bluuebunny/crossref_metadata_2025 huggingface dataset:
Periodontal bone loss in Porphyromonas gingivalisinfected specific pathogen‐free rats after preinoculation with endogenous Streptococcus sanguis
Authors: Fiehn N.‐E. , Klausen B. , Evans R. T.
Published: July 2006

Anaerobic Gram‐negative bacteria dominate in periodontitis locations, while Gram‐positive bacteria characterize healthy sites. A well‐established Gram‐positive flora might therefore inhibit the colonization of Gram‐negative pathogens. The purpose of the present investigation was to examine whether endogenous S. sanguis could prevent, or reduce, periodontal bone loss in rats infected with a virulent P. gingivalisstrain. Sixty specific pathogen‐free Wistar rats were divided into 6 groups. Doxycycline was administered in the drinking water for 2 weeks to the groups A, B, C, and D to suppress the preexisting microflora in the mouth. Rats in groups A and C were subsequently inoculated with an 5. sanguis strain, isolated from one of the rats, once a day for 5 d. Infection with P. gingivalis 381 was then carried out for 5 d in groups A, B, and E. Group F was not treated with doxycycline nor infected with bacteria and served as untreated control. Six weeks after the P. gingivalis inoculation, the rats were killed. Periodontal bone levels were assessed radiographically and morphometrically, and serum antibody against P. gingivalis 381 was determined by a fluorescence immunoassay. Periodontal bone support, determined radiographically, was reduced in group B (doxycycline‐treated, P. gingivalis‐inoculated) compared with the other groups. In contrast, the morphometric determination showed no differences between the groups. In group B antibody levels against two different P. gingivalis 381 cell surface antigens were significantly elevated. The data indicated that the preinoculation of an endogenous S. sanguis strain protected against a reduction of the radiographically assessed periodontal bone support induced by P. gingivalis 381. and similarly prevented an elevation of the total serum antibody response to P. gingivalis 381.
Tetracycline administration increases protein (presumably procollagen) synthesis and secretion in periodontal ligament fibroblasts of streptozotocininduced diabetic rats
Authors: Sasaki Takahisa , Ramamurthy Nungavaram S. , Yu Zhao , Golub Lome M.
Published: July 2006

Streptozotocin‐induced, insulin‐deficient diabetic adult rats were daily administrated either minocycline or a chemically‐modified non‐antimicrobial tetracycline (CMT) by oral gavage for a 3‐week time period; untreated diabetic and non‐diabetic rats served as controls. On day 21, all rats received an intravenous injection of 3H‐proline followed by perfusion fixation with an aldehyde mixture at 20 minutes and 4 hours after isotope injection. The upper and lower mandibles of these rats were dissected and processed for quantitative electron microscopic autoradiography to study 3H‐proline utilization by fibroblasts in the periodontal ligament (PDL) of molars. In the non‐diabetic controls, at 20 min after 3H‐proline injection, radioprecursor was incorporated by the Golgi‐RER system of PDL fibroblasts. At the 4‐h time period, most of the label was present over the collagen fibers around these cells. In contrast, PDL fibroblasts in the untreated diabetic rats showed marked abnormalities ultrastructurally and minimal uptake (20 min) and secretion (4 h) of labeled proline. At both time periods, in both minocycline‐ and CMT‐treated diabetic rats, fibroblasts were structurally more normal and the radioprecursor was localized in the fibroblasts and the PDL matrix in a pattern similar to that seen in the control rats. These results suggest that the diabetes‐induced structural abnormalities and suppression of synthesis and secretion of protein (presumably collagen and its precursor) by PDL fibroblasts can be restored to near‐normal by administration of a tetracycline and that this effect is mediated by a non‐antimicrobial property of this family of antibiotics.
A sensitive enzymatic method (SK‐013) for detection of Treponema denticola, Porphyromonas gingivals and Bacteroides forsythus in subgingival plaque samples
Authors: Seida Kizuku , Saito Atsushi , Yamada Satoru , Ishihara Kazuyuki , Naito Yuko , Okuda Katsuji
Published: July 2006

An enzymatic method, SK‐013, was developed for rapid detection of the peptidase activity in subgingival plaque samples. This method was found to have specificity for Porphyromonas gingivalis, Treponema denticola, Bacteroides forsythus, and some Capnocytophaga strains. The purpose of this study was to determine whether SK‐013 could indicate the presence of periodontopathic bacteria, including T. denticola, P. gingivalis and B. forsythus, which produce trypsin‐like enzymes. Subgingival plaque samples were taken from 10 clinically healthy sites and 30 periodontally diseased sites with 3 paper points. SK‐013 activity of plaque samples was assayed, and the numbers of T. denticola, P. gingivalis and B. forsythus in the sample were counted by immunofluorescence technique. In diseased sites, the SK‐013 activity was significantly correlated with clinical parameters such as Gingival Index, Plaque Index, probing depth and bleeding on probing. A significant correlation was found between the presence of these organisms and SK‐013 activity. Correlation coefficients between the presence of T. denticola and SK‐013 activity were higher than those with other organisms. These findings indicate that the SK‐013 is useful as an indicator of cell population of T. denticola, P. gingivalis and B. forsythus in subgingival plaque.
Sulcus temperature distributions in the absence and presence of oral hygiene
Authors: Perdok J. F. , Lukacovic M. , Majeti S. , Arends J. , Busscher H. J.
Published: July 2006

