Abstract

Histomorphometric study was made on a series of sections of undecalcified epiphyseal femoral specimens from rats with experimental fluorosis. The results revealed osteosclerosis in Group A (5 ppm) being more severe than that in Group B (25 ppm). With the increase of fluoride dose, the parameters fell down instead of increased in parallel. There is seemingly a threshold over which osteosclerosis in fluorosis becomes less severe. In contrast to Bely’s conclusion the authors proposed that, fluoride toxicity, besides decreasing the number of osteoblasts, may also activate the osteoblasts. The number of osteoblasts may be increased with relative lower dose of fluoride also. The net outcome is the increment in bone volume. When toxic dose of fluoride is higher enough (higher than the proposed threshold), however, the number of osteoblasts and its activity are inhibited. So are the osteocytes. This interpretation may be the cytological basis for osteosclerosis in the experimental fluorosis.

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