Gingival wound healing in the presence of plaque-induced inflammation.

An accelerated loss of connective tissue attachment has been reported following surgery in plaque-infected dentitions. It was the purpose of the present study to evaluate histologically the healing of incisional wounds in the gingival supracrestal region in the presence and absence of bacterially induced inflammation. In the experimental group, marginal periodontitis was induced around the teeth by tying plaque-retentive ligatures at the gingival margins and 10 weeks later an incisional wound was made from within the gingival sulcus to the crest of the bone. In the control group, similar incisional wounds were made in normal gingiva. In each group, three specimens were available for histologic and histometric analysis 1, 3, 7 and 21 days after wounding. In the control group, the wound healing sequence in the supracrestal region was similar to that reported following incisional cutaneous wounds. In the experimental group, epithelial continuity across the wound was re-established earlier, and marked invagination of epithelium occurred into the incision. This invagination was significantly greater than in control specimens at all time points. In addition, within the experimental group a second significant epithelial migration into the wound occurred between 7 and 21 days. The epithelial invagination extended through the major portion of the supracrestal area and terminated near the cementum surface. It is conceivable that marked epithelial invagination into a supracrestal wound may predispose to an accelerated loss of connective tissue attachment.

Periodontal diagnosis. Current status and future needs.

This literature relating to current methods of periodontal diagnosis is reviewed. There exists a future need for objective diagnostic techniques which reflect the dynamics of periodontal disease activity.

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.

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.

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.

Effects of levamisole on experimental periodontitis.

Although the chemotaxis and efflux of functionally normal polymorphonuclear leukocytes (PMN) into the periodontal sulcus may have a protective role in periodontitis, these cells are also associated with periodontal tissue destruction. The immunomodulating agent, levamisole hydrochloride, is known to enhance PMN chemotaxis. The present study was designed to evaluate the effects of enhanced PMN chemotaxis on the tissue destruction associated with an experimental periodontitis. Levamisole was administered by oro-gastric intubation to 4 squirrel monkeys (experimental) at 3 mg/kg/bw every 2 days for 18 days. After 2 doses of levamisole, marginal periodontitis was induced around maxillary and mandibular bicuspids and the maxillary first molars by tying plaque-retentive ligatures at the gingival margins. Periodontitis was induced around corresponding teeth in 4 animals (control) which had not received levamisole. All animals were killed 2 weeks after induction of periodontitis. Clinically, gingival inflammation was more pronounced in experimental animals at both 7 and 14 days after periodontitis induction. The progression of periodontitis was evaluated histometrically and alterations in the cell populations characterized using step serial sections. The results were analyzed statistically. No significant differences were observed between the groups with respect to areas of infiltrated supracrestal connective tissue and total numbers of cells present, loss of connective tissue attachment and loss of coronal alveolar bone. However, in experimental specimens, a much denser band of inflammatory cells was evident between the apical extent of the bacterial plaque and the gingival sulcular tissues the connective tissue of which contained significantly fewer inflammatory cells and demonstrated more pronounced fibrogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell and fiber attachment to demineralized cementum from normal root surfaces.

The purpose of this study was to assess connective tissue and epithelial responses to cementum (from normal human root surfaces covered by periodontal ligament) after surface demineralization with citric acid. Each rectangular specimen had a face of cementum and an opposite surface composed of pulpal dentin. One half of the specimens were treated with citric acid (experimental group), while the remainder served as untreated control specimens. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. Four specimens in each group were available for examination 1, 3, 5, and 10 days after implantation. Histologic and histometric analyses of the implants included counts of adhering cells, evaluation of attached connective tissue fiber density and diameter, and assessment of epithelial migration. At day 1, a distinct lighter staining zone was present on the surface of both cementum and dentin in the experimental group which corresponded to a zone of surface demineralization produced by the acid treatment. Histometric comparisons between experimental and control groups at 10 days showed a greater number of cells attached to demineralized cementum surfaces. Also, a connective tissue fiber attachment system had developed on these experimental surfaces, but which differed morphologically from periodontal ligament fiber attachment to normal cementum. It was concluded that citric acid treatment can surface demineralize cementum from normal roots, and that the surface demineralization of this cementum facilitated a cell and fiber attachment to the cementum surface.

Factors associated with occurrence and reversibility of connective tissue attachment loss.