In this study we investigated the possibility of using sulcus temperature measurements as an early indicator for the beginning of gingival inflammation. Sulcus temperature distributions over the arches appeared to obey a quadratic polynomial. With a test group of 10 volunteers, all dental students, small changes in temperature were measured after subjects refrained from all oral hygiene: A slight but significant tendency for the frontal temperature to increase after 14 days of no oral hygiene was, however, present. The quality of a quadratic polynomial fit of the temperature distributions over the arches decreased significantly, already after 3 d of non‐oral hygiene. This indicates that the coefficient of quadratic correlation for the temperature distributions over the arches is a measure for the oral hygiene of patients and for changes in the physiology of gingival tissues. Furthermore, as its decrease was concurrent with an increase in plaque and gingival indices, it might serve as an early indicator for the beginning of gingival inflammation. However, further development work is needed in order to make this approach useful as a clinical tool.
Immunohistochemical localization of collagenous components in healthy periodontal tissues of the rat and marmoset (Callithrix jacchus).
Authors: Romanes G. E. , Schröter‐Kermani C. , Hinz N. , Wachtel H. C. , Bernimoulin J.‐P.
Published: July 2006

The distribution of collagen types I and III was demonstrated in healthy periodontal tissues of the rat and marmoset using immunofluorescent localization after decalcification of the maxillae and mandiblae in 0.2 N HC1. An intense fluorescence in the alveolar bone and cementum matrix, as well as in the soft periodontal tissue, was demonstrated with anti‐collagen type I antibodies. In the gingival connective tissue and in the periodontal ligament thick fibers of collagen type I could be observed. The fluorescent reaction in the rat periodontal ligament was not strong in comparison to the marmoset periodontal ligament. Sharpey's fibers, inserting into the cementum and alveolar bone, were also stained. On the other hand, collagen type III could not be demonstrated in the hard periodontal tissues, but could be in the bone marrow stroma and the incremental lines as well as around the Sharpey's fibers of the cementum, in accordance to previous studies. In the gingival connective tissue a strong staining was evident, especially near the basement membrane. The periodontal ligament showed an intense fluorescence that was, in some areas, continuous with Sharpey's fibers inserting into the cementum. The distribution of collagen types I and III was demonstrated with immunohistochemical techniques in the rat and marmoset periodontium. These results provide necessary information on healthy tissues that will be required for future studies on the effects of pathological, reparative and regenerative processes.
Phagocytosis of Porphyromonas gingivalis and Prevotella intermedia by human polymorphonuclear leukocytes in clots formed from human plasma or purified fibrinogen
Authors: Hurst T. J. , Wilton J. M. A.
Published: July 2006

We have studied the polymorphonuclear leukocyte (PMN) phagocytosis of Porphyromonas gingivalis (Bacteroides gingivalis) and Prevotella intermedia (Bacteroides intermedius) in three‐dimensional fibrin meshworks formed by either clotting human plasma or by clotting purified fibrinogen with human serum incorporated. PMN phagocytosis of rhodamine isothiocyanate‐labelled P. gingivalis in the fibrinogen clot was 43 ± 6% and in the plasma clot was 62 ± 10%; for P. intermedia the values were 15 ± 10% and 63 ± 10%, respectively. This showed that phagocytosis in the plasma clot system was significantly higher than in the fibrinogen clot system. However, increasing the concentration of serum in the fibrinogen clot abolished this difference, suggesting that opsonin levels determine PMN function in this assay. Labelling the bacteria with a different fluorochrome, fluoroscein isothiocyanate, reduced the level of PMN phagocytosis in both three‐dimensional systems but phagocytosis was unaffected when PMN were adherent to glass. It would appear that PMN phagocytosis in three‐dimensional systems can vary depending on the composition of the clot and the fluorochrome used to label the bacteria.
Activated lymphocyte subsets in adult periodontitis*
Authors: Afar B. , Engel D. , Clark E. A.
Published: July 2006

The activation state of T and B lymphocytes in the peripheral blood of periodontitis patients may be a reflection of disease activity. We have utilized 2‐ and 3‐color flow cytometric analyses using a new chromophore, peridinin chlorophyll A protein, and conventional dyes, fluorescein isothiocyanate and phycoerythrin, conjugated to monoclonal antibodies against activated lymphocyte surface markers to measure blood lymphocyte subsets from 18 periodontitis patients and 16 periodontally healthy control subjects. Two‐color flow cytometric analysis demonstrated that the frequency of CD4+ and CD5 + T cells, CD20+ B cells, and CD16+ NK (natural killer) cells were increased in periodontitis patients. Of particular interest, CD4+ activated “memory” T cells, CD5+ B cells, and CD56+ NK effector cells were increased significantly in periodontitis patients (p < 0.05). While the relationship of lymphocyte activation to periodontal disease activity remains unclear, there may be potential for using 2‐ and 3‐color flow cytometry to subcategorize periodontitis patients into high‐ and moderate‐risk groups.
Growth of acellular extrinsic fiber cementum (AEFC) and density of inserting fibers in human premolars of adolescents
Authors: Sequeira Patrick , Bosshardt Dieter D. , Schroeder Hubert E.
Published: July 2006

