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Inappetence in ruminants as a measure of fluoride solubility in various phosphates.

Experiments with soft phosphate and fertilizer grade concentrated superphosphate and diammonium phosphate were to measure effects on voluntary intake of their fluoride in relation to that from calcium fluoride and sodium fluoride given once daily by capsule. Mature wethers were offered 1200 or 1400 g daily of mixed grain-roughage diet, and responses to fluoride were measured by inappetence, consumption of less than 10% of offered diet. When 40 ppm fluoride as sodium fluoride was given for 2 days, inappetence resulted, whereas 2,400 ppm fluoride as calcium fluoride did not decrease feed intake. Time required for recovery of appetite increased with more fluoride. When soft phosphate, concentrated superphosphate, and diammonium phosphate were tested at 100, 200, and 400 ppm fluoride, inappetence occurred always but severity of reduction of intake was related to parts per million fluoride. Solubility of fluoride in soft phosphate, concentrated superphosphate, and diammonium phosphate is more similar to sodium fluoride than to calcium fluoride, and their use should be in keeping with fluoride tolerances established for ruminants fed sodium fluoride.

Animals↗

[Fluoride in the organism of mother and fetus. II. Fluoride cumulation in the organism of the fetus].

The authors present the results of measuring the content of fluoride, calcium and phosphates performed on material comprising 66 thigh bones of human fetus in 4 age groups. In the studies the division into epiphysis and metaphysis parts was taken into consideration. A prepared complication furnishes the ratios of calcium to fluoride and calcium to phosphates in epiphysis and metaphysis parts, as well as ratio of calcium in epiphysis to calcium in metaphysis parts of the studied bones in the respective age groups. It has been disclosed that the increasing fluoride cumulation in fetal bones is a signal that the human organism is likely to be exposed to fluorine action already during the fetal life period. The fluoride content in thigh bones of fetus does not correlate with the content of calcium and phosphates, which may be evidence that there is a lack of significant influence of the determined fluoride content on the mineralization process taking place in bones at this period of life.

Adult↗

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↗

Fluoride-inhibited calcium ATPase of sarcoplasmic reticulum. Magnesium and fluoride stoichiometry.

The sarcoplasmic reticulum (SR) CaATPase is inactivated by fluoride in the presence of magnesium (Murphy, A. J., and Coll, R. J. (1992) J. Biol. Chem. 267, 5229-5235). The inactive complex is very stable and can be isolated free of other components by 48 h of dialysis at 4 degrees C (Murphy, A. J., and Coll, R. J. (1992) J. Biol. Chem. 267, 16990-16994). In this study, we used a fluoride-specific electrode to determine that the amount of tightly bound fluoride in the complex was 9.4 +/- 2 nmol mg-1 SR protein. The rate constant of inactivation was very similar to the rate constant of fluoride incorporation and varied directly as the square of the fluoride concentration. Luminal Ca2+ accelerated reactivation of the inhibited enzyme, and the rate constants of activity regain and fluoride release were very similar. Although required for inhibition, added magnesium did not accelerate reactivation. Analysis for magnesium using antipyrylazo III of the inhibited enzyme showed 4.1 +/- 0.4 nmol mg-1 SR protein. As there is much evidence in the literature supportive of an estimate of calcium pumps equal to approximately 4-5 nmol mg-1 SR protein, our results indicate that each inhibited enzyme contains two tightly bound fluorides and one tightly bound magnesium.

Animals↗

Prevention by means of fluoride of enamel erosion as caused by soft drinks and orange juice.

Fluoride has been suggested to prevent erosion of the teeth, either after a topical treatment of the teeth or by addition of fluoride to the acidic drink. The main aim of the present study was to describe the dissolution of calcium fluoride in some soft drinks and orange juice and compare it with the amounts of calcium fluoride left on the enamel surfaces after a topical treatment. A further aim was to describe the dissolution of enamel in soft drinks and juice saturated for 3 days with solid calcium fluoride. Solid calcium fluoride was suspended in each of 10 soft drinks and orange juices and gently agitated for 72 h, after which the drinks were analyzed for calcium, phosphate and fluoride and pH was determined. To examine the erosion-preventive effect of the calcium fluoride-rich drink, intact teeth were exposed to the drinks with or without calcium fluoride. It was found that from 6 to 45 mg of calcium fluoride was dissolved per liter of drink. The more acidic the drink, the more calcium fluoride was dissolved, presumably due to HF formation. The teeth exposed to the soft drinks all showed erosion-like lesions. Very little effect of the 4-6 ppm ionic fluoride dissolved in the soft drinks was observed. In orange juice, however, the dissolved calcium fluoride established a saturation with respect to fluorapatite and consequently, the erosion-like lesion was replaced by a caries-like lesion. In conclusion, the acidic soft drinks are capable of dissolving considerable amounts of calcium fluoride and the erosion-preventive effect of even high fluoride concentrations is limited.

