| Research Abstract |
Decalcified coarse powders are said to have the capacity to reproduce endochondral ossification process after birth . We stimulates direct microcurrents on pellets made from those powders, which were inserted into muselein 30-40 day-male rats under the skin of the breasts, but many of those are affected with infections. We could not realize experimental systems. So next experiments were performed in vivo and in vitro. The former was done in adult mongrel dogs stimulated at 50 muA. Evaluations were done to seek the differences between eletrical stimulated side and non-stimulated one rentogenographically and histologically. The latter were examined using osteogenic MC3T3-E1 cells which have retained the capacity to differentiate into osteoblasts and form mineralized tissue in vitro.
Results as follows; In vivo; 1. A semicircular radiolucent area below the cathode gradually emerged and increased in size as time passed. As its radiolucent area expanded into, it assumed a fanlike or bowllike
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inner structure. This phenomenon did not occur on the stimulated side. When electrical stimulation was applied for relatively long periods, small transparent spots upper part of bone defect above the cathode. 2. Bone healing process began earlier on the stimulated side. At non-stimulated side, new bone tissue formed in such a way to encircle the mandibular nerve canal and blood-vessel bundles in the mandibular bone defect. On the other hand, new bone tissues were likely to compress the mandibular nerve and blood bundies towards the inferior mandibular margin on the stimulated side. On the stimulated side, the influence of electrical current flow seemed to account for a regular orientation of new bone tissues.
In vitro; Osteogeneic cells(MC3T3-E1) were stimulated by 1,5,10,20muA of constant direct currents. At 5muA of alkaline phosphatase(ALP) activities and^<45>Ca incorporation were maximum. The cells were stimulated by 5muA of current for a long term. ALP activity and ^<45>Ca incorporation significantly increased in the stimulated cultures compared to the controls.
These results suggest that stimulation by microcurrent directly affects osteogeneic cells and fosters the cellular mechanism in vivo and in vitro. Less
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