bluuebunny/crossref_metadata_2025 huggingface dataset:
Fibronectin‐degrading enzymes in saliva and their relation to oral cleanliness
Authors: Gibbons R. J. , Etherden I.
Published: July 2006

A reduction in epithelial cell Fibronectin associated with elevated salivary protease activity is thought to account for the enhanced adhesion and colonization of gram‐negative bacilli in seriously ill patients. Enzymes capable of degrading Fibronectin were therefore sought in whole human saliva. When plasma fibronectin was labeled with 3H‐formaldehyde and incubated with whole saliva, trichloracetic acid‐soluble radiolabeled peptides were produced. Competition experiments indicated that the radiolabeling did not alter the susceptiblity of the Fibronectin to the salivary proteases. Whole saliva also possessed hide powder‐degrading activity, but parotid or submaxillary secretions did not contain detectable levels of either activity. The levels of fibronectin‐ and hide powder‐degrading activities in whole saliva correlated with the state of oral cleanliness of the individuals studied, as reflected by the cellular elements present in their saliva. Also, strains of certain bacteria prominent in dental plaque produced enzymes which degraded fibronectin. Therefore. alterations in oral cleanliness may contribute to the rapid fluctuations in salivary proteases and epithelial cell fibronectin which underly the unusual susceptiblity of acutely‐ill patients to colonization by gram‐negative bacilli.
Proliferative behavior of periodontal ligament cell populations
Authors: Davidson D. , Mcculloch C. A. G.
Published: July 2006

Labeling index and total grain count data of periodontal ligament cells after either continuous infusion or single injection with tritiated thymidine were compared with values predicted by two different models of cell proliferation. One model assumes that all proliferating cells are homogeneous and proceed through the cell cycle at a rate described by an exponential distribution. In the second model, it is assumed that cell division is asymmetric. Mitosis produces one proliferating and one differentiated cell, each with a characteristic and distinct lifetime and proliferative capacity. The predictions of the first model deviated widely from the continuous labeling and total grain count data. In comparison, the second model predicted a linear relationship between labeling index and time which is consistent with data from mouse, hamster and rat periodontal ligament cells. The model also accurately predicted the total grain count after a single injection of tritiated thymidine. The data suggest that the periodontal ligament contains renewing and differentiated populations of cells which can be described in terms of proliferative potential and lifetime.
Calcium and phosphate concentrations and precipitate formation in whole saliva from smokers and non‐smokers
Authors: Macgregor I. D. M. , Edgar W. M.
Published: July 2006

Previous reports in the literature indicate that smoking is associated with increased plaque accumulation and/or mineralization. This might be due to an effect of tobacco smoke on properties of saliva. The present study examined the stability of components in fresh and incubated saliva in smokers and non‐smokers. Saliva from smokers, collected immediately after smoking a cigarette, did not differ significantly from that of non‐smokers in the turbidity developing after incubation (24 h, 37°C), which may reflect aggregation of salivary components by mechanisms analogous to those involved in plaque formation. This finding is in agreement with our previous result (Macgregor. Edgar & Greenwood 1985) which showed that the rate of plaque formation did not differ between smokers and non‐smokers. Although an intimation of higher initial calcium concentrations, greater precipitation of calcium and development of more turbidity during incubation was observed in the salivas of smokers than those of non‐smokers, the major reason for the greater plaque accumulation and calculus in smokers is probably inadequate oral hygiene.
Chemical composition and immunobiological properties of lipopolysaccharide and lipid‐associated proteoglycan from Actinobacillus actinomycetemcomitans
Authors: Nishihara Tatsuji , Fujiwara Taku , Koga Toshihiko , Hamada Shigeyuki
Published: July 2006

Lipopolysaccharide (LPS) and lipid‐associated proteoglycan (LPG) were isolated from Actinobacillus actinomycetemcomitans ATCC 29523 by the phenol‐water and butanol‐water procedures. The LPS was composed of 41 % neutral sugar. 8% hexosamine, 31 % fatty acid, 2% protein, and 2% phosphorus, while the butanol‐water‐extracted LPG was composed of 13% neutral sugar, 2% hexosamine, 14% fatty acid. 56% protein, and 1% phosphorus. The major fatty acids of LPS and LPG were β‐hydroxymyristic, myristic, and palmitic acids. These preparations induced mitogenic and polyclonal responses of LPS‐responsive C3H/HeN mouse spleen cells and enhanced in vitro immune responses of the spleen cells to sheep erythrocytes. Spleen cells of C3H/HeJ mouse that were nonresponsive to enterobacteriaceal LPS responded to the butanol‐water‐extracted LPG, but not to the phenol‐water‐extracted LPS. The Limulus amebocyte lysate clotting activity of A. actinomycetemcomitans LPS was comparable to that of Escherichia coli K235 LPS. These results indicate that A. actinomycetemcomitans LPS is biologically and immunochemically of Enterobacteriaceae type.
Cross‐sectional study of the effects of immunosuppressive agents on humoral immune responses to 6 oral microorganisms in humans
Authors: Tollefsen T. , Schenck K. , Tolo K.
Published: July 2006

