摘要:

Cell migration and the rate at which cells divide was examined in the periodontal ligament of mouse molars. A pulse injection of3H‐Tdr was administered, and mice were sacrificed between 1 hour and 60 days after injection. Analysis of radioautographs using labelling index and grain counts demonstrated that the majority of labelled cells divided within 3 days but a measurable population of cells had not divided after 14 days. These cells were G2‐blocked. The labelling index of cells adjacent to alveolar bone increased 8 times within 1 day, indicating that labelled cells had migrated to the bone surface. Migration of cells to the vicinity of the cementum was observed 3 days after labelling. The percentage of labelled cells located within 20μm of one another increased to 40% within 3 days, suggesting clonal proliferation of periodontal ligament c

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00369.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The use of tritiated thymidine labelling given by continuous delivery over long periods by means of an implanted osmotic minipump is a convenient method of accurately determining the rate of cellular proliferation in various tissues, but is especially advantageous for the periodontal ligament (PDL), the fibroblasts of which turn over at an extremely low rate. This technique was used to examine the hypothesis that differences exist between cell turnover in normal hamsters (N.D.) and those which had been placed on a periodontal disease inducing diet (S.S.D.). Turnover rates were then calculated for PDL and epithelial attachment (EA) for N.D and S.S.D animals before and after disease had been induced. No effect of disease was noted for either PDT or EA. However, the technique was sufficiently sensitive to demonstrate a significant effect of age on the turnover of cells in the epithelial attachment.

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00370.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

By the combined use of membrane filters and the antibiotic rifampin, intermediate‐size anaerobic spirochetes from periodontal pockets were routinely selected and separated from other oral bacterial contaminants. Electron microscopy of six newly isolated strains showed that they belong to the genusTreponema. The organisms had generation times of about twelve hours; they produced only acetic acid when glucose was used as the carbohydrate in the medium Serum, volatile fatty acids, and thiamine pyrophosphate could be omitted individually as supplements from the growth medium, but sodium bicarbonate was absolutely essential for growth. These treponemes could be maintained by monthly transfers into fresh medium, by freezing in glycerol‐broth medium or by lyophilizat

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00371.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Conventional biochemical characterization and an ELISA technique were compared for their ability to identify reference cultures and fresh isolates from suppurating and non‐suppurating periodontal pockets, as well as healthy gingival sulci in the same individual. Antisera toBacteroides gingivalisstrain 381,Bacteroides intermediusstrains 581 and VP1 8944, andBacteroides melaninogenicusss.melaninogenicusstrain 287 were prepared by immunizing rabbits. The antisera were conjugated with peroxidase and appropriate dilutions were chosen to minimize cross‐reactions in the ELISA technique. Conventional characterization of the isolates included cellular and colonial morphology, biochemical characterization, and gas liquid chromatography of acid end products. The antisera appeared to be specific for each black‐pigmented species, since cross‐reactions were not observed to reference strains of heterologous species. There was a 94% agreement between the ELISA and conventional identifications of over 300 fresh isolates from periodontal sites.The predominant black‐pigmentedBacteroidesspecies isolated from suppurating sites wasBacteroides intermediususing either identification technique. The median value of proportions of this species was significantly increased in the suppurating periodontal pockets (16.5%) when compared to non‐suppurating deep periodontal pockets (3%) and healthy gingival sulci (0%). Significant differences in proportions were not observed for the other species of black‐pigment

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00372.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Cell types in a human experimental gingivitis model were analyzed sequentially on days 0, 4, 8, and 21 of a no oral hygiene period. The cells were characterized using enzyme and surface antigen markers. In all but two of the day 0 specimens a small inflammatory infiltrate was localized immediately beneath the junctional epithelium. These, essentially lymphocytic lesions, consisted of over 70% T‐cells as suggested by the phenotype T‐enzyme +ve/T‐cell surface antigen +ve/B‐cell surface antigen −ve/HLA‐DR −ve/B‐cell subset antigen −ve. At days 4, 8, and 21, although the size of the infiltrate increased, its essential nature did not change. At all times the majority of lymphocytes (over 70%) had the characteristic T‐cell phenotype. These results show that in the developing gingival lesion in humans a T‐cell dominated lesion occurs and persists at least for the 3 week experimental period used

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00373.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

An objective methodology was employed in the present in vitro study to assess bristle pressure required for plaque removal from the enamel surface of freshly extracted teeth. This bristle pressure has indirectly reflected the plaque tenacity or total attachment force of the plaque on the tooth surface. Equipment used to measure bristle pressure was especially fabricated for this purpose and described in detail with illustrations. The mean bristle pressure required for the removal of 1‐day, 2‐day, and 3‐day old plaque was 5.509 gms/cm2, 7.757 gms/cm2and 14.28 gm/ cm2which shows a ratio of 5:7:13 respectively, indicating an increase in plaque tenacity as it advances in age Further, the increase in tenacity of plaque from 2‐day to 3‐day was more as compared to the increase in tenacity from 1‐day to

