Plasma fluoride and enamel fluorosis.

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.