| Project/Area Number |
60480414
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Kyushu University |
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Principal Investigator |
NAGASAWA Hisashi Kyushu University, Faculty of Dentistry, Professor, 歯学部, 教授 (10013848)
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| Co-Investigator(Kenkyū-buntansha) |
HAYASHI Yoshihiko Kyushu University, Dental Hospital, Lecturer, 歯学部附属病院, 講師 (20150477)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥6,400,000 (Direct Cost: ¥6,400,000)
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| Keywords | Dentinogenesis / Matrix Vesicles / 生活歯髄切断法 |
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| Research Abstract |
Matrix vesicles are involved in the early stages of the mineralization process, and it now seems to be generally agreed that they are sites of initial crystal formation. Present study was carried out to isolate these vesicles during initial dentinogenesis and to investigate the application for pulpotomy.
Apical pulps of Wistar rats were excised with a razor blade. Small slices of them were incubated with collagenase. Pulp digest was centrifuged. Fractions were obtained as follows : (1) 40,000 x g for 20 min ; (2) 300,000 x g for 10 min. Electron microscopy of the centrifugal sediments showed intact cells and cell fragments, and partially fragmented endoplasmic reticulum in fraction 1. Vesicles closely resembling the matrix vesicles, because of their small size, electron-dense contents, were concentrated in the 2nd fraction. The specific activity for alkaline phosphatase was 4.57 <+!-> 0.76 U. Total protein contents were 0.73 <+!-> 0.10 <mu> g /mg wet weight. Needle-like crystals did not grow within matrix vesicles in Ca・P solution containing ATP ( 2 - 5 h, 37゜C ).
These results indicate that matrix vesicles first isolated from dental pulp has biological activity and similar fine structure to that of in vivo ones. Further study would be necessory to form the hydroxyapatite in matrix vesicles in vitro; the contents of incubation medium and culture condition might be decisive factors. This future investigation could catch the basic data to applicate these vesicles for pulpotomy.
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