Analysis of Variance↗

Inhibitory effect of different anticoagulants on gamma-glutamyl transpeptidase activity.

Increased gamma-glutamyl transpeptidase (GGT) levels have been observed in patients with several types of liver diseases. However, since GGT activity can be inhibited or increased by several substances, the interpretation of these increased levels should be made with caution. The present study was designed to determine plasma GGT activity in blood samples obtained from 24 adult volunteers (13 males and 11 females aged 20 to 40 years) with the use of three different anticoagulants, i.e., ethylenediaminetetraacetic acid (EDTA), calcium fluoride and calcium citrate, and to compare it with GGT activity in serum obtained from the same blood samples. Serum GGT activity was significantly higher than plasma GGT activity (P less than 0.001) and significantly higher in men than in women (P less than 0.05), though plasma GGT activity was similar for both sexes.

Adult↗

Combination therapy for osteoporosis with estrogen, fluoride, and calcium.

Nine women with postmenopausal spinal osteoporosis were treated with combination therapy consisting of estrogen, fluoride, and calcium. Their data were compared with those of a control group treated with fluoride, and calcium without estrogen. Bone mass was measured about every six months by photon absorptiometry (bone mineral content/bone width (BMC/BW)] and total-body neutron activation analysis [total-body calcium (TB Ca)]. Time-trend analysis revealed positive slopes for TB Ca (P = 0.002) and BMC/BW (P = N.S.) for the combination therapy group. The change in BMC/BW in the combination therapy group was significantly different from the response in the fluoride - calcium group. These data suggest that combination therapy may be successful in increasing bone mass in postmenopausal osteoporosis. A clinical trial to establish efficacy and examine risk/benefit ratios should be performed.

Adult↗

Effects of fluoride on caries development and progression in vivo.

The dissolution rate of calcium-fluoride-like material from the enamel surface in vivo appears to be much slower than previously thought. This could be due to adsorption of phosphate ions and/or protein molecules to the surface of the calcium-fluoride-like particles. During cariogenic challenges, the phosphate/protein coating is released, resulting in increased solubility rate of the calcium-fluoride-like material. Due to this mechanism, calcium-fluoride-like material may be a major aspect of the cariostatic mechanism of topically applied fluoride. Topically applied neutral fluoride agents are able to inhibit caries development in enamel but not completely stop lesion development. A fluoride solution at low pH has been found to be more effective in caries model studies than neutral fluoride agents, which might be due to the formation of a larger depot of calcium fluoride. Data from fluoridated areas indicate that the fluoride ion as such has a limited effect on lesion development, and a major mechanism of the cariostatic effect may be reformation of apatite (remineralization). The product of lesion consolidation (a fluoridated apatite) may have a limited effect, since intra-oral caries model studies show that even pure fluorapatite, in the form of shark enamel, demineralizes. In fissures and around orthodontic appliances, conventional fluoride agents appear to have only a small effect.

Calcium Fluoride↗

'Calcium fluoride-like' material formed in partially demineralized human enamel in vivo owing to the action of fluoridated toothpastes.

In this paper are presented the results of a chemical analysis of partially demineralized enamel lesions positioned under plaque in vivo for 3 weeks. During the experimental period the samples were brushed with fluoridated or non-fluoridated toothpaste systems. After the experiment the fluoride and protein uptake was determined. Furthermore, KOH extractions of the lesions were carried out and the solutions analyzed for calcium, fluoride, and phosphate. The results show that 'CaF2-like' material is most likely formed inside lesions during the in vivo period. This in indicated from chemical analysis, Raman spectroscopy, and SEM observations. The amount of CaF2-like material is on the order of 0.1 wt% if we consider its formation all over the enamel lesions, or 1 wt% if we assume its formation in interprismatic regions of the enamel only. About 40% of the fluoride taken up from toothpaste systems is in the form of CaF2-like material. In vivo there is a substantial influx of proteins (approximately 0.3%) and also a very large influx of phosphate ions. The effect of CaF2-like material is most likely strongly dependent on conditions in the lesion, such as pH change.

Calcium↗

Fluoride acquisition on and in human enamel during topical application in vitro.

Fluoride acquisition during topical fluoride treatment was studied after different time intervals, at different concentrations and at different pH. The effects of pretreating the enamel with Ca++, and of pre-etching were also tested. Four experimental groups of repeated measures design were established. Chemical assessments were made of the amounts of fluoride formed on (as alkali soluble fluoride, i.e., calcium fluoride) and in enamel (as firmly bound fluoride). The depositions on enamel were also demonstrated by SEM. The amounts of alkali soluble fluoride on enamel increased with time, concentration, pH-decrease and calcium availability. The time of exposure seemed to be the major factor. The amounts of fluoride deposited on enamel outranged by far (greater than 70%) the amounts of fluoride acquired in the enamel. The formation of alkali soluble fluoride on enamel is probably limited by the availability of calcium ions. It is suggested that the fluoride on enamel may protect the enamel surface and serve as a reservoir of fluoride.

