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PubMed1997

[Content of fluoride and calcium in stapedial bone in otosclerosis].

The study dealing with the content of fluoride and calcium in stapedial bone and canal wall bone in otosclerosis was performed in 69 subjects (48 females and 21 males) out of the patients, in whom bone rebuilding activity had earlier been studied isotopically. The control group comprised 20 normal stapedies taken during autopsies. Fluoride content was determined by means of fluoride ions meter, the content of calcium was assessed by resorting to atomic absorptiometer. The content of studied elements was compared with the bone rebuilding activity and some clinical features such as the patient's age and duration of the disease. High fluoride content in otosclerotic stapes was revealed, being several times greater than in the bone of normal stapes. Concurrently the stapedial bone in otosclerosis contained less calcium as compared with the bone of normal stapes. In principle, that referred to otosclerotic focus and next to stapedial crura. The bones of stapedial footplates and otosclerotic foci with rebuilding activity lover han the means value had statistically significant, higher content of fluoride and calcium than the bones with greater rebuilding activity. Fluoride content in stapedial bone during otosclerosis dramatically increased with the patient's age and the length of the disease duration period, however, the calcium content had the tendency to decrease.

Adult↗
PubMed1990

Theoretical physical chemical studies of the cause of fluoride-induced osteomalacia.

In this study we investigated the possibility of the formation of a calcium fluoride surface film on the new bone matrix in patients undergoing fluoride treatment for osteoporosis. This calcium fluoride film could interfere with the normal mineralization process and lead to hyperosteoidosis (osteomalacia), a well-documented complication seen in fluoride-treated patients. During treatment, fluoride circulating in the blood and extracellular fluid of patients, could interact with the components of the serum, but particularly calcium and magnesium ions. The interrelationships among serum components in the presence of fluoride ion may result, at thermodynamic equilibrium, in deposition on the apatitic bone surface of phases such as calcium fluoride, fluorapatite, or fluorhydroxyapatite. Differences in the phase deposited among patients could result in differences in response to fluoride treatment. A computer program based on equilibrium thermodynamic data was utilized to study the physicochemical calcium, fluoride, and phosphate interrelationships in serum. In all the computer calculations, fluorhydroxyapatite (FHAP), alone or in combination with hydroxyapatite (HAP), was determined to be the thermodynamically stable precipitating surface phase. These data strongly suggest that calcium fluoride surface film is not the reason for the delay of mineralization of fluoride-stimulated new bone. Based on these calculations, we now advance the hypothesis that the effect of fluoride to cause osteomalacia is due to an effect on osteoblasts and also on osteocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1992

Fluoride and calcium content of enamel organ, muscle, liver and plasma in rats.

Nine-day-old rats were given oral fluoride doses (0.5 micrograms F/g body weight). Plasma, enamel organ, muscle and liver samples were collected from nondosed pups (baseline) and 15, 30, 60 and 120 min after the dose. Samples were assayed for fluoride and calcium concentrations. Adult rats were given 20 ppm F water for 6 weeks, and the same tissues were sampled and assayed for fluoride concentrations only. In the first phase of the study, enamel organ had significantly higher fluoride and calcium content than liver and muscle. In adult rats the fluoride content of enamel organ was again significantly higher than for liver and muscle.

Administration, Oral↗
PubMed1993

The influence of lining techniques on the marginal seal of Class II composite resin restorations.

Various sealing techniques using a light-curing dental adhesive (Scotchbond 2) and bulk application of a light-curing resin-bonded ceramic were examined in 203 Class II cavities. Different pretreatment procedures and lining materials were used, and in one series resin impregnation of the contraction gap was included. The presence of gaps or leakage was disclosed either by a dye or a fluorescent resin penetration technique. In many restorations, Scotchbond 2 and a light-curing glass-ionomer lining did not prevent gap formation at the cervical wall. The gap usually occurred between the liner and the dentin, with dye penetration into the dentin. Three liners, one containing polytrifluorethylene sodium fluoride and calcium fluoride, one containing polyamide resin, and one containing calcium hydroxide, did not prevent dye penetration to the dentin at all; good dentinal protection was frequently observed, however, in cavities treated with a hydrophilic shellac film prior to placement of a polystyrene liner. The best results were observed when dentinal treatment with this lining system was followed by resin impregnation of the contraction gap after the composite resin had set.

