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Biomedical subjects

M A Listgarten

Publications and source records attributed to M A Listgarten.

At least 91 records · Page 5Linked to original sources
PubMed1982

Progressive replacement of epithelial attachment by a connective tissue junction after experimental periodontal surgery in rats.

The purpose of this study was to test the hypothesis that the long junctional epithelium formed during the early stages of periodontal wound healing can become replaced, at least in part, by a connective tissue attachment. A surgical wound was created on the mesial surface of the left maxillary first molar of 4-month-old rats and the mesial root surface curetted free of soft tissue and cementum. The contralateral molar served as an unoperated control. Groups of five to eight animals were killed at intervals of 10 days, 3 and 6 weeks, and 3, 6 and 12 months after surgery. The histometric data demonstrated a progressive apical recession of the entire gingival unit on the unoperated control side during the experimental period. On the operated side, the junctional epithelium became reestablished by migration of epithelium from the wound edge along the cut gingival surface facing the tooth, until contact was established near the apical border of the instrumented root surface. Coronal migration of the epithelium from that level accounted for most of the lengthening of the junctional epithelium observed in 3 weeks. During the balance of the experimental period the junctional epithelium did not change in length significantly. However, the entire epithelial attachment was displaced coronally, primarily at the expense of sulcus depth which decreased with time, and by replacement of the apical portion of the junctional epithelium by a connective tissue junction of increasing dimension. These findings challenge the widely held belief that, once established, the dentoepithelial junction cannot be replaced by a connective tissue attachment.

Animals↗
PubMed1981

Comparative antibody titers to Actinobacillus actinomycetemcomitans in juvenile periodontitis, chronic periodontitis and periodontally healthy subjects.

Circulating antibody levels to four strains of Actinobacillus actinomycetemcomitans (Aa) were determined by means of an indirect immunofluorescent technique in three groups of 21 subjects each, including one with juvenile periodontitis (JP), one with chronic periodontitis (CP) and one free of periodontal disease (N). Mean levels of antibody to Aa were significantly elevated in the JP group as compared to the CP and N groups with respect to strains Y4, 29522 and 29524, but not strain 29523. Since strains Y4, 29522 and 29524 contain a leukotoxin that is missing from strain 29523, the results suggest that the leukotoxin could account for the difference in the immune response among the three groups of subjects. Varying the end-point considered to represent positive fluorescence did not significantly affect the results, although discrimination among the three groups appeared to be somewhat better at lower intensities of fluorescence. Because of wide variations in antibody titers recorded in individual subjects, elevated levels of antibody to certain strains of Aa may not be useful as a primary diagnostic test for JP, but may be of value in confirming an otherwise uncertain clinical diagnosis.

Actinobacillus↗
PubMed1980

Histological evaluation of probing depth following periodontal treatment.

The aim of this study was to compare the periodontal probing depth in teeth exposed to periodontal treatment with teeth having received no treatment. In pockets deeper than 4 mm, a significant difference was found between the two groups. In the non-treated teeth, metal strips used for probing penetrated an average of 0.29 mm into the connective tissue apical to the junctional epithelium. The average probing depth for teeth exposed to scaling, root planing, curettage and chlorhexidine rinses for 1 month was 0.31 mm coronal of the connective tissue attachment within the junctional epithelium. The results indicate that care should be taken when evaluating changes in periodental probing measurements during longitudinal studies.

Connective Tissue↗
PubMed1980

Periodontal probing: what does it mean?

The periodontal probe has been and continues to be used as an important diagnostic instrument by the dental profession. The measurements recorded with the probe have generally been considered to represent a reasonably accurate estimate of sulcus or pocket depth. Recent reports on the histopathology of the periodontal lesion and the histological features of a healing lesion, together with histological studies on the relationship of the probe to periodontal tissues, have shed some new light on periodontal probing. It is now apparent that probing depth measured from the gingival margin seldom corresponds to sulcus or pocket depth. The discrepancy is least in the absence of inflammatory changes and increases with increasing degrees of inflammation. In the presence of periodontitis the probe tip passes through the inflamed tissues to stop at the level of the most coronal intact dento-gingival fibers, approximately 0.3-0.5 mm apical to the apical termination of the junctional epithelium. Decreased probing depth measurements following periodontal therapy may be due in part to decreased penetrability of the gingival tissues by the probe. Following treatment aimed at obtaining new attachment in periodontal defects, wider variations may occur between the location of the probe tip and the most coronal dento-gingival fibers than in the case of untreated sites. This is due in part to the formation of a so-called "long" junctional epithelium. In the absence of inflammation this epithelium may not be penetrable during ordinary probing, but could account for a rapid increase in probing depth measurements when inflammatory changes allow the probe to traverse the epithelium and/or the adjacent infiltrated connective tissue. In view of the difficulty inherent in relating periodontal probing measurements to actual sulcus or pocket depth, the interpretation of periodontal probing in the practice of periodontics may need reappraisal.

Animals↗
PubMed1980

Comparative ultrastructure of certain Actinomyces species, Arachnia, Bacterionema and Rothia.

