bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial changes associated with the development of puberty gingivitis
Authors: Mombelli A. , Lang N. P. , Bürgin W. B. , Gusberti F. A.
Published: July 2006

In this study, longitudinal changes in the composition of the subgingival microbiota of children between the ages of 11 and 14 and their association with changes of clinical parameters describing gingival health were investigated. During 4 years, subgingival microbial samples were taken in 22 boys and 20 girls 10 times. At the same time the gingival bleeding tendency was recorded by the Papillary Bleeding Index (FBI). A total of 840 samples was evaluated using darkfield microscopy and anaerobic culturing on non‐selective and selective media. Children, who developed a marked and sustained increase in mean PBI scores (n = 21), had higher frequencies and mean proportions of spirochetes and Eikenella corrodens than children without pronounced puberty gingivitis (p < = 0.05). The mean proportion of Actinomyces viscosus was also higher in these children (p < = 0.05). Among the species discriminated, only Capnocytophaga sp. were found at a higher rate in samples taken immediately before a rise of PBI (p < = 0.05). The detection frequencies of black‐pigmented Bacteroides (particularly B. intermedius) increased later, and were significantly elevated after the establishment of a high bleeding tendency (p < = 0.05). These findings implicate Capnocytophaga sp. in the initiation of puberty gingivitis, whereas the increased presence of Bacteroides may reflect a change in the subgingival environment secondary to increased bleeding.
Salivary collagenase. Origin, characteristics and relationship to periodontal health
Authors: Uitto Veli‐Jukka , Suomalainen Kimmo , Sorsa Timo
Published: July 2006

Saliva collected from subjects with healthy and with diseased periodontium was assayed for collagenase activity by incubation at 25°C with soluble type I, II or III collagen. The degradation products were analyzed by separation in SDS‐polyacrylamide gel electrophoresis followed either by protein staining or by exposure of the dried gel to X‐ray film in the case of radioactively labeled type I collagen. Collagenase of vertebrate type was detected in the whole saliva of all subjects but not in parotid, sublingual or submandibular fluids. Most of the collagenase was in the soluble fraction of saliva that also contained factors which both activated and inhibited the enzyme. The salivary collagenase resembled the collagenase of human PMNs and gingival sulcular fluid in its molecular size of 70000 daltons, in its activation by gold thioglucose and in its tendency to degrade types I and II collagens over type III collagen. Before periodontal treatment, the saliva of periodontitis patients had significantly higher collagenase than after treatment. In periodontitis, collagenase existed mainly in the active form, while in the healthy mouths most of the enzyme was latent but could be activated by sulfhydryl reagents or proteolytically with trypsin, and chymotrypsin but not by human plasma kallikrein or plasmin. In some of the samples from untreated periodontitis patients bacterial collagenase may have been present in small quantities. Most of the collagenase in the saliva from all subjects appeared to originate from PMNs entering the oral cavity through the gingival sulcus.
Lectin binding of rat gingival epithelia
Authors: Takata Takashi , Nikai Hiromasa , Miyauchi Mutsumi , Ito Hiroshi , Kobayashi Joji , Ijuhin Naokuni
Published: July 2006

Oral gingival epithelium (OGE), oral sulcular epithelium (OSE) and junctional epithelium (JE) were examined histochemically by using different lectins as markers for epithelial differentiation. The staining pattern of gingival epithelia was compared with that of the buccal and palatal epithelia. Binding of WGA had a uniform distribution in all the epithelia examined. A positive reaction was found in all the basal and spinous layers, but not in the cornified layer of the epithelia. BPA binding was seen in the lower spinous layer of OGE, OSE, buccal and palatal epithelia, and in most of the JE. The basal layer and the cells directly attached to the tooth surface at the apical part of JE were nonreactive with BPA. GS‐I reacted with the basal and suprabasal layers of each epithelium and with the cells attached to the tooth at the apical part of JE. UEA‐I reacted with the upper spinous layer of OGE, OSE and epithelia of hard palate, but not with any of the cells of the JE. Our results agree with previous data suggesting that OGE and OSE exhibit squamous differentiation similar to that of the masticatory epithelium of hard palate. Furthermore, our results suggested that the JE cells undergo differentiation equivalent to that of the suprabasal and lower spinous cells of OGE. The cells along the tooth surface at the apical part of JE, however, form a distinct population of cells with basal nature.
A simple, combined fluorogenic and chromogenic method for the assay of proteases in gingival crevicular fluid
Authors: Cox S. W. , Cho K. , Eley B. M. , Smith R. E.
Published: July 2006