Specific serum antibodies o the IgM. IgG and IgA classes against extracts from Bacteroides gingivalis, Bacteroides ureolyticus, Capnoc ytophaga ochracea, Eubacterium saburreum, Fusobacterium nucleatum and Selenomonas sputigena were measured by an enzyme‐linked immunosorbent assay. The study groups were: (1) 15 renal transplant recipients, (2) 5 patients treated with hemodialysis, (3) 29 systemically healthy subjects with healthy periodontium and (4) 23 systemically healthy persons with chronic periodontitis. The renal patient groups showed significant evidence of alveolar bone loss, had abundant dental plaque, but significantly (p<0.05) fewer bleeding gingival units and lower mean pocket depth than the periodontitis group. Two‐way analyses of variance, comparing the renal patient groups with the healthy control group, showed statistically significant group effects for the specific IgG responsiveness during hemodialysis (F=4.94, p<0.05) and the IgA responses in the renal transplant group (F=7.78. p<0.05) (reduced values). As compared with the periodontitis group, the renal patient groups displayed significantly (p<0.05) lower serum antibody concentrations against B. gingivalis. C. ochracea and F. nucleatum within at least 2 of the 3 immunoglobulin isotypes assayed. The results support the contention that some forms of periodontitis are mediated by prolonged low‐grade local immune reactions which at times may escape homeostatic control.
Detection of active alveolar bone destruction in human periodontal disease by analysis of radiopharmaceutical uptake after a single injection of 99m‐Tc‐methylene diphosphonate
Authors: Jeffcoat M. K. , Williams R. C. , Holman B. L. , English R. , Goldhaber P.
Published: July 2006

Previous studies have shown that, following a single injection of 99m‐Tc‐MDP, measurement of bone‐seeking radiopharmaceutical uptake can detect “active” alveolar bone loss due to periodontal disease in beagle dogs, as determined by radiographs taken at the time of, and several months after, the nuclear medicine procedure. The efficacy of this diagnostic test. however, had not been assessed in human periodontal disease. The ability of a single bone‐seeking radiopharmaceutical uptake examination to detect “active” alveolar bone loss due to periodontal disease in human patients was assessed by comparing a single uptake measurement to the rate of bone loss determined from serial radiographs taken over a 6‐month period. Uptake was expressed as a ratio of the cpm from the alveolar bone divided by the cpm from the non‐tooth supporting bone of the nuchal crest. High uptake ratios were associated with “active” loss and low uptake ratios were associated with little if any change in alveolar bone height (p < 0.001). The nuclear medicine examination was an accurate detector of periodontal disease activity in nearly 80% of the individual teeth studied. These data indicate that high bone‐seeking radiopharmaceutical uptake ratios may be pathognomonic of active bone loss in human periodontal disease.
A staining method for monitoring subgingival bacteria associated with periodontal disease
Authors: Quee Trevor Ciiin , Bergeron Marr‐Joséf , Amsei Rhonda , Chan E. C. S.
Published: July 2006

Dark‐field microscopy to monitor subgingival bacteria has been advocated as an accepted adjunct in monitoring periodontal disease. By aging two flagella stains (Gray's and Ryu's) for at least 3 wk at room temperature, we were able to stain four morphological groups, spirochetes, motile rods, coccoids and “other types” which have been suggested as indicator organisms of periodontal destruction. The relative proportions of these groups present in plaque samples from 17 clinically diseased sites were compared using dark‐field microscopy and the two staining methods. All three techniques gave similar proportions of spirochetes. However, the staining methods revealed significantly more flagellated cells than motile cells seen with dark‐field microscopy. Advantages of the staining method over dark‐field microscopy include the convenience of examining plaque samples at a later time and the availability of a permanent record.
Effect of chlorhexidine gluconate mouthrinse on plaque bacteria
Authors: Briner W. W. , Grossman E. , Buckner R. Y. , Rebitski G. F. , Sox T. E. , Setser R. E. , Ebert M. L.
Published: July 2006

The antimicrobial effect of a 0.12% chlorhexidine gluconate mouthrinse on plaque bacteria was compared to that of a placebo mouthrinse without chlorhexidine gluconate. Forty subjects in each treatment group rinsed twice daily with 15 ml mouthwash for six months. They were instructed to continue their usual oral hygiene practices. After six months, the subjects stopped using the mouthrinse. Supragingival plaque was collected from each subject and assayed for eight representative microbial populations at baseline, after three and six months of treatment, and after a three‐month post‐treatment period.

During the six months of mouthrinse use, significant reductions in the numbers of total aerobes. total anaerobes, streptococci, and actinomyces were observed in plaque samples taken from subjects using the chlorhexidine mouthrinse. The effect of chlorhexidine on actinomyces accumulation was especially pronounced with reductions ranging from 85–97%. This was considered to be particularly significant since actinomyces is one of the bacteria known to be periodontopathic in both experimental animals and in humans. Although chlorhexidine treatment reduced the number of microbes on teeth, it did not produce a detectable shift in microbial populations.

