bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neutrophils Die in the Gingival Crevice, Periodontal Pocket, and Oral Cavity by Necrosis and Not Apoptosis
Authors: Crawford John M. , Wilton James M.A. , Richardson Peggy 
Published: February 2005

Background: Neutrophils play important roles in the homeostasis of periodontal tissues. However, remarkably little is known about how these cells live and die in the gingival crevice and periodontal pocket. We have examined whether subgingival neutrophils die by necrosis or apoptosis and have begun to study the mechanisms controlling the functional lifespan of these cells.Methods: Neutrophils collected from clinically healthy gingival crevices, periodontal pockets, and the oral cavity (saliva) were examined with Hoechst dye 33342, propidium iodide/eithidium bromide, and FITC‐annexin V to identify live, dead, and apoptotic cells. Blood neutrophils were cultured for 17 to 20 hours in the presence or absence of gingival crevice washings (GC‐w) to study the effect of GC‐w on neutrophil apoptosis. In addition, endotoxin was removed from GC‐w by affinity resin to investigate the contribution of LPS to the inhibitory effect of GCw on blood neutrophils.Results: The percentage of dead neutrophils in all subgingival sites and in all oral samples far exceeded the percentage of apoptotic neutrophils. In all 3 locations, approximately 30% of neutrophils were dead, whereas less than 1% of neutrophils were apoptotic. We conclude that the majority of neutrophils which lose their viability within gingival crevices, periodontal pockets and the oral cavity die by necrosis and not by apoptosis. Washings obtained from clinically healthy gingival crevices (GC‐w) variably, but significantly, delayed apoptosis of peripheral blood neutrophils (mean suppression 45.7% ± SD 22.3). Removal of endotoxin from GC‐w significantly reduced this inhibitory effect.Conclusions: Our findings provide insights into the mechanisms of neutrophil death and the control of the functional lifespan of neutrophils in gingival crevices and periodontal pockets and therefore into the pathogenesis of periodontal diseases. J Periodontol 2000;71:1121‐1129.
The Influence of Genetic Variation on the Splenic T Cell Cytokine and Specific Serum Antibody Responses to Porphyromonas gingivalis in Mice
Authors: Gemmell Erica , Winning Tracey A. , Grieco Dorothy A. , Bird Philip S. , Seymour Gregory J. 
Published: February 2005

Background: T cell cytokine profiles in the spleens and anti‐Porphyromonas gingivalis antibodies in the sera of P. gingivalis‐immunized BALB/c (H‐2d), CBA/CaH (H‐2k), C57BL6 (H‐2b), and DBA/2J (H‐2d, C5 deficient) mice were examined.Methods: Mice were immunized either by intraperitoneal injections of P. gingivalis outer membrane antigens and Freund's incomplete adjuvant weekly for 3 weeks or sham‐immunized with PBS and adjuvant, followed by subcutaneous challenge with live organisms 1 week after the final immunization. Spleens were excised and blood samples collected by heart puncture at 0 and 7 days after challenge. Splenic CD4 and CD8 cells were stained for intracytoplasmic interleukin (IL)‐4, interferon (IF)‐gamma, and IL‐10 and levels of anti‐P. gingivalis antibodies in the serum samples determined by ELISA.Results: Lesion sizes in immunized BALB/c mice remained stable for the 7‐day experimental period. Immunized CBA/CaH and C57BL6 mice exhibited large lesions at day 1 reducing by day 7 particularly in the latter strain. Lesions in immunized DBA/2J mice were still larger than the other strains at day 7. With the exception of DBA/2J mice, sham‐immunized mice demonstrated lesions which did not show signs of healing by day 7. T cell cytokine responses in sham‐immunized mice at day 0 were low, increasing to a variable degree by day 7 after challenge in the 4 strains. Immunized BALB/c mice demonstrated intermediate T cell responses while generally exhibiting a stronger IFN‐gamma response than IL‐4 or IL‐10. Immunized CBA/CaH and C57BL6 mice showed weak T cell cytokine responses while immunized DBA/2J displayed the strongest T cell responses particularly in regard to IL‐4 positive cells. Sham‐immunized mice had low levels of serum anti‐P. gingivalis antibody levels at day 0 with levels increasing significantly by day 7 after challenge. Antibody levels in immunized mice seemed to correlate with lesion sizes. Immunized C57BL6 mice had the highest antibody levels followed by CBA/CaH, BALB/c with DBA/2J exhibiting low levels. The T cell and B cell antibody responses in each strain appeared to exhibit an inverse relationship.Conclusions: This study has shown that genetic differences at the level of H‐2 haplotype induce variations in the local and T and B cell responses to P. gingivalis antigens. The responses of DBA/2J mice which have the same haplotype as BALB/c mice suggest that factors other than H‐2 haplotype such as the C5 deficiency may influence this immune response. The significance of the specific antibody and T cell responses and of their inverse relationship to susceptibility to periodontal disease remains to be determined. J Periodontol 2000;71:1130‐1138.
A spartate Aminotransferase Activity in Crevicular Fluid From Dental Impiants
Authors: Paolantonio Michele , Di Placido Giacinto , Tumini Vincenzo , Di Stilio Mauro , Contento Alessandro , Spoto Giuseppe 
Published: February 2005