Substrate impregnated paper discs were prepared using peptidyl derivatives of 7‐amino‐4‐trifluoromethylcoumarin (AFC). After incubation with test solutions, the green, UV‐induced fluorescence of AFC liberated by enzyme activity was distinguishable from the blue‐violet fluorescence of the substrates. The AFC could then be coupled with p‐dimethylaminocinnamaldehyde to form a colored Schiff base. Semi‐quantitative assessments of disc fluorescence and color were made by comparison with AFC/substrate standards. Assays with discs impregnated with MeOSuc‐Ala‐Ala‐Pro‐Val‐AFC, Z‐Gly‐Gly‐Arg‐AFC and Ala‐Pro‐AFC for elastase‐, trypsin‐, and dipeptidyl peptidase (DPP) IV‐like activities respectively were evaluated using purified DPP IV and 100 eluates of crevicular fluid collected on filter paper strips from 10 gingivitis and periodontitis patients. The results showed that, within their working ranges, scores of disc fluorescence and color were reasonably accurate and reliable by comparison with enzyme activities measured in parallel quantitative fluorimetric assays with the same substrates. Using disc color, which was more sensitive than fluorescence, it was generally possible to measure all three enzyme activities in crevicular fluid samples from 5 periodontitis patients with varying degrees of gingival inflammation and pocketing. Disc color assays require no special apparatus and could be used for enzyme estimations in the clinical setting.
Biochemical comparison of proteolytic enzymes present in rough‐ and smooth‐surfaced capnocytophagas isolated from the subgingival plaque of periodontitis patients
Authors: Söderling E. , Mäkinen P. L. , Syed S. , Mäkinen K. K.
Published: July 2006

Four rough‐surfaced (R) and three smooth‐surfaced (S) clinical isolates of Capnocytophaga obtained from the subgingival plaque of periodontitis patients were studied for their peptidase and protease profiles. The results were compared with those obtained with C. gingivalis (which has a smooth morphology). All cell extracts obtained by ultrasonic treatment displayed high peptidase activity toward N‐aminoacyl‐2‐naphthylamines, the best substrates being the arginyl, aspartyl, and leucyl derivatives. The R and S isolates did not differ in these enzyme activities. Also the protease profiles studies with 4‐phenylazobenzyloxy‐carbonyl‐L‐prolyl‐L‐leucylglycyl‐L‐prolyl‐D‐arginine (PZ‐PLPGA) and casein were similar. All extracts also hydrolyzed furylacryloyl‐L‐leucylglycyl‐L‐prolyl‐L‐alanine (FALGPA), reconstituted type I [3H]‐collagen, and gelatin. NaBenzoyl‐DL‐arginyl‐2‐naphthylamine was hydrolyzed faster by the R than the S strains. Comparison between cell suspensions and cell extracts of C. gingivalis showed the suspensions to be enzymatically more active than the extracts. In general, peptidase substrates and PZ‐PLGPA were hydrolyzed at a higher rate by suspensions than by extracts, while protease substrates (such as casein) were hydrolyzed faster by the extracts. Gelatin and FALGPA were hydrolyzed by cell extracts only. Fast protein liquid chromatography of peptidases on a gel column was found to be a suitable method to differentiate between R and S isolates in diagnostics, while the chromatographic profiles of proteases were not suitable for this purpose.
Vacuoles and vesicles in the rat junctional epithelium: A study with serial ultrathin sections
Authors: Shimono Masaki , Hashimoto Sadamitsu , Abiko Yoshihiro , Hamano Hironori , Chen Sheng‐Huei
Published: July 2006

To investigate whether the electron‐lucent structures resembling vesicles and vacuoles in the rat molar junctional epithelium (JE) are in fact intracellular or extracellular, a study using serial ultrathin sections was carried out. In one series of experiments, the animals were not treated before the tissues were conventionally fixed; in another, anesthetized animals were administered horseradish peroxidase 20 min before the tissues were fixed. A large number of electron‐lucent structures resembling vesicles and vacuoles were detected in both the peripheral and central cytoplasm of the JE localized at enamel and connective tissue sites. These were 70 to 800 nm in diameter and had a lucency similar to that of the extracellular space in untreated specimens fixed with conventional fixative. Serial ultrathin sectioning revealed that the electron‐lucent structures gradually became part of the extracellular space in the following sections. These were also found in the middle portion of the cytoplasm in specimens pretreated with horseradish peroxidase. Numerous vacuole‐like structures containing peroxidase‐positive materials were found to be contiguous with the extracellular space. A small number of vesicles, also containing peroxidasepositive materials, did not appear in the previous or following sections. These results indicate that almost all electron‐lucent structures resembling vesicles and vacuoles in the JE are located at the end of a long infolding, and are still in contact with the extracellular space.
CD11b expression on neutrophils in human crevicular fluid collected from clinically healthy gingivae
Authors: Watanabe Keiko , Hagen Karen L. , Andersen Burton R.
Published: July 2006

This study investigated the cell surface expression of CD11b (Mo 1, Mac‐1, CR 3) by neutrophils (PMNs) from human crevicular fluid (CF‐PMNs). CD11b expression on CF‐PMNs was compared, using flow cytometry, to that on peripheral blood PMNs (PB‐PMNs) isolated simultaneously from the same subjects. CD11b expression by CF‐PMNs was also compared to that on PBPMNs stimulated with formylmethionylleucylphenylalanine (fMLP) or crevicular fluid supernatant (cell‐free portion of CF diluted with buffer) (CFS). Crevicular PMNs consistently expressed more CD11b than unstimulated PB‐PMNs (p<0.001). The level of CD11b expressed on these CF‐PMNs was significantly greater than that expressed by PB‐PMNs stimulated with 10−8 M fMLP (p<0.05). The level of CD11b surface expression on CF‐PMNs was not statistically different from that expressed on PB‐PMNs stimulated with CFS or 10−6 M fMLP. However, CFS significantly stimulated upregulation of surface CDllb expression on PB‐PMNs relative to that achieved with 10−8 M fMLP (0.01<p<0.025). Thus it is concluded that CF‐PMNs express a high level of CD1 Ib and CFS can upregulate CD11b expression on PB‐PMNs to a level that is at least as great as that achieved with 10−8 M fMLP.
Isolation and characterization of a 180‐kiloDalton salivary glycoprotein which mediates the attachment of Actinomyces naeslundii to human buccal epithelial cells
Authors: Babu Jegdish P. , Dabbous Mustafa K. , Abraham Soman N.
Published: July 2006

