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Results for “Calcium Fluoride”

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PubMed2001

Calcium fluoride uptake by human enamel after use of fluoridated mouthrinses.

The aim of this study was to evaluate, using scanning electron microscopy (SEM), the calcium fluoride uptake by human enamel in situ after topical application using three fluoridated mouthrinses: a neutral pH solution (Fluordent), an acidulated solution (Fluorgard) and a solution associated with chlorhexidine (Duplak). Twenty-four samples from 6 third sound human molars were divided into two groups: 5-min treatment and 10-min treatment. In both the 5-min and 10-min treatment samples, those treated with the chlorhexidine-associated solution showed higher formation of CaF2-like material. In the 10-min treatment group, the samples treated with the neutral solution showed higher formation of CaF2. These results indicated that the products used deposited CaF2 on the enamel surface and may be recommended to aid the prevention and control of dental caries.

Adsorption↗

PubMed2000

Oxygen determination in calcium fluoride by deuteron activation analysis.

Oxygen at trace level in calcium fluoride was determined by instrumental deuteron activation analysis based on the 16O(d,n)17F reaction. The irradiations were performed with 2.5 MeV deuterons for 60 s at currents ranging from 300 to 500 nA. The results obtained for powders and single crystals were compared.

Journal Article↗

PubMed1999

Effects of caffeine on fluoride, calcium and phosphorus metabolism and calcified tissues in the rat.

This 6-week study was designed to determine the effects of graded doses of caffeine intake (3, 25 or 100 mg/kg per day) on the metabolic balance and tissue concentrations of fluoride, calcium and phosphorus in Sprague-Dawley rats. Caffeine intake did not affect the absorption, urinary excretion or balance of fluoride, the plasma, bone or enamel concentrations of fluoride, nor the occurrence of incisor enamel fluorosis. Neither did it affect the metabolism of calcium or phosphorus except that the urinary excretion of calcium was increased. This effect, however, was not sufficient to influence significantly calcium balance. The ash content of the femur epiphysis and bone mineral content of the tibia were significantly reduced only in the group exposed to the highest dose of caffeine. These effects on bone were not significantly related to the balance of calcium or phosphorus. It was concluded that caffeine, even at an extremely high level of intake, has no detectable effect on the balance or tissue concentrations of fluoride, calcium or phosphorus in the rat.

Animals↗

PubMed1983

A method for concentration of nucleoside triphosphates by coprecipitation with calcium fluoride.

A method for concentration of nucleoside triphosphates (NTP) is described. NTPs are quantitatively coprecipitated from the solution with calcium fluoride. The precipitate is separated by filtration through a membrane filter and NTPs are dissolved from the filter by immersing it in 0.5 N H2SO4. With this method also nucleoside diphosphates can be efficiently concentrated, but the method does not work with nucleoside monophosphates or cyclic AMP.

Adenosine Monophosphate↗

PubMed1995

Fluoride retention of incipient enamel lesions after treatment with a calcium fluoride varnish in vivo.

The aim was to determine the fluoride retention in plaque-covered and clean incipient enamel lesions after topical application of a CaF2/NaF varnish (Bifluorid 12). In 50 specimens of bovine enamel an incipient lesion was produced with acidic hydroxyethylcellulose (pH 4.8; 72 h). 40 specimens were fluoride varnished; the 10 remaining specimens were used for measuring baseline fluoride content. Each six of the fluoridated specimens were recessed in the buccal aspects of an intraoral appliance worn for 5 days. During the experimental period one side of the appliance was kept clean, and plaque growth was allowed on the other. KOH-soluble and structurally bound fluoride were determined immediately, 1 day, 3 days and 5 days after fluoridation, and compared with the baseline fluoride content of the enamel. Immediately after fluoridation, a considerable amount of KOH-soluble fluoride was bound, but after 5 days 80% had been lost. Simultaneously a significant increase of non-KOH-soluble or structurally bound fluoride was detected in both plaque-covered and clean enamel. It is evident that this CaF2/NaF varnish deposits more KOH-soluble fluoride on the surface of demineralized enamel than other varnishes, but after 5 days fluoride retention is similar to that from other varnishes.

Analysis of Variance↗

PubMed1980

Effect of sodium fluoride, calcium carbonate, and vitamin D on the skeleton in multiple myeloma.