A comparative ultrastructural study was carried out on several species of Acinomyces and related Gram-positive rods including Arachnia, Bacterionema, Rothia and Leptotrichia. A total of 52 well characterized strains were examined by transmission electron microscopy. Particular attention was paid to the ultrastructure of the cell periphery, that is the plasma membrane, periplasmic space, the cell wall per se and extramural structures, including surface "fuzz". In addition, the ultrastructure of various features of the cytoplasm were also examined. A good correlation appeared to exist between certain ultrastructural characteristics of the microorganisms and their taxonomic position as determined by other criteria. It should be noted, however, that the ultrastructure of certain strains differed markedly from that of the remaining strains of the species. This observation raises some doubt on the appropriateness of the current classification for these particular strains. The ultrastructural features of the cell periphery were found to be particularly stable for all strains grown under standard conditions. For this reason, ultrastructural features of the cell wall and associated structures are probably a more reliable source of morphological criteria for identification purposes than the ultrastructural characteristics of the cytoplasmic components which tend to be more variable. The results suggest that certain ultrastructural features are useful criteria for the identification and classification of these Gram-positive rods.

Actinomyces↗
PubMed1979

The effect of tetracycline and/or scaling on human periodontal disease.

The objective of this study was to test the efficacy of scaling and root planing with or without adjunctive tetracycline therapy in the treatment of periodonitis in humans. The presence of plaque, gingival inflammation, probing depths and attachment levels was assessed for all teeth in 12 patients with chronic, advanced periodontitis. After an initial examination all patients were given detailed oral hygiene instructions. The teeth in one-half of each arch were then scaled and root planed. The teeth in the contralateral half were not treated. Six patients were given tetracycline (1 gm/day) during the first and second weeks and the seventh and eighth weeks of the trial. The study thus included four different treatment groups: 1) no treatment, 2) scaling and root planing alone, 3) tetracycline administration alone, and 4) scaling and root planing combined with tetracycline administration. All patients were reexamined at 8 and 25 weeks subsequent to the initiation of therapy. Both PlI and GI scores decreased significantly in all groups. The GI scores were significantly lower in the scaled and root planed areas as compared to the contralateral sides at both the 8- and 25-week examinations. The PlI score was lower in the scaled and root planed areas only at the 25-week interval. The gingival probing depths were reduced in all groups. A significantly greater decrease in probing depth, however, was noted in scaled and root planed areas. There was a trend to gain of attachment in the treated areas but the magnitude of the gain was very small. The findings of the trail also revealed that the administration of tetracycline had only a minor effect on the parameters examined.

Adult↗
PubMed1979

Prevention of periodontal disease in the future.

Existing knowledge about periodontal disease is sufficient to permit the interested individual to carry out a preventive program which can result in preventing the major forms of the disease from developing. It is likely that the sooner such a program is started in a person's lifetime, the likelier it is to succeed. With the additional knowledge obtained from current avenues of research, clinical microbiology and immunology will become applicable to the management of selected forms of periodontal disease, both for diagnostic and therapeutic purposes. Some of the information gained may help in fostering the establishment of a desirable microbial flora and in better control of potentially pathogenic strains. The implementation of an effective preventive program for periodontal and other dental diseases will vary on a regional basis depending on political, economic, social and ethical considerations.

Bacteria↗
PubMed1979

Immune labeling of certain strains of Actinomyces naeslundii and Actinomyces viscosus by fluorescence and electron microscopy.

A total of 12 well-characterized strains of Actinomyces viscosus and A. naeslundii grown on Trypticase soy agar plates supplemented with sheep erythrocytes were examined by light microscopy and transmission electron microscopy after treatment with appropriately labeled antisera to homologous and heterologous strains. Cells incubated with homologous rabbit antisera followed by fluorescein-isothiocyanate (FITC)-conjugated goat anti-rabbit immunoglobulin G (IgG) exhibited a completely smooth fluorescent outline in the case of A. naeslundii and and interrupted, irregular fluorescent outline in the case of human strains of A. viscosus. The different labeling patterns appeared to be related to the presence at the ultrastructural level of long, unevenly distributed strands of "fuzz" on the surface of human A. viscosus cells, whereas A. naeslundii cells had a narrower layer of fuzz, or more even thickness. The immunocoating reaction revealed homologous antibody binding to the irregular strands of fuzz on the surface of human A. viscosus cells, whereas homologous antisera to A. naeslundii coated A. naeslundii cells with a moderately electron-dense coating of antibody of even thickness. Human strains of A. viscosus incubated with heterologous antiserum to A. naeslundii followed by FITC-labeled goat anti-rabbit IgG exhibited a segmented fluorescent outline, which differed from that produced with homologous antisera. A. naeslundii incubated with heterologous rabbit antisera to human A. viscosus strains and FITC-labeled anti-rabbit IgG exhibited a completely smooth fluorescent outline similar to that produced with homologous antiserum. A. viscosus strains of hamster origin differed from A. viscosus strains of human origin by the absence of a surface fuzz and the comparatively smooth, even fluorescence produced by incubating these cells with homologous rabbit antiserum followed by FITC-labeled goat anti-rabbit IgG. Antiserum to a hamster strain did not cross-react with A. naeslundii or human strains of A. viscosus. Under the growth conditions of this experiment, ultrastructural features and labeling patterns with the indirect fluorescent technique may be useful in differentiating these serotypes from one another.

Actinomyces↗