At the end of the three‐month post‐treatment period, the microbial profile was similar to the pre‐treatment profile for both groups. Therefore, no residual effects of chlorhexidine on plaque bacteria were observed after cessation of rinsing.
Organization of an oriented fiber system in vitro by human gingival fibroblasts attached to dental tissue: Relationship between cells and mineralized and demineralized tissue
Authors: Pitaru S. , Melcher A. H.
Published: July 2006

The purpose of this study was to examine the effect of partial demineralization of cementum on the morphology of the interface between gingival fibroblasts (HGF) and tooth in an in vitro oriented cell‐fiber system. Thirty‐two pairs of transversally‐cut root slices, 150 μm thick, were obtained from porcine premolars. Each pair of root slices was attached to the floor of a 35 mm culture dish, leaving an interdental space (IDS) of 500 μm between their peripheral surface. The root slices in half of the dishes were partially demineralized in a solution of 12% EDTA. Cocultures of root slices and HGF were examined using light and electron microscopy after 20 and 30 d. HGF were found to be oriented approximately perpendicular to the partially‐demineralized tooth surface. The cells exhibited cell processes that were attached to, and embraced, the exposed collagen. Similarly oriented fibrillar material, possibly collagen, was present between the cells and adjacent to exposed organic matrix of the tooth, sometimes appearing to be continuous with the collagen fibrils of the organic matrix. The HGF were oriented parallel to the non‐demineralized cementum. They were attached to it and formed a continuous capsule‐like covering. Fibrillar material, apparently newly synthesized, was oriented parallel to the tooth surface and was separated from it by the continuous cell layer. These observations suggest that the nature of the tooth surface that provides a substrate for the HGF may influence the morphology that they express in vitro.
Comparison between histological and clinical parameters during human experimental gingivitis
Authors: Brecx M. C. , Schlegel K. , Gehr P. , Lang N. P.
Published: July 2006

The purpose of this investigation was to study stereologically the histopathologic alterations occurring during a human experimental gingivitis, and to establish a relationship between clinical parameters and histologic findings. Eight dental students volunteered for the study. After a prophylaxis they performed optimal oral hygiene for 3‐4 weeks to reach mean plaque and gingival indices approaching zero. They then abandoned all oral hygiene procedures for a period of 21 days. At d 0, 4, 7, 14 and 21, Plaque Index (PII), Gingival Index (GI) and Gingival Exudate Flow Rate (GEFR) were assessed, and a buccal biopsy of their gingiva was taken. Point counting procedures were performed at 2 different levels of magnification to estimate the volume densities of epithelium, infiltrated and non‐infiltrated connective tissue, and collagen. The percentages of polymorphonuclear neutrophilic granulocytes, lymphocytes, plasma cells, macrophages and fibroblasts were estimated by counting the number of profiles of these cells in the connective tissue area close to the apical end of the junctional epithelium. The histological picture during the entire experiment was one of an early lesion (Page & Schroeder 1976). The clinically healthy gingiva did not correspond to a histologically healthy gingiva containing only a few inflammatory cells, probably because the 3‐4 wk of perfect oral hygiene were not sufficient to generate histological health. Furthermore, no chronic inflammation of the gingiva, as characterized by a predominance of plasma cells, was observed after 3 wk without oral hygiene. Thus, more than 3 wk of no oral hygiene are necessary to obtain an established gingival lesion. With increasing gingivitis scores between GI = 0 and GI = 2 there was a significant increase in the percentages of lymphocytes and a significant decrease in the percentages of fibroblasts. With increasing GEFR similar trends in percentages were observed for lymphocytes and fibroblasts. It was concluded that GI scores and GEFR reflect histologic changes in tissue and, hence, are valid indicators of gingivitis development.
Human gingival proteases. I: Extraction and preliminary characterization of trypsin‐like and elastase‐like enzymes
Authors: Uitto Veli‐Jukka
Published: July 2006

In order to characterize neutral proteases in gingiva, tissue specimens from periodontitis patients were subjected to different extraction procedures. In addition to collagenase and gelatinase, serine proteases having trypsin‐like and elastase‐like properties were detected by utilizing synthetic aminoacid substrates. High salt concentration was required for the optimal extraction of these enzymes. They also needed a certain ionic strength for their activity. The pH optimum for the trypsin‐like activity was 7.5 and for the elastase‐like activity 8.0. A synthetic plasmin substrate was also degraded by the extracts but no activity against native fibrin was found. These neutral proteases may play a significant part in the extracellular protein degradation in periodontium during inflammation.
The efficacy of a new dentifrice in treating dentin sensitivity: Effects of sodium citrate and sodium fluoride as active ingredients
Authors: Clark D. Christopher , Al‐Joburi W. , Chan E. C. S.
Published: July 2006

The purpose of this clinical trial was to study the effectiveness of three new test and one control dentifrice. A total of 120 subjects participated in the study. Measurement of dentin sensitivity consisted of three clinical tests (saturated sucrose solution, cold air blast, and tactile) and a subjective patient assessment. The patients were first stratified by previous treatment attempts and presence of a history of periodontal surgery. Patients were randomly assigned into four groups: 1) dentifrice containing precipitated silica abrasive; 2) dentifrice containing 0.2% sodium citrate buffer in a pluronic gel with precipitated silica abrasive; 3) dentifrice containing 0.2% NaF with precipitated silica abrasive; 4) a formula containing both the 0.2% NaF and the 2% citrate buffer. Neither patients nor examiners were aware of the group assignments. The patients were examined at baseline and after 2 and 4 wk, and 2 months. The efficacy of the new dentifrice system was not established in this investigation nor were the separate efficacies of the major components of the dentifrice. Although subjective and clinical assessments demonstrated a placebo effect, it was present to the same extent for all products, including the placebo.
Hydroxyproline determination in serum and gingival crevicular fluid
Authors: Svanberg G. K.
Published: July 2006