Fifteen patients with multiple myeloma were treated with sodium fluoride (50 mg twice daily) plus calcium carbonate (1 g four times daily) or with the same fluoride-calcium dosage plus vitamin D (50,000 U twice weekly). All patients had increased bone formation, as shown by microradiography and videodensitometry. Ten patients had osteosclerosis demonstrated by roentgenograms. Compressive strength of the vertebral bodies was greater among those who received fluoride-calcium than among controls. Densitometry studies were not helpful. Side-effects were minimal and consisted of nausea and fibrositic symptoms. Hypocalcemia occurred less frequently in patients who received vitamin D along with fluoride-calcium. Administration of sodium fluoride and calcium carbonate produces an increase in bone mass and is a useful adjunct treatment for patients with multiple myeloma.

Bone Diseases↗

PubMed1984

[Pharmacokinetics of a fluoride-calcium preparation for the treatment of osteoporosis].

The pharmacokinetics of fluoride and calcium were studied after administration of a combined fluoride and calcium preparation (Tridin) (1, 2 and 3 tablets) in 9 healthy male volunteers, using a cross-over study design. The total estimation of the pharmacokinetic data was performed by a simultaneous curve fitting to all single values, using a direct search procedure based on an open two-compartment model and three-compartment model, respectively. Maximum plasma concentrations and areas under the curve are proportional to the dose administered. Inter-subject variations are comparatively small, computerized multiple dose simulation for 3 days does not show any cumulation. The data fit the two-compartment model and the three-compartment model as well. The behaviour of the calcium concentrations reflects the immediate response of calcium homeostasis: plasma calcium concentrations are not affected.

Adult↗

PubMed1999

Interaction of Citric or Hydrochloric Acid with Calcium Fluorapatite: Precipitation of Calcium Fluoride.

The interaction of citric acid (H(3)Ci) with calcium fluorapatite(Ca(10) F(2)(PO(4))(6)) was explored for two reasons: (i) to determine the role of the acid in the dissolution process and hence in the mechanism of tooth fluoridation and (ii) to determine whether there is any formation of calcium citrate. It was found that the concentration of calcium or fluoride ions is not stoichiometric with respect to that of phosphate ions in the solution and the stoichiometric deficiency of the amount of fluoride ions in the solution is twice that of the calcium ions and this demonstrates that some calcium fluoride is precipitated. The interaction may be represented by the following chemical equation (pH approximately 2.5): where x (presently < 1) is related to the amount of CaF(2) that has precipitated and may be calculated from the experimental ratio of Ca to P in the solution. In order to establish that the interaction occurs generally with all acids, the reaction of hydrochloric acid with fluoroapatite was studied, and exactly analogous behavior was observed. These facts are also in accord with the solubility of fluorapatite and calcium fluoride. When the amounts of Ca and P in solution are corrected for the precipitated CaF(2), the ratio of Ca to P becomes stoichiometric (= 1.67). Preliminary X-ray analysis of the reacted fluorapatite showed that it contained calcium fluoride. The precipitated CaF(2) may act as a reservoir for the subsequent fluoridation of the mineral and may inhibit bacterial action in the mouth. The concentration of citrate ions does not change in solution, and no formation of calcium citrate is observed.

Journal Article↗

PubMed2004

Blue light stimulated luminescence in calcium fluoride, its characteristics and implications in radiation dosimetry.

Strong optically stimulated luminescence (OSL), stimulated by blue light, has been observed, for the first time, in natural calcium fluoride (CaF(2)) phosphor, used as thermoluminescence dosemeters. Traps responsible for all three thermoluminescence (TL) peaks appearing upto 300 degrees C, i.e. 126, 196 and 264 degrees C, were observed to contribute to the blue light stimulated luminescence (BLSL) in CaF(2). When the areas under the respective curves (BLSL and TL) were measured, the BLSL measured at room temperature was found to be approximately 1.8 times the TL output of the dosimetry peak that appeared at approximately 264 degrees C. However, when measured after thermally annealing the first two TL peaks, the BLSL signal was found to be 0.26 times the TL output of the dosimetry peak at 264 degrees C. This paper describes the characteristics of the BLSL signal using linearly modulated OSL after subjecting the phosphor to different annealing treatments. Feasibility studies to assess the usefulness of BLSL in CaF(2) for environmental radiation monitoring are also discussed.

Calcium Fluoride↗

PubMed1978

Structural studies on calcium fluoride formation and uptake of fluoride in surface enamel in vitro.

