bluuebunny/crossref_metadata_2025 huggingface dataset:
The absence of binding sites for antigens of Actinomyces viscosus on rat fibroblasts
Authors: Hefti A. , Guggenheim B.
Published: July 2006

Antibody‐complement‐mediated cytotoxicity for rat fibroblasts was investigated in an in vitro test system after preincubating monolayers with soluble antigens of A. viscosus. The high molecular weight, water‐soluble, extracellular fraction (HMW‐WS) and the ammonium sulfate precipitate of disrupted cells (BCS‐ASP) were used as antigens, a rabbit anti‐Actinomyces v/scosus‐serum as antibody, and guinea pig serum as source of complement. In a positive control, a marked cytotoxic effect for rat fibroblasts was induced with an anti‐rat‐thymocyte serum and complement. Preincubation of fibroblasts with the antigen preparations of A. viscosus Ny 1 and subsequent exposure to antibodies and complement had no cytotoxic effect on rat fibroblasts. This finding indicates the absence of binding sites for soluble antigens of A. viscosus on these cells.
An ultrastructural study of epithelial specialization at the porcine mucogingival junction
Authors: Newcomb Guy M.
Published: July 2006

The ultrastructural changes occurring in porelne epithelium across the mucogingival Junction were studied. Passing from attached gingiva to alveolar mucosa the most striking change in the deeper epithelial layers was a marked decrease in cytoplasmic tonofilaments. There was a gradual reduction in the thickness of the stratum corncum and also in the number of cells contained in this layer. Attached gingiva cells in the upper stratum spinosum and stratum corneurn displayed few interdigitations but as the junctional region was traversed interdigitating cell processes became common in these strata. Intercellular spaces became wider. There is no well defined line which represents vhe mucogingival junction. Rather there is a transitional zone where features of attached gingiva coexist with features of alveolar mucosa. These changes occurring across the mucogingival junction can be correlated with the functional requirement for attached gingiva to be relatively immoveable whilst alveolar mucosa remains flexible.
Scanning electron microscopy of the epithelium‐connective tissue interfacein human gingiva
Authors: Ooya K. , Tooya Y.
Published: July 2006

The morphological characteristics of the interface between epithelium and connective tissue in normal human gingiva were examined by scanning electron microscogy after separation of epithelium and connective tissue by maceration in sodium bromide solution. Separated crevicular epithelium showed dispersed arcade‐shaped pits corresponding to long conical connective tissue papillae. In the epithelium and connective tissue of the free gingiva, horizontal ridges ran parallel to the gingival margin. At the transition from free gingiva to attached gingiva, short conical connective tissue papillae arose from horizontal connective tissue ridges. Toward the alveolar mucosa these papillae increased in number, forming a honeycomb pattern on the separated epithelial surface.
Development of immunological sensitization and alveolar bone loss in gnotobiotic rats infected with Actinomyces viscosus Ny 1
Authors: Burckhardt Johann J. , Gakgauf‐Zolllnger Ruth , Guggenheim Bernhard
Published: July 2006

Development of sensitization in rats monoassocialed with Actinomyces viscosus Ny 1 was estimated by titrating serum agglutinins and by measuring the anamnestic, in vitro response of spleen T lymphocytes to two antigen fractions. These parameters of the immune response were compared with the development of alveolar bone loss using germfree rats as controls. At 46 days of age, 19 days after monoassociation, we observed (i) a mean serum antibody litre of (log2) 3.6, (ii) considerable antigen‐dependent T‐cell proliferation, and (iii) statistically significant amounts of alveolar bone loss. Thereafter, sensitization to A. viscosus and total bone loss increased cuncomitantly until the end of the experiment at 88 days of age. However, the rate of bone loss decreased with time at some sites, suggesting that negative feedback mechanisms by suppressor cells enable bone remodeling. These results demonstrate that, in experimental periodontal disease elicited by A. viscosus. the immune response to dental plaque bacteria and bone loss occur simultaneously.
Leukotoxic effects of Actinobacillus actinomycetemcomitans
Authors: Mcarthur W. P. , Tsai C.‐C. , Baehni P. C. , Genco R. J. , Tajckman N. S.
Published: July 2006

A sonic extract of Actinobarillus actinomycetemcomitans Y4, a microorganism originally isolated from a patient with juvenile periodontitis, contains a leukotoxin (Aa‐leukotoxin) which specifically kills human polymorphonuclear leukocytes (PMNs) and monocytes. In the presence of normal human sera, the toxicity of the leukotoxin is enhanced, whereas sera from patients with juvenile periodontitis neutralize leukotoxic activity. In juvenile penodontitis serum immunoglobulin G was identified as the specific inhibitor of the Aaleukotoxin. The leukotoxin enhancing factor(s) in normal human serum appeared to be a large molecular weight protein which was not immunoglobulin. Pooled sera from rabbits immunized with A. actinomycetemcomitans Y4 sonic extract also neutralized Aaleukotoxic activity while normal rabbit serum enhanced toxicity. The presence of antileukotoxin antibody in sera from individuals with juvenile periodontilis suggests that these people have been immunized with A. actittotnyCetemeomitans microorganisms. Monitoring of this antibody may be a convenient tool in the study of the etiology of juvenile periodontitis.
Peripheral blood leucocytes with receptors for extracts of dental plaque
Authors: Hardy G. , Walker D. M. , Guest P.
Published: July 2006

The proportions of T and B lymphocytes, monocytes and polymorphs have been investigated in blood leucocytes expressing receptors for plaque antigens.

