bluuebunny/crossref_metadata_2025 huggingface dataset:
Topical flurbiprofen treatment of periodontitis in beagles
Authors: Williams R. C. , Jeffcoat M. K. , Howell T. H. , Reddy M. S. , Johnson H. G. , Hall C. M. , Goldhaber P.
Published: July 2006

The effect of the non‐steroidal anti‐inflammatory drug flurbiprofen, topically applied, on the progression of periodontal disease was studied in 12 beagle dogs over a 13‐month period. Standardized radiographs were used to measure the rate of bone loss. Following a 6‐month pretreatment baseline period, 6 dogs were treated daily with 0.3 mg flurbiprofen gently applied to the gingival margin in 1 ml of gel vehicle. Six untreated dogs served as controls. In the untreated control dogs the rate of bone loss in the treatment period did not change significantly from baseline, although the rate was elevated by 38%. In contrast, the rate of bone loss significantly decreased by 71% from baseline in the flurbiprofen‐treated dogs. The untreated control dogs lost 10 teeth during the treatment period whereas the topical flurbiprofen‐treated dogs lost only 1 tooth. The data indicate that topical application of flurbiprofen in a gel vehicle significantly inhibits alveolar bone loss in beagles over a 7‐month treatment period. The data also indicate that topical flurbiprofen is associated with the loss of considerably less teeth than in untreated control dogs over the 7‐month treatment period.
Immunohistochemical localization of epithelial cells expressing transferrin receptors in normal and diseased human dento‐gingival junction
Authors: Salonen J. , Sewón L. , Paunio K.
Published: July 2006

The rate of cell proliferation, which is associated with the density of transferrin receptors on the cell surface, may have an effect on the homeostasis of epithelial cell populations in the dento‐gingival junction. In addition to moderate labeling of basal cells, intensive labeling of transferrin receptors was found on suprabasal cells of sulcular epithelium towards the gingival margin of healthy tissues. In contrast, biopsies from diseased tissue exhibited increased labeling towards the base of the pocket. This distribution of labeling suggests that the distinct suprabasal population of cells expressing the transferrin receptors is associated with the process of pocket formation. The density of transferrin receptors decreased towards the lamina propria of gingiva and towards the apical termination of the junctional epithelium. In samples from periodontal pockets, the number of receptors was high eveo in the germinative cell layers. Labeled cells were also demonstrated in crevicular washings. The washing method together with the demonstration of transferrin receptors may provide a new approach for the study of epithelial cell homeostasis in the dento‐gingival tissues.
Black‐pigmented Bacteroides and spirochetes in the subgingival microbiota of prepubertal schoolchildren
Authors: Angela M. , van Oosten C. , Mombelli Andrea , Gusberti Francesco A. , Lang Niklaus P.
Published: July 2006

As part of an ongoing longitudinal study of the subgingival microbiota at the onset of – and during – puberty, the subgingival microbiota and clinical periodontal condition in prepubertal children were studied. Twenty‐two boys and 20 girls (age 11.4 ± 0.4) participated in the study. Using the criteria of secondary sex characteristics (Tanner index) and radiographic bone age, 15 boys and 16 girls were classified as clearly prepubertal. At the maxillary first molars, the Plaque Index (P1I) was assessed, subgingival samples were obtained and Gingival Index (GI) and Papillary Bleeding Index (PBI) were determined. Using continuous anaerobic techniques, samples were cultivated on selective and non‐selective media and were studied by darkfield microscopy. Special attention was focused on the occurrence of black‐pigmented Bacteroides (BPB) and spirochetes. In 75% of the children, BPB (> 104 colony forming units cfu) were detected. B. intermedius was the most commonly isolated BPB. At sites scoring P1I = 2 33%, at those scoring P1I= 1 22% and at sites scoring P1I = 0 none of the samples contained BPB > 106 cfu. Likewise, > 106 cfu of BPB were found in 40% of the sites with a PB1 of 3, in 35% of the sites with a FBI of 2, while none of the sites with a FBI of 0 or 1 contained these numbers of BPB. Similar observations were made for the proportions of spirochetes. The study confirmed that BPB and spirochetes are frequently found in prepubertal children and are correlated with the presence of supragingival plaque and the degree of gingivitis.
Immunocytochemical in vivo localization of fibronectin‐rich contact sites on fibroblasts of normal periodontal ligament and inflamed gingiva
Authors: Cho Moon‐ll , Garant Philias R. , Lee Yu Lin
Published: July 2006

Fibroblast‐to‐matrix attachment sites were studied by routine electron microscopy and immunocytochemistry. Rabbit antibodies to beagle dog plasma fibronectin and sheep antirabbit antibodies conjugated with horseradish peroxidase or ferritin were used to localize fibronectin at fibroblast‐to‐matrix attachment sites. In fibroblasts of healthy periodontal ligament, the attachment sites consisted of rectangular patches of amorphous material juxtaposed to the external surface of the plasma membrane. At these sites, the cell membrane was more densely stained and the adjacent cytoplasm was characterized by increased density and a high concentration of cytoplasmic filaments. The extracellular plaques contained fibronectin. Morphometric analysis indicated that the attachment plaques were approximately 90 nm thick, 250 nm wide, and 550 nm long, and distributed uniformly over both the cell body and peripheral cytoplasmic processes. In inflamed gingiva, the attachment sites were larger, irregular in shape, and with greater amounts of extracellular amorphous material and fibronectin associated to the cell surface. Cytoplasmic filaments were more often bundled as stress fibers which terminated in fibronexus‐type junctions with extracellular fibronectin‐coated filaments.
Infection with a gram‐negative organism stimulates gingival collagenase production in nondiabetic and diabetic germfree rats
Authors: Chang K. M. , Ramamurthy N. S. , McNamara T. F. , Genco R. J. , Golub L. M.
Published: July 2006

