bluuebunny/crossref_metadata_2025 huggingface dataset:
Osteopontin antisense deoxyoligonucleotides inhibit bone resorption by mouse osteoclasts in vitro
Authors: Tani‐lshii N. , Tsunoda A. , Umemoto T.
Published: July 2006

Osteopontin (OPN) is an acidic phosphoprotein synthesized by osteoblasts and osteoclastic cells that are localized in the mineralized phase of bone matrix. OPN is thought to bind to the vitronection receptor on the osteoclast membrane and regulates bone resorption by the osteoclast. In this study, we investigated whether or not OPN can relate to osteoclast differentiation and bone resorption in a co‐culture system. When C57Black/6N mouse bone marrow cells suspended on ivory slices coated with collagen were inoculated onto a MC3T3‐G2/PA6 cell layer, colonies containing TRAP(+) mononuclear and multinuclear cells were formed in the presence of 1α, 25‐dihydroxyvitamin D3 and dexamethasone. At the end of the culture period the number of TRAP(+) osteoclast‐like cells were counted and the resorption pits were evaluated by reflected light microscopy. The mRNA of OPN was detected by in situ hybridization. Osteoclast‐like cells expressed OPN mRNA. The addition of an OPN antisense oligomer(5’AAT CAC TGC CAA TCT CAT 3′) at the start of the co‐culture period decreased the number of TRAP(+) cells present after 7 d (30.3 ± 3.4 vs 56.9 ± 12.4), and the ratio of mononuclear and multinucleated cells was changed (77.6:23.2 vs 60.8:39.3). The total area of pits per ivory slice was also decreased by adding the OPN antisense oligomer(246813 vs 303139 μm2). These results showed that OPN can be an important mechanism for regulating differentiation and bone resorption.
Meta‐analysis of the effect of systemic metronidazole as an adjunct to scaling and root planing for adult periodontitis
Authors: Elter John R. , Lawrence Herenia P. , Offenbacher Steven , Beck James D.
Published: July 2006

The purpose of this meta‐analysis was to provide a quantitative overview of clinical trials assessing the use of systemic metronidazole (S‐MET) as an adjunct to scaling and root planing (S&RP) in the treatment of adult periodontitis. Eight clinical trials were chosen based upon a priori selection criteria, and two outcomes, “reduction in probing pocket depth” (PD) and “gain in clinical attachment level” (CAL), were analyzed. Results for each outcome were stratified by initial PD 1–3 mm, 4–6 mm, or ≥7 mm and length of follow‐up 4–6 wk, 9–13 wk, or 14–26 wk. S‐MET in conjunction with S&RP was superior to S&RP alone in reducing PD where initial PD was 4–6 mm and follow‐up was 9–13 wk (0.43 mm; 99% CI 0.12, 0.73). No significant advantage was observed for S‐MET for reducing PD where initial PD was less than 4 mm or follow‐up was longer than 13 wk. S‐MET in conjunction with S&RP was superior to S&RP alone in reducing CAL where initial PD was 4–6 mm and follow‐up was 4–6 wk (0.29; 99% CI 0.01, 0.58) and where follow‐up was 9–13 wk (weighted mean difference 0.32; 99% CI 0.03, 0.61). Significant heterogeneity of effect was not seen for PD or Cal at any level of initial PD or length of follow‐up. No significant dose‐response relationship was observed. This meta‐analysis was limited due to diversity of data presentation and the small number of trials in each stratum. These results suggest that S‐MET in conjunction with S&RP may offer a benefit over S&RP alone in the treatment of adult periodontitis patients in managing pockets of 4 mm or greater, but the additional benefit was not evident if initial PD was less than 4 mm or follow‐up was beyond 13 wk.
A study of attachment loss patterns in survivor teeth at 18 months, 36 months and 5 years in community‐dwelling older adults
Authors: Beck James D. , Sharp Tonya , Koch Gary G. , Offenbacher Steven
Published: July 2006

Most of our knowledge regarding the natural history of periodontitis in adults has come from clinical studies of dental patients. However, it is known that dental patients usually are not representative of what actually happens in the population. This paper presents population‐based attachment loss trends in survivor teeth to address the following issues; 1) whether attachment loss during 1 period in time is associated with higher risk for attachment loss at a subsequent period in the same subject; 2) whether sites in survivor teeth with deeper periodontal pockets at baseline are more likely to experience future attachment loss; and 3) whether the effect of regular use of dentists' services on attachment loss are demonstrated in a community‐dwelling population. In 1988, the University of North Carolina School of Dentistry initiated the Piedmont 65 + Dental Study, which was designed to elicit 800 dentate respondents in the 5‐county area who were examined again at 18, 36 and 60 months. Our findings indicated that, for the 3 time periods investigated, attachment loss during the first period was not related to the incidence of attachment loss at a subsequent period for most people. However, for people who experience multiple episodes, the second episode was likely to immediately follow the first episode. This pattern did not occur at the site level where no site experienced more than 2 successive episodes, and a previous episode did not put a site at higher risk for a subsequent episode. Our data also indicated that both baseline pocket depth and irregular dental visits were positively associated with the proportion of sites that demonstrated break‐down over the next 5 yr.
New cementum formation induced by cyclosporin A: a histological, ultrastructural and histomorphometric study in the rat
Authors: Ayanoglou Charles M. , Lesty Claude
Published: July 2006

