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991.
992.
Controversy surrounds the importance of keratinized gingiva in maintaining periodontal health. A well-defined animal model system is necessary to evaluate longitudinally the role of keratinized gingiva when plaque control is inadequate or where dental procedures (restorative, prosthetic or orthodontic) alter the periodontal environment. Facial gingiva was excised from eight primary incisors in miniature swine. Contralateral teeth were used as controls. The experimental teeth exhibited mucogingival defects at 3 and 6 month observation periods. The secondary teeth erupting into the experimental regions also exhibited recession and chronic mucogingival defects. The marginal tissue in regions devoid of keratinized gingiva demonstrated clinical signs of inflammation. No progressive gingival recession was present. Excision of keratinized gingiva to produce mucogingival defects in swine provides a convenient model system for evaluating the effect of dental procedures on periodontal health where little or no keratinized gingiva is present.  相似文献   
993.
Successful treatment of severe skeletal open-bite malocclusions has always demanded the utmost of the orthodontist. Long-term evaluation of this type of treatment is not often seen in the literature, for the results have often been disappointing. Combining the best of the surgical and orthodontic disciplines offers these cases an optimistic outlook for the first time. A case treated twice by conventional orthodontic means in 1965 and 1969 was re-treated in 1980 by a surgical orthodontic approach. The results are quite encouraging.  相似文献   
994.
Previous studies have indicated that a galactosephilic component present on the bacterial cell surfaces of Streptococcus sanguis ATCC 10557 may be responsible for the salivary glycoprotein-mediated binding of the cells. The purpose of this study was to investigate the purification and characterization of galactosephilic cell surface component from S. sanguis ATCC 10557. A galactosephilic component involving fibrils on the cell surfaces was isolated by the techniques of freezing and thawing, and purified by an affinity chromatography on beta-D-galactose binding-Bio-Gel P-2 followed by gel filtrations on Bio-Gel P-150 and on Bio-Gel P-30. Both disk gel electrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the purified product was homogeneous. The isoelectric point of the purified sample was 8.5 to 9.0. Treatment of the purified sample with pronase E reduced remarkably either the hemagglutinating activity or the precipitation reaction with proline-rich glycoprotein in human parotid saliva, suggesting that the active site may be present on the peptide moieties. When sugar specificity was examined by hemagglutination-inhibition test, D-galactose was the strongest inhibitor. The results of this study suggest that the galactosephilic component may be a bacterial lectin.  相似文献   
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Epidemiologic studies have suggested that the severity of periodontitis is greater in juvenile and adult onset diabetes. In juvenile diabetic patients, the periodontal disease seems to be initiated around puberty and progresses by age. Reviewing the medical literature indicates a similar age of onset for known systemic complications resulting from diabetes. Angiopathy, abnormal collagen metabolism, abnormal PMN function, and altered sulcular microbial flora have been found to be closely associated with the severity of periodontitis in diabetic patients. The association between abnormal neutrophil function and severity of periodontal disease in diabetic patients provides an opportunity for examining the role of neutrophil in periodontal disease. Future investigation in the function of sulcular PMN may shed light on the complex mechanism of periodontal disease.  相似文献   
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