Abstract
Fluoride is widely believed to be a useful chemical substance for preventing dental caries. However, the mechanism underlying crystal perforation in the tooth enamel and the effect of fluoride on hard tissues are unclear. To clarify the mechanism of the biological action of fluoride in the mineralization process, we examined the hard tissues of rats having received water containing a relatively low fluoride level. Electron microscopy revealed that fluoride ions could interrupt the crystal nucleation process, resulting in crystal perforation in the developing tooth enamel and the presence of amorphous minerals in bone crystals. Furthermore, the results of enzymatic analyses indicated that fluoride directly interfered with the synthesis of carbonic anhydrase by the enamel-forming cells, rather than being directly involved in the crystal formation. From the results, we would like to provide a possible mechanism of crystal perforation in the enamel induced by fluoride intake. Also, we would like to suggest that regardless of its amount, fluoride intake has harmful effects on both tooth and bone formation.
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Sirtuin1 and autophagy protect cells from fluoride-induced cell stress
Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD(+))-dependent deacetylase functioning in the regulation of metabolism, cell survival and organismal lifespan. Active SIRT1 regulates autophagy during cell stress, including calorie restriction, endoplasmic reticulum (ER) stress and oxidative stress. Previously, we reported that fluoride induces ER-stress in ameloblasts responsible for enamel formation,
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Effect of dietary protein or calcium supplement on the expression of collagen I and dentine phosphoprotein of rats with dental fluorosis.
This study aims to assess the roles of dietary protein (Pr) and calcium (Ca) levels associated with excessive fluoride (F) intake and the impact of Pr, Ca, and F on expression of collagen I (COL I) and dentine phosphoprotein (DPP) in rat incisors. Seventy-two rats were randomly allotted to six
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The relationship between water-borne fluoride, dental fluorosis and skeletal development in 11-15 year old Tanzanian girls
Dental fluorosis was evaluated by a classification system, previously shown to be sensitive, and skeletal changes evaluated by bone maturity and structure. Dental fluorosis was more severe in posterior than in anterior teeth in both jaws irrespective of fluoride concentration of the drinking water. There appeared to be no dependence between fluoride content
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Fluorosilicic acid induces DNA damage and oxidative stress in bone marrow mesenchymal stem cells.
Highlights Fluorosilicic acid is the most used additive for water fluoridation. Dental fluorosis can be caused by fluorosilicic acid present in drinking water. DNA damage was caused by fluorosilicic acid in mesenchymal stem cells. Fluorosilicic acid altered bone mineralization in mesenchymal stem cells. DNA damage caused by fluorosilicic acid
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Fluoride affects enamel protein content via TGF-B1-mediated KLK4 inhibition
Dental fluorosis is caused by chronic high-level fluoride (F-) exposure during enamel development, and fluorosed enamel has a higher than normal protein content. Matrix metalloproteinase 20 cleaves enamel matrix proteins during the secretory stage, and KLK4 further cleaves these proteins during the maturation stage so that the proteins can be
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Dental Fluorosis Is a "Hypo-mineralization" of Enamel
Teeth with fluorosis have an increase in porosity in the subsurface enamel ("hypomineralization"). The increased porosity of enamel found in fluorosis is a result of a fluoride-induced impairment in the clearance of proteins (amelogenins) from the developing teeth. Despite over 50 years of research, the exact mechanism by which fluoride impairs amelogin
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Mechanisms by Which Fluoride Causes Dental Fluorosis Remain Unknown
When it comes to how fluoride impacts human health, no tissue in the body has been studied more than the teeth. Yet, despite over 50 years of research, the mechanism by which fluoride causes dental fluorosis (a hypo-mineralization of the enamel that results in significant staining of the teeth) is not
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"Pre-Skeletal" Fluorosis
As demonstrated by the studies below, skeletal fluorosis may produce adverse symptoms, including arthritic pains, clinical osteoarthritis, gastrointestinal disturbances, and bone fragility, before the classic bone change of fluorosis (i.e., osteosclerosis in the spine and pelvis) is detectable by x-ray. Relying on x-rays, therefore, to diagnosis skeletal fluorosis will invariably fail to protect those individuals who are suffering from the pre-skeletal phase of the disease. Moreover, some individuals with clinical skeletal fluorosis will not develop an increase in bone density, let alone osteosclerosis, of the spine. Thus, relying on unusual increases in spinal bone density will under-detect the rate of skeletal fluoride poisoning in a population.
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Diagnostic Criteria for Dental Fluorosis: The TSIF ("Total Surface Index of Fluorosis")
The traditional criteria (the "Dean Index") for diagnosing dental fluorosis was developed in the first half of the 20th century by H. Trendley Dean. While the Dean Index is still widely used in surveys of fluorosis -- including the CDC's national surveys of fluorosis in the United States -- dental
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Diagnostic Criteria for Dental Fluorosis: The Thylstrup-Fejerskov (TF) Index
The traditional criteria (the "Dean Index") for diagnosing dental fluorosis was developed in the first half of the 20th century by H. Trendley Dean. While the Dean Index is still widely used in surveys of fluorosis -- including the CDC's national surveys of fluorosis in the United States -- dental
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