Experimental diabetes in the rat rapidly produces a shift in the gingival crevicular microflora which is followed, within weeks, by increased production of collagenase by the gingival tissues. To assess the contribution of endogenous (hormonal or metabolic) and exogenous (altered crevicular microflora) factors on this diabetes‐induced abnormality in collagenase production, the following series of experiments was undertaken: In each experiment, the germfree rats were housed in two isolators. Half of the animals in both isolators were rendered diabetic (D) with streptozotocin while the remainder were left untreated (non‐diabetic (ND) controls). All of the germfree ND and D rats in one isolator of the pair were then infected with either a Gram‐positive (S. mitis or A. odontolyticus) or a Gram‐negative (Capnocytophaga, A. aclmomycetemcomitans or B. gingivalis) organism. In the other isolator, the ND and D rats were maintained in their germfree state. After 3 wk, the germfree and monoinfected rats were killed and the gingiva (and in one experiment, skin) were dissected. Collagenase activity produced by gingiva in culture (or extracted from gingiva or from skin) was measured using 14C‐collagen fibrils (or [3Hmethyl] collagen molecules) as the substrate. Diabetes increased the collagenolytic activity in the gingiva and skin of the germfree rats. Infecting the germfree rats with a Gram‐positive organism had no effect on collagenase activity generated by the gingival explants in the tissue culture system. In contrast, infection with any of the Gram‐negative organisms dramatically increased the collagenase activity in the gingival tissues of the ND rats in culture, an effect not seen in the D group of rats using this system. However, monoinfection with B. gingivalis did increase collagenase activity in the extracts of gingiva (but not in skin) from both ND and D rats, with the latter group showing the highest level of enzyme activity. We suggest (i) that experimental diabetes stimulates collagenase production in gingiva by both endogenous (hormonal) and exogenous (bacterial) mechanisms, and (ii) that crevicular Gram‐negative organisms stimulate collagenolysis in the adjacent gingival tissues by releasing bacterial products (e.g. endotoxins) which penetrate into the connective tissue and enhance host cell collagenase production.
Bacterial chemotactic peptide‐degrading enzymes in human saliva
Authors: Ferguson M. M. , Mellor D. M. , Morris K. , Chadwick V. S.
Published: July 2006

Chemotactic N‐formyl oligopeptides are produced by bacteria at sites of bacterial colonization in the digestive tract, but are susceptible to degradation by intestinal mucosal and luminal carboxypeptidases. Since production of such peptides by oral bacteria may promote neutrophil leukocyte accumulation in periodontal inflammatory disease, the activity and source of chemotactic peptide‐degrading enzymes in human saliva was investigated. An N‐formyl‐methionyl‐leucyl‐phenylalanyl carboxypeptidase was identified in whole mixed, but not pure parotid or submandibular saliva. The enzyme activity was attributable to a bacterial rather than a host source.
Spontaneous periodontitis in a sample group of the monkey Macaca Fascicularis
Authors: Friskopp J. , Blomlöf L.
Published: July 2006

The frequency of periodontal disease in humans has been studied extensively and there are several reports which indicate an individual response. However, the non‐human primates are poorly described in regard to these matters. This study describes spontaneously occurring periodontitis in a sample group of the monkey Macaca fascicularis. Ninety‐seven animals were examined, pocket depths were measured with a graded probe and one “bite‐wing” radiograph was exposed on each side. Thirty‐two mean values for greatest pocket depth and 20 mean values for greatest distance from the cementoenamel junction (CEJ) to the alveolar bone were calculated. A tooth was said to have periodontitis if one site or more had a pocket depth of at least 5 mm and a distance of at least 2 mm from CEJ to the alveolar bone. Approximately 8% of the monkeys and 1% of all teeth had periodontitis. The results suggest that the ability to develop gingivitis is rather uniform among individuals of Macaca fascicularis and. further, that their susceptibility to developing destructive periodontitis varies greatly.
Ultrastructural evidence of directed cell migration during initial cementoblast differentiation in root formation
Authors: Cho Moon‐ll , Garant Philias R.
Published: July 2006

Root formation in 14‐day‐old Sprague‐Dawley rats was studied by light and electron microscopy. Special attention was focused on initial cementoblast differentiation. Disruption of the epithelial root sheath appears to be a consequence of directed cell migration by cells of the dental follicle proper which undergo differentiation into precementoblasts. Precementoblasts rapidly develop polarity towards the dentin, exhibiting major cytoplasmic processes rich in cytoplasmic filaments. These processes grow toward and eventually contact the dentin matrix. It is suggested that the cells of the dental follicle proper are cementoblast precursors which respond to chemoattractant substances released from newly deposited dentin matrix‐ and/or basal lamina‐associated material of root sheath origin.
Periodontal ligament fibroblasts, preosteoblasts, and prechondrocytes express receptors for epidermal growth factor in vivo:A comparative radioautographic study
Authors: Cho Moon , Garant Philias R. , Lee Yu Lin
Published: July 2006

