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Biomedical subjects

A M Polson

Publications and source records attributed to A M Polson.

At least 73 records · Page 4Linked to original sources
PubMed1984

Relationships between bitewing and periapical radiographs in assessing crestal alveolar bone levels.

Bitewing (BW) and periapical (PA) radiographic techniques are used in clinical and epidemiologic studies to assess crestal alveolar bone levels. Since there appeared to be no basis for choosing one technique over the other, the present study investigated relationships between these techniques by assessing alveolar crest location at the same site. BW and PA radiographs were available from posterior quadrants of 210 subjects. Individual radiographs were projected at a magnification x 5.9 using a Leitz Prado-Universal projector. The distance from the cemento-enamel junction to the alveolar crest (CEJ-CR) was measured for each proximal surface from the distal of the cuspid to the distal of the second molar. Data were arranged according to the proximal surface examined, and BW and PA measurements were compared using paired t tests. In addition, the degree of congruence of the two sets (BW/PA) of CEJ-CR measurements was evaluated through computation of the Pearson Correlation. The data showed significant differences between mean BW and PA measurements for 50% of the tooth surfaces, and this trend was consistent through maxillary and mandibular quadrants, and mesial and distal surfaces. In situations of a significant difference, the BW measurement was greater than the PA 94% of the time. The correlations between the two types of measurements showed low reliability. It was concluded that BW and PA techniques provided significantly different values in assessing crestal alveolar bone levels, and data generated by these techniques should not be used interchangeably on an individual or group basis.

Adult↗
PubMed1984

Long-term effect of orthodontic treatment on crestal alveolar bone levels.

It was the purpose of the present study to evaluate crestal alveolar bone levels in individuals (Study group, n = 104) who had completed orthodontic treatment at least 10 years previously and compare the findings with adults who had untreated malocclusions (Control group, n = 76). Crestal alveolar bone levels were determined on both bitewing and periapical radiographs by direct measurement from the cemento-enamel junction to the alveolar crest. Data from the individual tooth surface measurements were subjected to analyses of variance partitioned on group (Study vs Control), radiographic method, tooth type, dental arch and surface location. There was no significant difference between crestal alveolar bone levels between the study and control group. A Group/Tooth/Surface interaction occurred for the distal surface of molars. The alveolar crest level was significantly less in the orthodontically treated group. Examination of the numerical data suggested that the measured dimension was low relative to normal values, and this effect may have been related to tooth intrusion during orthodontic treatment. It was concluded that orthodontic treatment during adolescence had no detrimental long-term effect upon crestal alveolar bone levels.

Adult↗
PubMed1984

Effects of gold salts on experimental periodontitis. III. Ultrastructural observations.

Previous studies showed that the systemic administration of soluble gold salts resulted in significantly less periodontal destruction after 2 weeks of experimentally induced periodontitis. The present study compared the ultrastructural characteristics of the inflammatory lesion in animals receiving gold salts (experimental) with those in animals that had not received gold salts (control). Maxillary gingival biopsy specimens were obtained from the buccal aspect of ligatured teeth after 2 weeks of experimental periodontitis. A cellular and extracellular ultrastructural characterization was done in an "epithelial and superficial connective-tissue zone," and a "deep connective-tissue zone." Experimental (gold-receiving) specimens had an intact sulcular epithelium with narrow intercellular spaces overlying a collagen dense connective tissue. Control specimens had a degenerating disrupted epithelium overlying a collagen-poor connective tissue in which polymorphonuclear leucocytes predominated and often were closely apposed to morphologically altered fibroblasts. The cellular distribution of electron-dense deposits of gold salts was demonstrated, and their possible role in modulating mechanisms of cell cytotoxicity and collagen turnover is discussed.

Animals↗
PubMed1984

Effects of gold salts on experimental periodontitis. I. Histometric evaluation of periodontal destruction.