The adherence of Actinomyces naeslundii to human buccal mucosa is mediated by specific interactions between the bacterial cell surface fimbriae and complementary β‐linked galactoside receptors on the epithelial cell surface. The buccal mucosa and the bacteria that colonize its surface are constantly bathed in saliva. Several salivary components are thought to play an important role in modulating adhesive interactions between oral bacteria and the buccal epithelium. We have observed that pretreatment of isolated buccal epithelial cells (BEC) with human parotid saliva increased the attachment of three different strains of A. naeslundii. By employing affinity chromatography, ion‐exchange and high‐pressure liquid Chromatographic techniques we have isolated a 180 kDa A. naeslundii‐binding salivary glycoprotein (An‐SGP). This salivary glycoprotein was capable of mediating separate but specific binding interactions with A. naeslundii and BEC. Pretreatment of BEC with increasing amounts of An‐SGP resulted in a corresponding increase in the attachment of A. naeslundii. The adherence of A. naeslundii to An‐SGP‐coated BEC is sensitive to the same inhibitors previously shown to block adherence of A. naeslundii to uncoated BEC, namely lactose and galactosyl‐binding lectins. When a solubilized extract of freshly isolated and washed BEC was reacted on a Western blot with antibodies to An‐SGP, a prominent 180 kDa immunoreactive band was detected. Furthermore, the immunoreactive component was demonstrated on the BEC surface when assayed by immunofluorescence using An‐SGP‐specific antibodies, suggesting that An‐SGP or a protein structurally and immunologically identical to the isolated glycoprotein is present on BEC.
A study of inter and intraexaminer reliability of pocket depth and attachment level
Authors: Fleiss Joseph L. , Mann Jonathan , Paik Myunghee , Goultchin Joseph , Chilton Neal W.
Published: July 2006

Factors affecting inter‐ and intra‐examiner variability for probing pocket depth and periodontal attachment level were studied on a sample of 20 patients, each given six full‐mouth examinations, two by each of 3 examiners. The major determinant of both dimensions of variability was the degree of periodontal destruction, measured as either pocket depth or level of attachment: the greater the degree of destruction, the greater the disagreements within and between miners. Differences in variability were generally minor between sites on anterior and sites on posterior teeth, between midsites and proximal sites, and between sites on the facial and sites on the lingual surface. When differences were found between the average variances for different kinds of sites, they may have been due to corresponding differences between the average depths, and not to any inherently greater difficulty in measuring one kind of site than another.
Effect of the NSAID piroxicam, topically administered, on the development of gingivitis in Beagle dogs
Authors: Howell T. H. , Fiorellini J. , Weber H. P. , Williams R. C.
Published: July 2006

A single‐blind investigation was designed to study the effects of piroxicam in preventing gingival inflammation and plaque formation in beagle dogs. Twelve 1‐year‐old beagles were brought to optimum oral hygiene and gingival health. Thereafter, they were fed a moist plaque‐promoting diet and were divided into three groups. The first group received daily administration of 1.0 ml placebo gel (methylcellulose) painted on the teeth. The second group received 1.0 ml of gel containing 2 mg/ml piroxicam and the third group received 1.0 ml liquid containing 2 mg/ml of piroxicam. Placebo and test solutions were applied daily, and dogs were examined biweekly for evaluation of plaque accumulation, gingival inflammation, bleeding upon gentle probing and tooth staining. Data were analyzed using the Krushkal‐Wallis test. Over the treatment period, plaque accumulation was substantial in all three groups and was not significantly different between the three groups. By week 2, the gingival index in the piroxicam‐treated dogs was significantly lower than that of the placebo‐treated group and remained so throughout the study, with the exception of wk 6 and 12 in the topical gel‐treated group. Mean percent bleeding sites were also significantly less in the piroxicam‐treated groups than in the control dogs. Staining of the teeth increased for all groups over the 16‐wk treatment period. These data indicate that piroxicam can significantly inhibit the development of gingival inflammation in beagle dogs.
Inflammatory mediators and the destruction of bone
Authors: Mundy Gregory R.
Published: July 2006

Bone is remodelled by the coordinated actions of osteoclasts and osteoblasts. Cellular remodelling occurs in discrete packets of bone, and is regulated by local cytokines produced in the environment of the remodelling cells. These cytokines are secreted by immune cells and by bone cells. In addition, some growth regulatory factors are incorporated into the noncollagenous bone matrix and are released in an active form when bone is stimulated to resorb. Complex interactions between these cytokines and their target cells are responsible for the normal delicate balance between bone resorption and bone formation, and disorders of bone loss are due to imbalances between the rates of resorption and formation.
The role of inflammatory mediators in the pathogenesis of periodontal disease
Authors: Page Roy C.
Published: July 2006