Radioiodinated mouse epidermal growth factor (EGF) was used in light and electron microscopic radioautographic studies of the binding of EGF to various cells of young rats. High levels of bound EGF were noted on periodontal ligament fibroblasts, preosteoblasts, and prechondrocytes. Fibroblast in the oral mucosa, tail subepithelial connective tissue, and tail tendon demonstrated much lower levels of binding. Ultrastructural radioautography revealed that silver grains, indicative of radioiodinated EGF, were positioned adjacent to or over the plasma membranes of the cells at 5 minutes after injection of the growth factor. The significance of the high level of EGF receptors on periodontal ligament fibroblasts, comparable to the number observed on preosteocytes and prechondrocytes, is discussed in terms of the possible progenitor role of periodontal ligament fibroblasts for adjacent hard tissue‐producing cells.
Effect of collagen solution application on healing following surgical treatment in colony‐bred monkeys
Authors: Minabe Masato , Kogou Tatsuji , Kodama Toshiro , Sugaya Akira , Tamura Toshiyuki , Hori Toshio , Watanabe Yoshihisa
Published: July 2006

The present study was performed to investigate the effects on periodontal regeneration in flap surgery of acid conditioning and the application of a collagen solution to the root surface. Bone defects were artificially produced in 4 monkeys by removing cortical bone in an apical direction within 4 mm from the alveolar bone crest, following incision and elevation of the buccal gingiva of the second premolars, first molars and lateral incisors of the maxilla and mandibula. After root planing, the root surface at the bottom of the bone defect was notched. The root surfaces were then subjected to various types of root preparation and divided into (1) a group given topical application of collagen solution following acid conditioning, (2) a group given topically applied collagen solution, (3) a group given acid conditioning and (4) controls. The animals were sacrificed 3 or 6 weeks after surgery and histopathologically examined. The results indicated that the method of applying collagen solution to the root surface after acid conditioning in flap surgery promoted suppression of epithelial migration and new cementum formation more effectively than the conventional method of preparation using acid conditioning alone.
The effect of patient‐associated factors on the reproducibility of the mouth bleeding score
Authors: Janssen P. T. M. , Faber J. A. J.
Published: July 2006

Patient effects on the reproducibility of dichotomous measures of bleeding tendency after probing were investigated. Large variations in this reproducibility were observed between patients. Therefore the accuracy of the mouth bleeding score, a gingival index system, also depended on the type of patient. To illustrate the effects on the prediction intervals of the mouth bleeding score, the patients were divided into two groups using cluster analysis. The prediction intervals of the mouth bleeding scores determined for each group differed considerably from one another. Categorizing patients by the average probing depth and the average chance of bleeding, measured over all sites within a patient, provided a statistical evaluation of differences between successive mouth bleeding scores while considering the effect of the patient.
The action of sodium fluoride on suspected periodontopathogens
Authors: Yotis W. W.
Published: July 2006

Certain oal bacteria have been implicated in the initiation of chronic gingivitis and the progression of periodontitis. The present study was conducted to assess the influence of sodium fluoride on the in vitro growth and on various enzymes of Treponema denticola, Actinomyces actinomycetemcomitans, Fusobacterium nucleatum and 3 Bacteroides species. Complete inhibition of growth for 5 strains of T. denticola, 3 strains of A. actinomycetemcomitans, 3 black‐pigmented strains of Bacteroides and 3 strains of F. nuclatum was observed with 40, 80, 160, and 320 μg/ml of F‐ respectively. The API system, a convenient and rapid method designed to detect 19 enzymes, was employed primarily to determine the relative sensitivity of demonstrable enzymes to F‐ for the assay microorganisms. F‐concentrations of 10–60 μg/ml inhibited the acid phosphatase of T. denticola or the acid and alkaline phosphatase of A. actinomycetemcomitans. However, F‐ at a concentration of 10–60 μg/ml did not influence any of the detectable enzymes of the other assay bacteria. Periplasmic phosphatases hydrolyze impermeable phosphate esters to compounds that could then be transported and utilized by the cells.
Histopathologic features of spontaneous periodontitis in adult Macaca fascicularis monkeys
Authors: Bosshardt Dieter , Schroeder Hubert E.
Published: July 2006

In the general absence of histopathologic data on spontaneous periodontitis in non‐human primates, the present study was performed using a group of 6 M. fascicularis monkeys (1 female, 5 males) about 8 to 10 years of age. Four animals were given one intraveneous injection of 3H‐proline 24 h prior to death. The perfusion‐fixed jaws were processed for serial ground sectioning of the posterior teeth. Sections cut mesio‐distally or horizontally were examined by lightmicroscopy, polarized light, roentgenography and radioautography. It was shown that, (1) supra‐ and subgingival plaque and calculus were omnipresent interdentally, (2) chronic established gingivitis was most common, (3) incipient to moderate periodontitis occurred in 3 animals, primarily around maxillary premolars and molars, (4) characteristic histopathologic features allowed differentiation between inactive and postactive lesions, (5) moderate periodontitis could be associated with intensive new bone formation, and. (6) high protein synthetic activity was characteristic for the healthy periodontal ligament, a chronically inflamed gingiva, and the trabecular bone of the alveolar process with signs of peripheral bone loss. Severe periodontitis was seen in 1 animal only, and it also suffered from periodontogenic infections of the face, and from emaciation.
Identification of matrix metalloendoproteinase inhibitor (TIMP) in human parotid and submandibular saliva: partial purification and characterization
Authors: Drouin Louis , Overall Christopher M. , Sodek Jaro
Published: July 2006