Cyclosporin A (CsA), a widely used immunosuppressive agent, is known to induce gingival overgrowth; 30 mg/kg/d of CsA were administrated orally in young and adult male Sprague–Dawley rats. The same number of rats received oil‐based vehicle solution. After 4, 9, 14 and 19 wk of CsA or vehicle administration 3 control and 3 experimental rats were anaesthetized and tissues fixed by an intracardiac perfusion of fixative solution. Upper and lower jaws were dissected, demineralized and processed for Epon inclusion. Histological examination revealed the presence of large amounts of new cementum (NC) covering extensive areas of the acellular extrinsic fibre cementum (AEFC) in all the root surfaces. NC was particularly abundant at the cervical third of the roots facing the gingival connective tissue, where it occurred as layers, spurs or in both configurations. NC was characterized by its irregular outline, globular body content and infrequent presence of incremental lines. Histomorphometric evaluation by semi‐automatic image analysis indicated that the volume and the external surface of NC spurs were 2.86–6.49 and 1.29–1.97‐fold increased comparative to those of the AEFC covering the same root areas. Electron microscopy revealed that NC was a functional tissue with insertion of collagen fibres perpendicularly to the long axis of the root. It can be concluded that under some experimental conditions formation of abundant amounts of NC can be achieved and that these results must be taken into account for a new approach in the treatment of periodontal disease.
Six‐year clinical evaluation of HTR Synthetic Bone grafts in human Grade II molar furcations
Authors: Yukna Raymond A. , Yukna Charlotte N.
Published: July 2006

A biocompatible microporous composite of PMMA (poly‐methyl‐ methacrylare), PHEMA (poly‐hydroxy‐ethyl‐methacrylate) and calcium hydroxide bone replacement graft material (Bioplant HTR® Synthetic Bone) was evaluated in 16 maxillary molar and 10 mandibular molar Grade II furcations in 13 patients. Following initial preparation, full thickness flaps were raised to gain access to the furcations; mechanical hand and ultrasonic root and defect debridement and chemical tetracycline root preparation were performed; furcation and adjacent osscous defects in each patient were grafted with HTR Synthetic Bone; and the host flaps replaced or slightly coronally positioned. Weekly, then monthly deplaquing was performed until surgical re‐entry at 6–12 months. Patients were then followed on approximate 3‐month recalls for ≤6 yr. Evaluation of the primary clinical outcome of furcation grade change showed that in the maxilla 5/16 furcations were clinically closed, 9/16 were Grade I, and 2/16 remained Grade II; while in the mandible 3/10 were clinically closed, 5/10 were Grade I, and 2/10 remained Grade II. Other significant clinical changes included decrease in mean horizontal furcation probing attachment level from 4.4 mm at surgery to 2.2 mm at re‐entry to 2.0 mm at 6 yr, decrease in probing pocket depth from 5.4 mm at surgery to 3.0 mm at re‐entry to 3.2 mm at 6 yr, and improvement in vertical clinical probing attachment level from 5.4 mm at surgery to 4.2 mm at re‐entry to 4.1 mm at 6 yr (all p>0.05 from surgery to re‐entry and surgery to 6 yr, n.s. from re‐entry to 6 yr via ANOVA). These favorable results with HTR polymer are suggest to several reports with other graft materials and with GTR barriers, and suggest that HTR polymer may have a beneficial effect in the clinical management of Grade II molar furcations.
CD44 isoform expression in periodontal tissues: cell‐type specific regulation of alternative splicing
Authors: Hirano F. , Hirano H. , Hino E. , Takayama S. , Saito K. , Kusumoto Y. , Shimabukuro Y. , Murakami S. , Okada H.
Published: July 2006

CD44 functions as a receptor for various extracellular matrices and plays crucial roles in homotypic and heterotypic cell‐cell interactions. Recently, the molecular structure of CD44 has been extensively analyzed and multiple isoforms produced by alternative splicing of messenger RNA have been identified. In this study, we examined the expression of CD44 isoforms on different cell types isolated from periodontal tissue. In order to examine tissue differences in CD44 isoform expression, we established in vitro cell culture of human gingival fibroblasts (HGF), human periodontal ligament cells (HPDL) and human gingival epithelial cells (HGEC). These cells all expressed CD44 protein and messenger RNA. However, immunoprecipitation and Northern blot analysis revealed that HGEC expressed larger CD44 isoforms than HGF and HPDL. Reverse transcription‐polymerase chain reaction with primers flanking the insertion site of alternatively spliced exons was used to study details of the heterogeneity. All cells examined expressed a major band in the absence of alternatively spliced exons and additional larger bands. In particular, HGEC contained more abundant high molecular mass species. In vitro stimulation by IL‐1β, TNFα or phorbol 12‐myristate 13‐acetate induced an increase in total CD44 messenger RNA in HGF but not change in overall patterns of CD44 isoform expression. However, the isoform expression of HGEC was sensitive to cell density. The amount of larger isoform was decreased by culturing cells beyond confluence. These findings suggest that CD44 isoform expression is cell type‐specifically regulated in periodontium and altered according to growth phase of HGEC.
A fluid‐phase endocytotic capacity and intracellular degradation of a foreign protein (horseradish peroxidase) by lysosomal cysteine proteinases in the rat junctional epithelium
Authors: Yamaza T. , Kido M. A. , Kiyoshima T. , Nishimura Y. , Himeno M. , Tanaka T.
Published: July 2006

We investigated the co‐localization of lysosomal cathepsins B, H and L, and horseradish peroxidase (HRP) in junctional epithelial (JE) cells both as a fluid‐phase endocytotic marker to demonstrate the fluid‐phase endocytotic capacity of JE cells, and to understand the morphological relationships of the endocytosed foreign substances to lysosomal cathepsins in these cells. The diaminobenzidine (DAB) histochemical and cytochemical methods and immunohistochemical avidin‐biotin‐peroxidase complex and immunocytochemical post‐embedding colloidal gold methods were used. Under light microscopy, DAB reaction products based on HRP were found in JE but were rare or absent in the oral sulcular epithelium and oral epithelium. Immunolabeling for cathepsins B and H was found in the granular structures of the cells, but no cathepsin L was identified. With electron microscopy, DAB reaction products, which indicated both HRP and the azurophil granules of neutrophils, were endocytosed into JE cells. Using a post‐embedding technique, gold particles indicating HRP were present on the plasma membrane of JE cells, at the periphery of electronlucent vacuoles, and in the electrondense granules. Gold particles indicating cathepsin B or H were found in the electrondense granules. With different sizes of colloidal golds, the co‐localization of cathepsin B or H with HRP was indicated only in the electrondense portion of the larger vacuoles consisting of electronlucent and ‐dense parts. This study provided the first morphological data which indicate that JE has a fluid phase endocytotic capacity, and which suggest that the lysosomal cathepsins B and H are involved in the intracellular degradation of foreign substances invading through the gingivl sulcus in JE cells.
Effects of basic fibroblast growth factor on human periodontal ligament cells
Authors: Takayama S. , Murakami S. , Miki Y. , Ikezawa K. , Tasaka S. , Terashima A. , Asano T. , Okada H.
Published: July 2006

In order to clarify the regulatory mechanisms of periodontal regeneration by basic fibroblast growth factor (bFGF), effects of bFGF on proliferation, alkaline phosphatase activity, calcified nodule formation and extracellula: matrix synthesis of human periodontal ligament (PDL) cells were examined in this study. bFGF enhanced the proliferative responses of PDL cells in a dose‐ dependent manner. The maximum mitogenic effect of bFGF on PDL cells was observed at the concentration of 10ng/ml. In contrast, bFGF inhibited the induction of alkaline phosphatase activity and the mineralized nodule formation by PDL cells. Moreover, employing the reverse transcription‐ polymerase chain reaction (RT‐PCR) technique, we observed that the levels of laminin mRNA of human PDL cells was specifically upregulated by bFGF stimulation, but that of type I collagen mRNA was downregulated. On the other hand, the expression of type III collagen and fibronectin mRNA were not altered even when the cells were activated by bFGF. These results suggest that suppressing cytodifferentiation of PDL cells into mineralized tissue forming cells, bFGF may play a role in wound healing by inducing growth of immature PDL cells and that in turn accelerates periodontal regeneration.
Transforming growth factor‐β response and expression in junctional and oral gingival epithelial cells
Authors: Lu H. , Mackenzie I. C. , Levine A. E.
Published: July 2006

The junctional (JE) and oral gingival (OGE) epithelium show distinct morphological phenotypes and express different cell surface and keratin markers. Transforming growth factor‐β (TGF‐β) has been shown to stimulate extracellular matrix formation and inhibit proteolytic matrix degradation in periodontal wound healing. To elucidate potential roles of TGF‐β in gingival epithelial regeneration and reattachement, the present study examined the effects of TGF‐β on JE and OGE cell growth and determined the patterns of expression of mRNAs for the TGF‐β isotypes β1, β2 and β3 and TGF‐β receptor types I, II and III. Primary cell cultures were initiated from JE and OGE and the cell phenotypes confirmed using monoclonal antibodies to specific keratins. TGF‐β induced a significant growth inhibition in OGE cells derived from 6 different patients with a mean inhibition of 46% and a range of 16–70% (p=0.031). Although responses varied between patients, in general maximum inhibition occurred at 10 ng/ml TGF‐β. JE cells from 5 patients showed no significant growth inhibition by TGF‐β (p=0.125). Greater expression of TGF‐β2 and receptor type I mRNA was found in OGE than JE cells and thus appeared to be associated with differentiating epithelial cells. JE cells expressed more TGF‐β type II receptor specific mRNA than did OGE cells, but TGF‐β1 mRNA expression was similar in JE and OGE cells. JE or OGE cultures derived from 2 of 3 patients showed expression of mRNA for the TGF‐β type III receptor. TGF‐β3 mRNA was not detected in any of the JE or OGE samples examined. The greater sensitivity of OGE than JE to the growth inhibiting effects of TGF‐β correlated with higher expression of receptor type I mRNA which, together with the type II receptor, is required for sensitivity to growth inhibition by TGF‐β. The results suggest that, in addition to structural differences, the development of functional differences in the responses of JE and OGE to TGF‐β may be associated with the formation of JE from OGE cells and the reformation of attachement after periodontal surgery.
Effect of the NSAID flurbiprofen on remodelling after periodontal surgery
Authors: Bräger Urs , Mühle Tove , Fourmousis Loannis , Lang Niklaus P. , Mombelli Andrea
Published: July 2006

The aim of the present experiment was to assess the effect of the administration of the NSAID flurbiprofen (Froben®) on tissue healing after periodontal surgery. Sites from patients with the same treatment modality (modified Widman flap) but receiving a placebo drug and sites within each patient not exposed to surgery served as controls. Nineteen patients suffering from moderate to severe periodontal disease were recruited and they signed informed consent forms. These patients required periodontal surgery as assessed at the periodontal re‐evaluation. The sites chosen for the study were all diagnosed with PPD ≥ 5 mm and were bleeding on probing. During the healing phase 10 patients received 50 mg Froben® 3 times per day for 30 d whereas 9 patients received a placebo drug. Two sites with PPD ≥ 5 mm after initial therapy and bleeding on probing served as surgical sites, whereas 2 similar sites were not exposed to surgery. The study design was set up double‐blind. The radiographic examination consisted of 2–4 standardized vertical bitewings obtained at the periodontal re‐evaluation (BL) at 1, 3 and 6 months post‐surgically for digital subtraction and computer assisted densitometric image analysis (CADIA). The regions of interest analysed were mesial or distal crestal sites. Minimal remodelling activity was observed radiographically after periodontal surgery in both patient groups. There were no statistically significant differences between the four groups of sites regarding the mean changes in density when analysing the pairs of radiographs 0–1, 0–3, 0–6 months. A frequency analysis was performed to list the number of sites with different ranges of density change. No differences in the distributions of the numbers of sites were observed when comparing the 4 site groups (Kolmogorov‐Smirnov, p > 0.05). A significant reduction of the probing pocket depth and a significant amount of clinical attachment gain was noted at the surgically treated sites irrespective of whether the patients had used flurbiprofen or placebo. Whereas the pathways leading to bone resorption in periodontally diseased sites have been shown, in other studies, to be influenced by NSAID, the results of the present study could not justify general administration of Froben® for the purpose of reduction of bone resorption after periodontal surgical procedures in patients with adult periodontitis.
Radiography of spontaneous periodontitis in dogs
Authors: Hamp S.‐E. , Hamp M. , Olsson S.‐E. , Lindberg R. , Schauman P.
Published: July 2006

The pattern and distribution of periodontitis were investigated in 162 randomly selected dogs available for necropsy in veterinary practice. There were 82 males and 80 females of 50 different breeds (150 dogs were pure‐bred and 12 were mongrels, aged between 7 months and 14 yr. Presence of periodontilis was determined by assessment of alveolar bone loss on radiographs of the skulls and jaws. Periodontitis occurred frequently with increasing age, although the prevalence varied markedly among and within different breeds. Of the breeds most represented in the sample, periodontitis was most frequently seen in poodles and dachshunds but was rarely recognized in German shepherd dogs. Regardless of age, the vast majority of the dogs displayed either one or both of two different radiographic patterns of alveolar bone loss. One pattern was characterized by slight, horizontal alveolar bone loss involving interradicular and interdental areas. The other pattern was one of predominantly crater‐like, or narrow, vertical bone defects which, when advanced, often extended around a single root or tooth to surround the root apices. The two types of patterns did not seem to be breed‐dependent. The posterior maxillary and mandibular premolars and molars were the most frequently affected teeth. Alveolar bone loss was most severe in the maxilla, while corresponding bone loss in the mandible was more often related to increasing age.
An immunohistochemical study on the localization of Porphyromonas gingivalis, Campylobacter rectus and Actinomyces viscosus in human periodontal pockets
Authors: Noiri Yuichiro , Ozaki Kazumi , Nakae Hideaki , Matsuo Takashi , Ebisu Shigeyuki
Published: July 2006

The localization and distribution of Porphyromonas gingivalis, Campylobacter rectus and Actinomyces viscosus were studied in human periodontal pockets. After obtaining voluntary consent from 9 patients, 12 teeth and their surrounding periodontal tissue with advanced adult periodontitis were extracted carefully so as not to change the structure of the periodontal pockets. The specimens were processed into serial sections. One of the sections was stained with Brown & Brenn‐modified Gram stain to observe the distribution of bacteria. The others were stained immunohistochemically by the Labelled Streptavidin Biotin method (LSAB method) using specific rabbit antibodies against selected bacteria. Some bacteria could be found within epithelial cells. P. gingivalis was found in 9/12 of the samples examined. Small aggregates of P. gingivalis were scattered in all parts of the periodontal pockets, and some of these aggregates could be seen in close contact with the epithelium. Conversely, C. rectus was observed in 5/12 of the samples examined and was predominantly located in the middle and deep pocket zones. C. rectus tended to form large clumps in both the tooth‐attached and epithelium‐associated plaque area. A. viscosus was observed in 7/12 of the samples examined and was localized predominantly in the tooth‐attached plaque area, especially in the shallow and middle pocket zones. Although unexpected spills of unattached plaque from periodontal pockets was possible, immunohistochemical staining with species‐specific antibodies was extremely sensitive and revealed the localization and the distribution of periodontal disease‐associated bacteria in human periodontal pockets.
Attachment loss with postmenopausal age and smoking
Authors: Hildebolt C. F. , Pilgram T. K. , Dotson M. , Yokoyama‐Crothers N. , Muckerman J. , Mauser J. , Cohen S. , Kardaris E. , Vannier M. W. , Hanes P. , Shrout M. K. , Civitelli R.
Published: July 2006

