We describe a detailed study of fluoride distribution with age in the human cortical rib bone. Human ribs were obtained from 110 subjects (M:68, F;42) aged 20-93 years. The fluoride distribution from the periosteal to endosteal surfaces of the ribs was determined by sampling each specimen using an abrasive micro-sampling technique, and the samples were analyzed using the fluoride electrode, as described by Weatherell et al. [1]. The concentration of fluoride was highest in the periosteal region, decreased gradually towards the interior of the tissue where the concentration of fluoride tended toward the plateau, and then rose again towards the endosteal surface. Patterns of fluoride distribution changed with age, and the difference between periosteal and endosteal fluoride levels increased with age. Although average fluoride concentrations increased with age in both sexes, there was a significant difference between males and females at the age of about 55 years (P < 0.05).

The present study was undertaken to determine the fluoride distribution profile in the rat femur. Male Wistar rats were divided into four groups and given water containing 0, 25, 50, and 100 ppm of fluoride, respectively, for 10 weeks. The fluoride distribution from the periosteum to the endosteum was determined in each specimen after sampling using the abrasive microsampling technique. In the outer circumferential lamellae, the concentration of fluoride was relatively high in the periosteal layer and then decreased gradually towards its interior. In the haversian and interstitial lamellae, it was lower and roughly constant through the tissue. In the inner circumferential lamellae, it rose again to reach the highest level towards the endosteal surface. Fluoride concentration throughout the cortex increased significantly with increasing intake of fluoride. These increases were especially marked at periosteal and endosteal surfaces.

This study was conducted to determine the fluoride intakes in 94 preschool children aged 3, 4 and 5 (n = 30, 30, 34, respectively) residing in Yokkaichi, Mie Prefecture (< 0.16 ppm F water supply). The parents duplicated all the diets that their children ingested on 3 separate days during a 1-year period. The acid-diffusible fluoride in the diet was isolated by the acid-diffusion technique and measured with a fluoride electrode. The mean daily fluoride intakes from diet alone by children aged 3, 4 and 5 were 0.30 mg (n = 29, SD 0.19), 0.28 mg (n = 30, SD 0.19) and 0.30 mg (n = 34, SD 0.19), respectively. The total estimated mean values from diet and dentifrice were 0.35 mg (n = 29, SD 0.22, range 0.13–1.00), 0.33 mg (n = 30, SD 0.19, range 0.13–0.86) and 0.39 mg (n = 34, SD 0.18, range 0.18–1.01), respectively. It was concluded that the mean (±SD) total fluoride from diet and dentifrice in 3- to 5-year-old Japanese children was 0.35 ± 0.19 mg/day (0.021 ± 0.012 mg/kg body weight).

The present study was undertaken to determine the fluoride distribution profile in rat molar cementum with age in relation to fluoride in drinking water. Fifty-four female Wistar rats were used for the experiment. Before the experiment 6 rats were killed under chloroform anesthesia at 4 weeks of age as controls. The remaining 48 rats were divided into two groups: a control group given distilled water and the other group given water containing 100 ppm fluoride ad libitum. Six rats from each group were killed at the ages of 6,12, 24, and 48 weeks. The fluoride distribution in the molar cementum was analyzed from the surface to the cementodentinal junction by abrasive microsampling. The fluoride concentrations in molar cementum from control rats on distilled water remained relatively constant until 24 weeks. A small increase then occurred between 24 and 48 weeks. The fluoride concentration in cementum from rats drinking water containing 100 ppm fluoride increased markedly with age, both in outer and inner regions of the molar cementum for all rats. On the other hand, the fluoride concentration in the cementum of older rats drinking water with 100 ppm fluoride was significantly higher in the outer than in the inner region of the cementum. It was concluded that the fluoride distribution in rat molar cementum may increase throughout life in relation to the fluoride level in the drinking water.

Summary This study aimed to measure and evaluate the intakes for the four trace elements of Fe, Zn, Mn, and Cu in 3-to 5-y-old Japanese preschool children. The study group consisted of a total of 90 3-to 5-y-old children living in Yokkaichi, Mie, Japan. Diet samples were collected by the duplicate-portion technique on 3 d at three different seasons between summer in 1999 and winter in 2000. The medians of annual mean daily intakes (25th-75th percentile) of Fe, Zn, Mn, and Cu in the 3-to 5-y-old children were 3.1 mg (2.4 to 3.6), 4.0 mg (3.4 to 4.7), 1.3 mg (1.1 to 1.6), and 0.45 mg (0.35 to 0.56), respectively. The annual mean value of the total daily diet intake had significant correlations with the Fe, Zn, Mn and Cu intakes (Spearman's r ϭ 0.55, 0.67, 0.58, and 0.55, respectively; p Ͻ 0.001 for all). There were significant correlations between each mineral intake. The Zn and Mn intakes had differences among ages ( p ϭ 0.003 and 0.005, respectively) and the Zn intake significantly differed between boys and girls ( p ϭ 0.031). The proportion of subjects whose Mn intake was the AI or less was 82%, and the proportions of subjects whose Fe, Zn, and Cu intakes were the estimated average requirements (EARs) or less were 72, 83, and 13%, respectively. Many Japanese children are deficient in Fe and Zn compared with the dietary reference intakes (DRIs). However, data in a balance study examining intakes and excretion of trace minerals are insufficient in children and DRIs for trace elements may change in future.

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This study was conducted to estimate the relative contribution of particular foods and drinks to dietary fluoride intake in 94 preschool Japanese children in low-fluoride areas. The mean daily fluoride intake from all beverages (548 ± 162 g) was 0.108 mg (SD = 0.082), accounting for 37% of the total dietary fluoride; tea beverages showed the highest value, 0.093 mg (SD = 0.081), 32%. That from staple food and side dishes was 0.183 mg (SD = 0.146), 63%, followed by cereals (12%), fish (8%) and bean products (5%). In conclusion, the contribution of beverages excluding tea to dietary fluoride intake is small in Japanese children.