Matrix metalloendoproteinase inhibitor (TIMP) is constitutively expressed by a variety of cells and is present in most connective tissues, and in serum and amniotic fluid. In our previous studies, collagenase inhibitor activity has been identified in saliva (5). To determine the nature of this inhibitor, fresh human parotid saliva was first concentrated by ammonium sulfate precipitation and the 20–60% saturated ammonium sulfate fraction containing the inhibitor activity was chromatographed on an AcA 54 gel filtration column. The inhibitor eluted with an apparent Mr of 29000 and a 42‐fold purification was achieved. For characterization, the inhibitor was further purified by heparin‐Sepharose chromatography. The inhibitor, which bound to heparin‐Sepharose in 0.0 M NaCl at neutral pH and remained bound after a 0.18 M NaCl step elution, was eluted with 0.25 M NaCl. The partially purified inhibitor was characterized by its stability at low pH (pH 2.0) and after heat treatment (60° C and 95° C), and by its resistance to organomercurial (APMA) and trypsin treatments. These properties, together with immunoreactivity with an anti‐human TIMP polyclonal antibody on immunoblots. are consistent with the collagenase inhibitor activity being TIMP. Collagenase in either the active or precursor forms was not delected in parotid or submandibular ductal saliva nor after AcA 54 chromatography of parotid ductal saliva. The presence of TIMP in saliva has important implications. First, it has the potential to suppress the activity of matrix metalloendoproteinases released during periodontal inflammation; and second, in the analysis of collagenolytic enzymes in gingival crevicular fluid, it is clear that care must be taken to avoid contamination of the crevicular fluid with saliva.
Failure of Bacteroides gingivalis W83 to accumulate bound C3 following opsonization with serum
Authors: Schenkein Harvey A.
Published: July 2006

Our previous studies have demonstrated that strains of Bacteroides gingivalis are capable of proteolytic degradation and inactivation of complement proteins including the third component of complement C3. Since a crucial step in the ability of complement to control bacterial infections is the binding of C3 fragments to the bacterial surface with subsequent enhancement of phagocytosis, further examination of the importance of the proteolytic capacity of Bacteroides in interactions with complement proteins was carried out by quantitating the amount of C3 bound to two proteolytic Bacteroides gingivalis strains. Pooled normal human serum (NHS) containing 125I‐C3 was incubated with strains of B. gingivalis (W83 and ATCC 33277) and the non‐proteolytic pathogen A. actinomycetemcomitans strain Y4, and samples of the reaction mixtures were removed at various time intervals for determination of bound C3. B. gingivalis 33277 bound only half the number of C3 molecules as did A. actinomycetemcomitans, while B. gingivalis W83 bound very little C3. A large increase in the number of C3 molecules bound to B. gingivalis W83 was noted in assays carried out in the presence of the protease inhibitor TLCK, indicating that bacterial proteases may be responsible for the lack of binding of C3 to strain W83. TLCK treatment modestly increased the accumulation of C3 on strain 33277, but had no effect on A. actinomycetemcomitans. Analysis of 125I‐C3 in supernatants from reaction mixtures of strain 33277, W83, or a proteolytic strain of B. intermedius demonstrated no qualitative differences in the C3 fragments amongst the tested strains or in the presence or absence of TLCK. However, elution of the bound C3 fragments from the B. gingivalis strains following treatment with TLCK and analysis by autoradiography revealed that the majority of C3 fragments bound by both strains in the presence of TLCK was in the form of C3b or iC3b. Therefore, B. gingivalis W83 fails to accumulate C3 during opsonization by serum due to its proteolytic capacity.
Hertwig's epithelial root sheath differentiation and initial cementum and bone formation during long‐term organ culture of mouse mandibular first molars using serumless, chemicallydefined medium
Authors: Slavkin Harold C. , Bringas Pablo , Bessem Conny , Santos Valentino , Nakamura Masanori , Hsu Mingyoun , Snead Malcolm L. , Zeichner‐David Margarita , Fincham Alan G.
Published: July 2006

Studies were designed to test the hypothesis that Hertwig's epithelial root sheath (HERS) synthesizes and secretes enamel‐related proteins that participate in the process of acellular cementum formation. Our experimental strategy was to examine sequential root development of the mouse mandibular flrst molar in vitro and in long‐term organ culture in vitro using serumless, chemical1y‐defined medium. Using anti‐amelogenin, anti‐enamelin and anti‐peptide antibodies, enamel‐related antigens were localized within intermediate cementum during HERS differentiation and root formation in vitro. Cap stage molars maintained for periods of up to 31 days in organ culture expressed morphogenesis and cytodifferentiation as identified by tooth crown and initial root, cementum and bone formation. Metabolically‐labeled HERS products were analyzed by immunodetection using enamel‐related antibodies and one‐ and two‐dimensional SDS gel electrophoresis. A 72 kDa and 26 kDa polypeptide were identified in forming mouse cementum. Both of these root putative cementum proteins yield similar (identical) amino acid compositions; however, both proteins differed from the compositions of either mouse crown enamelin or amelogenin proteins. This approach provides a new and novel in vitro model towards understanding HERS differentiation and functions related to root and bone formation. The data support the hypothesis that HERS cells synthesize polypeptides related to but also difterent from canonical crown enamel proteins.
LPS‐elicited secretory responses in monocytes: Altered release of PGE2 but not IL‐1/β in patients with adult periodontitis
Authors: Garrison Scott W. , Nichols Frank C.
Published: July 2006