To determine whether postmenopausal bone loss and factors associated with osteoporosis affect tooth retention, we examined vertebral and proximal femoral (postcranial) bone mineral density in relation to tooth loss and attachment loss in a cross‐sectional study of 135 postmenopausal women (age range 41–70 yr). Women had at least 10 teeth and no evidence of moderate or severe periodontal disease. Full‐mouth attachment loss measurements were made using a pressure‐sensitive probe, and bone density was determined by dual‐energy X‐ray absorptiometry. Attachment loss was correlated with tooth loss (number of remaining teeth, radiologically determined), but not with vertebral or proximal femur bone density. Multivariate analysis showed current smoking (p = 0.01), years since menopause (p = 0.02) and the interaction of age and current smoking (p < 0.01), to be statistically significant predictors of attachment loss in our study population.
Detection and possible biological role of chondroitinase and heparitinase enzymes produced by Porphyromonas gingivalis W50
Authors: Smith A. J. , Greenman J. , Embery G.
Published: July 2006

Gingival crevicular fluid levels of the glycosaminoglycan (GAG) chondroitin‐4‐sulphate (C‐4‐S) have received increased attention as potential indicators of periodontal tissue turnover. However, little is known about the relationship between crevicular fluid connective tissue metabolites and microbial factors. In this study Porphyromonas gingivalis, a periodontopathogen, was investigated for its ability to degrade the GAGs C‐4‐S, dermatan sulphate (DS) and heparan sulphate (HS) in vitro. The effect of P. gingivalis extracts on the proteoglycans (PG) derived from human gingiva were also investigated. The presence of chondroitinase and heparitinase eliminase enzymes were identified from the vesicle fraction of P. gingivalis W50. These enzymes were extracted from the vesicle fraction by a differential centrifugation technique and partially purified by non‐denaturing gel filtration chromatography which revealed heparitinase enzyme peaks at 200 and 150 kDa and chondroitinase at 70 kDa. Gingival proteoglycans for use as substrates were purified using 4 M guanidinium chloride extraction and anion exchange chromatography; these proteoglycans contained 48% DS, 27% C‐4‐S and 13% HS P. gingivalis chondroitinase and heparitinase enzymes were capable of the degradation of C‐4‐S and HS but not DS GAGs. The presence of chondroitinase enzymes produced by P. gingivalis may influence levels of connective tissue metabolites in crevicular fluid. Furthermore these enzymes, particularly the heparitinase, may be involved in the initial permeation of the gingival epithelium, permitting the ingress of further microbial virulence factors.
Are bacterial proteases important virulence factors?
Authors: Lantz M. S.
Published: July 2006

The contribution of bacterial proteases to virulence has been relatively understudied. It is a simple matter to argue that bacterial proteases have the potential to destroy the structural and functional proteins that constitute host tissues as well as to destroy proteins important in host defense. Systematically demonstrating that such interactions occur during disease pathogenesis is more difficult, although a few studies have suggested that the ability of a pathogen to use proteases to cross proteinaceous barriers within the host contributes to bacterial virulence. This manuscript reviews concepts of bacterial virulence. Next, it describes how the host regulates the activities of its own proteases to maintain a state of health, and examines evidence suggesting that dysregulation of host proteases results in disease. Finally, evidence supporting a role for endogenous microbial proteases or acquisition of host proteases by microbes as virulence determinants is discussed as are suggestions for future directions for research in this area.
Underlying mechanisms at the bone‐surface interface during regeneration
Authors: Schwartz Z. , Kieswetter K. , Dean D. D. , Boyan B. D.
Published: July 2006

The goal of regenerative therapy around teeth and implants is to create a suitable environment in which the natural biological potential for functional regeneration of periodontal ligament and/or bone can be maximized. In order for the regenerative process to be successful, the following factors must be addressed: prevention of acute inflammation from bacteria, mechanical stability of the wound, creation and maintenance of blood clot‐filled space, isolation of the regenerative space from undesirable competing tissue types, and the creation of a desirable surface chemistry, energy, roughness and microtopography that can directly influence cellular response, ultimately affecting the rate and quality of new tissue formation and, therefore, the regeneration process. This paper will review how surface characteristics (chemistry and roughness) can affect cell response and local factor production. To evaluate the effect of surface chemistry on cell proliferation and differentiation costochondral chondrocytes were grown on standard tissue culture plastic dishes sputter‐coated with different materials. The results indicate that surface materials can elicit differential responses in cell metabolism and phenotypic expression in vitro. In a second study, the effect of varying titanium surface roughnesses on osteoblast‐like cell behavior was examined. Surface roughness was found to alter osteoblast proliferation, differentiation and matrix production in vitro. In addition, production of PGE2 and TGFβ by these cells was also shown to increase with increasing surface roughness, indicating that substrate surface roughness also affects cytokine and growth factor production. The role of surface roughness in determining cellular response was further explored by comparing the response of osteoblasts grown on new and previously used surfaces. The results of these latter studies showed that cell proliferation, expression of differentiation markers and overall matrix production are not altered when cells are grown on used vs. virgin surfaces. This suggests the possibility that implants may be re‐used, especially in the same patient, if they are appropriately treated. In this context, it should also be noted that rougher titanium surfaces may require more extensive cleaning procedures. From a global perspective, these studies provide some insight into how bone regeneration can be optimized in the presence of an implant or tooth root residing at the site of a bony defect. Since the new bone being produced, during regeneration, grows from a distal area toward the implant or tooth root surface, it is hypothesized that the osteoblasts growing on the surface of the implant may produce local factors that can affect the bone healing process distally. In short, it appears that the surface characteristics of an implant, particularly roughness, may direct tissue healing and, therefore, subsequent implant success in sites of regeneration by modulating osteoblast phenotypic expression.
Crevicular fluid and serum IgG subclasses and corresponding mRNA expressing plasma cells in periodontitis lesions
Authors: Kinane D. F. , Takahashi K. , Mooney J.
Published: July 2006