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00374.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Experiments were performed to determine the effect of delayed‐type hypersensitivity (DTH; cell mediated immunity) on subsequent periodontal bone loss in monoinfected (Actinobacillus actinomycetemcomitans [A actinomycetemcomitans]) gnotobiotic rats. Foot pad swelling reactions toA actinomycetemcomitanssonicate were used to monitor both immediate hypersensitivity and DTH. DTH was present inA actinomycetemcomitansimmunized (I) animals when initially challenged withA actinomycetemcomitans. This DTH was maintained throughout the experimental period Sham‐immunized (SI) animals did not show DTH until after 30 days of infection. The cellular infiltrate in the gingiva of immunized animals was relatively more mononuclear than the infiltrate of SI animals Serum IgG antibody toA actinomycetemcomitanswas significantly elevated in I compared to SI animals. The relationship between the foot pad swelling and serum antibody levels suggested that an active Arthus type reaction was observedA actinomycetemcomitansinjected rats demonstrated an Arthus‐type reaction throughout the duration of the experiment SI animals only showed this reaction 30 days after immunization; the extent of swelling was always less than in the I group. Immunized rats demonstrated significantly elevated horizontal bone loss after infection for 90 days. The data suggest that a “mixed” hypersensitivity reaction toA actinomycetemcomitansoccurs in presensitized rats and that the presence of this hypersensitivity can be associated with increased periodontal

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00375.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Permeability of the dento‐gingival vessels was studied during the development of the gingiva in rats. Groups of animals, aged 19 to 150 days, were injected intravenously with colloidal carbon, and the gingival vessels were observed both macroscopically and microscopically. As the tooth cusps emerged into the oral cavity, vessels labelled with carbon were observed in the connective tissue overlying the tooth and, two to four days later, tracer particles were found in the vessels adjacent to the junctional epithelium. The leaking vessels had a linear pattern beneath the dento‐gingival junction in young animals, while in adult rats these vessels formed loops. In the interdental papilla, labelled vessels were observed initially only in the gingiva adjacent to the distal of the first molars, and two days later also in the gingiva facing the mesial of the second molars. There was a progressive increase in gingival blood vessels labelled with carbon until the rats were 150 days old. The results indicate that the inflammatory process and the increased vascular permeability in the gingiva are initialed during tooth eruption and show quantitative and morphological modifications during the organization of the sulcular and junctional epithe

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00376.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A study was performed to clarify the temporal sequence of bifurcation development in human mandibular first molar teeth and to investigate the development of features of bifurcation morphology previously described in extracted teeth. This report presents the histometric findings from graphically reconstructed teeth at varying stages of development.Sixteen developing teeth were graphically reconstructed from tracings of serial sections of thirteen grossly and histologically normal human foetuses ranging in post fertilization age from 17 to 38 weeks. Accuracy of reconstruction was tested by retracing and repeated reconstruction and found to be acceptable.Furcation development began at about 24 weeks post fertilization with the appearance of two epithelial nodes which approximately maintained their position relative to one another at a time when the rest of the developing tooth expanded. These nodes were joined to the epithelial cap by isthmuses of epithelial cells. As furcation development occurs prior to root formation, it should be considered part of crown development. In the area of the developing furcation entrance the buccal isthmus of epithelial cells was narrower mesio‐distally than the lingual isthmus. The epithelial nodes and associated isthmuses were located within the ectomesenchymal tissue of the base of the dental papilla.These findings suggest the embryologic origins of enamel projections into the furcation, the difference in diameter between the buccal and lingual furcation entrances, and the abundance of cementum in the furcation area.An incomplete epithelial diaphragm, such as has been described in the marmoset, was not observed in any of the specimens examine

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00377.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The purpose of this study was to examine histological reactions in the dental pulp incident to the application of citric acid to a root‐planed tooth surface. Full thickness flaps were raised and the labial alveolar bone removed over maxillary and mandibular incisor roots in six beagles. The exposed root surfaces were subjected to either superficial or deep root planning. On either the right or left side in each dog, citric acid (pH 1) was applied to the root surfaces for 3 min. The flaps were then repositioned at their original level. Block sections of mandibular teeth were obtained at one week and of maxillary teeth at fifteen weeks after experimental procedures. Histological examination of the short‐term specimens showed a reduced width of the predentin corresponding to the instrumented root surface, but no cellular reactions in the odontoblast layer or the pulp. At 15 weeks, varying amounts of reparative dentin had formed in all specimens. More reparative dentin had formed after deep root planing than after superficial, while the difference between acid‐conditioned and non‐acid conditioned teeth was nonsignificant. The results indicate that root planing may result in the formation of reparative dentin but does not cause inflammatory cellular reactions in the pulp. The application of citric acid to the root planed surface does not significantly change the character of the histological pulpal r

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00378.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY