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PubMed2006

Deformation luminescence produced during application and release of pressure on to gamma-irradiated CaF2:RE crystals.

Calcium fluoride CaF2 is an interesting host lattice for rare earth (RE) activators. CaF2 crystals doped with different concentrations of Dy, Ce, Er and Gd have been grown by the Bridgman technique and their deformation luminescence (DL) induced by room temperature gamma irradiation has been recorded. When a uniaxial pressure is applied on to gamma-irradiated CaF2:RE crystals, initially the DL intensity increases with time, attains a maximum value and then it decreases with time. Although the DL intensity produced during the release of pressure is less, its rise and decay behaviours are similar to that obtained during the application of pressure. The DL intensity depends on dopant, concentration of dopant, irradiation doses and mass of the load or applied pressure. It is suggested that the moving dislocation produced during deformation of crystals capture holes from hole trapped centres (like perturbed Vk centre) and the subsequent radiative recombination of the dislocation holes with electrons give rise to DL.

Calcium Fluoride↗
PubMed2005

Recovering industrial sludge-derived slag as fine aggregate.

This study presents the result of using melting to recover both industrial sludge slag (the main constituent of which is calcium fluoride) and water works sludge slag as fine aggregate in cement. The main characteristics of both slag and cement mortars were measured to evaluate the feasibility of using slag as aggregate. In this study, the slag replacement ratios were 0, 10, 20, 30, 40, and 50% (w/w), and the curing periods were 7, 28, and 90 days. Slag quality was determined according to the standards of fine aggregates in the ASTM specifications, and cement mortars with various slag replacement ratios were evaluated based on their compressive strength, and Toxicity Characteristic Leaching Procedure (TCLP). The crushed slag produced in this study met the ASTM standards for fine aggregate, including gravity, unit weight, absorption, and grading, and the TCLP leached concentrations are far below existing limits, establishing the safety and suitability of slag as fine aggregate. The TCLP leached concentrations of slag and cement mortar were not significantly related to the replacement ratio, and declined with increasing curing period, revealing that the hydration strongly influenced metal leaching. The compressive strength test results of the cement mortars demonstrated that the optimal replacement ratio for maximizing compressive strength was 40%. This study also discussed the effects of replacement ratio and curing periods on cement mortars.

Calcium Fluoride↗
PubMed2000

Sodium fluoride increases intracellular calcium in rat renal epithelial cell line NRK-52E.

In our previous experiment using rats, fluoride was reported to cause renal calcification, whose mechanism was deduced to be due to an increase in parathyroid hormone (PTH) secretion. However fluoride-induced renal calcification that was independent of PTH has not been understood well in the nephron of fluoride-treated animals. Thus, we examined the effect of sodium fluoride on intracellular calcium mobilization in a normal rat kidney epithelial cell line (NRK-52E cells). The calcium accumulation was found to be remarkably increased by the addition of sodium fluoride (NaF). The elevation of [Ca2+]i was demonstrated to be due to calcium entry through nifedipine-sensitive calcium channels. In addition, fluoride activates phospholipase C, but inositol 1,4,5-triphosphate (IP3) didn't induce Ca2+ release from the endoplasmic reticulum (ER). Moreover, fluoride alone was deduced to enhance the activity of ER-type Ca2+-ATPase. Finally, on the mechanism of fluoride-induced calcium accumulation in NRK-52E cells, fluoride may activate phospholipase C to generate IP3 and diacylglycerol, and these increases can be elucidated to induce calcium entry through dihydropiridine-sensitive calcium channels. Moreover, fluoride was found to stimulate calcium accumulation through ER-type Ca2+-ATPase into the endoplasmic reticulum. The elevation of ER-type Ca2+-ATPase activity by fluoride was elucidated to operate as a regulatory system to protect against abnormally higher increases in cytosolic calcium concentration via an increase of calcium influx into the endoplasmic reticulum.

Animals↗
PubMed1985

Phalloidin shift on velocity sedimentation sucrose gradient centrifugation for identification of microfilament-associated proteins.