In both patients with periodontal disease and in normal subjects, at least 95 per cent of the antigen binding leucocytes were found to be T lymphocytes. Only a mean 2 percent of the leucocytes from diseased and normal groups were B lymphocytes according to their membrane immunoglobulin. Antigen binding monocytes or polymorphs detected by phagocytosis were uncommon (a mean of 0 and 2 per cent for patients and normal subjects respectively). No differences were found between the proportions of T and B lymphocytes or phagocytic cells constituting the antigen binding leucocytes in patients or controls.

There is no evidence of clonal deletion or receptor blockade of a particular subpopulalion of leucocytes amongst the antigen binding cells in severe periodontal disease.
Elevated thromboxane B2 levels in periodontal disease
Authors: Rifkin B. R. , Tai H. H.
Published: July 2006

Thromboxane B2, the stable end product of thromboxane A2, was measured by a sensitive radioimmunoassay in gingival tissue obtained from clinically normal beagle dogs and beagle dogs with gingivitis and periodontitis. The animals with gingivitis contained gingival thromboxane B2 levels nearly twice that of clinically normal gingiva, while animals with periodontitis revealed gingival levels of thromboxane B2 that were 3–1/2 times greater than clinically normal and twice that of dogs with gingivitis.
The influence of advanced periodontitis on the psychophysical threshold level of periodontal mechanoreceptors in man
Authors: van Sleenherghe D. , VAN DEN Bergh A. , DE Vries J. H. , Schoo W. H.
Published: July 2006

Two groups of volunteers were examined with regard to the threshold level of a maxillary incisor for axialIy applied forces. One group showed an advanced periodontilis around the examined tooth, while the other group presented no clinical periodontal pathology. The ascending method of limits was used to determine the psychophysical threshold level.

The relationship between the threshold level and the force application rate appeared to be linear on a lin‐log and a log‐log display. Higher rates gave lower threshold levels. For equal rales, the threshold level of the periodontilis group was significantly higher than for the control group.

The results indicate that the periodontal mechanoreceptors are sensitive to the rate of force application, whatever the periodontal condition. Advanced periodontitis. however, clearly impairs the tactile function of the tooth supporting tissues.
Early formation of dental plaque on plastic films
Authors: Brecx Michel , Rönström Anders , Theilade Jorgen , Attström Rolf
Published: July 2006

This study was designed to gain further information on early plaque formation using a previously described method employing plastic films for the collection of the initial deposits.

To prevent the loss of loosely adhering material during processing of dental plaque for microscopic observation, the method was further developed by introducing an agar protection of the deposits formed on plastic films prior to fixation, dehydration and embedding procedures.

Four human subjects with healthy gingiva developed microbial plaque during periods of 4 and 8 hours on plastic films applied on the buccal surfaces of premolars and cuspids. After 4 hours the plastic films were covered by a surface coating of an acellular material in or on which bacteria, epithelial cells and leukocytes were observed. The microorganisms were almost exclusively identified as Gram‐positive cocci. The deposit in the 8 hour samples exhibited the same general morphology, but with more cellular components. Bacterial aggregation to each other or to epithelial cells was frequently mediated by filamentous appendages on the bacterial cell walls. The frequent observation of a close association between bacteria and epithelial cells suggests that the latter may play an important role as a vehicle for transporting microorganisms to the solid surfaces in the mouth in the initial stage of plaque formation.
Effect of flap placement and defect size on healing of experimental furcation defects
Authors: Klinge Bjorn , Nilveus Rolf , Kiger Robert D. , Egelberg Jan
Published: July 2006

Through‐and‐through furcation defects were experimentally created in one group of monkeys (Study 1) and in one group of dogs (Study 2). The effect of reconstructive periodontal surgery using citric acid conditioning of the instrumented root surfaces was studied. Two experimental variables were investigated: (1) variation of the placement and suturing of the flaps and (2) variation of the size of the furcation defects.

The results of these studies indicate that adequate postoperative flap coverage of the furcations seems to be critical for successful healing of the furcation defects. Variations in the vertical dimension of the defects seems to play a secondary role. Future studies in experimental animals should evaluate methods which will provide improved post‐operative coverage of the furcation area during healing of furcation defects in human patients.
Association of oral Bacteroides with gingivitis and adult periodontitis
Authors: White D. , Mayrand D.
Published: July 2006

The microbial flora of healthy gingival crevices and of periodontal pockets was studied to determine if a relation exists between the presence of Bacteroides asaccharolyticus and/or saccharolytic subspecies of B. melaninogenicus and the severity of the disease. Seventy‐eight samples were collected with sterile absorbent points from 40 individuals. The samples were immediately placed in reduced transport fluid. After dispersal by sonic treatment, the samples were put into an anaerobic chamber, serially diluted and plated on modified MM10 medium. After incubation, plates were examined and major bacterial types were counted. Black‐pigmented colonies were selected for further characterization. Samples from patients with severe inflammation (gingival index, GI = 3) showed a greater proportion of Gram‐negative anaerobic rods and 31.8 % of these organisms were identified as B. asaccharolyticus. This organism was absent in healthy sulci. It was recovered from mildly inflamed sites (GI = 1 or 2) but less often than B. melaninogenicus ss intermedius. B. melaninogenicus ss melaninogenicus was found only occasionally and in low numbers.
Immunological labeling of oral bacteria after demineralization
Authors: Chern‐Hsiung Lai , Listgarttn Max A.
Published: July 2006