The structural changes in human enamel during exposure to an acetate buffer, pH 4, containing 150 parts/10(6) fluoride have been studied using scanning electron microscopy and polarized light microscopy. After exposure for 2 h the enamel surface was covered by a fine-granular layer of calcium fluoride. The underlying enamel was highly eroded with an increased pore volume in the outer layer. Following an equilibration period of 3 months the uptake of fluoride in the apatite lattice had resulted in a highly mineralized, 100-micrometer-thick surface layer rich in fluoride covering a subsurface porous zone with an unchanged fluoride content. The deeply located, caries-like porous zone may have provided calcium and phosphate for saturation of the liquid.

Acetates↗

PubMed1995

Formation of phosphate-containing calcium fluoride at the expense of enamel, hydroxyapatite and fluorapatite.

During the caries process complex reactions involving calcium, phosphate, hydrogen and fluoride ions as main species take place. In this study the precipitation and dissolution reactions occurring in suspensions of enamel, hydroxyapatite (HAP) and fluorapatite (FAP) on addition of fluoride were investigated under well-defined conditions. pH and pF were monitored; calcium and phosphate concentrations were measured at selected times; the solid phases were examined by infra-red, X-ray diffraction and transmission electron microscopy. Precipitation of phosphate-containing calcium fluoride crystals, CaF2(P), can cause severe reduction in the calcium ion concentration and release of hydrogen ions from the precipitated phosphate. These reactions result in considerable dissolution of enamel, HAP and even of FAP. More of the added mineral dissolves with 50 mmol/l fluoride than with 10 mmol/l fluoride, mainly due to the greater reduction in calcium ion concentration. This work shows that phosphate-containing calcium fluoride is most likely an important compound to be considered in the caries process.

Animals↗

PubMed1991

Fluoride, calcium and inorganic phosphorus concentrations in approximal plaque collected from young adults 1 and 24 h after toothbrushing with fluoride toothpastes.

A within-subject double-blind cross-over study was carried out to examine whether the chemical composition of approximal plaque was altered 1 and 24 h after brushing with fluoride toothpaste. Three fluoride toothpastes were tested, containing either sodium monofluorophosphate with calcium glycerophosphate supplement and calcium carbonate abrasive, a combination of sodium monofluorophosphate and sodium fluoride with the same supplement and abrasive or sodium fluoride with a silica abrasive. A fluoride-free toothpaste with a silica abrasive acted as the control. 19 subjects used the toothpastes separately in randomised order for 1 week each prior to collection of plaque. Contralateral half-mouth approximal plaque samples were collected 1 and 24 h after the last use of each toothpaste. Fluoride, calcium and inorganic phosphorus concentrations of plaque were estimated. The results indicated that brushing with toothpastes containing fluoride and/or calcium supplements resulted in increased concentrations of these constituents in approximal plaque 1 h after brushing. These elevated levels of inorganic ions were not observed in the samples collected 24 h after brushing. It was concluded that the potentially beneficial effect of a raised concentration of fluoride and calcium in approximal plaque observed soon after brushing is lost during the following 24 h.

Adult↗

PubMed2005

The influence of calcium fluoride (CaF2) on biaxial flexural strength of apatite-mullite glass-ceramic materials.

OBJECTIVE: The aim of this study was to evaluate the effect of varying the molar percentage of calcium fluoride (CaF2) on the biaxial flexural strength (BFS) of apatite-mullite glass-ceramics. METHODS: Three apatite-mullite glass-ceramic materials were produced based on a formula of 4.5SiO(2)-3Al2O(3)-1.5P2O(5)-3CaO-XCaF2, where X=0.5, 1 and 3 and called HG 1-3, respectively. These materials were used to produce discs of 2 mm thickness and 12 mm diameter using the lost-wax casting process. 30 discs per material were produced, 10 discs per material were cast and then left to bench cool (glass state), 10 discs per material were given a heat treatment at 765, 679 and 629 degrees C for 1h and then heat treated at 890, 860 and 824 degrees C for the HG 1-3, respectively, for another hour to form apatite. Ten discs per material were heat treated as previously described (765, 679 and 629 degrees C) then heat treated for 1h at 1022, 987 and 892 degrees C for the HG 1-3, respectively, to form apatite-mullite. The heat treatment temperatures were obtained from differential thermal analysis data. A lithium disilicate glass-ceramic was used as a control. Biaxial flexural strength (BFS) was determined using a LIoyd 2000R tester. RESULTS: Data showed that the BFS increased as the fluoride content increased, and the apatite-mullite samples had significantly higher BFS values than the as cast glass or apatite samples (p<0.05), with the control having significantly higher BFS values than all the HG glass-ceramic materials for every condition (p<0.05). The fictive glass transition temperature (Tg) was observed to drop with increasing fluoride content. SIGNIFICANCE: Increasing the CaF2 content increased the BFS and decreased the Tg of the glass-ceramic materials tested.