Lipopolysaccharide responsiveness in human subjects was assessed through the examination of LPS‐stimulated PGE2 and IL‐1/β release from counterflow isolated monocytes from patients with varying levels of periodontal destruction. This study was performed in order to investigate a possible relationship between LPS‐mediated secretory responses in monocytes and susceptibility to periodontal destruction in humans. Subjects were chosen based on apparent resistance or susceptibility to disease as measured by little or no periodontal destruction versus generalized severe destruction, respectively. Because IFN‐γ can influence LPS‐stimulated responses, the effect of IFN‐γ on the LPS‐stimulated release of PGE2 and IL‐1β was also assessed. Peripheral blood monocytes were separated by counterflow centrifugation and cultured (106/ml/well) with control medium or medium containing LPS from Bacteroides gingivalis, B. intermedius, Actinobacillus actinomycetemcomitans, or Salmonella typhimurium with or without 10 Units/ml recombinant IFN‐γ. Media were exchanged at 24 and 48 hours and culture supernatants assayed for both PGE, and IL‐1β by RIA. Patients classified as Susceptible to periodontitis demonstrated 2‐ to 3‐fold greater PGE2 release than Resistant patients. This difference was observed with all LPS preparations over both the 0–24 hour and 24–48 h culture periods. IL‐1β release, however, was not significantly different between patient groups. IFN‐γ did not affect the LPS‐stimulated release of PGE2 but significantly enhanced the release of IL‐1β. The IFN‐γ effects were similar for both patient groups. These findings indicate that LPS‐stimulated PGE2 release from peripheral blood monocytes may correlate with susceptibility to periodontitis in human subjects.
Prevalence of Bacteroides forsythus and Bacteroides gingivalis in subgingival plaque of prosthodontically treated patients on short recall*
Authors: Gmür R. , Strub J. R. , Guggenheim B.
Published: July 2006

The prevalence of Bacteroides forsythus and Bacteroides gingivalis in subgingival plaque of patients on short recall was analyzed in relation to the probing depth of the test sites. The subjects had excellent oral hygiene and therefore were unlikely to suffer from active periodontal destruction. Sixty‐four subgingival plaque samples, taken from gingival or periodontal pockets with probing depths ranging from 1 to 8 mm, were quantitatively assessed for the presence of the two species using species‐specific monoclonal antibodies in conjunction with a very sensitive indirect immunofluorescence technique. Both organisms were encountered in probes from sites as shallow as 2 mm, but the percentage of positive samples clearly rose in relation to the probing depth of the test sites. Overall, B. forsythus was found to colonize lesions earlier, that is at smaller probing depths, than B. gingivalis. Interestingly, whenever a sample was found to be positive for B. gingivalis it was also positive for B. forsythus. The numbers of B. forsythus and B. gingivalis and the total bacterial cell number found in the pockets were significantly correlated to the probing depth. However, with advancing probing depth the increase of the total cell numbers of the two Bacteroides species was considerably more pronounced than the increase of the total subgingival plaque cell number. The recall interval neither affected the frequency of sites positive for B. forsythus or B. gingivalis nor influenced significantly the proportions of the two species in subgingival plaque. Collectively, the present study identifies B. gingivalis and, in particular, B. forsythus as much more frequent and predominant members of the subgingival flora of gingival and/or periodontal pockets than previously suspected on the basis of culture investigations. Also, it contradicts the hypothesis that the mere presence of these two organisms may be taken as an indicator of active periodontal breakdown.
Langerhans cells in oral epithelium of chronically inflamed human gingivae
Authors: Baelum V. , Fejerskov O. , Dabelsteen E.
Published: July 2006

This study describes the histopathological features and the distribution of oral epithelial Langerhans cells in 19 gingival biopsies originating from an adult Tanzanian population characterized by very poor oral hygiene and severe gingival inflammation. Light‐microscopically, all biopsies contained often large inflammatory connective tissue infiltrates, 6 of which predominantly contained plasma cells while the rest were dominated by lymphocytes. Seven specimens contained peculiar accumulations of round lymphoid and dendritic cells in the lower cell layers of the oral epithelium. These phenomena have not previously been demonstrated in human gingiva and deserve further attention in studies on the pathogenesis of periodontal diseases. Immuno‐histochemical staining with OKT6, OKT4 and OKT8 antibodies showed markedly increased numbers of OKT6‐positive cells in 7 specimens and clusters of OKT4‐ and OKT8‐positive cells in the oral epithelium of 4 specimens. High numbers of OKT6‐positive cells were not related to the presence of intrae pithelial, non‐keratinocyte infiltrates or large connective tissue infiltrates. The variable numbers of oral epithelial Langerhans cells may therefore result from different bacterial antigens elucidating different responses or, alternatively, reflect different responses to similar plaque antigens penetrating the surface of the oral epithelium.
Altered free cytosolic calcium changes and neutrophil chemotaxis in patients with juvenile periodontitis
Authors: Agarwal S. , Reynolds M. A. , Duckett L. D. , Suzuki J. B.
Published: July 2006

