| Project/Area Number |
11672005
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Surgical dentistry
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| Research Institution | Keio University |
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Principal Investigator |
ASANAMI Soichiro Keio University, School of Medicine, Associate Professor, 医学部, 助教授 (70051670)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBA Hideyuki Keio University, School of Medicine, Instructor, 医学部, 助手 (60154233)
OKADA Yutaka Keio University, School of Medicine, Instructor, 医学部, 助手 (00129371)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Low-Power laser / Dental implant / Bone histomorphometry / 薄膜HAコーティング / 人工歯根 / 類骨石灰化速度 / 薄膜HAローティング |
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| Research Abstract |
The purpose of this study was to clarify the possible effects of Low-power laser irradiation on the initial fixing of implants subsequent to their placement. Implants used in the present study included pure titan-made cylinders of 2 mm in diameter and 3 mm in length having a gutter-form groove 0.5 mm in depth either with HA-coating (HA type) or without (Ti type), and the implants were inserted in to the jaw bone of rabbits. Immediately after implantation, 10-min of He-Ne laser irradiation was initiated with an output power of 12.3 mW and repeated daily for 4 days. Peri-implant bone tissue was investigated by bone histomorphometric method 2, 3, and 4 weeks after implant placement, and the following results were obtained:
1. Osteoid apposition rates of osteons in the endosteum area of the cortical bone and the cortical bone area itself in the peri-implant region in the irradiation group were 1.16 times as high as those in the non-irradiation group with statistical significance (P < 0.05)
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as shown by 4.41 ± 0.58 μm for the former and 3.93 ± 0.73 jxm for the latter. With regard to chronological changes in mean osteoid apposition rates, those in the non-irradiation group tended to decrease to a greater extent than those in the irradiation group as shown by 5.14 ± 1.19 μm, 3.82 ± 0.99 μm and 3.48 ± 0.32 μm in the former group and 4.55 ± 0.96μm, 4.46 ± 0.56 μm and 4.23 ± 0.86 μm in the latter group, each 2, 3 and 4 weeks after implantation, a difference in the mean rates at 4 weeks after implantation being statistically significant (P < 0.01).
2. The amount of bone formation adjacent to the gutter-form groove of the implants showed no difference between the implants of the Ti type and the HA type. It was found that laser irradiation facilitates bone formation as shown by the fact that the amount of bone formation was consistently larger in the irradiation group than in the non-irradiation group at any time of post-implantation measurement regardless of the difference of implant type. Particularly, each amount measured 4 weeks after implantation for Ti-type implants and 2 weeks after implantation for HA-type implants was larger with statistical significance (P < 0.05). The bone-implant contact rates were kept at high levels with the HA-type implants from the early stage of post-implantation in both irradiation and non-irradiation groups while their measurements with the Ti-type implants 2 weeks after their implantation in the irradiation group were 2.54 times as high as those in non-irradiation group with statistical significance (P < 0.01).
3. Under the conditions of the present study He-Ne laser irradiation was interpreted as favoring the progression of the initial fixing process of implants taking into account the observed increase in osteoid apposition rates, the increase in the amount of bone neogenesis and the increase in bone-implant contact rates with the Ti-type implants from the early stages of post-implantation. Less
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