Velocity sedimentation by sucrose density gradient centrifugation has been used to characterize ascites microvillar microfilament cores and to identify microfilament-associated proteins. Fluoride, calcium, phalloidin and chemical cross-linking treatments of microvilli during Triton X-100 extractions increase the sedimentation rate of the microfilament core, compared with untreated control samples. Electrophoretic analyses of the distributions of actin, alpha-actinin and other microfilament-associated proteins across the gradients indicate that the primary mechanism for stabilization of the microfilament core is the reduction of fragmentation of the microfilaments. Significantly, alpha-actinin could be completely removed from the microfilaments by calcium treatment without causing a decrease in the size of the microfilament core. Because of the specificity of phalloidin in the stabilization of microfilaments, the shift on the gradients of microfilaments and their associated proteins in the presence of phalloidin provides a diagnostic tool for the identification of microfilament-associated proteins. This phalloidin shift technique should have widespread utility in the analysis of actin forms and microfilament-associated proteins from complex cell fractions.

Actin Cytoskeleton↗
PubMed1977

[The influence of the quality of proteins in fluoride bone fixation].

45 rats Wistar, 30 days old, were divided into five groups, receiving different diets: casein, bean and wheat flour. The last two diets were supplemented or not by D-L Methionine and D-L Lysine, respectively. Diets and fluoridated water (25 ppm) were given "ad libitum" for 28 days. After this period of experience, the animals were sacrificed and the mandible and the tibias removed for analyses of fluoride, calcium, phosphorus and ash. The A.A. main conclusions are the following: The fixation of fluorides in bones is significantly increased with the supplement of the limitant factor to dificients diets. In this condition, the mandible shows smaller fixation of fluorides than tibias. The level of calcium, phosphorus and ash shows to be similar in the diferentes groups. This data suggests interaction of the protein quality and the percentual fixation of fluorides, and the necessity of further studies about this problem.

Animals↗
PubMedDate not supplied

Effect of a water rinse on 'labile' fluoride and other ions in plaque and saliva before and after conventional and experimental fluoride rinses.

Labile reservoirs are important in maintaining ion concentrations in oral fluids, especially after a fluoride dentifrice application, where a persistent increase in fluid fluoride can mitigate or reverse caries progression. In this study, the effect of experimental and conventional fluoride rinses on the in vitro and in vivo water-induced release of fluoride, calcium, phosphate, acetate and hydrogen ions from oral reservoirs was examined. At the start of each experiment, 13 subjects rinsed either with a conventional 228-ppm fluoride NaF rinse, a 228-ppm fluoride controlled-release rinse (CR rinse) or received no rinse. Sixty minutes later upper and lower molar plaque samples and 1-min saliva samples were collected. The subjects then rinsed with deionized water for 1 min, and 7 min later, a second set of samples was collected (in vivo study). Plaque fluid and clarified saliva were then recovered from samples by centrifugation, and the remaining plaque mass was sequentially extracted with water and acid to measure the water-extracted and total whole-plaque fluoride (in vitro study). All the samples were analyzed using microtechniques for pH, free calcium, phosphate, organic acids (plaque fluid) and fluoride (plaque fluid, centrifuged saliva and plaque extracts). Results showed that in vivo water rinsing decreased acetate and phosphate in plaque fluid, and fluoride in plaque fluid and saliva, but had no effect on plaque fluid pH. In vivo water rinsing, however, increased plaque fluid free calcium, apparently due to water-induced loss of calcium-binding ions. Water- or fluoride-rinse-induced changes in plaque fluid concentration were greater at the lower molar site, suggesting that rinse pooling may influence ion distribution. Before the water rinse, plaque fluid, saliva and whole-plaque total fluoride values were 1.7, 2 and 4 times higher after the CR rinse compared to the NaF rinse. Furthermore, the CR rinse deposited approximately 11 times more water-extracted fluoride compared to the NaF rinse, suggesting a 'more efficient' precipitation of 'labile' or 'loosely bound fluoride'. The results presented here, and in previous studies, suggest the possibility of formulating effective fluoride dentifrices with a lower fluoride content than is currently in use.