Marginal periodontitis appears to be site-specific, demonstrates rapid bursts of connective tissue attachment destruction, and may, at times, repair spontaneously. The present study was undertaken to investigate associations between bacterial populations and periodontal destruction parameters within the first 14 days after induction of experimental periodontitis in animals receiving metronidazole. Metronidazole was administered orally to four squirrel monkeys for 17 days at a daily dose of 100 mg/kg body weight. After three days (baseline), marginal periodontitis was induced by tying silk ligatures at the gingival margins of maxillary and mandibular bicuspids and molars. Subgingival bacterial samples were taken and periodontal destruction evaluated at baseline, and 3, 7 and 14 days after ligature placement. Dark-field microscopy was used to quantitate motile forms, spirochetes, straight and curved rods, filaments, cocci and fusiforms. Levels of connective tissue attachment, crestal alveolar bone and the volume of bone were assessed histometrically. Bacterial and histometric parameters were analyzed using analysis of variance. The results indicated that subgingival plaque, prior to induction of periodontitis, consisted primarily of cocci. At three days after ligature placement, cocci were significantly decreased, while straight rods became the predominant bacterial group for the remainder of the study. Spirochetes and motile forms were virtually absent at all time points. Histometric analyses showed significant loss of connective tissue attachment at three and seven days, which was reversed and repaired at 14 days. Factors relating to initiation, potentiation, and reversibility of connective tissue attachment loss are discussed.

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.

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.

Cell and fiber attachment to demineralized dentin from periodontitis-affected root surfaces.

This study assessed connective tissue and epithelial responses to dentin specimens obtained from periodontitis-affected roots of human teeth after surface demineralization. Rectangular dentin specimens with opposite faces of root and pulpal dentin were prepared from beneath root surfaces covered by sheets of calculus. One half of the specimens were treated with citric acid, pH 1, for 3 minutes, while the remainder served as untreated controls. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. Four specimens in each group were available 1, 3, 5 and 10 days after implantation. Histologic and histometric analyses included counts of adhering cells, evaluation of attached connective tissue fiber density and diameter, and assessment of epithelial migration. Analyses within each group comparing root and pulpal surfaces showed no differences between any of the parameters. Comparisons between experimental and control groups showed that demineralized surfaces had a greater number of cells attached, fiber attachment occurred and epithelial downgrowth was inhibited. Surface demineralization of dentin from periodontitis-affected roots predisposed toward a connective tissue attachment.

Cell and fiber attachment to demineralized dentin from normal root surfaces.

The study assessed connective tissue and epithelial responses to dentin specimens (obtained from normal roots of human teeth) after surface demineralization. Rectangular dental specimens with opposite faces of root and pulpal dentin were prepared from beneath root surfaces covered by periodontal ligament. One-half of the specimens were treated with citric acid, pH 1, for 3 minutes, while the remainder served as untreated control specimens. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. Four specimens in each group were available 1, 3, 5 and 10 days after implantation. Histologic and histometric analyses included counts of adhering cells, evaluation of connective tissue fiber relationships and assessment of epithelial migration. Analyses within each group comparing root and pulpal surfaces showed no differences between any of the parameters. Comparisons between experimental and control groups showed that demineralized surfaces had a greater number of cells attached, fiber attachment occurred and epithelial downgrowth was inhibited. The fiber attachment to experimental specimens differed morphologically from fiber attachment to normal root surfaces: the number of fibers attached per unit length and the diameter of attached fibers were significantly less on experimental specimens. Demineralized specimens at 10 days had a distinct eosinophilic surface zone. Surface demineralization of dentin predisposed toward a cell and fiber attachment system which inhibited migration of epithelium.

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.

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.

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 bone regeneration after removal of inflammatory and traumatic factors.

In this investigation periodontal destruction was produced by a combination of inflammatory and traumatic factors. After the inflammation was resolved and the trama stopped, a significant amount of alveolar bone regeneration took place. The implications of these findings for the management of advanced periodontal disease are discussed.

Histologic characteristics associated with bleeding after probing and visual signs of inflammation.

This study was designed to characterize histologically the gingival lesion associated with visual signs of inflammation and bleeding after probing. Sixty midfacial gingival sites in 26 persons were evaluated for visual presence of absence of 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 signs of inflammation. Gingival biopsy specimens were morphometrically analyzed to determine the percentages of cell rich--collagen poor connective tissue and blood vessel lumens. Histometric data were grouped and compared with respect to the presence or absence of inflammation and bleeding. Specimens associated visually with inflammation had significantly greater percentages of both cell rich--collagen poor connective tissue and blood vessel lumens. Bleeding upon probing was associated with a significantly greater percentage of cell rich--collagen poor connective tissue without an increase of blood vessel lumens. It was concluded that both observed signs of inflammation and bleeding after probing can be used to detect inflammatory lesions in the gingiva. However, in areas inaccessible for evaluation of inflammation, bleeding determinations using controlled insertion pressures provided an objective diagnostic method for detecting the presence of an inflammatory lesion.

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.

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.

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.