Calcium↗

Treatment of primary osteoporosis with fluoride and calcium. Clinical tolerance and fracture occurrence.

Thirty-six patients with primary osteoporosis were treated for up to six years with sodium fluoride, calcium supplements, and, in 24 patients, vitamin D. Major adverse reactions (synovitis, painful plantar fascial syndrome, recurrent vomiting, or anemia) occurred in 15 patients (42%). New vertebral fractures occurred at a rate of 329 fractures per 1,000 years of observation. Almost half of them occurred during the first year of therapy, and they were only one sixth as frequent in 12 patients who had fluoride-induced increased trabeculation on vertebral roentogenograms. Nevertheless, until long-term safety and antifracture efficacy are better established, this regimen should continue to be restricted to investigational use.

Adult↗

Multiple-myeloma bone disease. The comparative effect of sodium fluoride and calcium carbonate or placebo.

A randomized double-blind study was carried out in 26 patients with multiple myeloma to compare the therapeutic effect of sodium fluoride (50 mg twice daily) plus calcium carbonate (1 g four times daily) and placebo. All patients also received melphalan and prednisone for one week every six weeks. Bone biopsies for microradiography and histology, and videodensitometry as well as conventional roentgenograms, 99mTc-polyphosphate bone scans, and bone densitometry of the mid and distal radius, were done initially and one year after therapy. Microradiography and videodensitometry studies revealed significant increases in bone formation (P less than 0.01) and bone mass (P less than 0.005) in the fluoride-calcium group. Bone trabeculae appeared thickened on roentgenograms of six of 13 fluoride-calcium-treated patients (P less than 0.02). Technetium bone scans and bone densitometry determinations proved insensitive for detection of skeletal changes. Fluoride calcium should be considered a useful adjunct in the treatment for multiple myeloma.

Bone Diseases↗

Topical application of fluorides on teeth. New concepts of mechanisms of interaction.

Prevention of caries in exposed root surfaces constitutes an important clinical problem. It is thus important that clinicians involved with periodontology have an insight into fluoride prophylaxis. The understanding of the cariostatic mechanism of fluoride has improved during recent years. The aim of the present review is to give a short account of the present concept. Calcium fluoride appears to be the only product which is formed on enamel, dentin or cementum during brief topical treatments with fluoride or use of toothpaste containing fluoride. This calcium fluoride is stable in the oral environment; this is contrary to what was believed until recently. The calcium fluoride constitutes a pH-dependent reservoir of fluoride which releases fluoride when pH drops. The practical consequences of this concept is discussed.

Calcium Fluoride↗

The effect of time of exposure on fluoride uptake by human enamel from acidulated fluoride solutions in vitro.

Fluoride uptake on and in enamel during topical application of acidulated solutions was studied. The variables were different time intervals and different pH levels of the treatment solutions. The experiment was carried out with human enamel exposed to 2% NaF solutions, pH 3.5 and 5.5, for 30 sec, 60 sec, 5 min, and 60 min. The amounts of fluoride formed on (as calcium fluoride) and in (as fluorapatite) enamel were determined by chemical assessments, and scanning electron microscopy provided the visualization of the deposits on the surface. It could be demonstrated that the two pH levels caused deposition of large amounts of calcium fluoride and that almost twice as much was deposited at pH 3.5 as at 5.5. The amount of deposit increased rapidly with time of exposure in both situations compared with similar experiments with neutral fluoride solutions. Firmly bound fluoride was incorporated in the enamel only during the 60-min incubation.

Calcium Fluoride↗

The relationship of bone mass and fracture history to fluoride and calcium intake: a study of three communities.

Stimulated by the suggestion that water fluoride greater than 1 mg/L may protect against osteoporosis, we studied bone mass of women in three rural communities with differing mineral content of the water supply. Mean fluoride and calcium of community drinking waters were 4 mg/L and 16 mg/L, respectively, high fluoride community; 1 mg/L and 375 mg/L, respectively, high calcium community; and 1 mg/L and 65 mg/L, respectively, low calcium community. Bone mass was measured by single photon absorptiometry, and women were interviewed about fracture history, dietary intake, and other important covariates. We observed no protective effect with higher fluoride intake. Bone mass was lower in older women from the high fluoride community though not statistically so; these women reported significantly more fractures. There was no observed community difference in young women's bone mass or fracture history. Young women in the high fluoride community consuming calcium and vitamin D in excess of 800 mg/day and 400 IU/day, respectively, had significantly better bone mass (p less than 0.05) than their peers.

Adult↗