Demineralization of teeth with their adherent bacterial flora is a prerequisite for the localization of selected species in sections of undisturbed bacterial deposits by immunoelectron microscopy. The effect of EDTA dernineralization on the immunological labeling of Gram‐positive and Gram‐negative oral bacteria was tested on strains of Actinomycesviscosus, A. israelii, Eikertella corrodens, Bacieroides meloninogenicus. Capnocytophaga sputigena and Wolinella recta. After 3 months in EDTA, cells prefixed in paraformaldehyde‐picric acid were washed and incubated with homologous rabbit antiscrum followed by goat anti‐rabbit IgG to enhance the immunocoating reaction. Samples were then processed for transmission electron microscopy. Control specimens included (1) demineralized cells incubated with pre‐immune rabbit sera instead of homologous antisera (2) cells stored for 3 months in PBS instead of EDTA (3) fresh cells processed for immunocoating immediately after prefixation and washing. No detectable immunocoating layer was found on the cells of the control group incubated with pre‐immune rabbitserum, EDTA treated cells demonstrated an immunocoating layer of similar density and thickness to that of cells stored in PBS, or fresh cells. The results indicate that immunoelectron microscopic localization of bacterial cells may be feasible in ullrathin sections of demineralized dental specimens.
Immunolocalization of collagenase in periodontal disease
Authors: Woolley David E. , Davies Robin M.
Published: July 2006

Immunoreactive collagenase was detected in four of eight specimens of diseased gingival tissue when sampled prior to treatment. Specimens taken From patients who had previously received initial therapy and whose tissues showed no clinical signs of inflammation, showed insignificant immunoreactive collagenase. All specimens were frozen within minutes of surgery. The enzyme was associated with connective tissue adjacent to the pocket epithelium and at the advancing front of the lesion. No enzyme was observed in association with intact gingival epithelium, Immunoreactive enzyme was frequently associated with inflammatory cells but the precise cellular origin of collagenase remains uncertain. These findings demonstrate the presence of tissue collagenase at sites of active collagen resorption thereby suggesting a degradative role for this enzyme in periodontal disease.
Fibrinolytic activity of gingival epithelium
Authors: Southam J. C. , Moody G. H. , Kowolik M. J.
Published: July 2006

Specimens of both human and animal gingivae were examined by fibrinolytic autography and all showed lysis over the gingival pocket epithelium, lysis never occurring over oral gingival epithelium. Epithelium separated from the connective tissue also showed fibrinolytic activity confined to the pocket epithelium. Examination of human gingival crevice washings showed fibrinolysis over some nucleated squamous epithelial cells as well as over anuclcated cell fragments. Although ihe neutrophil leucocytes in crevicular washings have fibrinolytic activity, this activity does not compare with that of the epithelium. The fibrinolytic activity of gingival pocket epithelium may be important in the pathogenesis of gingivitis and periodontitis, particularly due to the ability of plasmin lo activate complement.
Predictability of probing depths in ligature‐induced periodontal defects in beagle dogs
Authors: Jansen Jan , Pilot Taco
Published: July 2006

The aim of the present study was to evaluate the predictability of a method of creating periodontal defects in dogs. The dentogingival fibres around the lower premolars of 12 beagle dogs were cut to the level of the alveolar bone and closely adapted copper bands were cemented to the teeth. After 3 weeks the copper bands were replaced by cotton ligatures which were left in place for 11 weeks. After this active phase the ligatures were removed, and the defects were allowed to heal for varying periods up to 30 weeks. Probing depths were recorded at different stages of the experiment. Indications for predictability were: 1° the magnitude of the standard deviations of the mean probing depths and 2° the differences between results from contralateral areas. Relatively deep defects were obtained immediately after creation, but the magnitude of the standard deviation of the mean indicated wide variations in probing depths. Following ligature removal probing depths decreased but were of a more uniform depth. These results indicate that variation of probing depths in artificial periodontal defects is rather high immediately after creation but decreases drastically during the healing phase. It was concluded that in young adult beagle dogs predictable periodontal defects, 3.0–3.5 millimeters in depth, can be produced artificially provided that the initial deeper artificially created defects are allowed to heal for at least 3 months.
Comparative ultrastructure of leukotoxic and non‐leukotoxic strains of Actinobacillus actinomycetemcomitans
Authors: Lai Chern‐Hsiung , Listgarten Max A. , Hammond Benjamin F.
Published: July 2006