The role of bacteria in the initiation of periodontitis is well‐documented and the end result, destruction of the alveolar bone and periodontal connective tissue, is readily observed; but the events occurring between these two points in time remain obscure and are the focus of this paper. Bacteria induce tissue destruction indirectly by activating host defense cells, which in turn produce and release mediators that stimulate the effectors of connective tissue breakdown. Components of microbial plaque have the capacity to induce the initial infiltrate of inflammatory cells including lymphocytes, macrophages, and PMNs. Microbial components, especially lipopolysaccharide (LPS), have the capacity to activate macrophages to synthesize and secrete a wide array of molecules including the cytokines interleukin‐1 (IL‐1) and tumor‐necrosis factor‐α (TNF‐α), prostaglandins, especially PGE2, and hydrolytic enzymes. Likewise, bacterial substances activate T lymphocytes and they produce IL‐1 and lymphotoxin (LT), a molecule having properties very similar to TNF‐α. These cytokines manifest potent proinflammatory and catabolic activities, and play key roles in periodontal tissue breakdown. They induce fibroblasts and macrophages to produce neutral metalloproteinases such as procollagenase and prostromelysin, the serine proteinase urokinase‐type plasminogen activator (μ‐PA), tissue inhibitor of metalloproteinase (TIMP), and prostaglandins. μ‐PA converts plasminogen into plasmin, which can activate neutral metalloproteinase proenzymes, and these enzymes degrade the extracellular matrix components. TIMP inactivates the active enzymes and thereby blocks further tissue degradation. Several amplification and suppression mechanisms are involved in the process. While LPS activates macrophages to produce IL‐1. IL‐1 is autostimulatory and can therefore amplify and perpetuate its own production. Interferon‐γ (INF‐γ) suppresses autostimulation, but it enhances LPS‐induced IL‐1 production. PGE2 exerts a control over the whole process by suppressing production of both IL‐1 and TNF‐α. Furthermore, the activated cells produce an IL‐1 receptor antagonist that binds to the IL‐1 receptor but does not induce the biologic consequences of IL‐1 binding. Other cytokines such as transforming growth factor‐β (TGF‐β) suppress production of metalloproteinases and μ‐PA. Thus the progression and extent of tissue degradation is likely to be determined in major part by relative concentrations and half‐life of IL‐1, TNF‐α, and related cytokines, competing molecules such as the IL‐1 receptor antagonist, and suppressive molecules such as TGF‐β and PGE2. These molecules control levels of latent and active metalloproteinase and μ‐PA, and the availability and concentration of TIMP determines the extent and duration of degradative activity.
Production of trypsin and chymotrypsin inhibitors by oral bacterial isolates
Authors: Grenier Daniel
Published: July 2006

Using an agar‐skim milk gel method, over 300 oral bacterial isolates were tested for their ability to produce trypsin or chymotrypsin inhibitor. Eleven bacterial strains, including seven isolates identified as Bacteroides intermedius, were found to inhibit both proteolytic activities. The inhibitory factors of the 11 bacterial strains could be divided into two categories: i) heat‐stable and dialysable, and ii) heat‐labile and non‐dialysable. The protease inhibitor activity of B. intermedius strains, which belongs to the latter category, was found in a membrane fraction as well as in a membrane‐free extract. Furthermore, three strains of B. intermedius showed this inhibitory activity in the culture supernatant. In combination with plasma‐derived protease inhibitors, the production of these additional protease inhibitors by oral bacteria could protect the host from tissue degradation.
Use of digital radiography to demonstrate the potential of naproxen as an adjunct in the treatment of rapidly progressive periodontitis
Authors: Jeffcoat M. K. , Page R. , Reddy M. , Wannawisute A. , Waite P. , Palcanis K. , Cogen R. , Williams R. C. , Basch C.
Published: July 2006

The effect of the non‐steroidal anti‐inflammatory drug, naproxen, in reducing periodontal disease activity was assessed in 15 patients with rapidly progressive periodontitis. All patients in this double‐blind study were treated with scaling and root planing. Thereafter, 7 patients receiving 500 mg naproxen b.i.d. for 3 months, and 8 patients received placebo. Disease activity was assessed in three ways. First, alveolar bone height was determined using standardized radiography. Second, alterations in alveolar bone metabolism were assessed using 99m‐Tc‐methylene diphosphonate uptake prior to dosing and 3 months later. Finally, bone loss or gain was detected using digital subtraction radiography. In this study, conventional subtraction images were processed to isolate the area of change and superimpose the change on the original radiograph. This allowed determination of both the direction and location of osseous changes. There was significantly less bone loss as determined by analysis of bone height during the 3‐month study in the naproxen‐treated patients when compared to the placebo‐treated patients (p < 0.001). Radiopharmaceutical uptake was significantly reduced in the alveolar bone in patients receiving naproxen (p <0.03), whereas no significant change was observed in the placebo‐treated patients. Furthermore, the subtraction radiographs showed a significant increase in the proportion of teeth demonstrating bone gain in the naproxen‐treated group. These findings indicate that naproxen may be a useful adjunct to scaling and root planing in patients with rapidly progressive periodontitis.
Penetration, clearance and retention of antigen en route from the gingival sulcus to the draining lymph node of rats
Authors: Abe Tatsuya , Hara Yoshitaka , Aono Masao
Published: July 2006