Composite Resins↗
PubMed1998

Extracellular volume in streptococcal model biofilms: effects of pH, calcium and fluoride.

Diffusion, which limits nutrient penetration and end-product export in biofilms, is restricted by reversible binding and extracellular volume fraction (Ve). Fluoride has been demonstrated to prevent calcium bridging, hence inhibiting calcium-mediated cell association (Rose, Lee and Shellis, Caries Res. 30 (1996) 458-464). 3H-inulin effusion measurements from streptococcal model plaques, at pH 7.0 or 5.0, 0-20 mmol/l Ca2+, and with or without 5 mmol/l KF, demonstrated that Ve was greatest in the absence of added Ca2+ and at pH 7.0, lowest at 20 mmol/l Ca2+ and pH 5.0, and that F- raised the minimum Ve. By bridging adjacent cells and reducing the net negative charge, calcium and low pH, respectively, reduce Ve. Fluoride eliminates the calcium-bridging effect, hence increasing Ve.

Bacterial Adhesion↗
PubMedDate not supplied

The role of calcium and fluoride in osteoporosis in rhesus monkeys.

Twenty-two female Rhesus monkeys were fed purified diets varying in calcium and fluoride content for five years and studied, using radiographic, photon absorptiometric and histologic techniques. The results suggested that: 1) the addition of fluoride (50 ppm) to a diet containing 1 per cent calcium resulted in a reduction in bone growth rate and resorption, without affecting bone size or density nor resulting in fluorosis; 2) a diet containing 0.15 per cent calcium resulted in osteoporosis due to an increase in bone resorption; and 3) fluoride added to a similar low calcium diet prevented osteroporosis by reducing bone growth rate and resorption resulting in bones with normal density, but at the same time fluoride interfered with mineralization of osteoid leading to osteomalacia.

Animals↗
PubMed1995

Effect of low levels of fluoride on calcium uptake by demineralized human enamel.

The effect of fluoride (ca. 0.1 parts/10(6)) on calcium uptake by enamel was examined under alternating remineralizing and demineralizing conditions. The remineralizing solutions contained either 0, 0.058, 0.104, or 0.138 parts/10(6) fluoride (ex NaF), while the demineralizing solutions contained no added fluoride. During the demineralization periods, calcium loss was similar for all groups. However, during the remineralizing periods, all levels of added fluoride were found to promote calcium uptake. Calcium levels taken up by the artificial lesions were sound to increase with increasing fluoride concentration in solution, and were independent of surface area of exposed enamel. In the absence of fluoride, even under conditions that are considered to be remineralizing, further demineralization took place.

Calcium↗
PubMedDate not supplied

Effects of aluminum hydroxide on fluoride and calcium metabolism.

In order to determine whether and to what extent aluminum affects the absorption of fluoride in man, a study of the effect of aluminum hydroxide on fluoride metabolism was carried out under strictly controlled dietary conditions. Relatively small amounts of aluminum hydroxide were used: 30 ml given three times daily, containing a total of 1.8 gm aluminum. Fluoride and calcium balances were determined in control studies and during the intake of aluminum hydroxide. The fluoride intake of approximately 4 mg/day was due to the fluoride content of the diet and the drinking water. A study was also carried out in patients with osteoporosis who received a high fluoride intake of approximately 50 mg/day of sodium fluoride therapeutically for osteoporosis. The intake of aluminum hydroxide was associated with a significant increase of the fecal fluoride and with a significant decrease of the net absorption of fluoride, by an average of 57%, irrespective of the intake of fluoride. The-plasma fluoride levels decreased by 41%. The fluoride balances were either negative or less positive. Relatively small amounts of aluminum hydroxide resulted in phosphorus depletion, in an increase of the urinary calcium, and in negative calcium balances.

Adult↗
PubMed2005

Effect of a carbamide peroxide bleaching gel containing calcium or fluoride on human enamel surface microhardness.