Fourteen strains of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) have been examined by transmission electron microscopy. The cells, which grow as coccobacillary forms on agar medium, have a cell periphery ultrastructurally compatible with that of other Gram‐negative species. However, the cell membrane and peptidoglycan layer are not readily visualized following standard processing. Of particular interest was the finding of numerous extracellular membranous vesicles in A. actinomycetemcomitans strains known to have leukotoxic activity, while non‐leukotoxic strains demonstrated few or no extracellular vesicles. Similar findings were noted whether cells were grown on blood agar plates or in thioglycollate broth. Antisera were obtained in rabbits against whole cells of leukotoxic strain Y4. The resulting antisera successfully labeled vesicles associated with 4 separate leukotoxic strains. The label was completely retained on the vesicles after absorption of the antisera with non‐leukotoxic strain ATCC 29523. Non‐leukotoxic strains showed some patchy surface labeling with non‐absorbed antiserum to Y4 and no labeling after absorption with ATCC strain 29523. These observations suggest that extracellular membranous vesicles are associated with leukotoxic activity and may serve as a useful source of leukotoxic factor. These conclusions are strengthened by the observation of a strong correlation between the concentration of extracellular vesicles in strains grown on agar and their relative leukotoxicity as reported by other investigators.
Immunological studies of young adults with severe periodontitis
Authors: Tew J. G. , Miller G. A. , Greene E. J. , Rice P. L. , Jordan W. P. , Palcanis K. G. , Ranney R. R.
Published: July 2006

Cellular responses of young adults with severe periodontitis (SP) were compared to the cellular responses of young adults with a healthy periodontium (HP). Analyses included T‐cell and B‐cell levels, blast transformation, production of leukocyte inhibitory factor (LIF), and phagocytosis and killing by peripheral polymorphonuclear leukocytes (PMN's). The levels of T‐ and B‐cells were virtually identical in the HP and SP groups. In blastogenesis assays SP subjects tended to respond to bacterial extracts more frequently than did HP subjects although the differences in frequency were not statistically significant for any single stimulant. The average of the blastogenic response for the SP responders did not differ from the magnitude of the response for the HP responders for any stimulant. However, female SP responders tended to respond higher to the bacterial extracts than did the female HP responders. Conversely, the male SP responders tended to respond lower than the male HP responders. Responses to PHA did not differ between groups. However, thymidine uptake in unstimulated control cultures from the SP subjects was significantly lower than the average background in cultures from HP subjects. The difference held for both males and females. Production of LIF, assessed after stimulation by bacterial extracts, did not differentiate between the SP and HP groups, nor did phagocytosis or killing of Streptococcus sanguis by PMN's.
A highly sensitive and specific assay for vertebrate collagenase
Authors: Sodek J. , Hurum S. , Feng J.
Published: July 2006

A highly sensitive and specific assay for vertebrate collagenase has been developed using a [14C]‐labeled collagen substrate and a combination of SDS‐PAGE (sodium dodecyl sulfate‐polyacrylamide gel electrophoresis) and fluorography to identify and quantitate the digestion products. The assay was sufficiently sensitive to permit the detection and quantitation of collagenase activity in 0.1 μl of gingival sulcal fluid, and in samples of cell culture medium without prior concentration. The assay has also been used to detect the presence of inhibitors of collagenolytic enzymes in various cell culture fluids.
Continuous widening of the band of attached gingiva from 23 to 65 years of age
Authors: Ainamo Anja , Ainamo Jukka , Poikkeus Raija
Published: July 2006

In earlier studies it was shown that the distance from the cemento‐enamel junction to the mucogingival junction, i.e. the anatomical width of fibrously attached gingiva, increases significantly from 23 to 43 years of age. The aim of the present study was to examine whether alveolar growth continues to result in an increase in this dimension after the age of 43. In a total of 21 males aged 65.7 ± 9.1 years and 21 females aged 64.5 ± 6.1 years, with an average of 23 occluding teeth, the mucogingival junction was marked with short pieces of metal wire. Orthopantomograms were then taken and the distances measured from the mucogingival junction to the cemento‐enamel junction and to the orthopantomographic projection of the bottom of the nasal cavity in the maxilla and from the mucogingival junction to the cementoenamel junction and to the lower border of the jaw in the mandible. The measurements were taken along the long axis of each occluding tooth. The bilaterally pooled results indicated that alveolar growth continues to increase the distance between the cemento‐enamel junction and the mucogingival junction in both males and females from age 43 to 65 years. However, the growth was slower during this period than from age 23 to 43 years. The distance from the mandibular border to the mucogingival junction of the same jaw did not change from 23 to 65 years of age. In the maxilla, an increase in the distance from the floor of the nasal cavity to the mucogingival junction was indicative of a continuous growth through adult age of the basal bone in the male but not in the female cranium.
The attachment mechanism of epithelial cells to titanium in vitro
Authors: Gould T. R. L. , Brunette D. M. , Westsury L.
Published: July 2006

It has previously been difficult to examine the nature of the attachment between tissues and metal implants. To resolve this problem, a technique has been developed in which oral epithelial cells are grown on very thin films of titanium on epoxy resin. Discs of epon/araldite were formed by polymerizing the liquid resin in 60 mm tissue culture dishes. Discs were then placed in a vacuum deposition chamber and titanium wire vaporized onto the surface to a final thickness of about 300Å. Discs were cleaned in acetone and 70 % alcohol before being placed in plastic culture dishes and plated with epithelial cells cultured from porcine periodontal ligament in MEM plus 15 % calf serum and antibiotics for fourteen days. Cultures were fixed in situ in 2.5 % glutaraldehyde, post‐fixed in OsO4 and epon/ araldite polymerized on the surface of the discs. Thin sections were cut perpendicular to the surface and examined in the electron microscope. Results show that the epithelial cells attach to the titanium surface by means of basal lamina and hemidesmosomes, in much the same manner in which the epithelial attachment is applied to the surface of a tooth.
Synthesis of collagenolytic enzymes and their inhibitors by gingival tissue in vitro
Authors: Pettigrew D. W. , Wang H.‐M. , Sodek J. , Brunette D. M.
Published: July 2006

