The results of our experiments suggest that increased doses of NaF cause more extensive osteosclerosis due to the decrease in number and/or activity of osteoclasts. Therefore oateosclerosis is caused primarily, not by increased bone formation but, by the inhibition of bone resorption. This view is supported by the fact that fluoride inhibits acid phosphatase activity more than alkaline phosphatase (6). The acid phosphatase activity of osteoclasts is of greater inteneiry than that of osteoblasts

The results of our experiments suggest that increased doses of NaF cause more extensive osteosclerosis due to the decrease in number and/or activity of osteoclasts. Therefore oateosclerosis is caused primarily, not by increased bone formation but, by the inhibition of bone resorption. This view is supported by the fact that fluoride inhibits acid phosphatase activity more than alkaline phosphatase (6). The acid phosphatase activity of osteoclasts is of greater inteneiry than that of osteoblasts and the alkaline pbosphatase activity of oateoblasts is of greater intensity than that of osteoclasts. So fluoride inhibits the osteoclasts more than the osteoblasts.

In addition, the metabolism of osteoclasts of greater intensity than that of osteoblasts. Therefore osteoclasts ere more sensitive
to fluoride poisoning than osteoblasts. Osteosclerosis, caused by fluoride, is really the result of a toxic effect which is reflected by the dose dependent decrease of osteoclasts and of the hemopoietic elements. the irregular arrangement of the epiphyseal cartillage chondrocytes and also by skeletal necrosis.