Plasma fluoride and enamel fluorosis

Abstract

It is postulated that tissue fluid F concentrations are the primary determinants of flouride effects on bones and developing teeth and that these concentrations are dependent on, or mirrored by, blood plasma F. It has earlier been shown that the plasma F levels are dependent on the dietary F supply as well as on skeletal F concentration. Fasting and post-ingestion or postinjection plasma F levels have been determined in rats on F doses that cause different degrees of enamel fluorosis. The results indicate that temporary peak values rather than elevated fasting values are responsible for the occurrence of enamel fluorosis and that the peak values must approach about 10 muM in order to block enamel formation by the ameloblasts. The diagnostic and prognostic importance of plasma F determinations is discussed.

The Impact of Fluoride on Ameloblasts and the Mechanisms of Enamel Fluorosis

“…Mineralization defects in rat incisor maturation-stage enamel can develop during prolonged exposure to fluoridated drinking water at levels as low as 9-10 ppm fluoride (Shinoda, 1975;Angmar-Månsson et al, 1976), and are characterized by the development of a generalized hypomineralized porous subsurface area along the entire crown enamel (Fig. 3a) (Shinoda, 1975;Angmar-Månsson et al, 1976;Whitford, 1982, 1984;Richards et al, 1992;Kierdorf et al, 2004). This type of defect correlates to the porous white opacities seen clinically.…”

“…Essentially, small rodents, the rat in particular, have proved to be good models for the study of human dental fluorosis, since they show the same fluorotic disturbances at similar plasma levels as humans (Angmar-Månsson et al, 1976;AngmarMånsson andWhitford, 1984, 1985;DenBesten, 1986;Everett et al, 2002). However, for reasons not fully understood, but possibly related to increased urinary secretion or more rapid bone growth by rodents, the doses of fluoride in the drinking water of rats and mice used for the study of fluorosis in the continuously erupting incisor are approximately 10 times higher than those required for humans to achieve similar fluoride plasma levels.…”

“…In drinking water, fluoride levels of at least 10-30 ppm are necessary to induce lasting enamel disturbances in rodents, and levels used in most experimental studies are in the range of 25-100 ppm (Shinoda, 1975;Angmar-Månsson et al, 1976;Fejerskov et al, 1979;Ekstrand et al, 1981;Angmar-Månsson and Whitford, 1984;DenBesten, 1986;Kubota et al, 2005). The high fluoride levels in drinking water needed to cause enamel fluorosis in rats (about 10 times the amount of humans) have raised the question as to whether studies in rats have relevance for the development of enamel fluorosis in humans.…”

Estandarización de la técnica de biopsia para determinación de fluoruro en esmalte dental

“…Se ha encontrado una relación entre la concentración de fluoruro en el esmalte dental y la dosis de fluoruro ingerido durante la formación dental y el período preeruptivo (8). Sin embargo, influyen otros factores como la duración y el momento del desarrollo dental en el que se da la exposición al fluoruro (24), lo cual explica en parte la variabilidad existente entre los dientes evaluados. figura 2.…”

Pathogenesis Of Dental Fluorosis: Biochemical And Cellular Mechanisms

“…We know that the chronic and sustained presence of the F -ion in plasma increases the likelihood of adhering to tissues in the mineralization process, 10 but there is the misperception that the hypomineralization observed in dental fluorosis is the only consequence of the excessive addition of F -in enamel. In this literature review, we assume that the hypomineralized phenotype of fluorosis is the outcome of a series of possible effects of the F -ion on cell physiology and the proteins responsible…”