Aluminum Silicates↗

PubMed1978

Treatment of painful osteoporosis with fluoride, calcium, and calciferol.

Fourteen women averaging 69.5 years of age with painful osteoporosis of the spine were treated with sodium fluoride, calcium salts and calciferol. At assessment after 5-19 months of therapy 8 patients were free of pains while in 5 women pains had decreased and mobility improved. One patient had unaltered pains. Side effects were few and mild.

Age Factors↗

PubMed2005

Optical properties and upconversion in Pr3+ doped in aluminum, barium, calcium fluoride glass--I.

The absorption and the fluorescence spectra of Pr3+ ion doped in aluminum, barium, calcium fluoride (ABCF) glass have been studied. Judd-Ofelt theory has been used to derive the optical parameters, viz. the oscillator strength, transition probability, branching ratio, stimulated emission cross section, etc. A broadband upconversion has been observed at different wavelengths throughout the visible region when pumped with 810 nm radiation from a Ti-sapphire laser.

Glass↗

PubMed1994

Calcium fluoride formation on sound enamel using fluoride solutions with and without lactate.

The formation of calcium (Ca) fluoride (CaF2) on bovine enamel blocks during clinically relevant treatment times using neutral fluoride (F) solutions (0.26 mol/l F) with and without 0.1 mol/l lactate was investigated. Uncoated and pellicle-coated blocks were evaluated for alkali-soluble (1 mol/l KOH, three consecutive 24-hour treatments) Ca, PO4, and F after treatment by the F solutions for 0, 5, 15, 30, and 60 min. There was an overall time-related increase in F recovery, while Ca tended to remain at baseline levels. Less F was recovered from the pellicle-coated blocks. The addition of lactate to the F treatment solution did not result in an overall increase in alkali-soluble F recovery, but did result in the formation of cuboidal shaped crystals which closely approached the morphology of pure CaF2. A 1:2 stoichiometric ratio Ca:2F (mol:mol) was not established based on chemical analyses. The ultrastructural and elemental composition of surface deposits on the samples, as determined using scanning electron microscopy, X-ray diffraction, and energy-dispersive spectroscopy, established the presence of CaF2 after 24-hour F treatments; however, it was not possible to directly demonstrate the formation of CaF2 after clinically relevant treatment times.

Animals↗

PubMed2005

Influence of the interfacial adsorptions on the imbibition of aqueous solutions of low concentration of the non-ionic surfactant Triton X-100 into calcium fluoride porous medium.

The imbibition of aqueous solution of Triton X-100 in porous columns of calcium fluoride has been carried out in order to investigate the surfactant influence on the capillary rise. Experiments have consisted of the measurement of the increase in the weight of the porous columns caused by the imbibition of the solutions. From their analysis, it has been found that the capillary rise velocity does not depend on the surfactant concentration, and that imbibition of these solutions behaves as in the case of water. This unexpected finding can not be attributed to depletion of the surfactant molecules from the advancing meniscus, since this effect can not be caused by the adsorption at the solid. This lack of surfactant adsorption on the solid is precisely the reason that justifies the observed behaviour. So, it has been proved that the driving force for the capillary rise movement will remain unaltered despite the surfactant addition whenever the free energies of the solid interfaces are not modified by the adsorption on the solid. Therefore, it is concluded from this study that only if adsorption on the solid happened, the imbibition could be influenced by the surfactant concentration.

Journal Article↗

PubMed2002

High-accuracy measurements of the refractive index and its temperature coefficient of calcium fluoride in a wide wavelength range from 138 to 2326 nm.

The refractive indices of synthetic calcium fluoride for 69 wavelengths from 138 nm in the deep ultraviolet to 2326 nm in the near infrared were measured by the minimum-deviation method in a nitrogen environment. We made these measurements at 20 degrees and 25 degrees C, respectively, to determine the thermal coefficients of the refractive index over this wide-wavelength region. These refractive indices were fitted to a four-term Sellmeier dispersion formula. The temperature coefficients of the refractive index were fitted to a Hoffman-type dispersion formula. The standard deviation of the residual between the observed values and the calculated values was 0.6 x 10(-6) for the refractive index and was 0.13 x 10(-6)/degrees C for the temperature coefficient of the refractive index.

Journal Article↗