The present study describes for the first time the changes of both AEFC thickness and the numerical density of collagen fibers inserting into AEFC at specified levels and sites of human premolars at different stages of development. The investigation was based on 45 premolars (25 maxillary, 20 mandibular; 25 first and 20 second), extracted from adolescents and young adults. All teeth were free of disease and presented with roots developed from 30–100% of their final length. They were prefixed in Karnovsky's fixative, decalcified in EDTA and subdivided into about 14 slices each, cut from mesial and distal root surfaces, vertical to and along the root axis. The slices were postfixed in OsO4, embedded in Epon and cut for light‐microscopic study. AEFC thickness (4086 measurements) and the density of the collagenous fiber fringe (454 counts) inserting in AEFC were measured at 1, 3, 5 and 7 mm apical to the cementoenamel junction. The data obtained showed: AEFC thickness increased with age and varied between 0 and 57.5 μm. Between 9 and 17 years, cervical AEFC thickness increased in maxillary first premolars from an average of 5 to 30 μm, and in mandibular second premolars from 6 to 20 μm, i.e., AEFC grew at approximately the same rate as later in life. Depending on the differences in tooth development, AEFC on maxillary first premolars became thicker than that on mandibular second premolars. Due to the corono‐apically decreasing gradient of AEFC development, its increase in mid‐root regions lagged behind that in cervical regions of all teeth in people younger than about 14 yr. During the phase of AEFC development and growth, the density of collagen fibers inserting in AEFC remained constant, irrespective of site, root aspect, AEFC thickness, and patient age.
Automated enzyme immunoassay to measure prostaglandin E2 in gingival crevicular fluid
Authors: Nelson Sandra L. , Hynd Barbara A. , Pickrum Harvey M.
Published: July 2006

An automated enzyme immunoassay (EIA) to measure prostaglandin E2 (PGE2) in gingival crevicular fluid (GCF) of humans and dogs was developed as an indicator of periodontal disease. GCF is noninvasively collected on Periopaper strips and the PGE2 is extracted by a simple method. Samples containing 10‐500 pg/ml PGE2 can be measured. A commercially available kit is used to perform the competitive EIA in microtiter plates. In the EIA, rabbit anti PGE2 antisera binds to either the PGE2 in the sample or to the acetylcholinesterase‐linked PGE2. The assay is automated using the Biomek 1000 workstation, resulting in day‐to‐day variability of less than 5% CV. Dog models of chronic and ligature‐induced periodontitis were used to demonstrate that increased GCF PGE2, as measured by our assay, correlates with increased pocket depth and gingival bleeding scores.
Neutrophil modulation by Actinobacillus actinomycetemcomitans II. Phagocytosis and development of respiratory burst
Authors: Ashkenazi Malka , White Robert R. , Dennison David K.
Published: July 2006

Compromised neutrophil function has been found in a number of patients with localized juvenile periodontitis (LJP), although the pathogenic mechanism is unknown. Since infection with Actinobacillus actinomycetemcomitans is frequently found in patients with LJP, we have evaluated in vitro the effect of a bacterial extract of A. actinomycetemcomitans on the development of the respiratory burst by neutrophils. Pre‐incubation of neutrophils with bacterial extract increased H2O2 induced by FMLP and zymosan in a dose‐dependent fashion. Substitution of FMLP for bacterial extract produced similar results. Moreover, FMLP and bacterial extract had an additive effect on superoxide production following phagocytosis of zymosan. In contrast, bacterial extract significantly decreased PMA‐stimulated H2O2, but pre‐incubation with FMLP instead of bacterial extract failed to decrease PMA‐stimulated H2O2. Bacterial extract did not change the percentage of cells activated by FMLP, opsonized zymosan, or PMA. Heat‐treated bacterial extract induced effects similar to non‐treated extract Bacterial extract treated with proteinase K or phenol extraction increased FMLP or zymosan stimulated H2O2 equivalent to non‐treated bacterial extract. In contrast, proteinase K or phenol extraction abolished the inhibitory effect of bacterial extract on PMA‐stimulated H2O2 production. The bacterial extract component(s) that inhibits PMA‐stimulated H2O2 is therefore a protein(s), resistant to 56° C, and is not endotoxin. The partially activated state of PMNs exposed to A. actinomycetemcomitans extract, combined with their reduced ability to respond to a protein kinase C‐dependent stimulus, may partially explain the abnormalities noted in LJP patients.
Platelet‐derived growth factor reduces the inhibitory effects of lipopolysaccharide on gingival fibroblast proliferation
Authors: Bartold P. Mark , Narayanan A. Sampath , Page Roy C.
Published: July 2006

Lipopolysaccharide from a variety of bacterial sources is known to inhibit gingival fibroblast proliferation and synthetic activity and has been implicated in the pathogenesis of periodontal inflammation. However, it may be involved not only in pathogenesis but also be responsible for delayed wound healing following periodontal therapy. The aim of this investigation was to determine whether the inhibitory effect of LPS on gingival fibroblast proliferation could be reversed by growth factors. Human gingival fibroblasts were cultured in the presence of varying concentrations of platelet‐derived growth factor (PDGF) or Salmonella enteritidis LPS to determine the optimal concentrations for stimulation and inhibition of proliferation respectively. The effect of PDGF on LPS inhibition of fibroblast proliferation was studied by combining PDGF and LPS together at the outset of the experimental period or adding PDGF to cells which had been previously primed with LPS. Cell proliferation was monitored by incorporation of 3H‐thymidine into precipitable DNA. The results indicated that maximal inhibition of fibroblast proliferation was obtained with 50 μg/ml LPS and maximal stimulation of proliferation with 5 ng/ml PDGF. PDGF was found to restore the proliferative activity of the cells exposed to LPS to approximately 60% of their control counterparts. A similar value was obtained for cultures exposed to PDGF after an extended priming period of LPS exposure. Subtle differences were noted in the time taken for cells to complete their cell cycle in the various culture conditions and this may reflect variations in subpopulations of cells in their response to various mitogenic stimuli. Overall the results indicate that PDGF has the capacity to significantly negate and reverse the inhibitory effects of LPS on human gingival fibroblast proliferation.
Inhibition of human endothelial cell proliferation in vitro in response to n‐butyrate and propionate
Authors: Tse C. S. , Williams D. M.
Published: July 2006