A high‐performance liquid chromatographic assay for total hydroxyproline in serum and gingival crevicular fluid has been developed. The Clq component of the first complement factor was precipitated out of the samples with a 0.02 M sodium acetate solution. Aliquots of the supernatants were dried, vapor hydrolyzed with 6 M hydrochloric acid at 105°C for 24 hours and derivatized with phenylisothiocyanate. The derivatives were chromatographed using a multilinear solvent gradient with detection at 254 nm. The regression of peak areas on the concentrations of hydroxyproline was linear with a correlation coefficient of 0.99 within the range of assayed quantities (2.5 to 25 ng). Analytical recovery was 90.5 ± 2.54% (X̄± SD) and the determination level was 2.5 ng (19.1 pmol). The precision of the assay as determined by the coefficient of variation for five consecutive runs of six concentrations of hydroxyproline in serum hydrolysate (“within‐run” precision) and five series run on different days (“between‐run” precision) was 1.8 ± 1.28% and 4.2 ± 2.59% (X̄± SD), respectively. Hydroxyproline concentrations in GCF from single sites during developing experimental gingivitis in the beagle dog showed an irregular pattern of low and high concentrations ranging from 5.2 to 17.4 ng/μl.
Clinical trials in periodontal therapy
Authors: Lindhe Jan , Nyman Stare
Published: July 2006

The success of periodontal therapy is evaluated not only after the termination of the comparatively short active treatment phase, but also at regular intervals during the extended maintenance phase. The main objectives of the active treatment include: (1) elimination of the inflammatory lesions present in the periodontium (2) reduction of probing pocket depth and (3) improvement of attachment levels, while the aim of the maintenance phase of therapy is the prevention of disease recurrence.

Elimination of the inflammatory lesions in the periodontium is accomplished by meticulous plaque and calculus removal performed either as a single measure or combined with one of several different surgical treatment modalities. Findings from clinical trials have demonstrated that it is not the technique ‐ nonsurgical‐surgical ‐ used during basic therapy, but the degree of root debridement accomplished that seems to be the determining factor for success in terms of resolution of periodontitis. Furcation involved premolars/molars constitute a problem with respect to effectiveness of therapy. Reliable research data describing treatment effects in the furcation regions of multirooted teeth are scarce. As a result of the elimination of the inflammatory lesions the periodontal tissues will offer more resistance to probing. This is clinically identified as probing pocket depth reduction, attachment level imrpovements and recession of the marginal gingiva. Research findings reveal that surgical and nonsurgical methods are almost equally effective in these respects. The concept that surgical methods which include resective measures will cause more gingival recession than non‐resective measures should be questioned.

Long‐term clinical trials have demonstrated that patients who, following active treatment, are enrolled in carefully supervised plaque control programs only occasionally show signs of disease recurrence, while in this respect non‐monitored patients frequently display signs of recurrent disease. It is suggested that the long‐term effect of periodontal therapy is more related to the quality of the maintenance care program than the techniques utilized during active therapy.
The effect of chlorhexidine and Octapinol®on early human plaque formation. A light and electron microscopic study
Authors: Brecx M. , Theilade J. , Attström R. , Glantz P.‐O.
Published: July 2006

The influence of chlorhexidine and Octapinol® on early plaque formation in humans was assessed in vivo. Three subjects with healthy gingiva were used. Plastic films were applied to the buccal surfaces of the maxillary right first premolars and plaque was allowed to form for either 4 or 24 hours. After 1 minute of plaque development, a drop of water, 1 % chlorhexidine or 1 % Octapinol was gently applied in situ; in the 24‐h experiment an additional drop was added at 12 h. In total, 76 films were obtained, with a comparable number of specimens in each of the 6 groups. The samples were processed for light and transmission electron microscopy, using standardized techniques for area sampling and cell counting. All control films were covered by a surface coating of acellular material in or on which bacteria, epithelial cells and leukocytes were observed. The controls and to a lesser extent the Octapinol samples exhibited a significant increase in bacterial count between 4 and 24 h. However, the number of bacteria in the chlorhexidine samples showed only a slight increase within this period. Some microorganisms in the chlorhexidine samples appeared to be undergoing degeneration. In the Octapinol specimens the bacterial morphology was generally intact with many extracellular areas of high electron density. Chlorhexidine and Octapinol both had a qualitative effect on early plaque formation, but only the former had a detectable quantitative effect at this initial stage of plaque accumulation.
Comparison of gingival attachment level measurements with an automated periodontal probe and a pressure‐sensitive probe
Authors: McCulloch Christopher A. G. , Birek Peter , Hardy Valerie
Published: July 2006

