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Although potential toxic effects of sodium fluoride on early pro-genitor and stem cells have been reported previously, surprisingly few inves-tigations have examined the effects of fluoride on human leukemic cells. To address this need, four different human leukemic cell lines (HL-60, HEL, TF-1, and K562) were exposed to increasing levels (0, 0.24, and 1.19 mM F) of two forms of fluoride: sodium fluoride (NaF) and sodium hexafluorosilicate (Na2SiF6). Because of its widespread use in water fluoridation, Na2SiF6 was investigated in addition to NaF.  The early response effect of Na2SiF6 was greater, and in several cases significantly greater, than NaF on clonogenic growth and the induction of apoptosis in all four cell lines.  These findings show that human leukemic cells can be influenced and damaged by fluorine compounds.

The Intelligence Quotient (IQ) was measured in 512 children, aged 8–13 years, living in two villages in Sihong County, Jiangsu Province, China, differing in the level of fluoride in their drinking water. In the high-fluoride village of Wamiao (water fluoride: 2.47±0.79 mg/L; range: 0.57–4.50 mg/L), the mean IQ of 222 children was significantly lower (92.02±13.00; range: 54–126) than in the low-fluoride village of Xinhuai (water fluoride: 0.36±0.15 mg/L; range: 0.18–0.76 mg/L), where the mean IQ of 290 children was higher (100.41±13.21; range: 60–128). The children’s IQs were not related to urinary iodine, family income, or parent’s education level. Higher drinking water fluoride levels were significantly associated with higher rates of mental retardation (IQ <70) and borderline intelligence (IQ 70–79). The Benchmark Concentration (BMC) for the concentration-response relationship between IQ <80 and the drinking water fluoride level was 2.32 mg/L, and the lower-bound confidence limit (BMCL) of the BMC was 1.85 mg/L. Taking dental fluorosis and other sources of dietary fluoride into account, the reference value con-centration (RfC) for fluoride was calculated to be 0.925 mg/L, which is very close to the current national Chinese standard of <1.0 mg/L. In endemic fluo-rosis areas, drinking water fluoride levels greater than 1.0 mg/L may adversely affect the development of children’s intelligence.

The quality of environment that human society had in the beginning of the twentieth century was far better than what has been handed over to the mankind of the first century of the new millennium. On account of ruthless development activities and over exploitation of natural resources, several animate and inanimate objects of the nature have either lost their quality or had perished. This has necessitated that people should learn more about the environment and educate themselves to protect it from further degradation and destruction, not only in terms of human health and welfare, but also in perspective of safety of other living and non-living constituents of the environment.

This study evaluated fluoride-release and recharging with the fluoride mouth rinsing technique on fluoridated materials. Three fluoride containing materials and one non-fluoride containing composite resin were used for this study. Samples for each material consisted of 15 discs, 9 mm diameter with a thickness of 1 mm. Initial fluoride release was assessed over a 60-day period. After that, 15 discs for each material were divided into 3 groups: distilled water group, 450-ppm and 900-ppm mouth rinsing groups. Fluoride release increased in combination with fluoride mouth rinse, and fluoride was higher in the 900-ppm group than the 450-ppm group. Moreover, S-PRG or F-PRG fillers materials released fluoride in higher than fluoroaluminosilicate glass fillers materials. In addition fluoride release from control samples was not observed. Therefore, only fluoride release material takes up fluoride. The findings of the present investigation suggest that the rate of fluoride release was different for each material, because they contained different function fillers. The results showed the importance of the fluoride mouth rinsing technique for fluoride-releasing restorative materials for the prevention of secondary caries.

One of the most important and exciting properties of recently introduced dental restorative materials is their ability to release fluoride ions, as this has several advantageous effects on tooth structures. They have been extensively used as fluoride-releasing filling and luting materials. Recently, fluoride-releasing adhesive resins and fluoride-releasing adhesive resin cement have been developed and introduced for clinical use. The purpose of this study was to evaluate the fluoride release from these adhesive resins and the fluoride uptake by both enamel and dentin, as well as the acid-resistance of these tooth structures. Based on our results, we conclude that fluoride-releasing adhesive resins and luting cements are useful for the prevention of initial or secondary caries, especially along the margins of restorations.