The study aimed to investigate the effects of n‐butyrate and propionate on the proliferation and viability of human endothelial cells in culture. Proliferation was assessed by a 24‐hour bromodeoxyuridine pulse labelling and immunoperoxidase method and viability was assessed by a colorimetric viability (MTT) assay. Endothelial cells were isolated from human umbilical vein by collagenase digestion. Experiments were performed on 96‐well plates and cultures were exposed to different concentrations of n‐butyrate and propionate for 2 days, n‐butyrate and propionate caused significant reductions in the proliferation of endothelial cells at concentrations of 1.25 mM and 10 mM respectively (p<0.05); the reduction in proliferation was dose‐dependent for both agents, n‐butyrate was a more potent inhibitor of proliferation than propionate. However, there were no significant effects on the viability of the cells with both agents up to the highest concentrations tested (25 mM). The data indicate that n‐butyrate and propionate inhibit endothelial cell proliferation which may contribute to the pathogenic effects of dental plaque in periodontal disease.
Phospholipase A2 in rat gingival tissue
Authors: Shinohara H. , Ishida H. , Fernandezf E. J. , Amabe Y. , Nagata T. , Wakano Y.
Published: July 2006

Phospholipase A2 (PLA2) is a proinflammatory enzyme in the synovial fluids of all ‐ and sera of some ‐ patients with rheumatoid arthritis. Due to the similarities in pathogenesis between rheumatoid arthritis and periodontitis, we sought to study the enzymatic properties of PLA2 in periodontal tissue. In this study, we demonstrated PLA2 activity in rat gingival tissue, about 80% of which was present in the cytosolic fraction. We characterized the cytosolic PLA2 enzyme with respect to substrate specificity, sensitivity to detergent, Ca2+ ion dependency and optimum pH. We found that phosphatidylethanolamine, rather than phosphatidylcholine, was the preferred substrate, the Ca2+ ion was essential for the expression of PLA2 activity, the enzyme was active over a broad pH range, with the optimum at pH 9.0, and sodium‐deoxycholate inhibited the enzyme activity strongly in a concentration‐dependent manner. These results are consistent with those which have been obtained with synovial fluid PLA2 and suggest that gingival PLA2 may be involved in the pathogenic processes of gingivitis and periodontitis.
Micropuncture measurements of interstitial fluid pressure in normal and inflamed gingiva in rats
Authors: Fjærtoft M. , Johannessen A. C. , Heyeraas K. J.
Published: July 2006

Interstitial fluid pressure (IFF) in normal and inflamed gingiva of rats was measured by sharpened glass capillaries (diameter 2–4 μ) connected to a servocontrolled counterpressure system ad modum Wiederhielm. Gingival inflammation was induced by a steel ligature placed unilaterally around the first maxillary molar. After 8 weeks, the ligature was removed and measurements of IFF in normal and experimentally inflamed gingiva were made by puncture through the intact oral epithelium. Average IFF on the control side was 3.5 mm Hg in free, and 7.4 mm Hg in attached gingiva. Compared to the control side. IFF on the experimental inflamed side was elevated significantly (p<0.05) both in free and attached gingiva. In the ligated inflamed side IFF in free gingiva averaged 6.7 mm Hg, whereas in attached gingiva it showed a mean value of 10.4 mm Hg. Histological examinations showed a dense infiltrate of inflammatory cells in the connective tissue, while the contralateral control side showed normal features of epithelial and connective tissue. The present finding of increased IFF in the inflamed gingiva may in theory contribute to augmented crevicular fluid flow during inflammation.
Gingival crevicular fluid gelatinase and its relationship to periodontal disease in human subjects
Authors: Teng Y. T. , Sodek J. , McCulloch C. A. G.
Published: July 2006