Acetates↗
PubMedDate not supplied

Composition of fluoridated dental enamel studied by x-ray photoelectron spectroscopy (ESCA).

A combination of ESCA and argon-ion etching has been shown to be effective in determining the surface and subsurface composition of dental enamel. The heavy organic coating on enamel has been investigated. Beneath this coating, untreated enamel was found to have invariant phosphorus and calcuim concentrations over the region surface. The surface of enamel treated with an acid phosphate-fluoride gel was shown to be almost entirely connected to calcium fluoride. A phosphate species, noncalcium and possibly a sodium salt, was found to be present in the surface layer. At a depth lower than about 60 nm, there was a gradual increase in phosphorus concentration that approached the value for untreated enamel with increasing depth. The increasing phosphorus and decreasing fluorine concentrations were primarily caused by the increasing concentration of unreacted hydroxyapatite. These results have shown that ESCA coupled with argon-ion etching, can be used effectively to examine the surface and subsurface composition of dental enamel. The surface sensitivity, ability to strip thin layers of material, sensitivity to low atomic weight elements, and ability to differentiate between different oxidation states makes a combination of these two techniques extremely useful for dental research.

Acetates↗
PubMed1993

Defluoridation of water at high pH with use of brushite, calcium hydroxide, and bone char.

The aim of this study was to improve the efficiency of the bone-char method of water defluoridation by pre-treating the water with brushite and calcium hydroxide. Various amounts of brushite, calcium hydroxide, and bone char were suspended batchwise in 100 mL of distilled water containing 0.53 mmol/L fluoride for 24 h under gentle agitation. At suitable intervals, pH and the concentrations of fluoride, calcium, and phosphate in the water were determined and, when possible, the degrees of saturation with respect to brushite, hydroxyapatite, and fluorapatite calculated. Bone char used alone took up fluoride slowly and inefficiently. The addition of brushite and calcium hydroxide resulted in high concentrations of calcium and phosphate, making the solutions highly supersaturated with respect to fluorapatite, and led to a 20-fold increase in fluoride removal from the water. The combined use of all three salts left low concentrations of phosphate in solution and optimized the fluoride uptake capacity. Repeated use of the same bone char for 18 consecutive runs demonstrated that uptake of fluoride by the bone char was improved by repeated use, provided that brushite and calcium hydroxide were added. Therefore, addition of the two salts to the water may prolong the life of the bone char indefinitely, ensure the removal of fluoride, and thus avoid the problem of determining when the bone char is exhausted. In conclusion, we show that the bone-char defluoridation technique can be improved by addition of brushite and calcium hydroxide to the water. The problem of high terminal pH remains, however, and further work is required to improve potability.

Animals↗
PubMed1994

Cariogenic potential of foods. II. Relationship of food composition, plaque microbial counts, and salivary parameters to caries in the rat model.

A series of rat caries experiments was carried out to test the relative cariogenic potential and to identify the major carcinogenic elements of 22 popular snack foods. Parameters that were measured included rat caries, number of cariogenic bacteria in plaque, salivary parameters including flow rate, buffering capacity, total protein, lysozyme and amylase content, and composition of test foods including protein, fat, phosphorus, calcium, fluoride, galactose, glucose, total reducing sugar, sucrose, and starch. Many interesting relationships were observed between food components, numbers of plaque bacteria, salivary components, and specific types of carious lesions. Protein, fat, and phosphorus in foods were all associated with inhibition of both sulcal and buccolingual (smooth-surface) caries. Food fluoride was associated with inhibition of buccolingual caries, whereas calcium was related to inhibition of sulcal caries. Glucose, reducing sugar, and sucrose in foods were all related to promotion of both sulcal and smooth-surface caries. The numbers of Streptococcus sobrinus in plaque were associated with promotion of smooth-surface caries only, whereas lactobacilli, non-mutans bacteria, and total viable flora were related to promotion of both smooth-surface and sulcal caries. The salivary flow rate was associated with inhibition of both buccolingual and sulcal caries. Salivary buffering capacity (at pH 7) and salivary lysozyme delivery were associated with inhibition of number and severity of sulcal caries, while the salivary amylase content was related to the promotion of the number of sulcal lesions.