We investigated the penetration and clearance of antigen in the rat gingiva and the antigen‐specific antibody response in the draining lymph nodes. Rats were primarily immunized into the alveolar submucosa with horseradish peroxidase (HRP) in complete Freund's adjuvant. Ultrastructural demonstration of antigen and specific antibody was performed by incubation of cryosections in an HRP solution, followed by peroxidase cytochemistry. Anti‐HRP antibody‐containing cells were observed in the draining lymph nodes from 2 to 9 weeks after immunization. The bulk of these cells were located in the medullary cords. The extracellular antibody and antibody‐containing cells were also found in germinal centers (GCs) from 3 to 9 wk, and 3 wk, respectively, after immunization. The results suggest that the specific antibody response was most enhanced 3 wk after primary immunization. Therefore, at this time we further challenged rats with the topical application of HRP to the gingival sulcus. The results showed that antigen penetrated through the junctional epithelium into the underlying connective tissue and from here was cleared by macrophages or via the lymphatics. In the draining lymph nodes, antigen first appeared in the subcapsular sinus and eventually became retained within GCs. Between 3 and 5 days, the GCs of challenged rats contained more mature‐type anti‐HRP antibody‐containing cells than those of non‐challenged rats. The sequence of events observed suggests that antigen challenge applied topically to the gingival sulcus can induce the active GC reaction in the draining lymph nodes of immunized rats.
Tetracycline fiber therapy monitored by DNA probe and cultural methods
Authors: Maiden M. F. J. , Tanner A. , McArdle S. , Najpauer K. , Goodson J. M.
Published: July 2006

Oligonucleotide DNA probe and selective cultural methods were compared in their ability to monitor 6 putative periodontal pathogens in a study evaluating local tetracycline fiber therapy. Subgingival plaque was sampled from 4 sites in each of 20 subjects. Samples were taken before and after therapy from sites assigned to the following test groups: tetracycline (TC) fiber, scaling and root planing, control fiber, and untreated. Each sample was analyzed by both DNA probe and cultural methods. Total anaerobic cultivable counts, Porphyromonas (Bacteroides) gingivalis and Prevotella intermedia (Bacteroides intermedius) were enumerated on nonselective blood agar. Actinobacillus actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum and Wolinella recta were isolated on selective media. TC fiber therapy and scaling reduced total cultivable counts from an initial value of 1 × 107 to approximately 2 × 105 following therapy. Total counts at untreated sites and at sites with control fibers did not change from baseline. A. actinomycetemcomitans and E. corrodens were detected more frequently by the cultural method; the other monitored species were detected more frequently by DNA probes than by the cultural methods. Agreements between methods were: 77.2% for A. actinomycetemcomitans; 72.2% for P. intermedia; 75.6% for E. corrodens; 39.4% for F. nucleatum; 35.6% for P. gingivalis; and 68.9% for W. recta. Limitations of the selective cultural methods used probably contributed to the discrepancies for P. gingivalis and F. nucleatum. DNA probe and cultural methods indicated comparable levels of suppression of the monitored species following TC fiber therapy and scaling. The microbiota of control fiber and untreated sites did not appear to be significantly altered by either method.
Epithelial‐connective tissue interaction on the tooth surface: An in vitro model
Authors: Pitaru S. , Hekmati M. , Metzger Z. , Savion N.
Published: July 2006

In the present study, an in vitro system was developed and designed to examine the interaction between gingival fibroblasts (GF) and epithelial cells (EC) on the tooth surface. Porcine roots were cut transversely into 300 μ‐thick root slices (RS). Gingival explants were placed on the upper RS surface and cultured in a defined medium permissive for the growth of EC. After 4 or 6 days, RS yielding EC were transferred onto confluent cultures of GF and further co‐cultured for either 4 or 8 d. Cultures were then fixed and examined by SEM. The upper RS surfaces and the upper half of their peripheral aspect were covered by EC. The lower half of the peripheral RS surfaces were populated by GF originating from the confluent culture of GF. EC and GF made contact at approximately the middle of the side of the root slice. In cultures of epithelial components grown in defined medium for either 4 or 6 d and harvested 4 d after assembling the system, the EC‐GF junction was located 117 ± 45 and 271 ±82 μ, respectively from the upper RS aspect. Extending the co‐culture period did not affect the EC‐GF junction location. These results indicate that GF‐EC contact stops the migration of these cells on root surfaces in vitro. The described system should be valuable for studying cellular events that may affect the formation of a new dentogingival junction following surgical periodontal therapy.
Attachment of cementum on different hydroxylapatite ceramic (HAC) substrata in vivo. A light and electron microscopic study
Authors: Holtgrave E. A.
Published: July 2006

The role of substrate surface characteristics for periodontal regeneration was studied in rats. Cementogenesis was initiated by dental follicle cells retained after dissecting out a molar tooth germ in 5‐day‐old rats. The tooth germ was substituted by a bone replacement material, namely HAC granules of porous consistency. Tissue blocks were removed after 24 weeks and processed for light and electron microscopic examination. On all HAC surfaces a new cementumlike tissue developed, similar to that of natural root surfaces. The results strongly indicate that the exposure of collagen fibers is not essential in order to achieve new periodontal attachment.
Use of synthetic oligonucleotide DNA probes for the identification of different strains of Fusobacterium nucleatum
Authors: Bolstad Anne Isine , Skaug Nils , Jensen Harald B.
Published: July 2006