Porcine gingival explants maintained in culture produced collagenase and non‐specific gelatinase. These enzymes were detected in both latent and active forms in explant culture medium. The latent enzymes could be activated by limited proteolysis with trypsin or by treatment with organomercurials (4‐hydroxy mercuribenzoate, PCMB and 4‐aminophenylmercuric acetate, APMA). The explants also produced protein capable of inhibiting the collagenase and non‐specific gelatinase activities. Treatment of inhibitor with trypsin or organomercurials under latent enzyme activation conditions blocked the inhibitory activity against both enzymes suggesting that the latent enzymes are enzyme‐inhibitor complexes. A specific gelatinase was also detected in the culture medium in an active form which was not inhibited by other macromolecules in the medium. The addition of endotoxin (30 μg/ml) to the gingival explant medium increased the synthesis of the collagenase and non‐specific gelatinase activities but had no apparent effect on the production of the inhibitor activity nor the specific gelatinase activity.
Classification and prevalences of plaque streptococci after two years oral use of chlorhexidine
Authors: Mikkelsen Lena , Jensen S. Borglum , ScHiøtt C. Rindom , Löe Harald
Published: July 2006

The purpose of the present study was to examine the influence of two years daily oral use of chlorhexidine (Löe et al. 1976) on the distribution of different streptococcal types in dental plaque. Plaque samples were collected from the molars in 16 persons in the chlorhexi dine group and from 17 control persons having used placebo solution. The samples were homogenized in yeast extract, and dilutions plated on mitis salivarius agar incubated micro aerophilically for 24 hours followed by aerobic storage at room temperature for 24 hours.

Colonies of each morphological type present were counted on plates having 30–300 colonies and their number related to the total number. One colony of each type was isolated and identified by biochemical tests. The study showed that 84.8 % of the strains could be classified as S. mutans, S. sanguis, S. mitior, S. milleri, S. salivarius, a group intermediary to S. sanguis and S. mitior, and a group resembling S. milleri, using only five biochemical tests: production of extracellular polysaccharide from sucrose, fermentation of mannitol, raffinose and inulin, and hydrolysis of esculin. In the chlorhexidine group the prevalences of S. sanguis and the group of streptococci intermediary to S. sanguis and S. mitior were higher, and the prevalence of S. milleri plus streptococci resembling S. milleri lower, among the streptococcal flora in dental plaque than those observed in the control group.
Sulcular penetration and diffusion into surrounding tissues of 14C‐phenytoin and 14C‐albumin
Authors: Steinberg Arnold D. , Joseph Charles E. , Evans Michael A.
Published: July 2006

Sulcular penetration patterns of phenytoin (PHT) and albumin (BSA), in New Zealand white rabbits, were followed through the sulcular lining tissue, overlying gingiva, interposed connective tissue, proximating periosteum and blood over 180 minutes. The time course study revealed that a steady‐state uptake of both molecules from the sulcus into the sulcular lining tissue was reached approximately 60 minutes after local tracer application. It was also found that PHT, after penetrating the sulcular lining tissue, was maintained at higher levels in gingiva than in other adjacent tissues while BSA levels were found highest in periosteum. Kinetic studies of these tissues demonstrated that sulcular tissue had a greater capacity for PHT than BSA and that uptake by this tissue had a capacity‐limited characteristic. The other adjacent tissues and blood also showed capacity‐limited characteristics probably reflecting uptake by the sulcular tissues. BSA degradation or PHT metabolism did not occur in any of these tissues or in serum.
Collagen degradation in the gingiva of the mouse incisor
Authors: Beertsen W. , Everts V.
Published: July 2006

In this study we investigated the possible role of the junctional epithelium of the mouse incisor in the degradation of collagen fibers carried during eruption from the periodontal ligament into the gingiva. To eliminate the contribution of fibroblasts to collagen breakdown the periodontal ligament was frozen in the sub‐crestal region by local application of liquid nitrogen. As a result of this treatment the fibroblasts were disrupted and, with ongoing eruption, the ligament was split into two separate sets of collagen fibers, one attached to the incisor and the other to the alveolar bone. The injured connective tissue in the tooth‐related compartment continued to move in the occlusal direction and made contact with the intact gingiva. Following its arrival in the sub‐epithelial region, the collagen fibers were not degraded but carried further towards the incisal edge, a process resulting in a forward shift of the level of connective tissue attachment. The degree to which this occurred was inversely proportional to the number of fibroblasts which had repopulated the connective tissue adjacent to the incisor. The data suggest that degradation of collagen and maintenance of connective tissue attachment in mouse incisor gingiva cannot solely be performed by cells of the junctional epithelium but require primarily the degradative activity of fibroblasts.
The phenotypic characterization of lymphoid cell subpopulations in gingivitis in children
Authors: Seymour Gregory J. , Crouch Michael S. , Powel Robin N.
Published: July 2006

