Fluoride accumulation in bone and the effect on their physical properties in guinea pigs given different levels of fluoridated water.

Guinea pigs were exposed to fluoridated water (2-20 ppm) for a period ranging from 15 to 42 weeks. The fluoride content of the bones increased in proportion to the concentration of fluoride in drinking water and the period of exposure. The rate constant of accumulation of fluoride in guinea pig bones was estimated to be 2.5 X 10(-2) week-1, with a half-life of plateau formation in the order of 28 weeks. This indicated that maximum accumulation of fluoride during a continuous exposure, or a computed complete elimination of fluoride after exposure, will take approximately four years. Although fluoridated water improved the weight gain of guinea pigs, no effect on physical properties of bones was observed. No other toxic effects of fluoride under these conditions were noted.