bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet‐Rich Plasma Contains High Levels of Platelet‐Derived Growth Factor and Transforming Growth Factor‐β and Modulates the Proliferation of Periodontally Related Cells In Vitro
Authors: Okuda Kazuhiro , Kawase Tomoyuki , Momose Manabu , Murata Masashi , Saito Yoshinori , Suzuki Hironobu , Wolff Larry F. , Yoshie Hiromasa
Published: February 2005

Background: Platelet‐rich plasma (PRP) is a fraction of plasma, in which platelet‐derived growth factor (PDGF) and transforming growth factor‐β(TGF‐β) are thought to be concentrated. It is plausible that topically‐applied PRP up‐regulates cellular activity and subsequently promotes periodontal regeneration in vivo. However, the concentrations of these growth factors in PRP have not been specifically determined and the biological effects PRP at the cellular and molecular levels have not been determined.

Methods: PRP obtained from 20 healthy subjects was prepared from plasma by centrifugation. These PRP preparations were immediately subjected to an evaluation for PDGF‐AB and TGF‐β1 using enzyme‐linked immunosorbent assay (ELISA) kits. The biological effects of the PRP preparations were evaluated on osteoblastic, epithelial, fibroblastic, and periodontal ligament cells. Cellular mitogenic activity was evaluated by counting cell numbers or evaluating 5‐bromodeoxyuridine (BrdU) incorporation. Expression of alkaline phosphatase (ALP) was immunocytochemically evaluated.

Results: In the PRP preparations, platelets were concentrated up to 70.9 104 cells/μl (283.4% of the unconcentrated plasma). The levels of PDGFAB and TGF‐β1 were also concentrated up to 182.0 ng/ml (440.6%) and 140.9 ng/ml (346.6%), respectively. Scatter plots revealed significant correlations between platelet counts and levels of these growth factors. PRP stimulated osteoblastic DNA synthesis and cell division (138% of control), with simultaneous down‐regulation of ALP, but suppressed epithelial cell division (80% of control). PRP also stimulated DNA synthesis in gingival fibroblasts and periodontal ligament cells.

Conclusions: These data demonstrated that both PDGF‐AB and TGF‐β1 were highly concentrated in the PRP preparations. It is suggested PRP modulates cell proliferation in a cell type‐specific manner similar to what has been observed with TGF‐β1. Since synchronized behavior of related cell types is thought to be required for successful periodontal regeneration, it is further suggested these cell type‐specific actions may be beneficial for periodontal regenerative therapy. J Periodontol 2003;74:849‐857.
Platelet‐Rich Plasma‐Derived Fibrin Clot Formation Stimulates Collagen Synthesis in Periodontal Ligament and Osteoblastic Cells In Vitro
Authors: Kawase Tomoyuki , Okuda Kazuhiro , Wolff Larry F. , Yoshie Hiromasa
Published: February 2005

Background: Platelet‐rich plasma (PRP) contains several growth factors, including platelet‐derived growth factor (PDGF) and transforming growth factor‐β (TGF‐β), at high levels. We have demonstrated the PRP functions like TGF‐β to modulate cell proliferation in a cell‐type specific manner. In addition, PRP forms gel‐like materials in several, but not all, cell cultures tested. This study was designed to investigate PRP's action on extracellular matrix production in periodontal ligament (PDL) and osteoblastic MG63 cell cultures.

Methods: PRP was prepared from the plasma obtained from autologous blood of healthy volunteers and stored at −20°C until used. Cells treated with PRP (0.5% to 2%) were immunocytochemically stained for type I collagen and fibrin and the viscosity of the culture media was visually evaluated. Fibrinogen in PRP was detected by immunodot‐blotting while endogenous thrombin expression in cells was detected by a modified enzymelinked immunosorbent assay.

Results: Gel‐like material rapidly (<30 minutes) formed in cultures of either PDL or osteoblastic MG63 cell cultures after addition of PRP (≥0.5%). PRP changed cell shape and up‐regulated type I collagen at 24 hours. Fibrinogen was detected in the PRP preparations and insoluble fibrin networks were found in the newly formed gel‐like material. PRP's action on collagen synthesis was mimicked by purified fibrinogen and blocked by thrombin inhibitor. Thrombin was expressed both in PDL and MG63 cells.

Conclusions: These findings demonstrated that the gel‐like material formed in cell cultures of either PDL or MG63 cells is fibrin clot that is capable of up‐regulating collagen synthesis in the extracellular matrix. Our data suggest the possibility that fibrinogen, converted to fibrin, in combination with growth factors present in PRP might effectively promote wound healing at sites of injury in periodontal tissue. J Periodontol 2003;74:858‐864.
Mandibular Fracture Caused by Peri‐Implant Bone Loss: Report of a Case
Authors: Meijer Henny J.A. , Raghoebar Gerry M. , Visser Anita
Published: February 2005

bold>Background: A major complication related to excessive bone loss around implants is fracture of the mandible. This complication is most likely to occur in a very atrophic mandible. A 57‐year‐old woman presented with progressive pain and swelling that had been present for 5 days in the right frontal region of the mandible. An intraoral radiograph revealed a radiolucency around one of the implants in the interforaminal region.

Methods: Ten years earlier, 4 hollow‐screw implants of 10 mm length had been inserted in the interforaminal region of the edentulous mandible. Throughout the 10‐year postoperative period, no adverse clinical events were seen; however, during the last 7 years, no radiographic follow‐up was performed. Mobility was tested after removal of the bar, on which one of the implants appeared to be mobile. The mobile implant was removed together with the fibrous tissue.

Results: At a recall visit 2 weeks later, a radiograph revealed a fracture of the mandible at the explantation site. Characteristic features of the hollow‐screw implant are the hollow body and the transverse openings in the side walls of the implant. It has been reported that these characteristic features can enhance infection and rapid bone loss, but a case of mandibular fracture has never been described.

Conclusion: Radiographs should be taken on a regular and perhaps more frequent basis to diagnose excessive bone loss, so that measures can be taken to prevent the risk of mandibular fracture. J Periodontol 2003;74:1067‐1070.
Bone‐Implant Contact on Machined and Dual Acid‐Etched Surfaces After 2 Months of Healing in the Human Maxilla
Authors: Trisi Paolo , Lazzara Richard , Rebaudi Alberto , Rao Walter , Testori Tiziano , Porter Stephan S.
Published: February 2005

Background: Recent clinical studies indicate that an implant with a textured surface may be loaded sooner than traditional healing protocols have recommended. In a previous study, the 6‐month bone‐implant contact for dual acid‐etched and machined implant surfaces was reported to be 72.96% and 33.98%, respectively. In 1991, a minimum of 50% bone‐implant contact was considered necessary for loading to ensure long‐term survival of the implant. This study evaluated the 2‐month bone‐implant contact for dual acidetched and machined implant surfaces to determine if this criterion had been met.

Methods: Custom manufactured implants (2 mm diameter and 5 mm length), having on one side a machined surface and on the other side a dual acid‐etched surface, were placed in the posterior maxilla of 11 patients, allowed to integrate for 2 months, then removed using a 4 mm internal diameter trephine with irrigation. Sections were processed and stained for histologic and histomorphometric analysis. The parameters calculated for each section were: bone volume (BV%), actual percent bone‐implant contact (BIC%), and expected bone contact (EBC%) as determined from 3 implant images superimposed onto the adjacent bone 150, 500, and 1,000 µm lateral to the actual implant surface and representing the bone‐implant contact expected on the day the implant was placed, based on the peri‐implant bone volume.

Results: Histomorphometric analysis indicated that the mean BV% of 36.77% from all sections was closely matched to the mean EBC% of 34.36% (P<0.001). The analysis showed that after 2 months of healing, the 47.81% BIC% on the dual acid‐etched side was statistically higher (analysis of variance, P<0.001) than the 19.00% BIC% on the machined side. In areas of low‐density bone (<40% BV%), the difference between the BIC% for the machined and dual acid‐etched sides was even greater. Nine of the 11 dual acid‐etched sides had a higher BIC% than the EBC% value. In the machined group, 1 of the 11 sides had a higher BIC% value than the EBC% value. The bone surrounding the dual acid‐etched surface was a woven bone with thin, connecting peri‐implant bony trabeculae projecting into and between the threads. Bone on the machined side was observed mostly contacting the tips of the screw threads.

Conclusions: At 2 months, the mean BIC% for the dual acid‐etched group increased 39.14% compared to the EBC% value, while the mean BIC% for the machined group decreased 44.70%. Based on the histomorphometric results of this study, sufficient bone for functional loading of the implant exists on a dual acidetched surface after 2 months of healing in the posterior maxillary arch. J Periodontol 2003;74:945‐956.
Clinical and Radiographic Evaluation of Soft and Hard Tissue Changes Around Implants: A Pilot Study
Authors: Joly Julio Cesar , de Lima Antonio Fernando Martorelli , da Silva Robert Carvalho
Published: February 2005

Background: The aim of this study was to evaluate the clinical and radiographic changes in the peri‐implant tissues around one‐stage implants with different smooth neck portion lengths before and after functional prosthetic loading.

Methods: Twelve one‐stage implants were placed in adult patients with bilateral edentulous posterior mandibular ridges. The sites were randomly assigned into two groups of six each: group 1: 2.8 mm neck implants and group 2: neck implants. The parameters plaque index (Pl), gingival index (GI), probing depth (PD), gingival margin level (GML), relative clinical attachment level (r‐CAL), and optical density (OD) were measured at loading (4 months) and 12 months after implant placement. The radiographic parameter osseous level (OL) was measured at implant placement, loading, and at 12 months. Analysis of variance and the paired Student t test were used to detect difference over time and between groups.

Results: The results showed significant differences (P <0.05) for both groups for PD, r‐CAL, and OL for intragroup comparisons over time. However, no significant differences were found for Pl, GI, PD, GML, OD, and OL for between‐group comparisons.

Conclusion: Bony loss occurred before loading, supporting the soft tissues and maintaining the biologic width irrespective of the smooth portion length. J Periodontol 2003;74:1097‐1103.
Evaluation of Human Recession Defects Treated with Coronally Advanced Flaps and Either Enamel Matrix Derivative or Connective Tissue. Part 2: Histological Evaluation
Authors: McGuire Michael K. , Cochran David L.
Published: February 2005

Background: A number of surgical procedures are effective in covering denuded root surfaces. The first paper in this series evaluated the subepithelial connective tissue graft and the coronally advanced flap with enamel matrix derivative (EMD). That paper revealed no significant difference in the percent of root coverage between the two treatments (P = 0.82). There is limited human histological evidence of the type of attachment achieved with these types of procedures. This paper presents a human case report detailing the histological nature of the attachment of these two treatments to the root surfaces previously exposed by recession.

Methods: One patient presented with two hopeless teeth that were randomized to receive either a subepithelial connective tissue graft or a coronally advanced flap plus EMD. The surgery was accomplished in accordance to the protocol previously described. The teeth and a small collar of tissue were removed at 6 months and underwent histological analysis.

Results: Histological evaluation of the subepithelial connective tissue graft revealed a connective tissue attachment between the tooth and graft, and no histological evidence of cementum, bone, or periodontal ligament (PDL) and, therefore, regeneration. In addition, there appeared to be some resorption of the dentin adjacent to the graft. Histological evaluation of the coronally advanced flap with EMD revealed new cementum, organizing PDL fibers and islands of condensing bone at a constant distance from the root surface.

Conclusions: The subepithelial connective tissue graft in this study was found to have adhered to the root surface primarily by a connective tissue attachment with some evidence of root resorption. The coronally advanced flap with EMD was found histologically to have all the tissues necessary for regeneration: new cementum, organizing PDL fibers, and islands of condensing bone. These histologic sections strongly suggest that enamel matrix derivative works in a biomimetic fashion by mimicking the natural process of tooth development. J Periodontol 2003;74:1126‐1135.
Effects of Low‐Dose Cyclosporin on Osteogenesis of Human Demineralized Bone Grafts in a Surgically Created Mandibular Defect in Rats
Authors: Fu Earl , Tseng Yueh‐Chin , Shen E‐Chin , Hsieh Yao‐Dung , Chiang Cheng‐Yang
Published: February 2005

Background: Demineralized freeze‐dried bone matrix (DFDBM) stimulates new bone formation; however, immune reactions from the residual antigens of prepared grafts might play a role in inducing osteogenesis. This study examined whether cyclosporine‐A (CsA), an immunosuppressant, enhanced the DFDBM‐induced new bone formation.

Methods: After creating a bony defect in the posterior mandible, 40 male Sprague‐Dawley rats were divided into four groups of 10 each: no graft with mineral oil (control); no graft with CsA in mineral oil; DFDBM with mineral oil; and DFDBM with CsA in mineral oil (combined therapy). CsA was administered at 2 mg/kg body weight. Five rats in each group were sacrificed at days 10 and 28 and tissue samples were taken for histological examination.

Results: Soft tissue was observed in the defects of all animals without grafts, whereas the repaired hard tissue formed in the defects of animals with grafts. Histometery, which was performed only at day 10, revealed both DFDBM and CsA therapies produced a significant increase in the total area of repaired hard tissue. Only CsA therapy significantly increased the new bone area. Compared with the DFDBM group, the composition of the repaired hard tissue in the combined therapy group shifted; i.e., the new bone area increased but the residual particle area decreased. The cartilage formation was greater in the combined therapy group than the DFDBM group.

Conclusion: Within the limitations of this study, we suggest that the DFDBM grafts play a major role, which could be enhanced by CsA, in the induction of new bone formation, especially at an early phase. J Periodontol 2003;74:1136‐1142.
Modulation of Porphyromonas Gingivalis Proteinase Activity by Suboptimal Doses of Antimicrobial Agents
Authors: Grenier Daniel , Roy Elizabeth , Mayrand Denis
Published: February 2005

Background: Antimicrobial agents are sometimes used as adjuncts for the treatment of aggressive and refractory forms of periodontitis. In this study, we used a culture plate assay to investigate the effect of suboptimal doses of antimicrobial agents on proteinase activity of Porphyromonas gingivalis.

Methods: A culture plate assay using gelatin as the substrate, which allows a semiquantitative determination of proteinase activity, was developed. Suboptimal inhibitory concentrations of tetracycline, minocycline, doxycycline, metronidazole, penicillin G, or chlorhexidine were added to the medium, and proteolysis zones were determined following the growth of three strains of P. gingivalis. The effect of antimicrobials on outer membrane vesicleassociated gingipains also was determined.

Results: The gelatin plate assay was a convenient, simple procedure for investigating the effect of suboptimal inhibitory concentrations of antimicrobial agents on proteinases produced by P. gingivalis. The largest reduction (>75%) in the proteolysis zones produced by three strains of P. gingivalis. was obtained with minocycline. Tetracycline and doxycycline also reduced the proteolysis zones. A suboptimal inhibitory concentration of chlorhexidine increased the proteolysis zones by up to 70%. Metronidazole and penicillin G produced no noticeable effect. The suboptimal inhibitory concentrations of minocycline, tetracycline, and doxycyline did not reduce the activity of outer membrane vesicleassociated Arg‐ and Lys‐gingipains.

Conclusion: Results from this study suggest that sublethal concentrations of some antimicrobial agents in subgingival sites have the potential to affect the physiology of P. gingivalis., notably by increasing or decreasing the proteolytic activity of the bacteria. J Periodontol 2003;74:1316‐1319.
Adhesion and Growth of Cultured Human Gingival Fibroblasts on Periodontally Involved Root Surfaces Treated by Er:YAG Laser
Authors: Feist Iliria S. , De Micheli Giorgio , Carneiro Silvia R.S. , Eduardo Carlos P. , Miyagi Sueli P.H. , Marques Márcia M.
Published: February 2005

Background: The application of Er:YAG laser irradiation, approved in 1997 to be used on dental hard tissues, has been investigated for periodontal therapy. The aim of this study was to analyze the biocompatibility of root surfaces treated by Er:YAG laser.

Methods: Adhesion and growth of cultured human gingival fibroblasts on root surfaces treated by either irradiation with Er:YAG laser or curet were compared. Thirty single‐rooted teeth extracted because of periodontal disease were used. Calculus deposits on all experimental surfaces were removed, and the teeth were divided into three groups according to the applied treatment: group A, root planing with Gracey curet no. 3/4; group B, two irradiations with laser (60 mJ/pulse, 10 Hz; 10″ each with 10‐second interval, 3 J/cm2); group C, two irradiations with laser (100 mJ/pulse, 10 Hz; 10″ each with 10‐second interval, 5 J/cm2). Fragments (5 mm × 6 mm) were obtained from the experimental surfaces. Then, 1 × 103 cells were seeded on the top of each fragment. One, 2, and 3 days after seeding the specimens were prepared for scanning electron microscopy analysis, and the cells on the electronmicrographs were counted. The data obtained in triplicate were statistically compared by the Kruskall‐Wallis test complemented by the Dunn test (P ≤0.05).

Results: Human gingival fibroblasts adhered to and grew on all treated surfaces. Group B presented a significantly higher cell count than did the other two groups at days 1 and 2. Three days after seeding the cultured fibroblasts of groups A and B reached total confluence. The cell count of group B was significantly higher than that of group C.

Conclusion: The surfaces treated with 60 mJ/pulse Er:YAG laser irradiation promoted faster adhesion and growth than surfaces treated with either root planing or 100 mJ/pulse Er:YAG laser irradiation. J Periodontol 2003;74:1368‐1375.
The Application of Multilevel Modeling in the Analysis of Longitudinal Periodontal Data – Part I: Absolute Levels of Disease
Authors: Tu Yu‐Kang , Gilthorpe Mark S. , Griffiths Gareth S. , Maddick Ian H. , Eaton Kenneth A. , Johnson Newell W.
Published: February 2005

Background: Statistical analyses of periodontal data that average site measurements to subject mean values are unable to explore the site‐specific nature of periodontal diseases. Multilevel modeling (MLM) overcomes this, taking hierarchical structure into account. MLM was used to investigate longitudinal relationships between the outcomes of lifetime cumulative attachment loss (LCAL) and probing depth (PD) in relation to potential risk factors for periodontal disease progression.

Methods: One hundred males (mean age 17 years) received a comprehensive periodontal examination at baseline and at 12 and 30 months. The resulting data were analyzed in two stages. In stage one (reported here), the absolute levels of disease were analyzed in relation to potential risk factors; in stage two (reported in a second paper), changes in disease patterns over time were analyzed in relation to the same risk factors. Each approach yielded substantially different insights.

Results: For absolute levels of disease, subject‐level risk factors (covariates) had limited prediction for LCAL/PD throughout the 30‐ month observation period. Tooth position demonstrated a near linear relationship for both outcomes, with disease increasing from anterior to posterior teeth. Sites with subgingival calculus and bleeding on probing demonstrated more LCAL and PD, and supragingival calculus had an apparently protective effect. Covariates had more “explanatory power” for the variation in PD than for the variation in LCAL, suggesting that LCAL and PD might be generally associated with a different profile of covariates.

Conclusion: This study provides, for a relatively young cohort, considerable insights into the factors associated with early‐life periodontal disease and its progression at all levels of the natural hierarchy of sites within teeth within subjects. J Periodontol 2004;75:127‐136.
Study of Bacterial Viability within Human Supragingival Dental Calculus
Authors: Tan Benjamin T.K. , Mordan Nicola J. , Embleton Jason , Pratten Jonathan , Galgut Peter N.
Published: February 2005

Background: There is evidence that supragingival calculus contains unmineralized channels and lacunae. The purpose of this study was to investigate the viability of bacteria within these areas.

Methods: Supragingival calculus harvested from patients with moderate to severe chronic periodontitis was immediately frozen to –70°C. Six samples were cryosectioned, stained with a bacterial viability kit, and examined with fluorescence microscopy. Controls comprised heat treatment of cryosections prior to staining. Four additional samples were stained and examined whole a confocal laser scanning microscope (CLSM). Nine additional samples were prepared for bacterial culture, after initial irradiation with ultraviolet light to kill viable organisms on the covering plaque layer. Test samples were crushed to expose internal bacteria, while two controls were used without crushing.

Results: Viable bacteria, as identified using the bacterial viability stain, were found within cavities/lacunae in supragingival calculus cryosections. Similar results were obtained from whole calculus samples using CLSM. Of the nine experimental samples where bacterial culture was attempted, five provided positive bacterial culture under both aerobic and anaerobic conditions; one showed positive growth under aerobic conditions only; while one showed no bacterial growth. The controls showed no bacterial growth.

Conclusions: From this study, it appears that viable aerobic and anaerobic bacteria may be present within supragingival calculus, specifically within the internal channels and lacunae. Clinically, this may be important, since incomplete removal of supragingival calculus may expose these reservoirs of possible pathogenic bacteria and be a factor in the recurrence of periodontal diseases after treatment. J Periodontol 2004;75:23‐29.
Interleukin‐11 and IL‐17 and the Pathogenesis of Periodontal Disease
Authors: Johnson R.B. , Wood N. , Serio F.G.
Published: February 2005

Background: Interleukin (IL)‐11 and IL‐17 are cytokines that modulate the inflammatory process and have not been assessed within normal or inflamed gingival tissues. Our purpose was to compare concentrations of human IL‐11 and IL‐17 within healthy and diseased human gingiva to determine their possible role in the initiation or progression of periodontal diseases.

Methods: Biopsies from healthy (non‐hemorrhagic gingiva adjacent to a ≤3 mm gingival sulcus) and diseased gingiva (hemorrhagic gingiva adjacent to a ≥3 mm periodontal pocket) were studied. IL‐11, IL‐17, RANTES, and IL‐6 concentrations were assessed within solubilized gingival biopsies by enzyme‐linked immunosorbent assay. Data were compared by factorial analysis of variance and a post‐hoc Tukey honestly significant difference (HSD) test. Regression analysis and partial correlation analysis (adjusted for sample weight) were also used to determine correlations between the variables.

Results: Interleukin‐11 concentrations were highest within gingiva adjacent to 3 mm diseased pockets (P <0.001), and IL‐17 concentrations were highest at 4 to 5 mm sites compared to other sites (P <0.001). Gingival concentrations of both cytokines were significantly lower in gingiva adjacent to a ≥6 mm pocket. RANTES concentrations were significantly greater in gingiva adjacent to ≥6 mm pockets than in tissues derived from other sites (P <0.001). IL‐11, IL‐6, and RANTES concentrations were significantly correlated with sulcular depth.

Conclusions: Gingival concentrations of IL‐11 and IL‐17 are different in diseased gingiva adjacent to 3, 4 to 5, and ≥6 mm pockets, suggesting that their concentrations change as a consequence of the progression of gingivitis to periodontitis and that both cytokines could have a significant role in this progression. These data may be useful for the design of procedures for prevention of periodontal disease. J Periodontol 2004;75:37‐43.
Vascular Endothelial Growth Factor in Gingival Tissues and Crevicular Fluids of Diabetic and Healthy Periodontal Patients
Authors: Güneri Pelin , Ünlü Füsun , Yeşilbek Banu , Bayraktar Firat , Kokuludag Ali , Hekimgil Mine , Boyaciolu Hayal
Published: February 2005

Background: Periodontal disease is one of the major oral problems encountered in patients with diabetes mellitus (DM). Vascular changes, neutrophil dysfunction, altered collagen synthesis, and genetic predisposition observed in DM may contribute to periodontitis; and the vascular alterations observed in such patients may depend on vascular endothelial growth factor VEGF) actions. Few reports are available about the mechanism of neovascularization and the angiogenic factors that contribute to the periodontal pathology and the role of VEGF in periodontal diseases. The aim of this study is to compare VEGF expression in healthy and periodontally diseased tissues with gingival crevice fluid (GCF) of healthy persons and diabetic patients.

Methods: Gingival tissue and GCF samples were collected from sites of periodontitis in 10 healthy subjects and in 10 type 2 diabetic patients, and from the sites of healthy gingiva within the same groups. Therefore, each patient became his/her own control. Additionally, 10 people without any systemic or periodontal diseases were enrolled, forming a negative control group. Thus, a total of 50 tissue and 50 GCF samples were provided.

Results: No VEGF staining was observed in the negative control group or in the systemically healthy people's healthy tissue samples, whereas four samples of diabetic patients showed positive staining (P <0.05). However, VEGF was revealed in two tissue samples of periodontal sites of systemically healthy people and in six samples of the diabetic patients (P >0.05). In all test groups, GCF VEGF levels were higher in periodontal sites (P <0.05) than in healthy sites.

Conclusion: The results of this study showed that VEGF is increased in all periodontal tissues of both groups and in the healthy sites of diabetic patients. Additionally, GCF VEGF values increased in periodontal sites of all test groups. J Periodontol 2004;75:91‐97.
The Effect of Occlusal Discrepancies on Gingival Width
Authors: Harrel Stephen K. , Nunn Martha E.
Published: February 2005

Background: A relationship between occlusal forces and gingival recession has been postulated in the past. However, minimal data are available to demonstrate a causal relationship between occlusal forces and recession.

Methods: The records from a private practice limited to periodontics were reviewed to find patients who had complete periodontal examination records, including occlusal analysis and gingival width, that were recorded at least 1 year apart. Patients who fit this criteria were divided into those who had none of the recommended treatment (untreated, n = 30), those who had only non‐surgical treatment (partially treated, n = 20), and a control group who had completed all recommended surgical and non‐surgical treatment (completely treated, n = 41). The data for each tooth of each patient, including occlusal status and gingival width, were placed in a database and analyzed for a relationship between occlusal discrepancies and changes in gingival width.

Results: No statistically significant relationship was detected between the presence of occlusal discrepancies and initial width of the gingival tissue (P = 0.414) or between occlusal treatment and changes in the width of the gingiva (P = 0.481).

Conclusion: Based on the current study, there does not appear to be a relationship between occlusal discrepancies and gingival recession. J Periodontol 2004;75:98‐105.
Dose‐Effect Relation of Smoking and the Interleukin‐1 Gene Polymorphism in Periodontal Disease
Authors: Meisel P. , Schwahn C. , Gesch D. , Bernhardt O. , John U. , Kocher T.
Published: February 2005

Background: Periodontitis is a bacterial inflammatory disease leading to attachment loss with the consequence of tooth loss. There exists a multifactorial risk pattern including bacterial challenge, smoking, age, gender, diabetes, and socioeconomic and genetic factors. Smoking has the highest impact on the course of the disease modulated by all the other factors. Here, we report the relationship between smoking and the genetic polymorphism of interleukin‐1 (IL‐1).

Methods: In a randomly selected population‐based study, we genotyped 1,085 test persons for the IL‐1 genotype, examined their periodontal status, and assessed their smoking behavior including present and past quality and quantity of smoking.

Results: There was a significant dose‐effect relationship between the exposure to tobacco smoke and the extent of periodontal disease assessed as attachment loss and tooth loss. Moreover, there was a gene‐environmental interaction. Subjects bearing at least one copy of the variant allele 2 at positions IL‐1A –889 and IL‐1B +3954 (genotype positive) had an enhanced smoking‐associated periodontitis risk as compared to their IL‐1 genotype‐negative counterparts. With genotype‐negative non‐smokers as a reference, logistic regression resulted in odds ratios of 0.98 (95% confi‐ dence interval: 0.83 to 1.14), 2.37 (1.96 to 2.87), and 4.50 (2.30 to 8.82) for genotype‐positive non‐smokers, genotype‐negative smokers, and genotype‐positive smokers, respectively.

Conclusions: There is a gene‐environmental interaction between smoking and the IL‐1 genetic polymorphism. Smokers bearing the genotype‐positive IL‐1 allele combination have an increased risk of periodontitis. The IL‐1 genotype has no influence in non‐smokers. J Periodontol 2004;75:236‐242.
Regulatory Effects of Interleukin‐1β and Prostaglandin E2 on Expression of Receptor Activator of Nuclear Factor‐κB Ligand in Human Periodontal Ligament Cells
Authors: Nukaga Jun , Kobayashi Makoto , Shinki Toshimasa , Song Hong , Takada Takatora , Takiguchi Takashi , Kamijo Ryutarou , Hasegawa Kohji
Published: February 2005

Background: Receptor activator of nuclear factor‐κB ligand (RANKL), which is expressed on the cell membrane of osteoblasts/ stromal cells, stimulates osteoclastogenesis. We investigated the regulatory effects of interleukin‐1β (IL‐1β) and prostaglandin E2 (PGE2) on expression of RANKL in human periodontal ligament (HPDL) cells and the mechanisms involved in the PGE2 effect.

Methods: The HPDL cells were treated with IL‐1β, alone or in combination with indomethacin (INDO) or NS398, a cyclooxygenase‐ 2 (COX‐2) inhibitor. The HPDL cells were also pretreated with H89, a protein kinase A (PKA) inhibitor or GF109203X, a protein kinase C (PKC) inhibitor and subsequently treated with PGE2, PGE receptor (EP)2 agonist, EP4 agonist, forskolin, dibutyryl cAMP (db‐cAMP), or 3‐(isobutyl)‐1‐methylxantine (IBMX). After each treatment, expression of EP2, EP4, or RANKL mRNA was analyzed by reverse transcription‐polymerase chain reaction and Southern hybridization. Expression of RANKL protein was detected by Western blotting, and cAMP accumulation was determined using a cAMP enzyme immunoassay kit.

Results: IL‐1β stimulated the expression of RANKL at messenger RNA (mRNA) and protein levels in HPDL cells. Endogenous PGE2 partially mediated the IL‐1β–induced RANKL mRNA expression. Exogenously added PGE2 also stimulated RANKL expression at mRNA and protein levels in the cells. The PGE2‐ stimulated RANKL expression was mediated by EP2/4 and cAMP‐dependent PKA, while PKC was possibly involved in the PGE2 action.

Conclusion: Human periodontal ligament cells activated with inflammatory factors such as IL‐1β and PGE2 may directly stimulate osteoclastogenesis through RANKL, which is stimulated to express by these factors. J Periodontol 2004;75:249‐259.
Nicotine Effects on Alveolar Bone Changes Induced by Occlusal Trauma: A Histometric Study in Rats
Authors: Nogueira‐Filho Getúlio R. , Neto Edgard B. Fróes , Casati Marcio Zaffalon , Reis Silvia R.A. , Tunes Roberto S. , Tunes Urbino R. , Sallum Enilson Antonio , Nociti Francisco H. , Sallum Antonio W.
Published: February 2005

Background: The aim of the present study was to verify nicotine effects on alveolar bone changes induced by occlusal trauma during a periodontitis experimental model in rats.

Methods: Thirty adult male rats were used. The animals were randomly assigned to one of three groups receiving daily intraperitoneal injections: A, nicotine solution (0.44 mg/ml) and occlusal overload; B, saline solution and occlusal overload; or C, saline solution. Rats from groups A and B underwent bilateral amputation of the second and third molar cusps to simulate an occlusal overload. The first molars were then randomly assigned to receive a cotton ligature in the sulcular area, while the contralateral tooth was left unligated. The animals were sacrificed 30 days later. The resected mandibles were processed, and histomorphometric measurements were performed in the alveolar bone adjacent to the furcation area of the first molars.

Results: Nicotine enhanced the bone loss induced by occlusal trauma (P <0.001) on the ligated teeth of group A (12.27 ± 4.4 mm2), when compared to groups B (8.43 ± 3.51 mm2) and C (4.43 ± 2.17 mm2). Alveolar bone loss (P <0.01) was also observed in the contralateral teeth of groups A (nicotine + trauma) and B (saline + trauma), when compared to group C (saline only).

Conclusion: Within the limits of the study, it is concluded that nicotine may influence the alveolar bone changes induced by occlusal trauma by enhancing bone loss. J Periodontol 2004;75:348‐352.
Role of the c‐myc Proto‐Oncogene in the Proliferation of Hereditary Gingival Fibromatosis Fibroblasts
Authors: Tipton David A. , Woodard Ernest S. , Baber Mark A. , Dabbous Mustafa Kh.
Published: February 2005

Background: Hereditary gingival fibromatosis (HGF) is a fibrotic gingival enlargement. In previous work, HGF fibroblasts grew faster and produced more collagen and fibronectin (FN) than normal gingival (GN) fibroblasts. HGF FN and collagen production, but not proliferation, were under autocrine transforming growth factor (TGF)‐β control, suggesting other means of activation of HGF proliferation. Elevated/prolonged expression of the protooncogene c‐myc is implicated in disregulation of cell growth. The objectives of this study were to: 1) determine if c‐myc expression is abnormal in quiescent and serum‐stimulated HGF and GN fibroblasts and 2) determine the relationship between c‐myc expression and fibroblast proliferation using a c‐myc antisense oligonucleotide (ODN).

Methods: Proliferation was determined by enzyme‐linked immunosorbent assay (ELISA), measuring incorporation of bromodeoxyuridine into DNA. Expression of c‐myc was determined by quantitative polymerase chain reaction (PCR), using incorporation of fluorescent dCTP and detection via electrophoresis.

Results: Proliferation was minimal until 24 hours or more after serum stimulation, when HGF proliferation was greater than GN (P ≤0.02). All cells expressed c‐myc mRNA at quiescence and ≥1 hour after serum stimulation. Expression of c‐myc in quiescent HGF fibroblasts was elevated, and it peaked and remained higher after serum stimulation than in GN cells. Proliferation of an HGF cell line was inhibited by 4 μM c‐myc antisense ODN (14% decrease; P ≤0.006) and 8 μM c‐myc antisense ODN (~80% decrease; P ≤0.0001), but generally not by c‐myc sense ODN. This effect was reversed by hybridizing the c‐myc antisense and sense ODNs (P = 0.007).

Conclusion: Data suggest that elevated proliferation of an HGF fibroblast cell line is related to elevated c‐myc expression. J Periodontol 2004;75:360‐369.
Root Coverage Using the Coronally Positioned Flap With or Without a Subepithelial Connective Tissue Graft
Authors: Silva Robert Carvalho Da , Joly Julio César , de Lima Antonio Fernando Martorelli , Tatakis Dimitris N.
Published: February 2005

Background: Various surgical techniques have been proposed for treating gingival recession. This randomized clinical trial compared the coronally positioned flap (CPF) alone or in conjunction with a subepithelial connective tissue graft (SCTG) the treatment of gingival recession.

Methods: Eleven non‐smoking subjects with bilateral and comparable Miller Class I recession defects were selected. The defects, at least 3.0 mm deep, were randomly assigned to the test (CPF + SCTG) or control group (CPF alone). Recession depth (RD), probing depth (PD), clinical attachment level (CAL), width of keratinized tissue (KT), and gingival/mucosal thickness (GT) were assessed at baseline and 6 months postoperatively.

Results: Recession depth was significantly reduced 6 months postoperatively (P <0.05) for both groups. Mean root coverage was 75% and 69% in the test and control groups, respectively. There were no significant differences between the two groups in RD, PD, or CAL, either at baseline or at 6 months postoperatively. However, at 6 months postoperatively, the test group showed a statistically significant increase in KT and GT compared to the control group (P <0.05).

Conclusions: The results indicate that both surgical approaches are effective in addressing root coverage. However, when an increase in gingival dimensions (keratinized tissue width, gingival/ mucosal thickness) is a desired outcome, then the combined technique (CPF + SCTG) should be used. J Periodontol 2004;75: 413‐419.
Periodontitis and Coronary Artery Calcification: The Atherosclerosis Risk in Communities (ARIC) Study
Authors: Nakib Sarah A. , Pankow James S. , Beck James D. , Offenbacher Steven , Evans Gregory W. , Desvarieux Moise , Folsom Aaron R.
Published: February 2005

Background: Periodontitis has been linked to coronary heart disease (CHD) risk, possibly through providing a systemic inflammatory burden. Few studies have evaluated periodontitis and subclinical measures of atherosclerosis. Coronary artery calcification (CAC) is an emerging marker for atherosclerosis, and past studies suggest that it predicts incident CHD in asymptomatic populations.

Methods: In 1996‐1998, dental examinations were performed on 6,931 participants in the Atherosclerosis Risk in Communities (ARIC) cohort. Extent of periodontitis was measured by the percent of sites with attachment level (AL) ≥3 mm. In 1999‐2000, CAC was measured by cardiac gated mechanical or helical computed tomography in 269 dental examinees and edentulous subjects from the Minnesota and North Carolina field centers of ARIC who were free of clinically recognized CHD. A traditional Agatston score for CAC was calculated.

Results: Compared to subjects with no or mild periodontitis (<10% of sites with AL ≥3 mm), subjects with moderate or severe periodontitis (≥10% of sites with AL ≥3 mm) were more likely to have CAC ≥100, but this difference was not statistically significant (odds ratio [OR]: 1.78; 95% confidence interval [CI]: 0.65 to 4.86). This association was partially but not completely attenuated when adjusted for demographic factors and traditional CHD risk factors (OR: 1.51; 95% CI: 0.54 to 4.23).

Conclusions: These results suggest that periodontitis is not strongly associated with CAC. This study offers some reference for the magnitude of the association between CAC and periodontitis and information regarding the minimal power necessary for future studies. J Periodontol 2004;75:505‐510.
Association of Fcγ Receptor IIa Genotype With Chronic Periodontitis in Caucasians
Authors: Yamamoto Kouji , Kobayashi Tetsuo , Grossi Sara , Ho Alex W. , Genco Robert J. , Yoshie Hiromasa , De Nardin Ernesto
Published: February 2005

Background: Functional polymorphisms of immunoglobulin G (IgG) Fc receptors IIIa and IIIb (FcγRIIIa and FcγRIIIb) have been shown as risk factors for periodontitis. The aim of this study is to examine whether FcγRIIa polymorphism is associated with a disease risk as well.

Methods: Baseline periodontal and general health examinations were carried out on 1,221 Caucasian adults. From these, 422 subjects with moderate to severe, or little or no periodontal disease were assigned to two groups according to their mean clinical attachment loss (CAL). Subjects with mean CAL ≥2.94 mm were diagnosed with chronic periodontitis (n = 213, 62 never‐smokers and 151 smokers). Subjects with mean CAL ≤1.77 mm were considered as having little or no periodontal disease and designated as controls (n = 209, 125 never‐smokers and 84 smokers). The FcγRIIa genotype for three bi‐allelic polymorphisms (FcγRIIa‐R/ R131, R/H131, and H/H131) was determined by means of allelespecific polymerase chain reactions.

Results: The distribution of FcγRIIa genotype between the patient and control groups was significantly different, with enrichment of the high ligand‐binding genotype FcγRIIa‐H/H131 in the patients (patients versus controls: 36.6% versus 25.4%; P = 0.04). Multivariate logistic regression model demonstrated that subject age and gender, smoking, and the FcγRIIa genotype were significantly associated with severity of chronic periodontitis. For smokers, a signifi‐ cant over‐representation of FcγRIIa‐H/H131 in the patient group compared to the control group (patients versus controls: 35.1% versus 19.0%; P = 0.03). Additionally, smokers with FcγRIIa‐H/H131 exhibited significantly greater mean CAL (mean ± SE: 3.44 ± 0.16 mm) than those with FcγRIIa‐R/H131 (2.91 ± 0.14 mm) and R/R131 (2.82 ± 0.16 mm) (P = 0.04). There was no association between FcγRIIa genotype and the disease susceptibility or severity in subjects who had never smoked.

Conclusions: Our results suggest that the FcγRIIa‐H/H131 genotype may be associated with chronic periodontitis risk (and disease severity) in Caucasian smokers. Further studies with families and studies of mechanisms are necessary to help establish the extent to which this is a genetic determinant of periodontal diseases. J Periodontol 2004;75:517‐522.
Inhibitory Effect of a Novel Bisphosphonate, TRK‐530, on Dental Calculus Formation in Rats
Authors: Haq Sikder M.N. , Itoh Masatoshi , Iwatsuki Naofumi , Shinoda Hisashi
Published: February 2005

Background: A newly developed bisphosphonate, TRK‐530 (disodium dihydrogen[4‐(methylthio)phenylthio]methanebisphosphonate), has recently been reported to show anti‐inflammatory and anti‐bone‐resorbing activity. Since bisphosphonates have been shown to inhibit the formation of calcium‐phosphate crystals in vitro, TRK‐530 may inhibit the formation of dental calculus. Therefore, the present study was performed to examine whether this compound has such an effect.

Methods: Three groups of Wistar rats fed a calculogenic diet (RC16) were treated with TRK‐530 in drinking water at concentrations of 0 (control group), 0.75, and 1.5 mM. Another group received a daily subcutaneous injection of TRK‐530 at a dose of 2.25 µmoles/rat, which was assumed to correspond to the maximum amount of this compound absorbed from the intestine when rats received 1.5 mM TRK‐530 in drinking water. Rat dental calculus formation was evaluated. The crystalline nature of dental calculus was studied by x‐ray diffraction analysis. Finally, the effects of TRK‐530 on the precipitation of calcium‐phosphate from solution were tested in vitro.

Results: TRK‐530 in drinking water inhibited dental calculus formation dose‐dependently. However, subcutaneous injection of TRK‐530 did not have any significant effect, suggesting that the anticalculus effect of TRK‐530 in drinking water was topical, not systemic. The calculus that formed in both the control and experimental groups was primarily hydroxyapatite, a main constituent of human dental calculus. TRK‐530 inhibited the precipitation of calcium‐phosphate from solution in vitro.

Conclusions: TRK‐530 inhibited the formation of dental calculus in a dose‐dependent fashion via a local effect. Inhibition of the precipitation of calcium‐phosphate from solution might be involved in the anticalculogenic mechanism of this drug. J Periodontol 2004;75:537‐545.
Soluble Cell Adhesion Molecules in Gingival Crevicular Fluid in Periodontal Health and Disease
Authors: Hannigan E. , O'Connell D.P. , Hannigan A. , Buckley L.A.
Published: February 2005

Background: Cell adhesion molecules (CAMs) are cell surface proteins involved in the binding of cells to each other, to endothelial cells, or to the extracellular matrix. The soluble forms of CAMs (sCAMs) are thought to be produced by proteolytic cleavage from the cell surface and are shed into the gingival crevicular fluid (GCF). The aim of this study was to investigate whether sCAMs, sICAM‐1, sVCAM‐1, and sE‐Selectin were present in GCF in both periodontal health and disease and to examine their relationship with periodontal inflammation.

Methods: GCF was collected from a clinically healthy, a gingivitis, and a periodontitis site in 29 subjects with chronic periodontitis and from a single clinically healthy site in 22 subjects without chronic periodontitis. The volume of GCF was measured and each sample was analyzed for sCAMs by enzyme‐linked immunosorbent assay (ELISA). The effect of treatment (oral hygiene instruction, scaling and root planing) on the levels of sCAMs in each site of the diseased group was also investigated.

Results: Statistically significant differences (P <0.05) were found between the levels of sVCAM‐1 in periodontal health and disease. These results indicate that changes in the levels of sCAMs may be a sensitive indicator to differentiate healthy sites from those with periodontitis. Statistically significant changes in the levels of sICAM‐1 were recorded after treatment (P <0.05).

Conclusions: Further studies are required to establish if these potential biomarkers will enable the identification of those sites most at risk for disease progression and also evaluate the response to treatment, thereby playing a preventive role in the pathogenesis of periodontal disease. J Periodontol 2004;75:546‐550.