Phenotypic characterization of lymphoid cell subpopulations in gingivitis associated with the deciduous dentition in children was carried out. Biopsies were obtained from 10 children aged between 5 and 9 years. The tissues were processed for either histochemistry or for immunofluorescence. T‐cells were identified by their T‐enzyme staining pattern and lack of immunoglobulin. B‐cells on the other hand were identified by their lack of T‐cell enzymes and presence of surface or cytoplasmic immunoglobulin. Morphologically the lesions consisted of approximately 70 % lymphocytes, between 11 and 26 % macrophages and fewer numbers of polymorphonuclear leukocytes and plasma cells. The majority of lymphocytes (approximately 70 %) were T‐enzyme positive/Ig negative indicative of a Tcell population. Approximately 12 % of the infiltrating cells were immunoglobulin positive. These results showed that gingivitis in children is essentially a T‐cell lesion and supports the hypothesis that the conversion from a stable to a progressive lesion involves shifts in cell populations.
Functional characterization of human gingival lymphocytes
Authors: O'Neill P. A. , Woodson D. L. , Mackler B. F.
Published: July 2006

Lymphoid cells were isolated from human gingival tissues which were indexed clinically as normal, periodontal inflammation without pocket formation, and periodontitis or inflammation with pocket formation. These isolated gingival inflammatory cells were then assessed for their ability to kill gingival fibroblasts in vitro and to produce lymphotoxin without in vitro stimulation. Lymphocytes isolated from clinically normal gingival tissues showed no cytotoxic activity and did not produce significant amounts of lymphotoxin. Conversely, cells from inflamed tissues with no pocket were cytotoxic at a low level for gingival fibroblasts and produced some lymphotoxin. Cells isolated from periodontitis tissues (inflamed with pocket) showed a greater degree of cytotoxicity for the fibroblasts. and the activity increased with increasing numbers of lymphoid cells. These cells appeared to be very active. since a ratio of one lymphocyte per fibroblast still showed significant killing. In addition, lymphotoxin was elaborated by these periodontitis lymphocytes in culture. These data indicated that a local hyperimmune response was present in chronically inflammed gingiva and that the lymphoid cells were activated and had the potential for tissue destruction.
Interexaminer agreement in the measurement of periodontal disease
Authors: Feldman R. S. , Dpurlass C. W. , Loftus E. R. , Kapur K. K. , Chauncey H. H.
Published: July 2006

Six variables of periodontal pathology were independently measured by two periodontists in a study of healthy male adult participants from the VA Dental Longitudinal Study. Two examination sets containing a total of 50 volunteers were compared to establish interexaminer agreement. Measures of gingival recession, tooth mobility, calculus accumulation, and plaque accumulation exhibited high interexaminer correlation. The measures of periodontal pocket depth and gingival health also showed good levels of agreement, but reflected the examination order; the second examiner consistently scored more severe disease because of the invasive nature of these measures. Establishment of the reproducibility of periodontal pathology measurements is essential for studies which involve more than one examiner. This investigation demonstrated a high confidence level of reproducibility for the six measures utilized and showed that recalibration enhanced the initial training procedure and increased examiner agreement above the initial level.
Effects of supervised chlorhexidine mouthrinses in children
Authors: Lang N. P. , Hotz P. , Graf H. , Geering A. H. , Saxer U. P. , Sturzenberger O. P. , Meckel A. H.
Published: July 2006

The study tested the effects of supervised chlorhexidine digluconate (CH) mouthrinses on plaque and gingivitis in school children. 158 children (aged 10–12 years) participated in the study. They were divided into four groups matched according to age, sex. DMFS, and GI. Following a sealing and prophylaxis procedure. Group A was assigned to daily mouthrinses 6 times per week using a .2 % solution of CH. Group B used the same solution only twice per week, and Group C was assigned to daily rinsing using a .1 % solution of CH. Group D served as control and rinsed daily with a placebo solution. All the rinsings were supervised and timed for 30 seconds. No attempt was made to influence the oral hygiene habits of the children. Prior to the initial prophylaxis and after 6 months of supervised rinsing, plaque was scored using the Plaque Index (PII), and gingivitis was assessed using the Gingival Index (GI). Calculus was scored according to the Calculus Surface Index (CSI), and stain was also graded. DMFS indices were assessed using clinical and radiographic examinations. At the end of the study plaque was significantly reduced in all CH groups when compared with the controls, and calculus increased significantly in all CH groups. In Group A the GI dropped from .88 to .15 and in Group C from .80 to .24. In Group B the GI dropped from .79 to .38. In the control group a slight reduction from GI = .93 to GI = .75 was noted. The study has shown that gingivitis can be controlled successfully on a longitudinal basis using .1 % or .2 % mouthrinses of CH as an adjunct to daily toothbrushing.
Enhancement of cell attachment to a substrate coated with oral bacterial endotoxin by plasma fibronectin
Authors: Porvaznik M. , Cohen M.E. , Bockowski S. W. , Mueller E. J. , Wirthlin M. R.
Published: July 2006