The ability of three different otigonucletide probes to identify different oral strains of Fusobacterium nucleatum was tested. Probes 119 and 214 were designed on the basis of known amino acid sequences from the N‐terminal end of an outer membrane protein of F. nucleatum strain Fevl. Probe H 2.1, was a randomly cloned chromosomal DNA fragment of 2.1 kbp. The specificities of the probes were examined by testing each of them against a panel of five other species of Fusobacterium (six strains), oral and non‐oral, and also against seven different oral species of six other genera. The chromosomal DNA of the bacteria to be examined was digested to completion using the restriction enzymes Hinc II, Hind III, Eco RI, Eco RV and Sau 3AI. Digests were run on agarose gels and subjected to southern blotting before being hybridized with the probe in question. The results were confirmed by running a slot blot of genomic DNA from all of the 19 strains and hybridizing with a probe H 2.1. Probe H 2.1 turned out to be the most specific and useful of the three probes investigated. By use of this probe, interstrain identification of the six different strains of F. nucleatum could be performed and the strains could be distinguished from other oral species found in the oral cavity, such as Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Capnocytophaga sputigena, Porphyromonas (Bacteroides) gingivalis, Eikenella corrodens and Leptotrichia buccalis. The probe reacted weakly with other non‐oral species of the genus Fusobacterium, and there was no problem in distinguishing between the different strains.
Black‐pigmenting Gram‐negative bacteria in periodontal disease. II. Screening strategies for detection of P. gingivalis
Authors: Mombelli Andrea , McNabb Hal , Lang Niklaus P.
Published: July 2006

The purpose of this analysis was to evaluate the feasibility of detecting P. gingivalis using selected sites and to indicate increased proportions of this organism in periodontitis patients. In 10 patients suffering from moderate to advanced periodontal disease, separate microbiological samples were taken from the mesial, buccal, distal and oral (lingual or palatal) aspects of every tooth. This yielded a total of 927 microbiological samples, 84 to 102 per patient. Three distinct patterns of distribution and relative proportion of P. gingivalis were recognized. In one group of patients, the organism was not cultured. In a second group, few positive sites with low proportions of P. gingivalis were present. A third group of patients yielded high frequencies and proportions of P. gingivalis. The number of samples necessary to diagnose the presence of P. gingivalis at a 95% confidence level varied considerably between the three groups. In 4 patients, sampling 4 randomly selected sites was sufficient, while in the remaining 3 positive patients, 25 or more samples were required to detect the organism with equal certainty. Seven different protocols for multiple subgingival sampling were studied. When considering the number of samples needed to detect the presence of P. gingivalis and to estimate the highest proportion of this organism, selection of the deepest pocket in each quadrant was the most efficient method of sampling.
Identification of components in Fusobacterium nucleatum chemostat‐culture supernatants that are potent inhibitors of human gingival fibroblast proliferation
Authors: Bartold P. M. , Gully N. J. , Zilm P. S. , Rogers A. H.
Published: July 2006

This present investigation concerned the effect of chemostat‐culture cell‐free supernatants of Fusobacterium nucleatum on the growth and synthetic activity of human gingival fibroblasts in vitro. Human gingival fibroblasts were cultured in fetal calf serum supplemented Dulbecco‐Vogt medium containing various dilutions of conditioned or unconditioned bacterial culture medium. Cell proliferation was monitored by assessing cell growth over 5 days or incorporation of [3H]‐thymidine into DNA. Protein and proteoglycan synthesis were monitored by the incorporation of [3H]‐proline and [35S]‐sulfate, respectively, into macromolecules. While the conditioned culture medium caused a complete inhibition of cell growth and incorporation of [3H]‐thymidine DNA, there was no discernible effect on protein or proteoglycan synthesis. This indicated that the cells remained viable yet unable to divide. Such a view was supported by the observation that the inhibitory effect was reversible upon removal of the conditioned medium. This activity had a molecular size less than 30000, was heat‐stable and nonvolatile. Chemical analysis of the conditioned bacterial culture supernatants indicated that high proportions of butyrate, ammonium, and acetate were present. When these components were added to unconditioned medium and tested, most of the inhibitory activity could be attributed to ammonium and butyrate. Since many bacteria which constitute the subgingival microflora release ammonium and butyrate, a very high concentration of these metabolites may well accumulate. Clearly, the potential for inhibition of fibroblast proliferation has ramifications related to diminished tissue repair following bacterially‐induced periodontal destruction.
Immunohistochemical localization of collagenous components in healthy periodontal tissues of the rat and marmoset (Callithrix jacchus). II. Distribution of collagen types IV, V and VI
Authors: Romanos G. E. , Schröter‐Kermani C. , Hinz N. , Wachtel H. C. , Bernimoulin J.‐P.
Published: July 2006