Systemic administration of gold salts for treatment of arthritis is thought to limit tissue destruction through alteration of inflammatory cell function. The present study ascertained if gold salts could modify the tissue destruction associated with an experimental marginal periodontitis. Therapeutic levels of serum gold salts were established in four squirrel monkeys (experimental) by intramuscular injection of Myochrisine (gold sodium thiomalate 25 mg/ml) at 5 mg/kg/body weight at 4-day intervals for 12 days. Marginal periodontitis was then induced around mandibular bicuspids by tying plaque retentive ligatures at the gingival margins. Periodontitis was induced around corresponding teeth in four control animals which had not received gold salts. Serum levels of gold salts were maintained in experimental animals, and all animals were killed 2 weeks after induction of periodontitis. Progression of periodontitis was evaluated histometrically on step-serial sections, and the results analyzed statistically. Specimens from gold-receiving animals had significantly smaller areas of infiltrated supracrestal connective tissue, and less loss of connective tissue attachment and coronal alveolar bone. Quantitation of total plaque around the ligatures showed no differences; however, there was less plaque located apical to the ligatures in gold-receiving specimens. Although the study design did not permit identification of the relative importance of cellular or microbial factors, it was concluded that administration of systemic gold salts was associated with significantly less periodontal destruction.

Animals↗
PubMed1984

Effects of gold salts on experimental periodontitis. II. Cell population characteristics.

A previous study showed that the systemic administration of soluble gold salts (gold sodium thiomalate) resulted in significantly less periodontal destruction after 2 weeks of experimentally induced periodontitis. In order to provide information on the possible mechanisms of action of gold salts in the experimental periodontitis situation, the present study analyzed and compared the characteristics of the inflammatory cell populations in animals receiving gold salts with those present in animals which had not received gold salts. Maxillary gingival biopsy specimens were obtained from the buccal aspect of ligatured teeth after 2 weeks of experimental periodontitis. Cell populations were characterized and enumerated, on 1-micron sections, in an epithelial and superficial connective tissue zone, and a deep connective tissue zone. Significantly fewer inflammatory cells were present in experimental (gold receiving) specimens, and this reduction was due primarily to fewer polymorphonuclear leucocytes (PMNs). No significant reduction occurred in any other inflammatory cell-type. The reduction in number of PMNs in experimental specimens was associated with a decreased number of morphologically altered, degenerating fibroblasts in the connective tissue compared to the PMN-dominated lesion of control specimens. Mechanisms whereby gold salts can reduce chemotaxis and functional capabilities of inflammatory cells are discussed.

Alveolar Process↗
PubMed1984

The production of a root surface smear layer by instrumentation and its removal by citric acid.

The purpose of this study was to characterize, using the scanning electron microscope, the nature of root surfaces denuded by (1) root planing alone or (2) root planing plus citric acid treatment. Six teeth were extracted from three squirrel monkeys, and the coronal half of the root surface was planed to remove attached periodontal ligament fibers and cementum. Citric acid, pH 1, was topically applied to the denuded surfaces of 3 teeth. The surface of only root-planed specimens had an irregular surface which corresponded to a smear layer. Root surfaces that had received acid treatment after root planing exhibited funnel-shaped orifices of dentinal tubules, and intertubular zones with a fibrillar, mat-like morphology. The implications of the different root-surface characteristics are discussed.

Administration, Topical↗
PubMed1983

Osseous repair in the presence of active tooth hypermobility.

The present investigation was undertaken to evaluate the periodontal response after resolution of inflammation in a situation of established marginal periodontitis, but in the presence of active, continued tooth hypermobility. Periodontitis was induced unilaterally around mandibular second and third bicuspids in 4 squirrel monkeys by tying plaque retentive silk ligatures at the gingival margins. Jiggling trauma to the periodontium between these bicuspids was begun 5 weeks later and continued for the remaining 20 weeks. Ligatures were removed 15 weeks after placement, whereupon regular oral hygiene was begun and continued. Periodontitis and trauma were produced around the corresponding contralateral teeth (control) so that the interproximal area represented the situation immediately prior to ligature removal. Infiltrated connective tissue, loss of connective tissue attachment and alveolar bone, and percentage of bone were determined histometrically for each coronal interproximal periodontium. In control specimens, 58% of the supracrestal tissue was infiltrated with inflammatory cells compared to 19% in experimental specimens. There were no differences in levels of connective tissue attachment or crestal alveolar bone. However, bone repair occurred in the experimental specimens which increased bone volume from 11 to 18% (P less than 0.05). It was concluded that osseous repair occurred in the presence of active, continued tooth hypermobility after resolution of inflammation.