Collagenolytic enzymes released by neutrophils are associated with the destruction of periodontium in periodontal diseases. Measurement of these enzymes in gingival crevicular fluid (GCF) could be used to test for periodontal diseases and thereby simplify diagnosis. To test this hypothesis, gelatinase (MMP‐9) was analyzed in GCF samples with a simple assay system. GCF was collected by a mouthrinse method from 10 patients with gingivitis (G); 10 well‐treated and maintained periodontitis patients (TP) without detectable loss of attachment; and 9 patients with recurrent loss of periodontal attachment (>2 mm) and/or abscess formation (RP). Clinical measurements including tooth mobility (MOB) and gingival attachment level (GAL) were made monthly for a maximum of 10 months. Active and latent forms of gelatinase were measured by a functional assay using gelatin substrate‐gel enzymography and the activities were quantified by laser densitometry. Reproducibility analysis demonstrated that the assay (inter‐gel, inter‐assay, inter‐scan) and diurnal variations were small compared to biological variation. The presence of active gelatinase was detected in 97.8% of TP samples, 86.4% of RP samples, but in only 11.4% of G samples. In addition, the mean active gelatinase activity was found to be significantly higher (p<0.001) in the RP (71 006 U) than the TP (43814 U) groups, both of which were higher (p< 0.001) than the G group (2824 U). During periods of attachment loss, samples from the RP group exhibited a 2‐fold increase of mean active gelatinase activity (129414 U). Correlation and regression analyses demonstrated that active gelatinase activity was most strongly associated with loss of GAL (r = 0.52, p<0.0001) and to a lesser degree with mean MOB (r = 0.35, p<0.03). However, neither total (latent plus active) nor latent gelatinase levels were associated closely with any clinical parameters of periodontitis. Metronidazole treatment (250 mg, tid, for 7 days) of RP patients significantly reduced the level of active and latent gelatinase 4‐ to 6‐fold (p< 0.002). These data indicate that measurement of active gelatinase in mouthrinse samples may provide a simple and robust diagnostic test for periodontal diseases and for assessment of treatment response.
Microvascular volumes in healthy and inflamed gingiva in humans
Authors: Brecx M. C. , Nuki K. , Lang N. P. , Gestach A. , Sollberger K.
Published: July 2006

It has been suggested that the vascular alterations found in inflamed gingiva may be of significance in the enhanced extension of the pathological process into the periodontium. The purpose of this investigation was to measured the changes in blood vascular volume occurring in gingiva with the onset of gingivitis and its resolution. Twenty‐six individuals participated in this study. Gingival biopsies were taken following a 21‐day experimental gingivitis, following resolution of a 21‐d experimental gingivitis and during a 6‐month experimental gingivitis and a 6‐month period of optimal oral hygiene. A total of 126 biopsies was obtained, from which 378 sections were cut at 2 μm for stereological analysis. At low magnification, reference volumes were estimated using point counting procedures and expressed as mm3 of gingiva per mm length of vestibular gingiva, in a vestibulo‐lingual plane. At higher magnification the ratio between the volume of vessels and connective tissue was calculated. The final results were expressed as mm3 of vessels per mm length of vestibular gingiva, in a vestibulo‐lingual plane. The mean vessel volume expressed per unit length of vestibular gingiva ranged from 0.010 to 0.024 mm3/mm. No statistically significant differences in vascular volumes were found between inflamed and non‐inflamed gingiva. It was concluded that the changes in vascular architecture during early gingivitis described in the literature had either taken place in the subjects prior to the time of experimentation or that any vascular changes (cytologic or functional) which had taken place may be compensatory for the changes in architecture described in the literature.
Wolinella recfa in adult gingivitis and periodontitis
Authors: Lai C.‐H. , Oshima K. , Slots J. , Listgarten M. A.
Published: July 2006

Wolinella recta has been associated with adult periodontitis, but its role in the disease remains uncertain. This report clarifies the distribution of W. recta in periodontally healthy and diseased subjects, and treated patients with recurrent disease. A specific polyclonal rabbit antiserum against W. recta strain 372 was used for indirect immunofluorescence localization of W. recta in dental plaque from untreated and treated patients. Supragingival plaque was collected from 15 periodontally healthy individuals (H), 10 adults with mild gingivitis (G1), 8 with severe gingivitis (G2) and 15 with periodontitis (AP). Subgingival samples from 23 diseased sites (G2 and AP) were examined as well. There was a significant difference (p = 0.000) between the proportions of W. recta in subgingival (4.4%) vs. supragingival (0.3%) plaque samples from AP. A significant difference (p = 0.000) in W. recta proportions was also detected between subgingival plaque samples of AP (4.4%) vs. G2 (1.2%). No significant difference in the mean % of W. recta was found between supragingival plaque of AP (0.3%) and G2 (0%), and samples of G1 (0.01%) and H (0.1%). In a separate study, 85 adults previously treated for moderate to severe adult periodontitis were monitored over a 12‐month period for evidence of disease recurrence. Recurrent disease was detected at 32 sites in 18 subjects. Of these, 20 sites in 13 subjects were positive for W. recta. With subjects as the experimental unit, a significant increase in the proportions of W. recta was found at sites with recurrent disease (3.12%) as compared to stable, paired control sites (0.24%), but only when sites with breakdown and positive for W. recta were compared with their controls. These results indicate that W. recta is associated with some, but not all sites with advanced adult periodonlilis. The association of W. recta with gingivitis was not statistically significant.
Predominant obligate anaerobes in human periodontal pockets
Authors: Uematsu H. , Hoshino E.
Published: July 2006