Amylases↗
PubMedDate not supplied

Reaction characteristics of a tooth-bleaching agent containing H2O2 and NaF: in vitro study of crystal structure change in treated hydroxyapatite and chemical states of incorporated fluorine.

This in vitro study was performed to elucidate the reaction mechanism of sodium fluoride (NaF), which is added to tooth-bleaching agents to lessen the adverse effect of hydrogen peroxide (H2O2) on teeth. Both hydroxyapatite (HAP) and dihydrated dicalcium phosphate (DCPD), model substances for dental hard tissues, dissolved easily in a simple H2O2 solution. In the H2O2/NaF solutions, however, fluorine compounds that could not be identified by X-ray diffraction (XRD) due to the smallness of the products were formed on the surface of the HAP. X-ray photoelectron spectroscopy (XPS) studies demonstrated that fluoridated hydroxyapatite (FHAP) was formed on HAP, and that calcium fluoride (CaF2) formation was accelerated by increasing the concentrations of fluorine and H2O2 along with the partial dissolution of HAP. In H2O2/NaF solution, DCPD also transformed easily to FHAP and CaF2, which are favorable to the remineralization process on the tooth surface. Thus, the mechanism of NaF was elucidated, and its use together with H2O2 for tooth bleaching was proved to be effective. Methodologically, the XPS two-dimensional plot made it possible for the first time to directly estimate the ratio of FHAP and CaF2 in the reaction products, in contrast to the conventional wet-analytical method, which is simply based on the difference in solubility of the two components.

Crystallization↗
PubMed1989

Studies on the treatment of hydrofluoric acid burn.

Changes in serum and tissue and urinary levels of fluoride, calcium and other biochemical consequences were investigated in rats after experimental hydrofluoric acid (HF) burns, to obtain adequate method of emergency treatment for the injury. Increases in ionized fluoride and decreases in total and ionized calcium, in the sera were observed after contact with HF. Hyponatremia and hyperkalemia were observed over a 24 hour period. Parathyroid hormone (PTH) concentrations were elevated in the sera taken within 24 hours after burn and fell to reference range once the calcium concentration had been raised. Electrocardiographic changes including severe bradycardia were observed. These results indicate that an HF skin burn results in systemic fluoride poisoning followed by hypocalcemia, hypersecretion of PTH, hyponatremia, hyperkalemia and other electrolytes imbalance. Flushing with running water was effective for HF burns. By applying 2.5% calcium gluconate jelly, concentrations of fluoride in the urine and the tissues surrounding the injured region were reduced. Thus, the present results proved that the irrigation with running water and the jelly applications was evaluated as the most effective therapy among various methods tested for the HF burn.

Animals↗
PubMed1988

[Drug therapy of osteoporosis].

It has proved worthwhile to treat osteoporosis simultaneously in two ways. For symptomatic treatment of the pain, passive and active physiotherapy is important, backed up by treatment with analgesic and antirheumatic agents and calcitonin, while any other drugs are given mainly for treatment of the osteoporosis itself. For women in high-risk categories for osteoporosis long-term (10-12 years) preventative treatment with estrogens (plus progesterone) is indicated. When osteoporosis is already apparent on radiological examination, fluoride (+ calcium) is generally given over 3-4 years, while calcitonin therapy is appropriate in acute painful and rapidly progressive osteoporosis with fresh vertebral fractures. In this case both the antiosteoclastic and the analgesic effect of the hormone come into play. Calcium can be used for pre- and postmenopausal prophylaxis and as a supplement to fluoride therapy.

Aged↗
PubMed1985

Influence of repeated APF applications on long-term remineralization of initial lesions in bovine enamel.