An automated periodontal probe (APP) has been developed which measures gingival attachment level using the occlusal or incisal surface of the tooth as a fixed landmark and which transfers data directly to a computer. To assess the precision of data obtained with the new probe, duplicate measurements of gingival attachment level were made. Differences between paired data (d values) were compared with those obtained with a pressure‐sensitive probe (PSP) in order to test the hypothesis that there is no significant difference in the distribution of d values between the two probes. Duplicate measurements were made 1 wk apart around 220 teeth in 19 patients using the automated probe and around 218 teeth in 24 patients with the pressure‐sensitive probe. A probing force of 0.50 N was used for both probes. Greater than 83% of the d values obtained with the automated probe were less than 0.5 mm. There was no significant difference between the frequency distribution of d values for the automated probe (d = 0.28 ± 0.28 mm) and the pressure‐sensitive probe (d = 0.23 ± 0.42 mm). Further, no significant differences between the two different probes were observed in maxillary, mandibular and anterior teeth. The PSP did exhibit slightly fewer d values greater than 1.0 mm for posterior teeth in comparison to the APP (0.9% for PSP, 4.4% for APP). However, d values obtained with the APP exhibited significantly less variance than the PSP for all areas of the mouth (p < 0.005). These findings support the null hypothesis that the precision of data obtained with the automated probe is not significantly different from the pressure‐sensitive probe. The automated nature of the new probe and its utility in providing rapid, unbiased and precise measurements of gingival attachment level suggest that it would be very useful for the study of the natural history of periodontitis in human populations.
Collagenolytic activity in crevicular fluid from patients with chronic adult periodontitis, localized juvenile periodonitis and gingivitis, and from healthy control subjects
Authors: Villela Benardo , Cogen Ronald B. , Bartolucci Alfred A. , Birkedal‐Hansen Henning
Published: July 2006

Collagenolytic activity in gingival crevicular fluid (GCF) sampled from 25 healthy control subjects, 25 gingivitis, 25 chronic adult periodontitis (CAP) and 8 LJP patients was correlated with clinical disease parameters using both the site and the patient as sampling units. Among patients collagenase activity increased with the severity of the disease in the order: healthy < gingivitis < periodontitis. Among sites, significant correlation was found between GCF collagenase activity and pocket depth in CAP and LJP, but not in gingivitis patients. Enzyme activity was also correlated with GI score in LJP, but not in CAP and gingivitis patients. In a subset of 10 patients in each of the healthy, gingivitis and CAP groups the association of enzyme activity and crevicular fluid volume (flow) was examined. Significant correlation was found between fluid volume and pocket depth in CAP patients, and between fluid volume and GI score in gingivitis patients, but no association was observed between collagenase activity and fluid volume. The Collagenolytic enzyme was shown to be a genuine vertebrate collagenase derived from unidentified host cells. The concentration of the enzyme in crevicuar fluid from CAP patients was in the order of 10 μg/ml.
Characterization of N‐CBz‐glycyl‐glycyl‐arginyl peptidase and glycyl‐prolyl peptidase of Bacteroides gingivalis
Authors: Suido H. , Neiders M. E. , Barua P. K. , Nakamura M. , Mashimo P. A. , Genco R. J.
Published: July 2006

Bacteroides gingivalis produces large amounts of proteolytic enzymes which may play a role in its virulence. These enzymes may participate in the tissue destruction of the inflammatory process. In this study, the characteristics of two such enzymes, N‐CBz‐glycyl‐glycyl‐arginyl peptidase (N‐CBz‐Gly‐Gly‐Arg peptidase) and glycyl‐prolyl peptidase (Gly‐Pro peptidase) were investigated. The enzymes eluted in different peaks from an anion exchange column. N‐CBz‐Gly‐Gly‐Arg peptidase was associated with cells up to 48 h in culture. If cultured longer, it also released in the supernatant. It exhibited optimal activity between pH of 7.0 and 7.5 and was readily inactivated by heat treatment (45°C for 15 min). The enzyme activity was inhibited by p‐chloromercuribenzoic acid (PCMB), leupeptin and antipain, suggesting that it is a thiol protease. The B. gingivalis N‐CBz‐Gly‐Gly‐Arg peptidase was different from the serum enzyme that digests the same substrate. The serum enzyme was more resistant to heat treatment and was inhibited by diisopro‐pylfluorophosphate (DFP). B. gingivalis also produced Gly‐Pro peptidase that is released in the supernatant. The enzyme has an optimal pH range between 7.5 and 8.0. The B. gingivalis Gly‐Pro peptidase was inhibited by DFP, suggesting that it represents a serine protease. The serum Gly‐Pro peptidase did not differ from the bacterial enzyme with respect to its sensitivity to inhibitors; however, they were markedly different in heat sensitivity. The bacterial enzyme was completely inactivated at 60°C for 30 min, whereas the serum enzyme was not inactivated even at 1 h at 60°C.
Variability of histologic criteria in clinically healthy human gingiva
Authors: Brecx M. C. , Gautschi M. , Gehr P. , Lang N. P.
Published: July 2006