Nearly 70–75% of patients with localized juvenile periodontitis (JP) have abnormal polymorphonuclear leukocytic (PMN) chemotaxis. The objective of this study was to determine whether the lower chemotactic response in PMNs from JP patients is associated with a defect in intracellular signal transduction, as measured by stimulus‐induced changes in free cytosolic calcium (Ca2+) mobilization. We report that peptide chemoattractants such as N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) and the complement fragment C5a in direct comparative studies induced lower amounts of initial Ca2+ mobilization in PMNs from JP patients than healthy controls, as monitored by intracellular fura‐2 fluorescence. The initial resting levels of free cytosolic Ca2+ in PMNs from JP patients and normal individuals were found to be similar. fMLP and C5a both mobilized Ca2+ in PMNs in a dose‐dependent manner. Treatment of PMNs from 0.16 to 20 nM fMLP and 0.2 to 20 nM C5a resulted in elevated levels of free cytosolic Ca2+. However, above 20 nM fMLP and 5 nM C5a concentrations the extent of total Ca2+ mobilization did not differ significantly. Although fMLP and C5a caused Ca2+ mobilization in PMN cells from JP and healthy control subjects, fMLP stimulation induced higher levels of free cytosolic Ca2+ mobilization in PMN cells from healthy control subjects (141.29 ± 25.55 nM/ 2 ± 106 PMNs), than PMNs from JP patients (62.33 ± 23.76 nM/2 ± 106 PMNs). Similarly C5a induced higher levels of Ca2+ mobilization in PMNs from healthy control individuals (130.43 ± 18.26 nM Ca2+/2 ± 106 PMNs), when compared to JP patients (49.92 ± 14.92 nM Ca2+/2 ± 106 PMNs). JP patients also exhibited significantly lower chemotaxis towards fMLP (74.51 ± 6.31%) and C5a (69.25 ± 5.44%) as compared to healthy control subjects. The data suggest that PMNs from JP patients exhibit an intrinsic anomaly in the mechanism(s) responsible for intracellular Ca2+ mobilization which correlates with a PMN chemotactic defect.
Changes in cell phenotype during regeneration of junctional epithelium of human gingiva in vitro
Authors: Salonen Jukka I. , Kautsky Mikael B. , Dale Beverly A.
Published: July 2006

The relationship between cell attachment and the phenotype of the attached oral epithelial cells was studied by comparing junctional epithelium (JE) with a culture model for JE in which epithelial cells form an equivalent organization of tissues. Gingival explants were cultured on either a high or a low protein‐binding membrane. The cut edge of epithelium and connective tissue was placed on the membrane; epithelial cells migrated to form a sheet of tissue between the explant and the membrane substratum. Cells which grew in contact with the high protein‐binding membrane attached to the substratum and assumed a cuboidal shape. With time in culture these cells showed a decrease in reactivity with antibodies to φ‐3 antigen (an antigen associated with epithelial migration) and an increase in reactivity with antibodies to cytokeratin 19 (a marker for JE). Cells grown on the low protein‐binding membrane did not exhibit changes in shape or antigens. Because similar features were found in the JE in vivo, it was concluded that the junctional cells which are Directly attached to the tooth (DAT cells) have a nonmigratory phenotype that develops as a response to the tooth surface. Because the cells are in contact with a metabolically inert material the changes appear to be largely self‐induced. The culture method allows studies on putative inducer molecules and on mechanisms which may control the phenotype of epithelial cells at the dentogingival interface.
Ultrastructural and histochemical study of β‐tricalcium phosphate resorbing cells in periodontium of dogs
Authors: Wada Takashi , Hara Kohji , Ozawa Hidehiro
Published: July 2006

β‐TCP was implanted in surgically prepared alveolar bone defects on the mesial side of the upper canine. The dogs that we used were sacrificed after 5 weeks, fixed by perfusion, and the β‐TCP resorbing cells were examined ultrastructural‐ly and histochemically, with the following results: (1) β‐TCP was resorbed by macrophages and multinucleated giant cells. (2) Mitochondria, vacuoles and Golgi apparatus were abundant in β‐TCP‐resorbing multinucleated giant cells that possessed neither ruffled borders nor clear zones. (3) The addition of tartric acid inhibited acid phosphatase activity in the cytoplasm of the multinucleated giant cells and macrophages.
Transition dynamics in experimental gingivitis in humans
Authors: Danielsen B. , Manji F. , Nagelkerke N. , Fejerskov O. , Baelum V.
Published: July 2006

This study was conducted in order to investigate the dynamics of the gingival inflammatory status during periods of plaque accumulation and thorough oral hygiene. After a period of prophylaxis, 42 volunteers were asked to abstain from all oral hygiene measures for 2 weeks, whereafter oral hygiene was reinstituted. In the absence of oral hygiene, plaque was found at virtually all sites after 7 days and the number of sites with gingivitis increased simultaneously. A reduction in gingival inflammation occurred subsequent to plaque removal. During phases of both plaque accumulation and thorough oral hygiene, sites were found to convert from non‐inflamed to inflamed status concurrently, as in the reverse direction. No association between plaque and gingivitis was revealed. The gingival status of a single site was a poor predictor of its status on the subsequent occasion. The proportion of inflamed sites converting to non‐inflamed status was greater than the proportion of non‐inflamed sites converting to inflamed status at any time. The estimated incidence rate remained fairly constant during both the plaque accumulation phase and the oral hygiene phase, whereas the estimated recovery rate was considerable lower during the plaque accumulation phase compared to oral hygiene phase. The clinical appearance is the outcome of the dynamics between these rates. The steadystate prevalences derived from the estimated “incidence” and “recovery” rates were quite similar to the actual findings after 14 d of plaque accumulation and the subsequent 10 d of thorough oral hygiene.
Non‐invasive intravital fluorescent microscopy of the hamster gingiva
Authors: Miller F. N. , Collins J. G. , Feldhoff P. A.
Published: July 2006