Recent reports suggest that specific serum IgG subclasses are a feature of several forms of periodontitis. GCF antibodies are both serum‐derived and locally produced by the abundant plasma cells of the diseased periodontal tissue. Previous work has shown that crevicular fluid (GCF) levels of IgG may be reduced in active and deep periodontal pockets when compared to other sites in chronic periodontitis patients (7). These findings, and more recent findings for IgA levels in GCF (5), suggest that GCF immunoglobulins may indicate “high risk“ sites for periodontitis. In these studies, the relative distribution of IgG isotypes was not investigated, nor was the relative contribution of local and serum antibodies to the GCF immunoglobulin profile. Therefore, more precise investigation of the tissue distribution of local gingival IgG subclass producing plasma cells and their protein levels in the GCF from the same sites and in serum, was undertaken.
Tetracycline inhibits Porphyromonas gingivalis lipopolysaccharide‐induced lesions in vivo and TNFα processing in vitro
Authors: Shapira L. , Houri Y. , Barak V. , Soskolne W. A. , Halabi A. , Stabholz A.
Published: July 2006

Lipopolysaccharides (LPS) are considered one of the more important virulence factors related to the pathogenesis of periodontal diseases. Based on tetracycline (TTC) ability to bind divalent metal ions, the present study was designed to examine the effect of TTC on P. gingivalis LPS‐induced lesions in vivo and on LPS‐induced TNFα production in vitro. Subcutaneous injection of 50‐100 μg of P. gingivalis LPS into BALB/C mice induced a visible lesion within 24 h with evident tissue necrosis. Daily systemic administration of TTC for the first 4 d following LPS challenge reduced the size of the lesion, and total inhibition of lesion formation was observed in 75‐100% of the treated mice. A non‐related broad spectrum antibiotic, ampicillin, or the IL‐1 inhibitor ML‐20, had no effect on the lesion size. In order to explore some aspects of the mechanism involved, we tested the effect of TTC on LPS‐induced TNFα secretion by human monocytes in vitro. TTC (1 mM) was found to block LPS‐stimulated TNFα secretion. Western blotting of monocyte cytoplasmic membranes for membrane‐bound TNFα show that TTC causes the retention of membrane‐associated TNFα on monocyte membranes, thereby preventing the release of TNFα into the culture media. The results suggest the TTC is an effective in vivo therapy for preventing P. gingivalis LPS‐induced subcutaneous lesion formation in the murine model. The mechanism of TTC treatment probably involves blocking the activity of metal] oprotemases. including TNFY processing enzyme, thereby preventing LPS‐induced tissue destruction.
Interleukin‐10 promotes anticollagen antibody production in type I diabetic peripheral B lymphocytes
Authors: Stein S. H. , Hart T. E. , Hoffman W. H. , Hendrix C. L. , Gustke C. J. , Watson S. C.
Published: July 2006

Previous studies have shown that type I diabetes (IDDM) increases the risk of developing periodontitis by 2‐3‐fold. IDDM patients exhibit destruction of the pancreatic beta cells, most probably caused by an autoimmune reaction. Evidence is accumulating to support the role of the autoimmune response in periodontal pathogenesis. A cytokine, interleukin (IL)‐10, has been reported to selectively promote the expansion of a B lymphocyte lineage (CD5/LY1/B1) which has the propensity for secreting high levels of autoantibody. Therefore, the purpose of this project was to evaluate IL‐10 production, percentage of CDS B cells and the frequency of anti‐collagen secreting cells in peripheral blood mononuclear cells of age, gender and race matched IDDM patients and controls. IL‐10 production was evaluated by an ELISA using the supernatant of adherent peripheral blood cells cultured for 24 h in the presence of Porphyromonas gingivalis lipopolysaccharide (LPS). In 8 of 31 patients, IL‐10 levels were significantly increased in IDDM compared to controls and a higher percentage of CD5 B cells was also observed by flow cytometry. In addition, these patients exhibited a higher frequency of anti‐collagen secreting cells as elucidated by an ELISPOT. Moreover, treatment with a neutralizing anti‐IL‐10 antibody diminished the anti‐collagen antibody response by 70%. These findings support the concept that a subset of IDDM patients possess an extremely robust IL‐10 response following exposure to Gram‐negative LPS, which could predispose them to the development of periodontitis through a heightened autoimmune mechanism.
A quantile plot for simultaneous representation of clinical and statistical attributes of probing change: application to early identification of the downhill patient
Authors: Cohen Marie E. , Horning Gregory M.
Published: July 2006

