“…Because of these difficulties, fluoride excretion is taken as a good indicator of fluoride intake in children and adults who are in fluoride balance [Murray, 1986;Newbrun, 1986]. For example, fluoride excretion studies have been used extensively to determine optimum levels of salt fluo ridation [Ericsson, 1971;Marthaler, 1983;Mcnghini et al, 1989]. Most of these studies have recorded fluoride con centration in urine (which is the most important vehicle for fluoride excretion) but few have recorded the volume of urine excreted over 24 h or urinary tluoride excretion during 24 h. This is partly due to the technical difficulties of obtaining 24-hour urine collections from large numbers of volunteers and partly because a close positive correla tion between fluoride concentration in drinking water and fluoride concentration of spot samples of urine has been observed [McClure and Kinser, 1944], However, these lat-ter studies were conducted in adults who were generally well-nourished, living in temperate climates, before the widespread availability of fluoride toothpastes, and the correlations were closest in areas with water fluoride lev els over 1 ppmF [Myers.…”