After prophylaxis, 5 dental hygienists performed optimal oral hygiene under supervision for 6 months. At months 0, 1, 4 and 6, Plaque Index, Gingival Exudate Flow Rate and Gingival Index were assessed, and a buccal biopsy of their gingiva taken. Point counting procedures were performed at 2 different levels of magnification to estimate the volume densities of epithelium, infiltrated and non‐infiltrated connective tissue, and collagen. The percentages of fibroblasts, polymorphonuclear neutrophilic granulocytes, lymphocytes, plasma cells and macrophages were estimated by counting the number of profiles of these cells in the connective tissue area close to the apical end of the junctional epithelium. All the changes inside the tissue occurred slowly. During the 6‐month period there was a continuous increase of the volume density of the epithelium in the gingiva. An increase in the percentage of fibroblasts was observed between months 1 and 4 together with a decrease in the percentage of lymphocytes and in the volume density of the infiltrated connective tissue. Between months 4 and 6 an increase of the volume density of the collagen was found together with a further increase in the percentage of fibroblasts and a further decrease in the percentage of lymphocytes. After 6 months of perfect oral hygiene no more plasma cells were visible. This study has shown that, even in presence of clinically healthy gingiva, subclinical changes may take place. It appears realistic to accept the presence of a very mild gingivitis localized in an area adjacent to the attachment as compatible with gingival health.
Fusobacterium nucleatum‐mediated immunomodulation of the in vitro secondary antibody response to tetanus toxoid and Actinobacillus actinomycetemcomitans
Authors: Tew J. G. , Thomas S. S. , Ranney R. R.
Published: July 2006

The present study was undertaken to determine if one of the most prevalent periodontitis‐associated organisms, Fusobacterium nucleatum (F. NUC), was capable of modulating secondary immune responses, including responses against Actinobacillus actinomycetemcomitans (AA). Peripheral blood lymphocytes (PBLs) were obtained from individuals known to have high serum antibody against Tetanus toxoid (TT) or AA. The addition of either TT, sonicated F.NUC, or pokeweed mitogen (PWM) to PBLs from subjects with high anti‐TT titers stimulated production of anti‐TT in vitro. However, the addtion of TT in combination with either F.NUC or PWM resulted in dramatic enhancement of anti‐TT production over antigen or nonspecific activator alone. Similarly, an in vitro secondary response could be induced with antigen from AA, and the addition of F.NUC likewise showed a marked immunoadjuvant effect. The data indicate that F.NUC has potent immunomodulatory activity. The high titers of locally produced specific antibody in gingival crevicular fluid to AA and certain other periodontitis‐associated bacteria may result from the combined effect of specific antigen together with an immunomodulator of bacterial origin.
Polyamine analysis of human gingival crevicular fluid
Authors: Walters John D.
Published: July 2006

Crevicular fluid from inflamed periodontitis sites was analyzed for polyamines by high performance liquid chromatography. Putrescine and cadaverine concentrations were positively correlated with site probing depth (p<0.01). Spermidine concentrations were poorly correlated with probing depth (p<0.30), but were significantly higher at moderately inflamed sites (as assessed by the Gingival Index) than at mildly inflamed sites (p<0.02).
Selection of a filter paper with optimum properties for the collection of gingival crevicular fluid
Authors: Griffiths G. S. , Curtis M. A. , Wilton J. M. A.
Published: July 2006

Four different paper types were evaluated in vitro for their suitability for the collection of gingival crevicular fluid and its subsequent quantification using both the Periotron® 6000 and measurement of the area of paper wetted. Whatman 3MM chromatography paper (Wh.3MM) was found to be the most suitable and strip dimensions of 2x8 mm were found to be the most absorbent whilst remaining compatible with the dimensions of the Periotron electrodes. The 2×8 mm Wh.3MM paper strips were used to derive a quadratic calibration curve, for a range of fluid volumes, which was shown to be a better fit than a straight line. Recovery of human serum proteins applied to these strips exceeded 90% even after compression of the strip between the electrodes of the Periotron during fluid volume measurement.
Possible role of T cells in the establishment of IgG plasma cell‐rich periodontal lesion –Augmentation of IgG synthesis in the polyclonal B cell activation response by autoreactive T cells
Authors: Ito Hiroö , Harada Yasushi , Matsuo Takashi , Ebisu Shigeyuki , Okada Hiroshi
Published: July 2006

The effect of T cells on T‐independent polyclonal B cell activation (PBA) was studied in vitro in mice. Helper/inducer T cells were activated by interaction with la antigens expressed on B cells. The activated T cells enhanced IgG synthesis in the PBA reaction. la antigen expression on B cells increased when stimulated by polyclonal B cell activators. An autoreactive T cell line was established by longterm culture of spleen cells with polyclonal B cell activators. The culture supernatant from this autoreactive T cell line enhanced IgG synthesis in PBA. The above results suggest that autoreactive T cells were activated by la expressed on B cells stimulated with polyclonal B cell activators, and then prompted B cells to synthesize IgG. Therefore, autoreactive T cells may play an important role in the establishment of the IgG plasma cell‐rich periodontal lesion.
Permeability of rodent junctional epithelium to exogenous protein
Authors: Romanowski A. W. , Squier C. A. , Lesch C. A.
Published: July 2006

It has generally been assumed that oral sulcular epithelium, being nonkeratinized, is a vulnerable region which allows bacterial products to pass from the gingival sulcus to the subjacent connective tissue. It has also been suggested that inducing keratinization of the oral sulcular epithelium might create a better barrier to such material. However, this approach ignores the effect of a permeable junctional epithelium, for if exogenous material penetrates this epithelium then the presence of keratinization may be unimportant. Rats possess an orthokeratinized oral sulcular epithelium and so represent what might be considered as an ideal sulcus lining. The protein tracers horseradish peroxidase or microperoxidase were instilled into the gingival sulcus of anesthetized rats. After 1 h, the animals were killed and fixative applied topically and by perfusion. The mandibles were detached, decalcified in EDTA to permit removal at the gingival attachment and sectioning, reacted with diaminobenzidine and H2O2 to visualize the tracer, and prepared for light and electron microscopic examination. Controls consisted of: a) animals that had not been treated with horseradish peroxidase, and b) horseradish peroxidase‐treated animals incubated without H2O2. Microscopic examination revealed penetration of the tracers through the junctional epithelium and into the underlying connective tissue, but never through the adjacent oral sulcular and gingival epithelium. These results suggest that material placed in the sulcus can enter the connective tissue via the junctional epithelium even when the adjacent oral sulcular epithelium forms a keratinized barrier.
Long‐term culture of human periodontal ligament cells with autologous root discs
Authors: Preisig Elisabeth , Schroeder Hubert E.
Published: July 2006