When multiple periodontal sites are observed in patients over time there is an intention to identify those sites where there is important change, typically loss of attachment or increase in probing depth. A change may be declared if it: (a) exceeds a threshold level, and/or (b) is determined to be statistically significant (e.g. regression slope different from zero), perhaps after (c) that significance level has been corrected for multiple testing. These criteria are not often considered when clinical or research decisions are made and there is no universal protocol for their evaluation. A quantile (uniform probability) plot, modified to incorporate additional information, is proposed as a graphical method for the display of changes at multiple sites within a mouth. This plot identifies, for each site, clinical changes beyond a threshold, site‐wise statistical significance and statistical significance adjusted for multiple testing. These alternative criteria for attachment change are, thereby, made explicit, providing a detailed evaluative context. In addition, this methodology permits incorporation of an estimation procedure for the number of sites for which the null hypothesis of no change is false. This statistic can provide evidence of progressive disease even when no site has significant clinical or statistical change and even if the average change is zero. Use of the quantile plot was elucidated by application to simulated data, and to a clinical dataset using a BASIC program to automate the computational process. In the clinical example presented, the approach appeared more effective in detecting periodontal change than traditional clinical and statistical criteria. Pending technical refinement, this graphical approach may represent a new tool for the early identification of the downhill patient.
Inflammatory mediators of the terminal dentition in adult and early onset periodontitis
Authors: Salvi G. E. , Brown C. E. , Fujihashi K. , Kiyono H. , Smith F. W. , Beck J. D. , Offenbacher S.
Published: July 2006

Based upon the prosthodontic literature, subjects who are at the transition stage between natural dentition and edentulism are called “terminal dentition” (TD) cases. The aim of the present cross‐sectional investigation was to characterize the local and systemic inflammatory responses in 2 groups of patients with terminal dentition periodontitis. Eight severe adult periodontitis terminal dentition (AP‐TD) subjects and 8 early onset periodontitis terminal dentition (EOP‐TD) subjects were entered into the study. Our purpose was to measure an extended battery of cytokines in the gingival crevicular fluid (GCF) and in lipopolysaccharide (LPS)‐stimulated monocytic culture supernatants as well as gingival mononuclear cell messenger RNA (mRNA) transcripts determined from biopsy samples. Within the GCF there were 3 tiers (levels) of mediators based upon approximate 10‐fold differences in concentration. The highest tier included prostaglandin E2 (PGE2), interleukin‐1β (IL‐1β) and interleukin‐2 (IL‐2), the intermediate tier included tumor necrosis factor alpha (TNFα) and interferon gamma (IFN‐γ) and at the lowest concentration level were interleukin‐4 (IL‐4) and interleukin‐6 (IL‐6). Thus, the GCF analysis dearly indicated that in both AP‐TD and EOP‐TD groups the monocytic, i.e. IL‐1β and PGE2 and Th1, i.e. IL‐2 and IFN‐γ, inflammatory mediator levels quantitatively dominated over the Th2 mediators, i.e. IL‐4 and IL‐6. LPS‐stimulated monocytic release of IL‐1β, PGE2 and TNFα was significantly elevated in both AP‐TD and EOP‐TD groups compared to those of a control group of 21 subjects with moderate to advanced adult periodontitis. The cytokine mRNA expression of isolated gingival mononuclear cells showed that in both the AP‐TD and the EOP‐TD groups Th1 and Th2 cytokines were expressed, with low levels of IL‐4 and IL‐12. In conclusion, our data suggest that this cross‐sectional TD periodontitis model may reflect progressive periodontal disease associated with tooth loss. Furthermore, although Th1 cytokine levels in the GCF dominate over the Th2 response, monocytic activation provides the main source of proinflammatory mediators. In addition, LPS‐stimulated peripheral blood monocytes demonstrate an upregulated inflammatory mediator secretion in the terminal dentition.
Elastic modulus, permeation time and swelling ratio of a new porcine dermal collagen membrane
Authors: Lu H. K. , Lee S. Y. , Lin F. P.
Published: July 2006

The goal of a single step therapy has been an important consideration in the development of guided tissue regeneration devices. It would spare the patient from the need for repeated surgery and eliminate many problems associated with a non‐resorbable barrier. Animal studies of a collagen membrane extracted from porcine dermis (PDCM), as conditioned by different concentrations of glutaraldehyde (GA), have shown it to be biocompatible and biodegradable (up to 9 wk). This in vitro study further investigated the physical properties of this membrane. A PDCM modified and cross‐linked with various concentrations (0.01%, 0.05% and 3.00%) of GA was used. A similar control series was not conditioned. At least 4 specimens for each experimental condition were prepared. The elastic modulus (EM) was measured by a universal testing machine. In the permeability test, Al2O3 particles of different sizes (5‐23 μm) were mixed with normal saline to make 5 v/v% suspension and the time needed for collecting 7.5 ml of the filtered suspension from 10 ml suspension was recorded. Swelling ratio (γ) was also measured according to γ= 1/Vf (volume fraction). Data were analysed using ANOVA and Tukey's LSD test. The EM (40.8 ± 3.8 gf/mm2) for the GA conditioned membranes showed no significant difference but was greater (p<0.05) than that of the control. There was a significant increase (100–300%) in the permeation time with GA concentration (control 0.168 vs. 3% GA 0.100). The results suggest that the physical properties of the GA conditioned PDCM (especially in 3%) may fit the clinical requirements of membrane materials used in guided tissue regeneration techniques.
Use of hyaluronic acid binding protein for detection of hyaluronan in ligature‐induced periodontitis tissue
Authors: Shibutani T. , Imai K. , Kanazawa A. , Iwayama Y.
Published: July 2006