The immunohistochemical distribution of collagen types IV, V and VI has been demonstrated in healthy periodontal tissues of rats and marmosets following decalcification of the maxillae and mandiblae in 0.2 N HC1. An intense fluorescence with anti‐collagen type IV antibodies was demonstrated in the basement membranes of the epithelium and of the blood vessels and nerves. In the alveolar bone stroma and in the periodontal ligament (PL) collagen type IV was present only in the basal membranes of the blood vessels and nerves. In comparison, collagen type V was observed in a fibrillar pattern in the gingival connective tissue, as well as the PL. In the PL, type V collagenous fibers demonstrated a parallel distribution with stronger fluorescence near the cementum surface. Collagen type VI could be demonstrated in fine fibers present in the gingival connective tissue and the PL. Blood vessels and nerves were not stained in the marmoset, but were in the rat, where a localization of collagen type VI was demonstrated in these areas. Alveolar bone and cementum, as well as the Sharpey's fibers embedded in these tissues, were not stained with antibodies against collagen type V and type VI, but a pericellular localization of these collagenous components could be observed. Collectively, these results provide basic information on the relative distribution of different collagen types in normal tissues of rats and marmosets that will be required for future studies on the effects of pathological, reparative and regenerative processes.
Immunoshistochemical localization of epidermal growth factor receptors in human gingival epithelia
Authors: Nordlund L. , Hormia M. , Saxén L. , Thesleff I.
Published: July 2006

Epidermal growth factor (EGF) is a small molecular weight polypeptide which is thought to have important functions in epithelial growth and differentiation and in wound healing. EGF exerts its action on cells through binding to a cell surface receptor. Using immunohistochemistry and a monoclonal antibody (mAb) directed against the EGF receptor, we have examined gingival specimens of periodontally healthy individuals and patients with adult adult (AP) and juvenile periodontitis (JP), as well as epithelial cell rests of Malassez. EGF receptors were expressed at high levels on the cell surface of basal cell layers of gingival epithelium. In normal junctional epithelium, on the other hand, specific labeling was faint or negative, indicating that receptors are poorly expressed or absent in these cells. No differences were detected between uninflamed gingival specimens of periodontally healthy subjects and of patients with JP. Instead, in biopsies of inflamed tissue from AP patients, an intense cell surface labeling was revealed in proliferating epithelial cells. Moreover, the epithelial cell rests of Malassez bound the antibody intensely. The results suggest that EGF is involved in control of epithelial growth and differentiation in periodontal tissucs.
Multicenter evaluation of tetracycline fiber therapy: II. Clinical response
Authors: Goodson J. M. , Cugini M. A. , Kent R. L. , Armitage G. C. , Cobb C. M. , Fine D. , Fritz M. E. , Green E. , Imoberdorf M. J. , Killoy W. J. , Mendieta C. , Niederman R. , Offenbacher S. , Taggart E. J. , Tonetti M.
Published: July 2006

The safety and efficacy of periodontal disease treatment by intrapocket placement of tetracycline (TC) fibers was investigated in a 60‐day multicenter study conducted by selecting 4 sites in each subject with 6–10 mm pockets that bled on probing. Sites were randomly assigned to 1 of 4 test groups: TC fiber therapy, scaling, control fiber (fibers without drug), or untreated. TC fibers and control fibers were placed to fill the pocket and were maintained with a cyanoacrylate adhesive for 10(±2) d. Scaling was performed for a minimum of 5 min under local anesthesia. Following initial tooth cleaning procedures, pocket depth, attachment level and bleeding on controlled‐force probing were measured at baseline and at 30 d, and 60 d following therapy. Analysis of data from 107 subjects who had complete clinical data sets indicated that TC fiber therapy significantly decreased pocket depth, increased attachment level, and decreased bleeding on controlled‐force probing to a greater extent than observed in all other test groups including scaling. These effects were greater than, and in addition to, effects that occurred due to prophylaxis and improved home care. No serious adverse side‐effects attributed to TC fiber therapy were observed. No TC fiber‐treated sites abscessed and superinfection was not noted. A transient redness at fiber removal was seen at 21% of the sites. Although fibers were placed without anesthesia, mild pain on initial placement was infrequent (19%) and abated rapidly. The results indicate that TC fiber placement provides a safe and effective means for treatment of periodontal infections.
Ultracytochemical localization of basal lamina anionic sites in the rat epithelial attachment apparatus
Authors: Oyarzún‐Droguett Alejandro
Published: July 2006

The basal lamina anionic sites of the epithelial attachment apparatus (EAA) were investigated at the electron microscopic level in adult rat periodontium. After 1M NaCl junctional epithelium detachment, an irregular and fluffy basal lamina‐like structure appeared to cover the cementum surface. This structure reacted positively with polyethyleneimine (PEI), a strongly cationized ultrastruc‐tural tracer, appearing to be composed of highly electron‐dense microaggregates. Depending on section plane, double‐tracked structures of undefined length were found within PEI precipitates and closely related to cementum collagen fibrils. After nitrous acid de‐N‐sulphation, 8 nm wide sets of two parallel lines were clearly identified. “Double tracks”, i.e., sets of paired lines with peripherical PEI electron‐dense material, were found to self‐assemble to form dimers, clusters or more complex organizational patterns. From sensitivity towards nitrous acid oxidation and positive control observations, it was concluded that basal lamina anionic sites in the EAA. represented by PEI microaggregates, contain heparan sulfate proteoglycans (HSPGs). Furthermore, high resolution ultrastructural images demonstrated that HSPGs adopt a morphological appearance of “double tracks” in the tissue. On the other hand, the present findings suggest that HSPGs clusters, never found in the mucosal basement membrane used as positive control, may be related to a functional specificity of the tissue at the dento‐gingival junction.
Logical and analytic issues in dental/oral product comparison research
Authors: Imrey Peter B.
Published: July 2006