Initial lesions in bovine enamel were remineralized in vitro for periods lasting from one hour to two weeks; in some cases, remineralization was interrupted daily for a ten-minute APF application. After two weeks, surface coatings appeared on APF-treated specimens; SEM and TEM observations, including selected area and micro-electron diffraction, indicated both a layered structure within these coatings, and the predominance of calcium fluoride single crystals, ranging from 0.1 to 1.0 micrometer in size. Using double (45 Ca and 32 P) labeled remineralizing solutions, we obtained depth profiles of deposited labeled calcium and phosphate; these indicated that repeated APF applications prevented inward penetration of calcium and phosphate and limited the deposition of these ions to an outer surface region corresponding to the surface coating. These phenomena are explained in terms of the composition and apparent reactivity of the coating.

Acidulated Phosphate Fluoride↗
PubMed1990

[Osteoporosis as a cause of pathological fractures].

More than a fifth of all females suffer from the risk to develop spinal osteoporosis. Hip fractures occur about 50,000 times per year in Federative Republic of Germany, about 1/3 in males and 2/3 in females. Estrogen deficiency is a risk factor of major importance for females; both sexes gain risk because of nutritional calcium deficiency and reduced mobility. Estrogen replacement therapy was proven to reduce the risk in females; and calcium supply reduces risk in both sexes. Therapy of developed spinal osteoporosis includes fluorides, calcium, vitamin D and calcitonin. No drug therapy has been developed so far for patients with senile osteoporosis and hip fractures.

Aged↗
PubMed1983

Bilateral fractures of femoral neck in patients with moderate renal failure receiving fluoride for spinal osteoporosis.

Two patients with moderate renal failure sustained spontaneous bilateral hip fractures during treatment with fluoride, calcium, and vitamin D for osteoporosis. They had been taking sodium fluoride (40-60 mg/day) for 11 and 21 months, respectively. Histological examination of a specimen of the bone showed severe fluorosis in the first case, and quantitative analysis of bone showed osteomalacia and skeletal fluorosis in the other case. These abnormalities were considered to be the consequence of excessive retention of fluoride due to renal insufficiency. As bilateral femoral neck fractures are very rare these data suggest a causal link between fractures and fluoride in patients with renal failure. Thus fluoride should be given at a lower dosage, if at all, to patients with even mild renal failure.

Aged↗
PubMed1989

[Effect of fluoride iontophoresis in dentin hypersensitivity of periodontally treated patients].

Independent of chosen stimulus, age or differences in selected groups of teeth, a reduction in pain intensity of about 50% can be attained following initial treatment with fluoride iontophoresis. The second treatment after 4 weeks leads to a nearly complete reduction in dentin-hypersensitivity. Subsequent to a third application of fluoride iontophoresis only minimal hypersensitivity is detectable. Precipitation of calcium-fluoride and blockage of dentinal tubules should be discussed. A decrease in hypersensitivity is likewise observed in the control group. The results of the final clinical examination show that slightly greater sensitivity remains. Electroanalgetic effects are probably responsible for the reduction of dentinal pain. Treatment of hypersensitivity is dependent upon such factors as age and oral hygiene. Supervised therapy for refractive dentinal pain appears to have greater success when fluoride iontophoresis is used.

Adult↗
PubMed1993

Dental caries and fluorides in relation to fixed orthodontic treatment: a review.

This paper reviews the cariological aspects of fixed orthodontic treatment and discusses the role played by topical fluorides. During fixed orthodontic treatment, carious lesions may occur in the form of white spots. These may constitute an aesthetic problem. The clinical management of white spot lesions remains unresolved. In order to prevent development of these lesions, the use of topical fluorides is advocated. The need for patient co-operation in the use of self-administered topical fluorides is critical. To reduce this critical need, the use of fluoride-releasing orthodontic cements is recommended. The literature suggests that calcium fluoride, which is the major reaction product on enamel during topical fluoride application, plays an important role in the cariostatic mechanism.

Dental Bonding↗