Alveolar Process↗
PubMed1983

Effect of periodontal trauma upon intrabony pockets.

Conflicting results have been reported regarding the effect of periodontal trauma upon progression of periodontitis. In these studies, different initial pocket morphologies were present. This study investigated the effect of trauma superimposed upon existing intrabony pockets. Localized intrabony pockets were produced adjacent to the mesial and distal surfaces of the mandibular third bicuspids in 10 squirrel monkeys. Two animals were killed after 10 weeks of periodontitis. In four (experimental) of the remaining eight animals, mesio-distal jiggling of the third bicuspid was begun 10 weeks after induction of periodontitis, and continued for another 10 weeks. The other four animals (control) were killed 20 weeks after initiation of periodontitis. Step-serial histologic sections were selected from experimental and control specimens and analyzed for loss of connective tissue attachment, loss of crestal alveolar bone and percentage of bone in the coronal interproximal periodontium. When corresponding dimensions from experimental and control surfaces were compared statistically, there were no differences in loss of connective tissue attachment but a greater loss of bone had occurred in specimens with the combination of periodontitis and trauma. In addition, there was a marked difference in osseous morphology between the experimental and control specimens. It was concluded that trauma superimposed upon existing intrabony pockets increased loss of alveolar bone and altered osseous morphology, but did not affect the loss of connective tissue attachment.

Animals↗
PubMed1983

A periodontal attachment mechanism without alveolar bone. Case report.

A 22-year-old black male was referred for periodontal therapy because of radiographic evidence of advanced bone loss associated with the posterior teeth. Clinical examination revealed gingivitis, normal sulcus depths, and minimal loss of clinical attachment. Complete blood counts, serum chemistry, and neutrophil function were within normal limits. Histological, histochemical and ultrastructural analysis of an extracted tooth revealed no loss of attachment; large areas of the cementum were collagen-poor and, ultrastructurally, resembled afibrillar cementum. It is proposed that the periodontal attachment mechanism present in this case was associated with a localized failure in normal periodontal development.

Adult↗
PubMed1983

Fibrin linkage: a precursor for new attachment.

Previous studies indicated that connective tissue attachment to the root surface appeared to be dependent upon a chronologic healing sequence related to fibrin and collagen interactions. It was the purpose of the present study to try and substantiate this hypothesis by using histologic techniques designed to differentiate between fibrin and collagen during healing at the root surface interface. In four squirrel monkeys, 24 normal teeth were extracted and reimplanted after either (i) surgically denuding the coronal root surface of connective tissue fibers and cementum by root planing or, (ii) surgical denudation followed by topical application of citric acid (pH = 1; 3 minutes). Three specimens were available for histological analysis 1, 3, 7 and 21 days after reimplantation. Mallory's phosphotungstic acid hematoxylin staining technique was used to differentiate between fibrin and collagen. Epithelium migrated rapidly along the denuded, non-acid-treated, root surfaces, had reached the alveolar crest at 3 days, and was within the ligament space to the level of root denudation at 21 days. Epithelium did not migrate apically along denuded root surfaces treated with citric acid. At 1 and 3 days, inflammatory cells were enmeshed in a fibrin network which appeared to be attached to the root surface by arcade-like structures. At 7 and 21 days, the region had repopulated with connective tissue cells, and collagen fibers had replaced the fibrin. It was concluded that collagen fiber attachment to the root surface was preceded by fibrin linkage, and that the linkage process occurred as an initial event in the wound healing response.

Animals↗
PubMed1983

Cell populations associated with gingival bleeding.

