Abstract
Genetic factors underlie the susceptibility and the resistance to dental fluorosis (DF). The A/J (DF susceptible) and 129P3/J (DF resistant) mouse strains have previously been used to detect quantitative trait loci (QTLs) associated with DF on chromosome (Chr) 2 and Chr 11. In the present study, increased marker density genotyping followed by interval mapping was performed to narrow the QTL intervals and improve the logarithm of the odds (to the base 10) (LOD) scores. Narrower intervals were obtained on Chr 2 where LOD ? 6.0 (57-84 cM or ? 51 Mb), LOD ? 7.0 (62-79 cM or ? 32 Mb), and LOD ? 8.0 (65-74 cM or ? 17 Mb); and on Chr 11 where LOD ? 6.0 (18-51 cM or ? 53 Mb), LOD ? 7.0 (28-48 cM or ? 34 Mb), and LOD ? 8.0 (31-45 cM or ? 22 Mb). Haplotype analysis between A/J and 129P3/J mice further reduced the QTL intervals. Accn1 was selected as a candidate gene based upon its location near the peak LOD score on Chr 11 and distant homology with the Caenorhabditis elegans fluoride-resistance gene, flr1. The severity of DF between Accn1(-/-) and wild-type mice was not significantly different. Hence, the loss of ACCN1 function does not modify DF severity in mice. Narrowing the DF QTL intervals will facilitate additional candidate gene selections and interrogation.
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Barrier formation: potential molecular mechanism of enamel fluorosis
Enamel fluorosis is an irreversible structural enamel defect following exposure to supraoptimal levels of fluoride during amelogenesis. We hypothesized that fluorosis is associated with excess release of protons during formation of hypermineralized lines in the mineralizing enamel matrix. We tested this concept by analyzing fluorotic enamel defects in wild-type mice
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Histone acetyltransferase promotes fluoride toxicity in LS8 cells.
Highlights Fluoride activates histone acetyltransferase (HAT) in enamel organ-derived LS8 cells. HAT inhibitors suppressed fluoride-mediated acetylation of p53 and cell toxicity. Modulation of HAT activity may be a potential target to mitigate fluoride toxicity. Previously we demonstrated that fluoride increased acetylated-p53 (Ac-p53) in LS8 cells that are derived from mouse enamel
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Micromolar fluoride alters ameloblast lineage cells in vitro.
Fluorosed enamel is caused by exposure to fluoride during tooth formation. The objective of this study was to determine whether epithelial ameloblast-lineage cells, derived from the human enamel organ, are directly affected by micromolar concentrations of fluoride. Cells were cultured in the presence of fluoride, and proliferation was measured by
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Fluorosed mouse ameloblasts have increased SATB1 retention and Gaq activity
Dental fluorosis is characterized by subsurface hypomineralization and increased porosity of enamel, associated with a delay in the removal of enamel matrix proteins. To investigate the effects of fluoride on ameloblasts, A/J mice were given 50 ppm sodium fluoride in drinking water for four weeks, resulting serum fluoride levels of
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Plasma fluoride levels and enamel fluorosis in the rat.
This study examined the relationship between transient peak plasma fluoride levels (subcutaneous injections) as well as lower but relatively constant levels (subcutaneous constant infusion) and the occurrence of disturbances in the enamel mineralization of the rat incisor as determined microradiographically. The fluoride doses were administered for 1 week, and the
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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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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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Racial Disparities in Dental Fluorosis
In 2005, the Centers for Disease Control published the results of a national survey of dental fluorosis conducted between 1999 and 2002. According to the CDC, black children in the United States have significantly higher rates of dental fluorosis than either white or Hispanic children. This was not the first time that black children were found to suffer higher rates of dental fluorosis. At least five other studies -- dating as far back as the 1960s -- have found black children in the United States are disproportionately impacted by dental fluorosis.
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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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Dental Fluorosis in the U.S. 1950-2004
Before the widespread use of fluoride in dentistry, dental fluorosis was rarely found in western countries. Today, with virtually every toothpaste now containing fluoride, and most U.S. water supplies containing fluoride chemicals, dental fluorosis rates have reached unprecedented levels. In the 1950s, it was estimated that only 10% of children in
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