Several attempts have been made to visualize the gingival microcirculation of small animals. Most of these attempts have required surgical procedures without control of the local tissue environment. In our current study of the hamster gingiva, a tissue bath was designed to allow microcirculatory observations of the periodontium of the superior incisors without the need for invasive surgical procedures and with controlled pH and temperature of the bathing solution. Dextrans (m.w. = 70 000 and m.w. = 150 000), bovine serum albumin (mw = 66 210) or a globulin fraction (mw= > 450 000 < 825 000) were conjugated to fluorescein isothiocyanate and injected into the animal. Fluorescent images, produced by epi‐illumination, were analyzed for the light intensity of the interstitium. There was a large and rapid increase in light intensity (leakage of the macromolecules) near the venules while capillaries of the gingival margin developed interstitial fluorescence at a slower rate and with a lower maximal effect. Molecular weight, shape or charge of the macromolecular or age of the animal did not affect the results. This new preparation could be used to study the contribution of the microcirculation to gingivitis, the role of gingivitis in the development of periodontal disease, or the effects of drugs and hormones on the microcirculation of the gingiva.
Histochemical localization at the electron microscopic level of sulfated glycosaminoglycans in the rat gingiva
Authors: Kogaya Y. , Haruna S. , Vojinovic J. , Iwayama Y. , Akisaka1 T.
Published: July 2006

Using the high iron diamine thiocarbohydrazide silver proteinate (HID‐TCH‐SP) staining technique, we investigated ultrastructural localization of sulfated glycosaminoglycans (GAGs) in the rat gingiva shortly after eruption, especially those associated with internal and external basal laminae. In the apical portion of the internal basal lamina, HID‐TCH‐SP stain deposits were distributed mainly in the region of the lamina lucida located between the lamina densa and the distal surface membrane of the junctional epithelium and inside the depression of the distal surface membrane adjacent to the basal lamina. Stain deposits were also detected on the surface membrane of cytoplasmic protrusion. Interestingly, the density of HID‐TCH‐SP stain deposits in the internal basal lamina was highest in the apical portion of the junctional epithelium and decreased in the coronal direction, finally tending to disappear completely. On the other hand, in the external basal lamina the deposits were localized in the whole region of the basal lamina or at both sites of the lamina densa. HID‐TCH‐SP stain deposits were also detected external to the lamina densa in the basement membrane associated with capillaries and in the connective tissue where they were distributed in close relation to collagen fibrils. Testicular hyaluronidase digested most HID‐TCH‐SP stain deposits in the connective tissue, whereas those in the region of basement membranes resisted this enzymatic digestion.
Long junctional epithelium produced by application of bacterial protease in rats
Authors: Suzumura Yoshihiro , Kameyama Yoichiro , Mizutani Makoto , Kato Masahisa , Kondo Kiichiro , Mabuchi Ryoji
Published: July 2006

In the present study, the effect of bacterial protease on the periodontal tissues in rats was investigated histologically and histometrically. In the control group, 0·03 ml distilled water was applied to the lingual marginal gingiva of the mandibular incisor while, in the experimental group, 0·03 ml bacterial protease (distilled water with 300 units, Sigma type XIV) was applied to the same area. Both groups were treated once a day for 1, 3, 6, 9, 15 and 21 d. Histologically, the junctional epithelium in the experimental group showed a marked apical proliferation along the tooth surface, and the gingival connective tissue displayed also a slight inflammatory cell infiltration subepithelially. The remaining periodontal tissues were almost similar to those of the control group. Histometrically, the length of the junctional epithelium between the base of the gingival crevice and the most apical portion of the junctional epithelium in the experimental group at 9, 15 and 21 d were significantly greater (p<0·01) than those of the control group, respectively.
Initial attachment of principal fibers to the root dentin surface in rat molars
Authors: Yamamoto Tsuneyuki , Wakita Minoru
Published: July 2006

The initial attachment of principal fibers to the root dentin surface was investigated in developing rat molars by light and electron microscopy. Ruthenium red was used to intensely stain the first deposited material on the root dentin surface. Observations suggested that when the principal fibers became embedded in the ruthenium red‐positive material, there was no complicated interweaving between the principal fibers and the root dentinal matrix fibers. Therefore, it is likely that the initial principal fiber attachment to the root dentinal matrix fibers is mediated by the ruthenium red‐positive material.
Evaluation of the activity of four antimicrobial agents using an in vitro rapid micromethod against oral streptococci and various bacterial strains implicated in periodontitis
Authors: Chraïbi D. I. , Girond S. , Michel G.
Published: July 2006

The activity of various antibacterial agents (amoxicillin, josamycin, doxycycline and metronidazole) was established in vitro using a rapid micromethod. The activity of these agents, which are widely used in oral medicine, was evaluated against microorganisms responsible for periodontitis and bucco‐dental infections. Their action against α‐hemolytic streptococci (including pneumococci) which make up the majority of the indigenous oral flora was also tested. Amoxicillin was found to be effective against all the strains tested. Doxycycline was active against periodontal bacteria, but not against 50% of the streptococcal flora. Josamycin was found to be effective against streptococci, but appeared without effect on Eikenella corrodens and Actinobacillus actinomycetemcomitans. Metronidazole, inactive against streptococci, displayed greater activity towards the strict anaerobes. The use of these antibiotics for the treatment of bucco‐dental infections, especially periodontitis, is discussed. For periodontitis and periodontal suppurations, antimicrobial agents present a valuable adjunct to local treatments such as scaling or rootplaning. This may prevent more serious infections such as endocarditis that can develop after tooth extraction.
Interleukin‐1 regulation of procollagenase mRNA and protein in periodontal fibroblasts in vitro
Authors: Richards David , Rutherford R. Bruce
Published: July 2006