This study was carried out to investigate the predominant anaerobic bacteria of periodontal pockets in patients with advanced periodontitis, who had no previous treatment other than supragingival scaling, no history of recent or chronic systemic illness, nor any intake of antibiotics within 6 weeks prior to bacteriological sampling. Care was taken not to ignore tiny‐colony‐forming anaerobes, by means of a stereoscope and an anaerobic glove box system. Out of 422 (100%) isolates, 380 (90%) were obligate anaerobes, suggesting that the environment in periodontal pockets was anaerobic and favors the growth of obligate anaerobes. Among the 380 obligate anaerobes isolated, strains belonging to Eubacterium (54%) were predominant, and many of them occurred in tiny colonies. The other obligate anaerobes isolated were assigned to Wolinella (9%), unidentified motile rods which resemble Wolinella (7%), Peptostreptococcus (6%), Fusobacterium (5%), Bacteroides (2%; including those reclassified to Prevotella and Porphyromonas) and Selenomonas (0.5%). Among the isolates, 67% were Gram‐positive bacteria, including 59% of rods (mostly asaccharoly‐tic Eubacterium), suggesting that these bacteria, particularly strains of the Eubacterium species, may play an important role in etiology of adult periodontitis.
Bundle formation of principal fibers in rat molars
Authors: Yamamoto Tsuneyuki , Wakita Minoru
Published: July 2006

The bundling of principal fibers was investigated in tangential sections through the tooth‐related portion in developing rat molars by light and electron microscopy. When root dentin calcification began, cross sections of principal fibers emerged as fibril aggregates in the narrow intercellular spaces in a densely packed population of periodontal ligament cells. Subsequently, these cells changed shape and location to widen the intercellular spaces. The fibril aggregates became thicker in these spaces. With root development, the collagen fibrils formed loosely aggregated bundles and the periodontal ligament cells extended cell processes between the bundles. The cell processes usually contained microfilaments suggestive of actin filaments, and as the cell processes extended and came in close apposition, they formed delimited compartments. These compartments appeared to be a sheath‐like structure, and the loose fibril bundles developed into tight fibril bundles in the compartments. Finally the principal fibers consisted of many tight fibril bundles, which were partially or entirely surrounded by cell processes and cell bodies. The findings suggest that the sheath‐like, cellular compartments cause the tight bundling of the principal fibers.
Effects of non‐steroidal anti‐inflammatory drugs on demineralized bone‐induced bone formation
Authors: Yazdi Mohamadreza , Cheung David T. , Cobble Stephanie , Nimni Marcel E. , Schonfeld Steven E.
Published: July 2006

The inhibitory effect of some non‐steroidal anti‐inflammatory drugs (NSAIDs) on bone resorption is well documented. To explore the effect of NSAIDs on bone formation, we investigated the time course and dose/response characteristics of treatment with various non‐steroidal anti‐inflammatory drugs (NSAIDs) on ectopic bone formation induced by demineralized bone matrix (DBM) in the rat model. Using biochemical assays, both inhibitory and stimulatory effects on bone formation were found in rats treated with NSAIDs prior to DBM implantation depending on the type and amount of drug administered. There appears to be an enhancement of bone formation for acetaminophen (50 mg/kg), acetylsalicylic acid (50 mg/kg), and ibuprofen (50 mg/kg). Indomethacin (4 mg/kg) and piroxicam (4 mg/kg) had inhibitory effects. Flurbiprofen, on the other hand, did not appear to affect bone formation significantly. In contrast, there was no effect of NSAIDs on bone formation in rats treated with the drugs after implantation of the DBM. It appears that the time course of the drug administration is critical, suggesting that early events in bone formation may be modulated by arachidonic acid metabolites.
Morphological characteristics of the depository surface of alveolar bone of diabetic mice
Authors: Johnson Roger B.
Published: July 2006

Sharpey's fibers support teeth by attachment of periodontal ligament fibers to alveolar bone. The effects of diabetes mellitus on this support mechanism have not been described and were the subject of this study. Male Swiss mice were rendered diabetic by streptozotocin. Mandibles were removed 9 weeks after injections, the mineralizing front of the depository surface of the interdental septum was exposed by fracture through the periodontal ligament, rendered anorganic, and examined by scanning electron microscopy. No significant reduction in alveolar crest height was evident in diabetic as compared to control animals; however, significant changes in the a) mineralization patterns of bone depository surfaces and Sharpey's fibers, and b) number of Sharpey's fibers inserting into alveolar bone were evident in diabetics. Unmineralized fissures, characteristic of Sharpey's fibers of control, were nearly obliterated by mineralized tissue in diabetic animals. The mineralizing front of the middle and apical thirds of the diabetic alveolar wall was covered by numerous large calcified globules resembling enlarged calcospherites, which were not evident over the cervical third or control tissues. The mean Sharpey fiber density was greater in controls than in diabetics (p<0.001); however, there was no significant difference between their mean diameters. These observations suggest that, in early diabetes, Sharpey's fibers and depository surfaces of the middle and apical thirds of the interdental septum have morphologic evidence of aging, which precedes significant reduction in alveolar crest height. These changes may weaken the attachment of periodontal ligament fibers to bone and reduce resistance of the periodontium to intrusive forces.
Monoclonal antibodies to lipopolysaccharide of four oral bacteria associated with periodontal disease
Authors: Shelburne Charles E. , Sandberg Gregory P. , Binsfeld Christine A. , Wolff Larry F. , Curry Russell A.
Published: July 2006