This study was designed to demonstrate, by use of biotin‐labeled hyaluronic acid binding protein (HABP) and an avidin–enzyme system, the localization of hyaluronan (HA) in periodontal tissue of beagle dogs during experimentally induced periodontitis. Experimental periodontitis was induced in the dogs by ligation of the gingival sulcus. Experimental tissue was collected at 0, 3, 7 and 21 days after ligation. HA was revealed by strong staining in the intercellular space around epithelial cells and periodontal ligament, and by light staining in the gingival connective tissue. According to the progression of periodontal tissue breakdown, HA was detected in a small number of leukocytes and monocytes, on the surface of osteoclasts, the surface of alveolar bone, thickened endothelium and in epithelial cells related to rete peg formation. Streptomyces hyaluronidase‐treated specimens gave negative staining. This study suggests that HA may be associated with the inflammatory reaction in experimental periodontitis tissue.
Increased adhesion of peripheral blood neutrophils from patients with localized juvenile periodontitis
Authors: Hurttia H. , Saarinen K. , Leino L.
Published: July 2006

Adhesion of peripheral blood neutrophils from 5 patients with localized juvenile periodontitis (LJP) and age‐ and gender‐matched healthy controls was measured using a semi‐automated 96‐well microtiter plate assay method. Both unstimulated and formyl‐methionyl‐leucyl‐phenylalanine (FMLP, 10–1000 nM)‐stimulated neutrophils from LJP patients showed in general higher adhesion than did their controls. After 15–60 min incubation with 100 and 1000 nM FMLP the numbers of adherent cells were significantly (p<0.05), 2.1–2.6‐fold higher in LJP patients than in controls. Neutrophils from these LJP patients showed also enhanced respiratory burst activity in response to unopsonized zymosan stimulation. To test whether a decrease in intracellular diacylglycerol (DAG) kinase activity could account for the increased neutrophil adhesion of LJP patients normal neutrophils were treated with R59949 (10 μM), a DAG‐kinase inhibitor. Both unstimulated and FMLP‐stimulated normal neutrophiis showed significantly (p<0.05) enhanced adhesion after R59949‐treatment. Taken together, our data indicate that neutrophils from the 5 LJP patients investigated here exhibit 2 parallel hyperactivities, namely increased adhesion and enhanced production of reactive oxygen species. Furthermore, our present and previous (Hurttia et al, J Periodont Res 1997; 32: 401‐407) results suggest that the observed neutrophil functional abnormalities in some LJP patients may be associated with decreased cellular DAG‐kinase activity. It is proposed that the hyperadherent and ‐active neutrophils may promote the development of LJP by causing tissue damage in the periodontium.
Biofilm formation by Porphyromonas gingivalis and Streptococcus gordonii
Authors: Cook G. S. , Costerton J. W. , Lamont R. J.
Published: July 2006

Confocal scanning laser microscopy (CSLM) was used to visualize and quantify biofilm formation by the oral bacteria Streptococcus gordonii and Porphyromonas gingivalis, A saliva‐coated glass coverslip under continuous bacterial challenge and conditions of low shear force was used to investigate attachment to the salivary pellicle and also the effect of cell‐cell interactions on the extent of colonization and biofilm development. S. gordonii bound to the salivary pellicle and outcompeted P. gingivalis for attachment sites. Both P. gingivalis and S. gordonii failed to establish substantial biofilm formation independently. However, biofilm formation did occur subsequent to initial adherence of P. gingivalis to S. gordonii cells deposited on the salivary pellicle. The commensal species S. gordonii may. therefore, provide an attachment substrate for colonization and biofilm accretion by the potential pathogen, P. gingivalis.
Effect of projective aspect variations on estimates of changes in bone mass using digital subtraction radiography
Authors: Loftin R. , Webber R. , Horton R. , Tyndall D. , Moriarty J.
Published: July 2006

This study tests the hypothesis that estimates of changes in bone mass derived from subtraction data obtained in accord with published methods are independent of the spatial aspect of the lesion being evaluated when calibrations are performed independently. Nineteen sliver‐shaped bone chips ranging in mass from approximately 1 to 35 mg were orientated with broad side parallel to the facial surface of a hemisectioned dry human mandible and radiographed using conventional exposure parameters on conventional E‐speed dental X‐ray film. Also attached to the film was a standardized aluminum calibration wedge that facilitated quantitative analysis of resulting subtraction data using established methodology. The effects of scatter were simulated by the addition of a 1‐cm‐thick slab of tissue‐equivalent plastic. A second series of exposures then was produced using the same respective spatial chip locations and projection geometries but each chip was reorientated such that its broad side was now positioned perpendicular to the mandibular facial surface. Finally, a comparable series of control exposures was produced without any chips or calibration wedge to facilitate subtraction. When paired bone estimates derived from the two chip orientations were compared (paired comparisons) using Student's t‐test, a statistically significant difference (p<0.05) was observed. These results also were tested for statistical significance using the non‐parametric Wilcoxon test. As with the parametric analysis, the discrepancy between the parallel and perpendicular mass estimates was found to statistically significant (p<0.05). The methods employed in this investigation thus resulted in bone mass estimates that varied significantly depending upon lesion orientation.