The objectives of this study were to investigate the effect of low and high fluoride on microhardness and compositions of the rat bone.
Forty-eight Sprague-Dawley strain female rats were divided into four groups, and they were supplied with 0, 1, 10 and 100ppm fluoride containing water for three and six weeks. Animals were killed and femur, tibia and mandible were dissected. The slabs of each bone were embedded in unsaturated polyester for testing the surface microhardness with Vicker´s Microhardness Tester. The ashed bone powerders were digested in the Aicd Digestion Bomb. Calcium, magnesium and ferric ion were determined using the ICP Emission Spectrophotometer. Data analysis were conduct using the SAS package. Differences in each group were compared by one-way´ ANOVA and Duncan´s multiple range test. Corresponding p-values were considered significant at values < 0.05.
There was no significant growth disturbance due to administration of fluoride from 0 to 100ppm during 6 weeks of experiment. There were significant increases of surface microhardness at femur and mandible of 3 weeks group, but not at tibia. The surface microhardness of femur, tibia and mandible were increased with increased concentration of fluoride at 6 weeks group. The contents of calcium, magnesium and ferric ion in the femur and tibia were higher at low fluoride groups than high fluoride groups, but there were no statistical difference between low and
high fluoride groups with calcium and ferric ion in the mandible.
All of the findings presented support the conclusion that the maximum(I00ppm) administration of fluoride for six weeks did not affect the weight change of rats. Within the range of doses used in this experiment, there were increases of surface microhardness of three kinds of bones due to higher fluoride level. We suggested that lppm of fluoride could increase the surface microhardness and calcium content in the bone better than 10 and 100ppm of fluoride.
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