Periodontal disease is a common inflammatory disease which erodes the supporting structures of the teeth, and is initiated by a subgingival infection with selected Gram‐negative bacteria. Monoclonal antibodies (mAb) to lipopolysaccharide (LPS) of four periodontal pathogens, A. actinomycetemcomitans, P. intermedia, F. nucleatum and P. gingivalis were examined for specificity and their ability to bind these pathogens in a particle concentration fluorescence immunoassay (PCFIA). The mAb selected were specific for their homologous bacteira and when tested against a large battery of other bacteria, including 16 genera and 46 species, were found not to cross‐react with heterologous species. When each of the mAb was challenged with 40 or more homologous freshly isolated bacteria, more than 90% were positive. Non‐cellular antigens in the form of soluble LPS and extracellular vesicles were examined for their ability to bind to assay components and alter the apparent results of the assay. LPS was found to have potential as an interfering agent if bound to assay components prior to sample treatment, but this non‐specific binding was significantly reduced when a surfactant was added to the buffers. Extracellular vesicles had no significant effect on the estimation of P. gingivalis by the assay.
Purification of arginine‐sensitive hemagglutinin from Fusobacterium nucleatum and its role in coaggregation
Authors: Takemoto T. , Ozaki M. , Shirakawa M. , Hino T. , Okamoto H.
Published: July 2006

Hemagglutinin of Fusobacterium nucleatum was extracted from Triton X‐100‐pronase P‐treated cell envelopes, and was purified by affinity chromatography on L‐arginine agarose. The hemagglutinin was inactivated by heating at 70°C for 1 min. The activity was inhibited by L‐arginine but was not affected by any sugars or by EDTA. The hemagglutinin aggreggated 14 out of 17 strains of oral streptococci tested, and the bacterial aggregating activity was also inhibited by L‐arginine. The results indicate the dominant role of this hemagglutinin in the adherence of this bacterium both to host cells and to other bacteria.
Localization of interleukin‐1 (IL‐1) mRNA‐expressing macrophages in human inflamed gingiva and lL‐1 activity in gingival crevicular fluid
Authors: Matsuki Yutaka , Yamamota Tadashi , Hara Kohji
Published: July 2006

The exact cell type and site(s) involved in interleukin‐1 (lL‐1) production during gingival inflammation was determined by combining immunohistochemistry and in situ hybridization. IL‐1 messenger RNA (mRNA)‐expressing cells in human inflamed gingiva were identified as macrophages. The rate of IL‐α mRNA expression in these macrophages was the same as IL‐1β mRNA expression. The rate of IL‐1 mRNA expression was higher in connective tissue furthest from the pocket epithelium, although more macrophages were present at the connective tissue subjacent to the pocket epithelium. The IL‐1 activity in gingival crevicular fluid (GCF) obtained from inflamed gingiva was higher than that from healthy gingiva and decreased after periodontal therapy. The IL‐1 activity in GCF was almost completely abolished by the addition of anti‐IL‐1α antibody but not by anti‐IL‐1β antibody, indicating that IL‐1α is the predominant form in GCF. However, the IL‐1 activity in GCF was unrelated to the number of IL‐1 mRNA‐exprerssing macrophages in the same gingival site where the GCF was obtained at the same time. The results suggest that macrophages in the connective tissue subjacent to the oral epithelium contribute to the production of IL‐1 but those in connective tissue subjacent to the pocket epithelium play a different role in the generation of gingival inflammation.
Protein, albumin and cystatin concentrations in saliva of healthy subjects and of patients with gingivitis periodonitis
Authors: Henskens Y. M. C. , van der Velden U. , Veerman E. C. I. , Amerongen A. V. Nieuw
Published: July 2006

Salivary protein, albumin and cystatin concentrations were investigated in subjects with a periodontium and in patients with gingivitis or periodontitis were signigicantly increased compared with healthy subjects. Salivary protein ans albumin appeared to be positively correlated in all the groups, which suggests that the increase in salivary protein concentration in subjects with gingivitis or perodontitis is caused by leakage of plasma proteins. Cystatin concentrations in saliva of subjects with periodontitis wer significantly increased when compared with the healthy group and the gingivitis group (p<0.01). In the gingivitis and perodontitis group, salivary custatin was only weakly correlated with albumin concentations, which suggests that the increased salivary cystatin activity found in subjects with gingivitis and periodontitis is derived from sources otehr than plasma.
Patterns of cytokeratin expression in the epithelia of inflamed human gingiva and periodontal pockets
Authors: Mackenzie I. C. , Gao Z.
Published: July 2006

Fourteen specimens of periodontal pockets and the associated marginal gingiva were collected and either frozen for examination using antibodies against various defined cytokeratin specificities or processed for 2‐dimensional gel electrophoresis. The epithelium forming the pocket lining typically extended into the connective tissue of the pocket wall in the form of a network of finger‐like strips. Immunocytological staining indicated that keratins (K) 5, 6, 14 and 19 were expressed by almost all cells of the pocket lining and K13 and K16 by the suprabasal cells. The coronal region of the pocket lining showed some cells staining for K4, Staining for K8 and K18 was seen in the apieal region of the pocket lining and in the finger‐like extensions of epithelium into the connective tissue. Compared with normal gingiva, the sulcular and the oral gingival epithelia showed a marked increase in staining for K19. Surprisingly, the pattern of keratin expression of the epithelium of the pocket lining was found to be essentially similar to that of normal junctional epithelium and the anatomical position of the boundaries between each epithelial phenotype were not significantly altered. These patterns of keratin expression were confirmed by the 2D electrophoretic analyses of microdissected regions of epithelium. The potential significance of inflammation to the epithelial changes associated with pocket formation is discussed.
Dentine hypersensitivity: the measurement in vitro of streaming potentials with fluid flow across dentine and hydroxyapatite
Authors: Griffiths H. , Morgan G. , Williams K. , Addy M.
Published: July 2006