Possible meanings of “superiority” and “equivalence” in comparative dental studies are considered. A proposed refinement of vocabulary is introduced to precisely distinguish between these meanings. Implications for data analysis of different interpretations of “superiority” and “equivalence” are explored, as are implications for study design where design and analytic considerations are inseparable. Conceptual problems of equivalence studies are stressed. Choice of analytic unit(s), scaling of dependent variables, use of surrogate variables, and validity checking are discussed as they pertain to comparative studies. Analytic methods for correlated responses and categorized responses are briefly surveyed, particularly with reference to periodontal research.
Toward strategies for the analysis of periodontal disease clinical trials
Authors: Alemayehu D. , Goldberg J. D. , Koury K. J.
Published: July 2006

We consider design, analysis and regulatory issues relating to clinical trials in periodontal disease and identify complications commonly associated with such studies. Alternative statistical procedures that can be used for the analyses of data from periodontal research are reviewed and a case study of the analysis of a Phase II periodontal disease clinical trial is provided to illustrate the use of one of these procedures.
Some thoughts on the measurement of gingivitis
Authors: Proskin Howard M.
Published: July 2006

The selection of a method for measurement is of critical importance in the planning of a study. Despite the great strides afforded by research of gingivitis, a “gold standard” for its measurement has yet to be clearly established. Traditional clinical indices continue to serve as “gold standards” in many investigations. There is a need for some caution and tentativity in interpreting the results of such studies. Additionally, those studies which yield data on an ordinal scale should make more use of statistical methodologies specifically geared toward the analysis of such data.
Specific statistical considerations relevantto the design and analysis of gingivitis trials demonstrating
Authors: Kingman Albert
Published: July 2006

Simulation studies were conducted to address specific statistical issues which arise in the design and analysis of gingivitis studies whose principal aim is the demonstration of superiority or equivalence of one product to another. The effects of measurement scale, using differences or ratios of group means, particular statistical test produces and specific rules demonstrating superiority or equivalence were investigated. An alternative concept to equivalence—denoted “least as good”—was also defined and evaluated. For a wide class of possible distributions of gingivitis scores, characterized by specific gamma distributions, the student‐t test applied to means of subject GI gingivitis scores proved to be the most powerful of the test produces considered, having statistical properties quite similar to the randomization or permutation test procedure. Transformations of subject GI mean gingivitis scores did not produce an advantage in demonstrating either superiority or equivalence, and in some cases made it more difficult. Little difference was observed in test results when using the difference in group means as compared with using the ratio of group means for demonstrating either equivalence or superiority. The clinically significant rule produced the lowest false‐positive rates for products slightly better than the active control, and similar false‐positive and ‐negative rates as the statistically significant rule for products clearly superior to the active control. Demonstration of product equivalence will require more subjects per group than demonstrating product superiority, the size of this difference being a function of the definition of superiority that is accepted. Showing that the 90% confidence interval for 100*R is completely contained within the [90%, 110%] interval is the preferred method of demonstrating equivalence today, although much more research needs to be done to improve methods for demonstrating product equivalence. The “least as good” alternative to “equivalence” makes it easier to demonstrate “equivalence” for products slightly better than the active control product, but both experience great difficulty in demonstrating equivalence for lest products not quite as good as the active control.
Considerations for the interpretation of findings from single and multiple studies of periodontal conditions
Authors: Zimmerman Stuart
Published: July 2006

This paper reviews considerations involved in the interpretation of results of individual periodontal clinical trials and the synthesis of findings of multiple studies. The purpose of each study must be considered, particularly whether it is an epidemiological investigation, prevention trial or therapeutic clinical trial. The definition of clear end‐points, whether they be hygiene end‐points associated with calculus and plaque or disease end‐points that measure extent of gingivitis and periodontitis, is essential. Other statistical considerations include the following: adequate sample size, balanced design, use of covariates, issues of the appropriate sampling unit, and proper statistical analysis. Statistical issues that must be considered include the types of tests of hypotheses, use of multiple comparison procedures when more than two groups are involved, corrections for multiple testing and precise estimation of parameters with corresponding confidence intervals. When comparing across clinical trials, three sources of heterogeneity that must be considered are: treatments, diseases, and target populations. The technique of meta‐analysis is described for the statistical interpretation of data arising from several trials. A meta‐analysis is conducted for six dental clinical trials that evaluated a triclosan/copolymer formulation for the reduction of plaque, calculus or gingivitis. Results indicate that the first five studies, which were reported simultaneously, showed a common effect, i.e., that the formulation successfully reduced either plaque or calculus. When the sixth study, reported at a different time, was added to the analysis, the collection of studies did not satisfy the homogeneity assumption necessary for estimating a common effect size. This illustrates the importance of testing for homogeneity before pooling possibly dissimilar studies.