Fluoride Action Network


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.