2002 Fiscal Year Final Research Report Summary
Analysis of bacterial biofilms as a virulence factor for peri-implantitis
| Project/Area Number |
13672184
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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 |
Periodontal dentistry
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| Research Institution | Osaka University |
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Principal Investigator |
NOIRI Yuichiro Osaka University, Graduate School of Dentistry, Research Associate, 大学院・歯学研究科, 助手 (50218286)
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| Co-Investigator(Kenkyū-buntansha) |
EBISU Shigeyuki Osaka University, Graduate School of Dentistry, Professor, 大学院・歯学研究科, 教授 (50116000)
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| Project Period (FY) |
2001 – 2002
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| Keywords | peri-implantitis / bacterial biofilm / implant sulcus / immunohistQchemical stain / Porphyromonas gingivalis / periodontopathic bacteria / chlorhexidine gluconate / cloning |
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| Research Abstract |
We investigated morphologically initial biofilm formation in the human implant sulcus using healing abutments. After obtaining informed consent from 7 patients, twenty healing abutments were removed carefully on day 10, 30, 90 and 150 after insertion and treated for a scanning electron microscopy. On day 10, mono-layer biofilm have partially formed on the abutment surfaces. So called early colonizers: cocci and filaments, were observed. After 30 days, biofilms developed, and long and short rods were predominantly observed in human implant sulcus
Next, human periimplantitis associated bacteria have been examined immunohistochemically. Eight implants obtained from 4 voluntary patients were extracted and processed into semithin sections They were stained BrownBrenn modified Gram stain and streptavidinbiotin method using 4 kinds of antibodies with periodontopathic bactria. Gram positive bacteria were shown not only on the implant surface but also at the inner site of abutment screw, Porphyromonas gingivalis and Campylobacter rectus labeled with speciesspecific antibody were not found in the human implant sulcus
By use of the in vitro model with P. gingivalis biofilm, 1) the biological (ATP) activities, 2) the susceptibility to antimicrobial agents, and 3) the essential gene for development of biofilm (the homologue for polyphosphate kinase (ppk)) were examined. The rate of increase of ATP contents in the biofilm was quite low, and 1/3.0x10^5 compared with that of planktonic cells. Chlorhexidine gluconate was effective at reducing the viability of P. gingivalis biofilm, while minocycline hydrochloride and metronidazole did not have a variable effect. Identity of P. gingivalis ppk gene that was carried out cloning to Esherihia coli ppk gene was 35.8%, including \hat ppk from P. gingivalis was highly conserved
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