) were placed between the surface of the F − electrode and the surface of a reference electrode mounted end to end with the aid of a steel holder. In this position the two surfaces were used as an analysis chamber, retaining the sample by surface tension without the use of sleeves or other devices. The precision of the results and the absolute detection limit of the modified method were determined. The analytical performance of this set-up was tested by comparing the results with those obtained from the conventional method. The regression between the modified-method data and the conventional-technique data showed a strong correlation (R 2=0.993) between the results obtained using the two techniques. In the range of F − concentrations from 1000 and 0.48 parts/10 9. the precision of the results (coefficient of variation) was of 5–6%, improving to 0.9% at 0.9 parts/10 9 level.

Serum and urine ionic fluoride: normal range in a nonexposed population.

The present study was undertaken to evaluate the fluoride status in the general healthy population of Barcelona. Serum and urine fluoride ionic concentration was determined in a random sample of 250 subjects (age range 15-90 yr) by the Orion fluoride electrode system to determine the normal range of fluoride in this population. The results obtained show that in the general population of Barcelona, fluoride ionic serum concentration ranges between 1 and 47 microg/L (x = 17.5 +/- 9.7 microg/L) and fluoride ionic urine concentration ranges between 156 and 1990 microg/24 h (x = 671 +/- 373 microg/24 h). The mean serum fluoride concentration of the younger population was shown to be significantly greater (p < 0.05) than that of the older group. No sex-related difference was found.

Electronic level diagram and structure of metastable centers in CdF2:Ga and CdF2:In semiconducting crystals

A study is reported of the optical properties of wide-gap, predominantly ionic cadmium fluoride crystals in photo-and thermally stimulated transformations of metastable indium and gallium centers. An analysis of these properties leads one to a conclusion of gallium having two metastable states (two types of deep centers). The deep-center binding energies and the barriers separating the shallow (hydrogenic) and deep centers have been determined for both impurities. Configuration-coordinate diagrams are developed, and microscopic models for the deep centers are proposed. It is concluded that these centers are identical with the metastable DX centers in typical semiconducting crystals. Thus cadmium fluoride is the most ionic among the crystals where DX centers have thus far been found. The potential of using such crystals for optical information recording is discussed.

Effect of interfering ions on hexamethyldisiloxane microdiffusion method

Acid diffusion in the presence of hexamethyldisiloxane (HMDS) enables complete recovery of ionic fluoride from standards containing varying concentrations of aluminium as one of the main interfering ions. Acid diffusion without HMDS shows a decrease in fluoride recovery as aluminium ion concentration increases. The fluoride concentration in the trapping solution is determined directly on the diffusion cover with a combination fluoride electrode after neutralising and buffering. The same procedure was used for the analysis of fluoride in soil and plant materials containing high concentrations of aluminium ions. For the same samples, the concentrations of aluminium, iron and silicon were determined using atomic absorption spectrophotometer (AAS).

Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients.

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.

The effect of hemodialysis upon serum levels of fluoride.

Serum and dialysate ionic fluoride (F-) were determined in 29 patients under hemodialysis (HD) treatment. Serum creatinine (Cr), blood urea nitrogen (BUN) and phosphorus (P) were also examined before and after HD in 92 patients including the above 29 patients under the same treatment. Results reveal that serum F- levels of the patients before and after HD were statistically higher than those of the healthy subjects. The dialysis clearance of F- was 55.6 +/- 101.3 ml/min and the value was statistically significantly lower than those of Cr, BUN (95%, p < 0.001) and P (95%, p < 0.01). Based on these results, it is concluded that despite a net clearance of F- during a given HD procedure, serum F- failed to return to normal.

Adsorption Properties of CFC and CFC Replacements on Activated Carbon Containing Introduced Ionic Fluoride and Chloride

Plasma technology has been available for the chlorofluorocarbon (CFC) decomposition or etching of silicone. The adsorption properties of CFC (CFC113) and CFC replacements (HCFC141b, HCFC225cb, and 5FP) on several kinds of plasma-treated activated carbons (P-ACs) prepared under different treatment gases were investigated using the adsorption isotherms, the limiting pore volume (Wo) and the affinity coefficient and energy of adsorption (BEo) calculated by the Dubinin–Radushkevich plot, and the quality and kinds of introduced fluoride and chloride. The dissolved fluoride and chloride atoms were introduced to the surface of activated carbon by CFC113, HCFC141b, and HCFC225cb, while the dissolved fluoride atoms were those from 5FP and tetrafluoromethane. The adsorbed amount of CFC and CFC replacements, except for 5FP, on P-ACs was larger than that on U-AC. The specific adsorption site on plasma-treated activated carbon of the CFC and CFC replacements was the fluoride atoms which were introduced by plasma treatment. It is concluded that the plasma-treated activated carbon was suitable for the recovery of CFC and CFC replacements, because the adsorbed amount of CFC and CFC replacements was larger than that on untreated activated carbon, and the adsorbed CFC and CFC replacements on activated carbon were decomposed by the plasma treatment.