Recent attempts at gaining an understanding of the factors necessary for periodontal reattachment have employed an in vitro system in which connective tissue cells are cultured with dental root discs. The present study was undertaken to optimize culture conditions. Periodontal ligament (PDL) cells and root discs were derived from 2 wisdom teeth extracted from each of 3 patients. Pairs of planed root discs (0.5 mm thick) were gently placed in dishes containing autologous PDL‐cells and separated by a 0.5 mm wide gap. After 10 to 13 weeks in culture the specimens were processed for light‐ and electron microscopy and the collagen fibril diameter was determined. In the interdental space, all cultures contained an aggregate of cells and collagen fibrils. Adherent to root discs with exposed dentin was a loose capsule of cells and collagen fibrils oriented parallel to the disc surface. Adjacent to cellular cementum a discontinuous, dense, short fiber fringe was found along the cultureJroot interface. There was some intermingling between cemental and culture collagen fibrils. The fibril diameter of cemental collagen (59.4 ± 5.0 nm) and culture collagen (31.8 ± 3.5 nm) was very different. Thus, autologous PDL‐cell/disc‐cultures can be maintained for prolonged periods of time, resulting in the formation of discontinuous patches of condensed collagen fibrils radiating from some portions of the decalcified cemental surface.
Electron immunolocalization of type IV collagen, laminin and fibronectin synthesized by multilayered cells cultured from human oral epithelium
Authors: Poly H. , Couble M. L. , Hartmann D. J. , Faure M. , Magloire H.
Published: July 2006

Human palatal epithelial cells were grown on lethally irradiated 3T3 fibroblasts. Under these conditions, epithelial cultures become stratified. The basal cells have a cuboïdal shape and suprabasal layers are flattened. The reconstituted epithelium exhibits markers of differentiation: intracytoplasmic bundles of keratin‐like filaments and abundant desmosmes present in every layer. Type IV collagen fibronectin and laminin are synthesized by these cultures. Basal cells grip the culture substratum via an extracellular matrix made up of type IV collagen, laminin and fibronectin.
Characterization of collagenolytic activity from strains of Bacteroides gingivalis
Authors: Birkedal‐Hansen Henning , Taylor Robert E. , Zambon Joseph J. , Barwa Pankaj K. , Neiders Mirdza E.
Published: July 2006

Strains of B. gingivalis were shown to produce collagenolytic activity capable of dissolving reconstituted collagen (type I) fibrils and of cleaving the helical domain of types I. II and III collagens at 22° C. The catalytic activity was dependent on free thiol groups and on metal ions, as indicated by inhibition by thiol blocking reagents and metal chelators. The activity was associated with the bacterial cells and was not secreted to the medium. Under optimal conditions. 100 Units of collagenase per gram cell pellet (wet weight) were released by detergents such as Triton X‐100 and SDS. Zymography of detergent extracts revealed that collagen‐degrading strains, but not an inactive control strain (W), contained a discrete Mr 90 000 gelatin cleaving protease which may be identical to the collagenolytic enzyme. The initial attack on the helical domain of type I collagen occurred near the COOH‐terminus. The a1 and a2 chains were cleaved at the same site, generating a major helical fragment consisting of three shortened (Mr 82 000) a‐chains. Subsequent cleavages of this shortened collagen molecule resulted in generation of multiple fragments from the component a‐chains in the Mr 60 000 to 6000 range. This cleavage pattern was clearly distinct from the characteristic 3/4–1/4 pattern produced by vertebrate collagenases. Type II and III collagens were also cleaved first near the COOH‐terminus, generating fragments of similar size to those produced from type I collagen. In view of its ability to dissolve reconstituted collagen fibrils at 35°C and its ability to attack the helical domain of interstitial collagens in solution at 22°C, we suggest that this enzyme tentatively be classified as a true collagenase.
Phenotypic dynamics of macrophage subpopulations during human experimental gingivitis
Authors: Topoll H. H. , Zwadlo G. , Lange D. E. , Sorg C.
Published: July 2006