Normal human fibroblasts were inhibited from attaching to a culture surface that was coated with endotoxic lipopolysaccharide (LPS) isolated from oral strains of Bacteroides or Fusobacterlum. The LPS from Fusobacterium inhibited cell attachment to a greater degree (p < 0.001) than that of the LPS from Bacteroides, and at a concentration as low as 12.5 ng/cm2 (p < 0.001), When LPS‐coated culture dishes (12.5 ng/cm2) were incubated with concentrations of plasma fibronectin as low as 50 μg/ml for at least 15 min, the fibronectin significantly enhanced cell attachment, returning it to control levels (p < 0.001). Futhermore, when plasma fibronectin (50 μg/ml) was compared to other agents such as bile acids, citrated serum, and human plasma fraction IV1 (Cohn), which have been shown to affect the toxicity of LPS, fibronectin led to significantly more cell attachment in the presence of LPS than any other treatment (p < 0.001). Evidence is presented by means of transmission electron microscopy (TEM) that LPS may bind to fibronectin. Subsequently, the cell surface interacts with the fibronectin‐LPS and internalizes it via phagocytosis. This mechanism provides for the clearance of LPS from the culture surface.
Human gingival tissues in culture synthesize three metalloproteinases and a metalloproteinase inhibitor
Authors: Heath Joan K. , Gowen Maxine , Meikle Murray C. , Reynolds John J.
Published: July 2006

Explants of human gingiva obtained during periodontal surgery and maintained in tissue culture synthesized three metalloproteinases which degraded collagen, gelatin, and proteoglycan respectively. Collagenase and gelatinase were present in both active and latent forms suggesting that collagen degradation was taking place. Proteoglycan degrading activity, however, was present only in the latent form.

Human gingival fibroblasts in monolayer culture did not synthesize metalloproteinases, but did produce an inhibitor with properties similar to the purified inhibitor TIMP (Tissue Inhibitor of Metallo‐Proteinases) synthesized by rabbit bones in culture. Human gingival fibroblast inhibitor had an apparent molecular weight of 32,000 on gel filtration and blocked the activity of all three metalloproteinases.

These findings indicate that further investigation of the factors that control or modify metalloproteinase and TIMP activity in gingival tissues should help clarify the pathogenic mechanisms responsible for connective tissue loss in periodontal disease.
Variation in sialic acid concentration in gingival tissue from rats receiving excess vitamin A
Authors: de Paiva Yvonne A. S. , Nicolau José
Published: July 2006

The effect of 1 to 5 doses of 15,000 I.U. of vitamin A on N‐acetyl neuraminic acid (NANA) concentration in gingival tissue from rats was studied. Increased sialic acid concentration was observed in those animals receiving up to 4 doses of the vitamin, while a decreased concentration was found in the 5 doses group. Also examined was the interrelationship between vitamin A‐cortisol and vitamin A‐ascorbic acid. The profile of NANA variation in the groups receiving vitamin A plus ascorbic acid was similar to that of animals receiving only ascorbic acid. The data obtained for the groups receiving both vitamin A and cortisol, did not differ from that obtained for the groups receiving only vitamin A.
Histometric analysis of ligature‐induced periodontal defects in beagle dogs‐ evaluation following ligature removalLongitudinal
Authors: Jansen Jan , Van Dijk Johan , Pilot Taco
Published: July 2006

The aim of the present study was to investigate the sequence of events that takes place in ligature‐induced periodontal defects following removal of the ligature.

In eight beagle dogs the dentogingival fibres around six lower premolars (2P2, 3P3, 4P4) were cut to the level of the alveolar bone. Closely adapted copper bands were then cemented around the teeth. After 3 weeks the copper bands were replaced by cotton floss ligatures which were left in place for 11 weeks.

The dogs were sacrificed on different dates so that it was possible to analyse defects 3, 7, 15, or 31 weeks after ligature removal. Contralateral defects one week after ligature removal served as controls. Micrographic color slides of the histological sections were analyzed using a Ferranti‐Cetec digitizer.

Mean values for loss of attachment in the 15 and 31 weeks specimens were greater than in the control defects, suggesting that apical positioning of the junctional epithelium was irreversible. However, alveolar bone height tended to increase with experimental time, indicating bone repair. In the 15 and 31 weeks specimens junctional epithelium was occasionally found between the root surface and the alveolar bone

It was concluded that the model does not show all the histological characteristics of naturally occurring periodontitis even in those dogs examined 31 weeks after removal of ligatures.
Artificial periodontal defects around incisor teeth of beagle dogs
Authors: Jansen Jan
Published: July 2006

The aim of the present experiment was to investigate if it is possible to create deep periodontal defects around incisor teeth of beagle dogs with the use of orthodontic elastic bands, to investigate if this method is reproducible and predictable, and to evaluate if such defects possess the histopathological characteristics of naturally occurring periodontitis.

In eight beagle dogs the dentogingival fibres around four upper incisors, 3I3 and 2I2, were cut to the level of the alveolar bone. Orthodontic elastic bands were placed in these deepened sulci and removed after 8 weeks. Clinical data (probing depth and gingival recession) were recorded at the start of the experiment, immediately following removal of the elastic bands, and 2, 6, 14, and 30 weeks thereafter. The dogs were sacrificed on different dates so that is was possible to analyse defects histometrically 3, 7, 15, or 31 weeks after elastic removal. Contralateral defects one week after elastic band removal served as controls. Micrographic color slides of the histological sections were analysed using a Ferranti‐Cetec digitizer.

Immediately after elastic band removal mean values for probing depth and gingival recession were approximately 5.5 mm and 2.0 mm, respectively. Histometrical assessments revealed a loss of attachment of approximately 3.0 mm.