The presence of crevicular bleeding after probing is an objective clinical sign of gingival inflammation. It has been associated with a plasma cell-dominated inflammatory infiltrate in deep pockets and has been suggested as an indication of active periodontitis. The purpose of this study was to characterize the cellular composition of gingival connective tissue associated with shallow pockets which bled after probing. Prior to biopsy, the mid-facial gingiva associated with 30 teeth from 26 patients was assessed for the presence or absence of visual inflammation, pocket depth and bleeding after probing with a standardized force of 25 g. A horizontal reference incision was made on the facial aspect of the gingiva to demarcate for histologic analysis the specific gingival area probed and evaluated for inflammation. Cell populations were determined from histological sections using morphometric point counting techniques in six standard fields at and coronal to the level of the reference incision. The percentage of cell types and the per cent volume densities of all tissue components were compared between clinically normal and inflamed gingiva. In clinically inflamed gingiva there was a significantly greater percentage of lymphocyte/macrophage/monocyte cells and a smaller percentage of fibroblast/endothelial cells. The percentage of plasma cells was only a fraction of that found for other inflammatory cells. The results of this study indicated that a lesion in the gingiva associated with bleeding after probing can consist of an inflammatory infiltrate which is not dominated by plasma cells.

Adult↗
PubMed1982

Effect of root surface alterations on periodontal healing. I. Surgical denudation.

The present study was undertaken to evaluate the effect of root surface denudation on periodontal healing. Twelve teeth, distributed in four squirrel monkeys, were extracted and reimplanted after surgically denuding the coronal root surface of connective tissue fibers and cementum by root planing. The reimplantation schedule provided three teeth for histologic analysis at 1, 3, 7 and 21 days after reimplantation. One day after reimplantation a zone of fibrin enmeshing erythrocytes and inflammatory cells was interposed between th root surface and the remaining periodontal fibers attached to the alveolar bone. Epithelium migrated rapidly along the denuded root, had reached the alveolar crest at 3 days, and was within the ligament space at 7 days. At 21 days, the epithelium was at the apical limit of root instrumentation, which corresponded to the level of attached connective tissue fibers on the root surface. No evidence of new connective tissue attachment was observed on the denuded root surface. It was concluded that the absence of fibers on the root surface resulted in apical migration of the epithelium, and precluded formation of new connective tissue attachment.

Animals↗
PubMed1982

Effect of root surface alterations on periodontal healing. II. Citric acid treatment of the denuded root.

A companion study reported that new connective tissue attachment did not occur to a surgically denuded root surface when transplanted into a normal periodontium. It was the purpose of this study to evaluate periodontal healing adjacent to a citric acid treated denuded root surface. In four squirrel monkeys, 12 teeth were extracted and reimplanted after surgical denudation and citric acid conditioning of the coronal root surface. The study design provided three teeth for histologic analysis at 1, 3, 7 and 21 days after reimplantation. One and 3 days after reimplantation a zone of fibrin containing inflammatory cells and erythrocytes was interposed between the root surface and remaining periodontal fibers. The fibrin network appeared to be attached to the root surface by arcade-like formations. The apical termination of the epithelium was located at the coronal extent of the fibrin zone. Granulation tissue and new fibers were aggregating along and perpendicular to the root surface at 7 days, and new connective tissue attachment had been established at 21 days. Extensive root resorption was present along the intra-alveolar part of the root surface. Epithelium had not migrated apically along the denuded root surfaces. The results indicated that citric acid treatment of denuded root surfaces resulted in new connective tissue attachment, and the response appeared to be dependent upon early establishment of fibrin linkage with the root surface.

Animals↗
PubMed1982

Factors influencing periodontal repair and regeneration.