The purpose of the present study was to investigate whether functionally different macrophages are present in clinically healthy gingiva and during human experimental gingivitis. Eight male probands were introduced to an oral hygiene program until all reached mean Plaque and Gingival Index scores approaching zero. During the following 19 days all oral hygiene was abandoned. At d –14, 0, 2, 4, 7, 11 and 19 clinical indices and gingival biopsies were taken. Cryostat sections were incubated with monoclonal antibodies against mature macrophages (25F9), inflammatory macrophages (27E10) and anti‐inflammatory macrophages (RM 3/1). Positive cells were counted in the inflammatory infiltrate (IF) and the connective tissue (CT). At d – 14 elevated numbers of 27E10‐positive cells were observed which decreased significantly at d 0 (p < 0.018) and increased again at d 19 (p < 0.026). Significant differences in the number of RM 3/1‐positive cells were found between d 0 and d – 14, 2, 4 and 7 (p < 0.05) while no differences in the number of 25F9‐positive cells were observed throughout this study. It was concluded that experimental gingival inflammation is characterized by the appearance and disappearance of functionally different macrophage subpopulations.
Expression of blood group antigen‐related carbohydrates by human gingival epithelia
Authors: Mackenzie I. C. , Dabelsteen E. , Mandel U.
Published: July 2006

A panel of monoclonal antibodies was used to examine differentiation‐related carbohydrate structures on the surfaces of gingival epithelial cells. The patterns of binding observed indicate distinct differences in the expression of the epitopes examined for three regions of the gingival epithelia corresponding approximately to the regions defined anatomically as the junctional, oral sulcular and oral epithelia. However, epithelium with the staining pattern of oral sulcular epithelium consistently extended beyond the sulcular region to cover the gingival crest and often the uppermost part of the oral aspect of the gingiva. Differential staining of basal and suprabasal cells indicated an unusual pattern of differentiation of the junctional epithelium. The phenotype of this epithelium appears to differ from patterns reported for any other oral epithelium and the possible functional significance of this difference is discussed.
Immunoadjuvant effects of periodontitis‐associated bacteria
Authors: Ochiai K. , Kurita T. , Nishimura K. , Ikeda T.
Published: July 2006

Sonic extract (SE) from periodontopathic bacteria were studied for their effects on the immune response and adjuvanticity. The preparations of SE from A. actinomycetemcomitans, B. intermedius and B. gingivalis were found to have strong immunomodulating activity against the antigen itself and also sheep erythrocytes (SRBC) in in vivo experiments using C3H/HeN mice. All the SE enhanced the immune response to antigen and SRBC at low concentration. A strong immuno suppressive effect, however, was found at high concentrations of A. actinomycetemcomitans and B. intermedius but not of B. gingivalis. Moreover, these immunosuppressive effects were enhanced by the 3‐day‐prior injection to SRBC even at low concentrations, including that of B. gingivalis. The suppressive effect of SE from A. actinomycetemcomitans was dependent on the protein fraction in the SE tested, because suppressed anti‐SRBC immune response was restored by pronase treatment or heating. Failure to recover immune response, found in a similar experiment using Bacteroides intermedius, indicated that its suppressive effect was due to a heat‐stable and pronase‐resistant substance. These findings, along with the data presented in this paper, support the hypothesis that patients who harbor these bacteria could suffer systemic immune suppression not only from the initial periodontopathic bacteria but also from secondary infecting bacteria. These suppressive effects may also enhance the pathogenicity of other opportunistic organisms in the gingival crevice.
A stochastic model for periodontal breakdown
Authors: Manji Firoze , Nagelkerke Nico
Published: July 2006

This paper considers a possible explanation for the occurrence of periodontal breakdown in bursts and remissions. We show that such bursts and remissions, apart from being the result of major biological events, can also be generated by a stationary process of Brownian motion.
Altered distribution of type I collagen mRNA in periodontal disease
Authors: Larjava H. , Sandberg M. , Vuorio E.
Published: July 2006

Earlier studies on collagen metabolism in the periodontium have suggested that periodontal disease is associated with reduced amounts of type I collagen in the pocket walls, and with an overall increase in collagen synthesis. In this study we analyzed gingival biopsies of patients suffering from adult type chronic periodontal disease by in situ hybridization, which permitted localization of fibroblasts containing different amounts of proαl(I) collagen mRNA. The results showed that expression of type I collagen mRNA is reduced in the vicinity of periodontal pockets and dental plaque. Deeper in the connective tissue, high levels of proαl(I) collagen mRNA were observed particularly around inflammatory cell infiltrates which may contribute to the fibrotic reaction observed. In all areas studied the levels of type I collagen mRNA in periodontal fibroblasts varied considerably, supporting previous views about their heterogeneity.
Effects of atelocollagen on the wound healing reaction following palatal gingivectomy in rats
Authors: Minabe Masato , Kodama Toshiro , Hori Toshio , Watanabe Yoshihisa
Published: July 2006

Collagen membrane preparations have been manufactured with the aim of enhancing wound healing following periodontal surgery. After cross‐linking by various processing methods (with ultraviolet radiaiton or hexamethylenediiso‐cyanate) and to various extents, atelocollagen membranes were applied into dissection sites within palatal gingival tissue. Applied atelocollagen was histopa‐thologically compared with applied lyophilized porcine dermis (LPD®) and controls in rats, with regard to the time course of healing. The atelocollagen‐applied group showed more satisfactory regeneration of the epithelium and connective tissue in an artificially created gingival defect than did the control group or the LPD‐applied group. Epithelial downgrowth along the root surface was significantly suppressed by the use of atelocollagen. In addition, the postoperative inflammatory reaction and foreign body giant cell reaction subsided rapidly after surgery in the atelocollagen‐applied group. Our results show that the use of atelocollagen membrane in periodontal wounds should be the method of choice.