Abstract
Sodium fluoride (NaF) is widely used for the prevention of dental caries at various concentrations. The clastogenic effect of NaF has been tested by the use of several cytogenetic assay systems, but the findings on its genotoxicity are not consistent. In this study, the effects of NaF on chromosomes, unscheduled DNA synthesis (UDS) and sister-chromatid exchanges (SCEs) were investigated using cultured human lymphocytes. For clastogenicity testing, cells were treated for 24 h in various concentrations of NaF. At least two donors were tested for each concentration and more than 10,000 cells were totally observed. The frequencies of chromosome aberrations were 0.78 + 0.72, 0.88 + 0.56, 0.77 + 0.45, 5.95 + 5.35, 57.76 + 31.46, 108.00 + 59.40, 80.00 + 53.70 and 40.00 + 5.66 per 100 cells for concentrations of 0, 0.25, 0.5, 1.0, 2.0, 4.0, 6.0 and 8.0 mM, respectively. Considerable differences among individuals were observed, but there was no significant difference between sexes. Sodium fluoride treatment had remarkable effects on the induction of isochromatid gaps and chromosome breaks (NUpds). At various concentrations of NaF ranging from 1.0 to 4.0 mM, no increase in UDS and SCE was observed.
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Lack of DNA damage induced by fluoride on mouse lymphoma and human fibroblast cells by single cell gel (comet) assay
Fluoride has widely been used in Dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury on genetic apparatus. Genotoxicity tests constitute an important part of cancer research for risk assessment of potential carcinogens. In
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DNA damage induced by fluoride in rat kidney cells.
DNA damage by fluoride to newborn rat kidney cells isolated by enzymic digestion is reported. The cells were exposed for 24 hr to sodium fluoride at NaF concentrations of 0, 0.2, 0.4, 0.8, and 1.0 mM. Damage to DNA was determined by single cell gel electrophoresis assay (Comet assay). Significant breakage of DNA strands
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Is fluoride a mutagen?
Recent studies suggest that fluoride may be genotoxic. While the concentration of fluoride in artificially fluoridated water (1 mg Fl-1) is generally considered to be "safe", levels of fluoride present in a number of widely used dental health products, such as fluoride-containing toothpaste, appear to be potentially mutagenic. Since fluoride
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Mutagenic activity of fluorides in mouse lymphoma cells
The L5178Y mouse lymphoma cell forward-mutation assay was used to test for the mutagenic activity of sodium and potassium fluoride at the thymidine kinase locus. Mutants were detected by colony formation in soft agar in the presence of trifluorothymidine. Mutagenic and toxic responses were observed in the concentration range of
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Cytogenetic effects of gaseous fluorides on grain crops
Atmospheric pollution of fluoride from a non-ferrous industrial plant has been studied for its effect on the frequency of chromosome aberrations in root tips and shoot tips of wheat and barley. The anaphase-test was used. The percentage of mutations in the meristematic cells of plants growing in polluted areas was
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Fluoride's Mutagenicity: In vitro Studies
According to the National Toxicology Program, "the preponderance of evidence" from laboratory "in vitro" studies indicate that fluoride is a mutagenic compound. Many substances which are mutagens, are also carcinogens (i.e. they can cause cancer). As is typical for in vitro studies, the concentrations of fluoride that have generally been tested
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Fluoride's Mutagenicity: The "Oral Health Research Institute's" Studies
Although many in vitro and in vivo studies have detected mutagenic effects from fluoride exposure, the Oral Health Research Institute at Indiana University's School of Dentistry has repeatedly failed to find any such effect in multiple studies on the subject.
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NTP Bioassay on Fluoride/Cancer (1990)
In 1977, the U.S. Congress requested that animal studies be conducted to determine if fluoride can cause cancer. The result of the Congressional request was an extensive animal study conducted in the 1980s by the National Toxicology Program (NTP) and published in 1990. The main finding of NTP's study was a dose-dependent increase in osteosarcoma (bone cancer) among the fluoride-treated male rats.
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A Critique of Gelberg's Study on Fluoride/Osteosarcoma in New York
The case-control study by Gelberg, published first as a PhD dissertation and then later in two peer-reviewed journals, may represent the most substantive study on fluoride/osteosarcoma previous to Bassin’s 2001 analysis. In assessing Gelberg’s data, we were at first struck by the existence of several notable errors in both the thesis and papers. While these errors do raise questions about the study, our primary concern with Gelberg’s work relates to the methods she used to analyze her data.
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Fluoride & Osteosarcoma: A Timeline
Several human epidemiological studies have found an association between fluoride in drinking water and the occurrence of osteosarcoma (bone cancer) in young males. These studies are consistent with the National Toxicology Program's (NTP) cancer bioassay which found that fluoride-treated male rats had an dose-dependent increase in osteosarcoma. Although a number of studies have failed to detect an association between fluoride and osteosarcoma, none of these studies have measured the risk of fluoride at specific windows in time, which based on recent results, is the critical question with respect to fluoride and osteosarcoma.
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