The purpose of the present study was to evaluate independently the regeneration capacity of a reduced periodontium, and the potential for new connective tissue attachment to a periodontally exposed root surface. A reduced periodontium was produced around a maxillary central incisor in two Rhesus monkeys using orthodontic elastics. The regeneration capacity of this reduced peridontium was investigated by extracting the periodontally involved tooth and transplanting into the socket the contralateral incisor which had a normal periodontium. The potential for new connective tissue attachment to a periodontally exposed root surface was evaluated by transplanting an exposed root into a normal periodontium. These exposed roots were the incisors extracted from the reduced peridontium. Control specimens were obtained by extracting and reimplanting or transplanting the remaining maxillary and mandibular incisors. Forty days after the experimental procedures, block sections were removed and prepared for histologic analysis. The exposed root surface that had been put into the normal periodontium was lined with epithelium interposed between root surface and alveolar bone. The normal root surface that had been put into the reduced periodontium had connective tissue reattachment in the periodontal ligament and supracrestal regions. Areas of ankylosis and root resorption were present in all specimens, as was new cementum in the periodontal ligament region. The results indicated that root surface alterations, rather than presence of a reduced periodontium, inhibited new connective tissue attachment.

Animals↗
PubMed1981

Depth of periodontal probe penetration related to clinical and histologic signs of gingival inflammation.

The purpose of this study was to determine if the depth of periodontal probe penetration into the gingival sulcus was related to bleeding after probing with a standardized force, visual signs of gingival inflammation, and histological parameters of gingival inflammation. Sixty midfacial gingival sites in 26 persons were evaluated for presence or absence of visible inflammation and bleeding after probing using a controlled insertion pressure of 25 gm. In order to delineate the area for histologic analysis, a reference incision was made on the facial surface of the gingiva which corresponded to the depth and mesio-distal extent of the area probed and evaluated for visual signs of inflammation. Gingival biopsy specimens were histometrically analyzed to determine the depth of probe penetration and percentage of inflamed connective tissue. Statistical analysis of the data demonstrated that probe penetration was significantly greater in the presence of visible inflammation, but not with bleeding after probing. Furthermore, only a weak correlation existed between depth of probe penetration and percentage of inflamed connective tissue adjacent to the area probed.

Adult↗
PubMed1981

Relationships between epithelium and connective tissue in inflamed gingiva.

Since chronic inflammation has been associated with degenerative and proliferative responses in connective tissue and epithelium, it was decided to investigate quantitatively the proportions of epithelium and connective tissue in inflamed gingiva. Forty-five midfacial gingival sites were assessed prior to biopsy for the presence or absence of bleeding after probing using a controlled insertion force fo 25 g. In order to delineate the corresponding area for histologic analysis, a reference incision was made on the facial surface of the gingiva which demarcated the depth and mesio-distal extent of the area probed. Step-serial bucco-lingual sections were morphometrically analyzed to determine the percentages of epithelium, inflamed, and noninflamed connective tissues coronal to the reference incision. The data was compared with respect to the presence or absence of bleeding after probing. Specimens which bled after probing had significantly less epithelium and more connective tissue. The increase in overall connective tissue was due to a significant increase in the inflamed component, and it appeared that the decrease in epithelium corresponded to the increase in inflamed connective tissue. The findings of diminished epithelium overlying inflamed connective tissue reinforces the concept that connective tissue status is important for determining structure and function of epithelium.

Adult↗
PubMed1981

Interproximal and buccal cell populations apical to the sulcus before and during experimental periodontitis in squirrel monkeys.

The purpose of this investigation was to study inflammatory cell populations apical to the buccal and interproximal gingival sulcus during destructive experimental marginal periodontitis in squirrel monkeys. Specimens were obtained of the clinically healthy periodontium, and (after 2 and 10 weeks) of experimental periodontitis induced by the placement of plaque-retentive silk ligatures at the gingival margin. Cell populations were characterized and quantitated in a standard area of connective tissue immediately subjacent to the most apical cells of the junctional epithelium in buccal and interproximal locations. Comparisons of periodontitis cell populations showed there were no differences between the regions in relation to either total numbers of cells, or in the percentages of inflammatory cell types. The inflammatory cells consisted primarily of granulocytes and macrophages, with only small percentages of lymphoid and plasma cells. Mechanisms and consequences of these cell types relative to periodontal tissue destruction are discussed.

Animals↗