Vertebral Osteoporosis: Relationship of Serum Ionic Fluoride to Vitamin D Metabolites during Therapy

Vertebral Osteoporosis: Relationship of Serum Ionic Fluoride to Vitamin D Metabolites during Therapy

Gastroduodenal manifestations in patients with skeletal fluorosis.

A prospective case-controlled study was performed to evaluate the gastrointestinal symptoms and mucosal abnormalities occurring in patients with osteofluorosis. Ten patients with documented osteofluorosis and ten age- and sex-matched healthy volunteers were included in the study. Clinical evaluation, real-time ultrasound, and upper gastrointestinal endoscopy and biopsy from the gastric antrum and duodenum were performed in all subjects. The biopsies were subjected to a rapid urease test and light and electron microscopic examinations. Ionic fluoride levels were estimated in the drinking water, serum, and urine using an ION 85 ion analyzer. All patients with osteofluorosis had gastrointestinal symptoms, the most common being abdominal pain. Endoscopic abnormalities were found in seven patients with osteofluorosis. In all 7 of these patients, chronic atrophic gastritis was seen on histology. Electron microscopic abnormalities were observed in all 10 patients with osteofluorosis. These included loss of microvilli, cracked-clay appearance, and the presence of surface abrasions on the mucosal cells. None of the control subjects had any clinical symptoms or mucosal abnormalities. It was concluded that gastrointestinal symptoms as well as mucosal abnormalities are common in patients with osteofluorosis.

Models for Evaluating New Fluoride-Containing Systems: Reaction Paper

The type and number of control formulations to be used in model studies to evaluate new fluoride systems require careful consideration. While many controls may be justified on the grounds of scientific interest, some models can handle only small numbers of treatments without the statistical power of studies being compromised. In those cases, the results of more than one study may need to be combined. Current models for evaluating fluoride products have most often been developed with systems containing ionic fluoride in mind. To test new types of delivery vehicles or formulations which contain new fluoride agents, model protocols may need to be revised in order to account properly for differences in modes of action-for example, in rates of reaction with enamel or site specificity of active ingredient delivery in the mouth.

Oral administration of fluoride in pregnant women, and the relation between concentration in maternal plasma and in amniotic fluid

The aim was to measure the ionic fluoride concentration in maternal plasma and in amniotic fluid after oral administration of different doses of sodium fluoride (NaF) to 121 pregnant women. They were divided into six groups, according to the dose administered; 0 for the control group and 0.25, 0.50, 0.75, 1.00 or 1.25 mg of F − for the others. The subjects were instructed to take the corresponding NaF dose both 24 and 3 h before amniocentesis. Amniotic fluid (5 ml) and venous blood (5 ml) were obtained from each subject. Ionic fluoride concentration was measured with an expanded-scale potentiometer and a selective fluoride electrode. The results showed that F − concentration in amniotic fluid and, presumably, in fetal circulation, was not significantly different in groups taking 0.25, 0.50, 0.75 or 1.00 mg/day of F −. The F − concentration in amniotic fluid of the 1.25 mg/day group was, however, significantly higher than in all the other groups.

An Ex Vivo Investigation into the Release of Fluoride from Fluoride-containing Orthodontic Bonding Composites

This study was concerned with an evaluation of fluoride release from commercially available orthodontic bonding composite resins, known as Reliance and Mirage Dual Cure, which are claimed to release ionic fluoride. Forty-eight premolar teeth had brackets bonded with four different composite resins--Mirage Dual Cure, Reliance, Right-on and Heliosit. They were then immersed in a demineralizing solution. The amount of fluoride released from the composites into the solution was measured. The results indicated that Mirage Dual Cure released statistically significant amounts of fluoride over the first 2 days. A similar pattern was noted with Reliance albeit releasing a lesser amount. From the third day onwards, fluoride release levelled out to concentrations similar to those of the two control materials, Right-on and Heliosit (i.e. 0.09 ppm). Fluoride-releasing composite resins, therefore, failed to demonstrate any potential long-term fluoride release within the ex vivo model. Even in the short term, the amount of fluoride released was very small.

Studies on Plaque Fluoride After Use of F-Containing Dentifrices

Increased fluoride levels in plaque and saliva have been associated with improved protection against dental caries for dentifrices which contained sodium monofluorophosphate (Duckworth et al., 1992). The main aim of the present work was to test whether oral fluoride retention depended on F source after use of dentifrices containing either NaF or Na2FPO3. In study 1, plaque samples were collected from 474 subjects who had been using one of six test dentifrices for two years, and analyzed by F extraction with water. The dentifrices contained 1000 or 1500 micrograms F/g as either NaF or Na2FPO3. Significantly more fluoride was found in plaque from subjects who were using the NaF dentifrices than in plaque from subjects who were using Na2FPO3 dentifrices of the same F content. Subsets of plaque samples were large enough to divide into two parts for extraction by both acid and water. No significant difference was found between mean fluoride contents, indicating that the majority of fluoride retained in plaque from these conventional dentifrices appears to be relatively labile. The results of two small-scale human enamel studies showed that NaF dentifrices gave elevated F concentrations in plaque and saliva, respectively, compared with Na2FPO3 dentifrices of equivalent F content, consistent with the main plaque study 1. These findings demonstrate that oral F retention from dentifrices is dependent on the source of ionic fluoride and support the view that NaF dentifrices may be more clinically effective than dentifrices which contain the same amount of F as Na2FPO3.