An in vitro model is used to investigate the hypothesis that activated fibroblasts produce collagenolytic activity in inflammatory sites. Interleukin‐1, a cytokine present in the gingiva and crevicular fluid of periodontitis patients, has multiple biologic activities including the ability to stimulate collagenase in dermal and synovial fibroblasts. In this report IL‐1 is tested on gingival (GF) and periodontal ligament fibroblasts (PLF) for its ability to increase collagenolytic activity and procollagenase mRNA and protein. GF produce a 3‐ to 7‐fold increase in collagenase activity, while PLF collagenase activity is rarely increased above control amounts by IL‐1 treatment. In contrast, both cell types demonstrate an increase in procollagenase protein production with IL‐1 treatment. RNA from both GF and PLF contain procollagenase mRNA as demonstrated when northern blots of fibroblast total RNA are hybridized with the cDNA for human procollagenase. Treatment with IL‐1 increases the steady‐state levels of this message in GF by up to 10‐fold in 48 hours when measured with dot blot analysis standardized for poly‐A RNA. PLF also produce up to 7 times more message at the same dose and time. Since fibroblasts present in the lesion are exposed to inflammatory cell products it is possible that the production of collagenase by these cells could result in the destruction of the periodontal fibrous attachment.
Effects of topical applications of meclofenamic acid and ibuprofen on bone loss, subgingival microbiota and gingival PMN response in the primate Macaca fascicularis
Authors: Kornman K. S. , Blodgett R. F. , Brunsvold M. , Holt S. C.
Published: July 2006

Nonsteroidal anti‐inflammatory drugs (NSAIDs) have been shown to alter periodontitis in both animals and humans. This study was initiated in the nonhuman primate (Nhp) model to determine the effect of two NSAIDs on preexisting gingivitis, the conversion of gingivitis to periodontitis, the associated subgingival microbiota, and the gingival PMN response. Eighteen cynomolgus monkeys were divided into three groups and treated on a blind basis with ibuprofen 8%, meclofenamic acid 5%, or placebo applied topically 5 days/ week for 20 wk. After 4 wk of treatment, periodontitis was initiated in one quadrant by the placement of silk ligatures. Clinical parameters, bone loss by densitometric analysis of radiographs (CADIA), and cultural microbiology of subgingival plaque were monitored. In situ PMN chemotaxis was assessed by quantitating the PMNs which entered the sulcus in response to a challenge with n‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP). No significant differences in the clinical parameters were noted by treatment groups. Radiographic bone loss was detected in all experimental sites in placebo animals as compared with 67% and 44% for ibuprofen and meclofenamic acid animals, respectively. Mean CADIA scores/animal showed a significant loss in bone density for placebo at 6 and 16 wk, no change for ibuprofen animals, and a significant increase in density for meclofenamic acid animals. The microbiota of all groups changed with ligation consistent with previous reports of disease initiation in the Nhp. Similar patterns of PMN response to FMLP were elicited in the gingiva of the ibuprofen and placebo groups, with minimal change in PMN levels detected during disease induction: however, sulcular PMNs were significantly higher than placebo in meclofenamic acid animals at all time periods. In this study, ibuprofen inhibited significant bone loss and meclofenamic acid not only inhibited bone loss but produced a significant increase in bone density in the non‐human primate model. These effects were achieved without eliminating clinical gingivitis and without significant effects on the subgingival microbiota. In the meclofenamic acid‐treated animals this was accompanied by a significant increase in PMNs in the local area. Based on this report it appears that topical ibuprofen and meclofenamic acid do not affect the progression of alveolar bone loss equally. In addition, the local increase in PMNs at sites which did not exhibit bone loss may provide insights to the mechanisms involved in the initiation of periodontitis in the cynomolgus monkey.
Comparative effects of toothpaste brushing and toothpaste rinsing on salivary bacterial counts
Authors: Jenkins S. , Addy M. , Newcombe R.
Published: July 2006

The persistence of antimicrobial action of compounds and formulations in the mouth can be demonstrated by recording the magnitude and duration of the reduction of salivary bacterial counts following a single application. Such measures of substantivity appear to correlate with the plaque inhibitory properties of antimicrobial agents. For toothpastes, studies on the short‐term inhibition of plaque formation use a number of delivery methods to measure the direct effect of the preparation divorced from toothbrushing. Such methods include paste slurries, paste in trays or cap splints. This study determined whether toothbrushing with a toothpaste produced the same effects on salivary bacterial counts compared to rinsing with a slurry. A group of 24 volunteers brushed or rinsed with a slurry of a commercial toothpaste. Each regimen was repeated twice on 4 separate days by all volunteers and salivary bacterial counts recorded at baseline and time periods to 7 hours. There were no significant differences between brushing or slurry rinsing on salivary bacterial counts and each method produced reproducible effects. This supports the use of the slurry method where the direct plaque inhibitory action of an antimicrobial toothpaste is to be assessed; and indicates that both methods equally make available and activate the relevant ingredients in formulations.