The differences in probing depths between Contralateral defects in the same dog were small indicating rather high reproducibility of the method. Because of wide variations in probing depth and histometrical dimensions between dogs, it was concluded that the present method is not fully predictable.

Upon elastic removal values for probing depth decreased with approximately 1.5 mm, the result being a moderately deep defect of around 4 mm. Histometrically there was no evidence that the apical positioning of the junctional epithelium was reversible after elastic removal. However, alveolar bone repair could be demonstrated in the 7, 15, and 31 weeks specimens.

It was concluded that because of this bone repair, the present defects do not possess all histopathological characteristics of naturally occurring periodontitis.
Effects of repeated scaling and root planing and/or controlled oral hygiene on the periodontal attachment level and pocket depths in beagle dogs
Authors: Syed S. A. , Morrison E. C. , Lang N. P.
Published: July 2006

A study was performed to evaluate the effect of initial and/or repeated scaling with or without controlled oral hygiene on the level of periodontal attachment and pocket depth in beagle dogs. The clinical results of this three‐year longitudinal study have been reported previously (Morrison et al. 1979). The purpose of the present report is to present the microbiological results of subgingival plaque samples obtained from selected sites at the conclusion of the study.

Eight beagle dogs with moderately developed periodontitis were divided into experimental and control animals. The experimental group received a thorough scaling and root planing at the start of the experiment following which the animals were subjected to daily toothbrushing and rubber cup and pumice prophylaxis every second week for 36 months. Four control dogs were not subjected to any oral hygiene procedures for the entire period of the study. The teeth of two quadrants in each animal of the experimental and control group were scaled and root planed every six months.

After three years subgingival plaques from the mesial aspect of the fourth premolar in each of the quadrants of each animal were collected by sterile curettes, processed anaerobi‐cally, and cultured in an anaerobic glove box. Significantly lower total viable colony forming units (CFU) as well as significantly lower anaerobe/aerobe ratios were found in the subgingival plaques of the experimental animals. The total CFU of Bacteroides asaccharo‐lyticus was 25 times lower, and tie proportion of CFU of this organism was nine times lower in the experimental sites when compared with the control sites. Repeated scaling every six months also lowered the total CFU and the proportion of Bacteroides asaccharo‐lyticus in the subgingival plaques of the experimental as well as the control animals. The data suggest that the level of Bacteroides asaccharolyticus as key organisms as well as the anaerobe/aerobe ratio are valuable microbiological parameters in evaluating the efficacy of periodontal therapy.
The identification of lymphoid cell subpopulations in sections of human lymphoid tissue and gingivitis in children using monoclonal antibodies
Authors: Seymour G. J. , Crouch M. S. , Powell R. N. , Brooks D. , Beckman I. , Zola H. , Bradley J. , Burns G. F.
Published: July 2006

Monoclonal antibodies made against lymphocyte differentiation antigens were used to characterize phenotypically the lymphoid cell subpopulations in sections of human lymphoid tissue and inflamed gingival tissue associated with the deciduous dentition in children. Four monoclonal antibodies designated FMC 1, FMC 4, FMC 7, and UCHT1 were used. These antibodies are specific for B‐cells, p28,33 (la‐like) antigen, a B‐cell subset, and peripheral T‐cells respectively. FMC 1 and FMC 4 positive cells (B‐cells) were found mainly in the secondary follicles while UCHT1 positive cells (T‐cells) were found in the parafollicular areas of human tonsils. Cells in some, but not all, secondary follicles in the tonsils were FMC 7 positive.

In the gingival tissue only 12.6 % of the infiltrating cells were FMC 1 positive, 12.2 % were FMC 4 positive, and 4.8 % FMC 7 positive. On the other hand over 75 % of cells appeared to be UCHT1 positive.

These results indicate that the majority of inflammatory cells in gingivitis associated with the deciduous dentition in children have the phenotype B‐cell antigen‐/p28,33 (lalike) antigen‐/B‐cell subset antigen‐ and possibly T‐cell antigen+. Such a phenotype is, at least by exclusion, suggestive of T‐cells and as such confirms earlier studies using T‐cell enzyme markers.
Scanning electron microscopy of the gingival wall of deep periodontal pockets in humans
Authors: Saglie R. , Carranza F. A. , Newman M. G. , Pattison G. A.
Published: July 2006

The epithelial surface of deep periodontal pockets has been described using scanning electron microscopy. The presence of microtopographically distinct areas suggests that the pocket wall is constantly changing as a result of the interaction between the host and the epithelial‐ and pocket‐associated bacteria. Seven topographical areas were described: relative quiescence, bacterial accumulation, emergence of leukocytes, leukocyte‐bacterial interaction, epithelial desquamation, hemorrhage, and ulceration.
Magnification angiography in beagles with periodontal disease
Authors: Jeffcoat M. K. , Kaplan M. L. , Rumbaugh C. L. , Goldhaber P.
Published: July 2006

Magnification angiography was used to visualize the mandibular vasculature of beagle dogs with either minimal or moderate to severe periodontal disease. The arteriograms were qualitatively graded with respect to numbers of vessels and vessel architecture. Arteriograms of the dogs with moderate to severe periodontal disease revealed a significant increase in vessel density and tortuosity when compared to dogs with minimal disease. The technique presented in this report provides a non‐destructive method for the in vivo study of the vascular architecture in periodontal disease.