Toxic effects of chronic fluoride ingestion on the upper gastrointestinal tract.

In a prospective case controlled study, we evaluated the adverse effects of long-term fluoride ingestion on the gastrointestinal tract. Ten patients with otosclerosis who were receiving sodium fluoride 30 mg/day for a period of 3-12 months, and 10 age- and sex-matched healthy volunteers were included. They were all evaluated clinically and subjected to a real time ultrasound examination, upper gastrointestinal endoscopy, and biopsies from the gastric antrum and duodenum. The biopsies were subjected to a rapid urease test as well as light and electron microscopic examinations. Ionic fluoride was estimated in the serum, urine, and drinking water using an ION 85 Ion Analyzer. Seven subjects (70%) ingesting fluoride had abdominal pain, vomiting, and nausea. Petechiae, erosions, and erythema were seen on endoscopy in all the subjects, but not in the controls. Histological examination of the gastric antral biopsy showed chronic atrophic gastritis in all the subjects but in only one (10%) healthy volunteer. Scanning electron microscopic examination showed "cracked-clay" appearance, scanty microvilli, surface abrasions, and desquamated epithelium in the subjects ingesting fluoride, but not in the controls. We conclude that long-term fluoride ingestion is associated with a high incidence of dyspeptic symptoms as well as histological and electron microscopic abnormalities.

血清中イオン型フッ素の定量法に関する基礎的検討

血清中イオン型フッ素の定量法に関する基礎的検討

Ionic and nonionic fluoride levels in blood of dialyzed and undialyzed patients with renal failure and kidney transplanted patients.

The present study revealed that the total fluoride level in human whole blood is closely related to the renal function. For the undialyzed patients who had not undergone hemodialysis, the total fluoride level in whole blood linearly increased with the increase of creatinine (Cr) value. The increased fluoride was found to be nonionic in the other blood part than serum, while the nonionic fluoride level in serum was almost constant. That is, the hemodialysis treatment finally reduced the nonionic fluoride level in the other blood part than serum. On the other hand, one hemodialysis treatment could excrete ionic fluoride, but not nonionic fluoride. These results suggest that the ionic fluoride is transformed to nonionic fluoride to be accumulated in other blood part than serum and the nonionic fluoride is transformed to the ionic fluoride to be excreted. Thus the accumulation of nonionic fluoride in other blood part than serum plays a role of the buffer in preventing a too high serum fluoride level.

Serum fluoride as an indicator of occupational hydrofluoric acid exposure.

To define the relationship between ionic fluoride concentration in the serum of workers and the amount of hydrofluoric acid (HF) in the work environment, pre-and postshift serum and urine samples of 142 HF workers and 270 unexposed workers were examined. The maximum and minimum concentrations of HF in the air in each workshop varied from the mean by less than 30%. The preexposure levels of serum and urinary fluoride in HF workers were higher (P < 0.001) than the control values. This suggests that fluoride excretion from the body continues for at least 12h. The postshift serum and urinary fluoride concentrations of these workers were significantly higher (P < 0.001) than the preshift concentrations. A good correlation (r = 0.64) was obtained between postshift serum fluoride and postshift urine fluoride. There was a linear relationship between mean serum fluoride concentration and HF concentration in the workshop. A mean fluoride concentration of 82.3 micrograms/l with a lower fiducial limit (95%, P = 0.05) of 57.9 micrograms/l was estimated to correspond to an atmospheric HF concentration of 3 ppm. This is the maximum allowable environmental concentration recommended by the Japanese Association of Industrial Health, and it is also the threshold limit value suggested by the American Conference of Governmental Industrial Hygienists. The results demonstrate that exposure to HF can be monitored by determining the serum fluoride concentration.

Determination of Total and Ionic Fluoride in Formula Milk Produced in Japan.

Determination of Total and Ionic Fluoride in Formula Milk Produced in Japan.

Effect of Sodium Fluoride on Growth of Human Diploid Cells in Culture

Cytotoxicity of sodium fluoride (NaF) on human diploid cells in exponential growth was investigated using a) Flow 1000 cells, passage No. 13, obtained from skin and muscle tissues of male black foetus, b) IMR-90 cells, passage No. 22, derived from lung tissue of female Caucasian foetus and c) primary fibroblast-like cell cultures from 5 Japanese whole foetuses. Diploid cells did not survive at 20 p.p.m. of ionic fluoride (F-) concentration. However, the cells were capable of proliferation with no significant impairment of growth up to 0.2 p.p.m. F-, a level which is much higher than the plasma concentration in human subjects from areas with highly fluoridated water. The growth of the cells was markedly affected by F- concentrations greater than 2 p.p.m.