| Co-Investigator(Kenkyū-buntansha) |
UMEDA Makoto Tokyo Medical and Dental University Faculty of Dentistry Research Assistant, 歯学部, 助手 (90193937)
IZUMI Yuichi Kagoshima University Faculty of Dentistry Associate professor, 歯学部, 助教授 (60159803)
ODA Shigeru Tokyo Medical and Dental University Faculty of Dentistry Lecturer, 歯学部, 講師 (70160869)
HAGIWARA Satsuki Tokyo Medical and Dental University Faculty of Dentistry Lecturer, 歯学部, 講師 (70134715)
WATANABE Hisashi Tokyo Medical and Dental University Faculty of Dentistry Associate professor, 歯学部, 助教授 (40143606)
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| Research Abstract |
The relationship between the periodontopathic bacteria and host resistance in periodontal diseases has been investigated microbiologically, immunologically and genetically. The serum IgG antibody titers were measured by using an enzyme-linked immunosorbent assay(ELISA) to investigate the diagnostic value in order to find main periodontopathic bacteria, and to evaluate the clinical prognosis. A new method of ELISA measurement was developed to improve the efficiency. Using this new method, the serum IgG antibody titers to Porphyromonas gingivalis (P.g.), Prevotella intermedia (P.i.), Actinobacillus actinomycetemcomitans (A.a.) and Fusobacterium nucleatum were evaluated. The results indicated that this improved method showed 6 times more efficient in managing subjects as compared to the former one and might be effective for screening of serum with high antibody titers. The IgG antibody titers against P.g. and P.i. decreased significantly after periodontal treatment. There is a significant
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correlation between the reduction of antibody activity to P.g. and the frequency of periodontal surgeries or the duration of treatment. The serum antibody titers to P.i. was detected to reduce significantly in relation to the number of lost teeth. These results suggest that the reduction of the serum antibody titers to P.g. and P.i. can be used as parameters to show effectiveness of periodontal treatment. We also analyzed the relation between the antibody titers and clinical parameters about 60 patients with periodontal disease measured for two years from 1988 to 1989. As results, the serum antibody activity to P.g. was significantly correlated with the probing depth and the rate of alveolar bone resorption. The antibody titers to A.a. was also correlated with the rate of alveolar bone resorption. These findings suggest that P.g. and A.a. are key bacteria to be responsible for the development of periodontitis. Futhermore, non-radioactive DNA probes for periodontopathic pathogens, such as P.g. or P.i., were developed. These probes showed sufficient sensitivity and specificity for clinical trials. By using the DNA probe, P.g. was detected from all patients examined and the frequency of P.g. detection increased significantly in the sites with deep probing depth or bleeding on probing. These results indicate that P.g. may play an important role in adult periodontitis. On the other hand, using RFLPs analysis we examined P.g. strains on their fimbrillin gene locus. The results indicate that genetic heterogeneity seems to be existing within the fimbrillin gene locus. This may also reflect the difference of virulence within P.g. species reported before. Less
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