This in vitro study evaluated the surface microhardness of human enamel submitted to bleaching with 10% carbamide peroxide (CP) containing calcium or fluoride. Ninety-eight dental blocks (5 x 5 mm2) with polished enamel surfaces were randomly assigned to 7 treatment groups (n=14), as follows: without bleaching and storage in artificial saliva (control); 10% CP; 10% CP + 0.05% calcium; 10% CP + 0.1% calcium; 10% CP + 0.2% calcium; 10% CP + 0.2% fluoride; and 10% CP + 0.5% fluoride. During 14 days, enamel surfaces were daily exposed to a 6-h bleaching regimen followed by storage in artificial saliva. Surface microhardness was measured before (baseline), during (7th day), immediately after bleaching (14th day) and 1 week post bleaching. Data were analyzed by two-way ANOVA and Tukey's test (p<0.05). All treatments reduced SM significantly during the bleaching cycle (7th day), immediately after bleaching (14th day) and 1 week post bleaching, compared to baseline and to the unbleached control group. In conclusion, in spite of the addition of calcium and fluoride, all bleaching treatments affected the enamel surface microhardness.

Calcium↗
PubMed2004

Simultaneous exposure of excess fluoride and calcium deficiency alters VDR, CaR, and calbindin D 9 k mRNA levels in rat duodenal mucosa.

Fluoride ingestion reduces intestinal calcium absorption; its molecular basis has not been studied. We studied the mRNA expression of calcium-sensing receptor (CaR), vitamin D receptor (VDR) and calbindin D 9 k (D 9 k) by northern blot analysis in the duodenal mucosa of rats. Weanling pups fed with chow diet containing adequate calcium (0.5% w/w) and drinking water (NaF < 1 ppm) served as controls (Group I) and were studied at 9 and 15 weeks. The pups, born to rats fed with a calcium-deficient diet (0.03%) and excess fluoride water (NaF 50 ppm), were continued on the same diet and water (Group II) until 9 weeks of age. Subsequently, Group II rats were divided into 4 subgroups; 3 subgroups with fluoride free water [II-A adequate calcium, II-B excess calcium (Ca 2%) and II-D calcium deficient], whereas II-C received fluorinated water and adequate calcium diet until 15 weeks. At 9 weeks, as compared to group-I, group-II had decreased VDR (P < 0.001) and D 9 k mRNA (P < 0.001), whereas CaR mRNA levels increased (P < 0.05). At 15 weeks, as compared to group-I, VDR mRNA further reduced in group II-D (P < 0.001) and II-C (P < 0.001), whereas it increased in group II-A. Removal of fluoride ingestion and calcium replenishment increased D 9 k mRNA expression, maximally in adequate calcium group (P < 0.001), while it was further reduced in group II-C (P < 0.001). CaR expression decreased significantly in all the groups. We conclude that excess fluoride reduces the mRNA levels of VDR and D 9 k in the duodenal mucosa of rats, thereby possibly reducing calcium absorption. Calcium supplementation with simultaneous fluoride removal improves their expression.

Animals↗
PubMed1977

Salivary fluoride and calcium concentrations, and their relationship to the secretion of saliva and caries experience.

Samples were collected from the stimulated saliva of 113 students enrolled in institutions of higher education. The students were divided into three "carries-diagnostic groups" on the basis of indications given by the Dentocult saliva test, which shows the frequency of lactobacilli and other aciduric microorganisms in saliva. The frequency of such microorganisms in 1 ml saliva in Group A was less than or equal to 103, in Group B greater than 10(3), less than 10(4) and in Group C greater than or equal to 10(4). The rate of secretion of saliva in Group A was significantly higher than in Group C (P less than 0.05). On the average, a rise was noted in the fluoride and calcium concentrations with increasing "caries activity". In the material as a whole, there was a negative and highly significant correlation between the secretion rate of saliva and the concentrations of fluoride and calcium. In the examination by groups, significant correlations were observed between fluoride concentration and rate of saliva secretion in Group A, and with respect to fluoride and calcium only in Group C. The results suggest that the extra salivary fluoride is likely to be derived from the enamel.

Adolescent↗