Stimulus transmission across dentine, in conditions such as dentine hypersensitivity, is considered to occur via a hydrodynamic mechanism. This fluid flow in dentine may then induce a mechanoreceptor response in pulpal nerves. However, when fluid flows through a porous structure electrical potentials are also generated. The aim of this tudy was to develop a reproducible model system to measure streaming potential across dentine and hydroxyapatite and determine the influence of pressure. Using an acrylic cell, with silver electrodes, streaming potentials were recorded across dimensionally standardized dentine and hydroxyapatite specimens, over a pressure range of 1–6 atmospheres. Streaming potentials were found to be directly proportional to pressure and dependent on the electrical conductivity of the saline used in the cell. The results confirm the limited existing data on streaming potentials across dentine and indicate that at these low pressures excitation of pulpal nerves would not occur. However, if as may be the case, stimuli applied to dentine create very high pressures, the resultant potentials generated could indeed evoke a neural response. The model system is worthy of further use to study this phenomenon and the factors which may influence it.
Sub‐gingival microflora in Macaca mulatta species of rhesus monkey
Authors: Eke P. I. , Braswell L. , Arnold R. , Fritz M.
Published: July 2006

The Macaca mulatta species of rhesus monkey is one of several non‐human primate (nhp) models for periodontal disease. This report presents the bacteriology of the gingival sulci in M. mulatta monkeys. Three sub‐gingival sites (maxillary right central incisor, the disto‐buccal of the mandibular left second molar and mesio‐buccal of the mandibular right second molar) of 9 monkeys were evaluated clinically before scaling and 7 days after scaling. Plaque samples were obtained from sub‐gingival sites before clinical examination and studied bacteriologically by dark field microscopy, selective and non‐selective culture, and by primary phenotypic characterizations of culture isolates. Several gingival sites presented with mild gingival inflammation. Anaerobic and facultatively anaerobic bacteria were the predominant flora colonizing the gingival sulci. The major microbial groups were Haemophilus species (100% of sites; percentage of total anaerobic count (TAC); 21‐51), Peptostreptococcus micros (89%, 7.5–29.5), Actinomyces sp. (85%, 7–27), Fusobacterium nucleatum (90%, 5–8), Actinobacillus actinomycetemcomitans (73%, 1.3–12), black‐pigmented anaerobic rods (BPAR) (80%, 0.6–6.5) and oral streptococci (80%, 0.2–1.0). Microbial groups detected less often were Wolinella sp. (66%, 0–2.6), Capnocytophaga sp. (30%), Eikenella corrodens (4.7%, 0), Campylobacter sp. (28%, 0–0.1) and spirochetes (4.7%, 0–0.07). Seven days after gingival sites were scaled, the plaque score and indices for gingival inflammation declined significantly. The gingival flora after scaling were characterized by lower proportions of the Actinomyees sp., P. micros and BPAR; and increased proportions of the oral streptococci, relative to pre‐scaling levels. The major microbial groups at scaled gingival sites were the Haemophilus sp., oral streptococci, F. nucleatum and A. actinomycetemcomitans. The mutual proportions of microbial groups varied non‐significantly within gingival sites and between monkeys. In conclusion, the M. mulatta gingival sulci are colonized by microbial species that resemble putative pathogens of periodontal disease, and the composition and character of the gingival flora are similar to the gingival flora of other Old World monkey models.
Interleukin 1, interleukin 6 and transforming growth factor‐β production by human gingival mononuclear cells following stimulation with Porphyromonas gingivalis and Fusobacterium nucleatum
Authors: Gemmell E. , Seymour G. J.
Published: July 2006

Gingival mononuclear cell production of interleukin 1 (IL‐1), interleukin 6 (IL‐6) and transforming growth factor‐β(TGF‐β) after stimulation with the putative periodontopathic bacteria, Porphyromonas gingivalis and Fusobacterium nucleatum was investigated. Using an ELISA method, gingival mononuclear cells extracted from 18 adult periodontitis subjects were found to be producing IL‐1. However, IL‐1 activity could only be detected in 5 out of these 18 cases when tested using a thymocyte proliferation bio‐assay, suggesting the presence of IL‐1 inhibitors. Depletion of monocytes from peripheral blood cultures resulted in a significant decrease in IL‐1 activity following P. gingivalis stimulation while there was no effect in the level of IL‐1 activity following stimulation with F. nucleatum. This suggests that P. gingivalis and F. nucleatum stimulate different cell types to produce IL‐1. Like IL‐1. IL‐6 production by gingival mononuclear cells was significantly greater than that produced by the control peripheral blood mononuclear cells. Following P. gingivalis and F. nucleatum stimulation, higher levels of IL‐6 could be detected; however, both organisms stimulated similar levels. Intracytoplasmic immunofluorescence staining demonstrated a lower percent TGF‐β+ cells in bacterial stimulated peripheral blood mononuclear cell cultures compared with cells in medium alone. In the gingival mononuclear cell cultures, the percentage TGF‐β+ cells peaked at day 1 in F. nucleatum‐stimulated, whereas in P. gingivalis‐stimulated cultures the peak TGF‐β+ cells occurred at day 3, again suggesting stimulation of different cell subsets. These results ilustrate that different periodontopathic bacteria may stimulate different cell types to produce cytokines which may have synergistic or antagonistic effects.