| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Adult male mice were used whose lower second molars were extracted and the extraction socket was examined immunohistochemically with anti-mouse osteocalcin antibody, histologically, electronmicroscopically, and autoradiographically. The observations were made at 1, 2, 3, 4, 5, 6, 7, 10, 14 and 21 days after tooth extraction, and the summary of the results is as follows :
1. The course of healing events consisted of a extraction, a granulation tissue phase of 3-5 days, a bone formation phase at 6-14 days and a healing phase at 15-21 days after extraction.
2. Minerals deposited on the matrix formed by osteoblasts that proliferated in the tooth extraction socket after absorption of the blood clot.
3. The matrix formed in the central portion of the socket mineralized 4 days after extraction. In the area with periodontal ligaments remaining, mineralization was observed 5 days after extraction or later.
4. The newly proliferating cells in the socket showed high uptake of synthetic ability for the matrix, but were not labeled with osteocalcin antibody. With the progress of new bone matrix formation and its mineralization, the number of positively labeled cells increased in the socket.
5. The localization of osteocalcin was observed in the marginal portion of the new bone where the mineralization of the matrix was low or absent.
These results suggest that the process of new bone formation in the tooth extraction socket consists of absorption of the blood clot, formation of bone matrix by the osteoblasts and mineralization of the bone matrix. It is also suggested that in the area with periodontal ligaments remaining, the new bone matrix formation and its mineralization are a little delayed compared with those in the central portion of the socket. It is considered that osteocalcin acts on these healing processes as a regulation factor of mineralization.
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