Background:Aspartate aminotransferase (AST) is an enzyme normally confined to the cytoplasm of cells, but released to the exracellular environment upon cell death. Its levels are associated with the severity of experimental gingivitis and the loss of periodontal attachement. The aim of the present study was to investigate the presence and activity levels of AST in peri‐implant crevic‐ular fluid (PCF) healthy and diseased endosseous implants in order to assess if AST in PCF can be further studied as a possible objective diognostic aid in oral implantology.Methods: Eighty‐one fitures from 81 systemically healthy subject were divide into 3 groups, 27 healthy implants (HI), 27 implants with mucositis (MI) and 27 implants affected by periimplantities (PI)according to well‐defined clinical and radiographic criteria. PCF was collected by the insertion of a # 40 standardized ‐ point to the base of the crevice or pocket for 30 seconds. AST activity was determined spectrophotometrically at 25′ C. The results were expressed as AST Units/ml in PCF.Results: An AST activity was detected in each sample from HI, MI and PI. The mean AST activity in HI was 0.26 f 0.16 U/ml; in MI, 0.38 ± 0.27u/ml; in PI, 0.62 k 0.29 U/ml. ANOVA showed that the deference among HI, MI, and PI was statistically significant at P <0.01level. Post‐hoc tests demonstrated that a significant difference in AST activity existed between HI/PI (t = 5.14; P <0.01) and MI/PI (t = 3.09; P <0.01). No statistically significant difference was fond between HI/MI (t = 1.07; P>0.1) AST activity was significantly (P <1) associated with probing depth (r = 0.55), the amount of bone loss (r = 0.60) and bleeding on probing (r = 0.67). When the threshold for a positive AST test was set ≥0.4 U/ml, a sensitivity = 0.81 and a specificity = 0.74 were found in the detection of peri‐implantitis; the positive predictive value was 61% and the negative predictive value was 88%.Conclusions: within the limits of this study, our results may suggest the PCF analysis could be further investigated in longitudi‐nal studies as a suitable diagnostic strategy in the evaluation of dental implants. J Periodontol2000;71:1151‐1157.
Effects of Bisphosphonate on Matrix Metalloproteinase Enzymes in Human Periodontal Ligament Cells
Authors: Nakaya H. , Osawa G. , Iwasaki N. , Cochran D.L. , Kamoi K. , Oates T.W. 
Published: February 2005

Background: The host response is a critical component in the pathogenesis of periodontitis. In fact, the clinical benefits associated with regulating the host response have been demonstrated in studies using several different classes of drugs. Biophosphates are one host‐modulating class of drugs that has demonstrated this ability. These drugs are clinically effective at reducing bone resorption and have shown the ability to inhibit host degradative enzymes, specifically the matrix metalloproteinases (MMPs). Therefore, the purpose of this study was to investigate the regulatory effects of a bisphosphonate, tiludronate, on MMP levels and activity in human periodontal cells.Methods: MMP‐1 and MMP‐3 were assessed in cultured human periodontal ligament cells treated with a bisphosphonate, tiludronate. Reverse transcription‐polymerase chain reaction was used to identify mRNA levels for both enzymes, and also for tissue inhibitors (TIMP‐1). Enzyme immunoassay (EIA) and immunocytochemistry were used to assess MMP proteins in these cell cultures. Enzyme activity was assessed using FITCconjugated substrates and quantitated using spectrophotofluorometry.Results: Tiludronate significantly inhibited both MMP‐1 and MMP‐3 activity in a concentration‐dependent manner. A maximal reduction in activity of 35% was achieved for each of the enzymes at a 10‐4 M concentration. Tiludronate did not have a significant effect on the mRNA levels for MMP‐1, MMP‐3, or TIMP‐1. Similarly, there were no effects noted for either MMP‐1 or MMP‐3 on the protein level.Conclusions: This study demonstrates an inhibitory effect of tiludronate on the activity of both MMP‐1 and MMP‐3. These effects appear to occur without altering either mRNA or protein levels for these enzymes, supporting a possible mechanism of action that involves the ability of bisphosphonates to chelate cations from the MMPs. Furthermore, these results support the continued investigation of these drugs as potential therapeutic agents in periodontal disease. J Periodontol 2000;71:1158‐1166.
Induction of Experimental Periodontitis in Mice With Porphyromonas gingivalis‐ Adhered Ligatures
Authors: Kimura Shigenobu , Nagai Atsushi , Onitsuka Tokuya , Koga Toshiya , Fujiwara Taku , Kaya Hidehiro , Hamada Shigeyuki 
Published: February 2005

Background: Little information is available on the colonization of periodontopathic bacteria and alveolar bone loss in a mouse system, because of the difficulty in establishing bacteria in the oral cavity. The aim of this study was to establish experimental periodontitis in mice by applying a Porphyromonas gingivalis‐adhered ligature onto the molars.Methods: Specific pathogen‐free C3H/HeN mice were divided into 3 groups: 80 infected, 80 sham‐infected, and 48 non‐treated control mice. Sterile silk ligatures were preincubated with and without P. gingivalis 381 in vitro and then physically tied on the right maxillary first molar of infected and sham‐infected mice, respectively. Ten mice from the infected and sham‐infected groups and 6 from the control group were sacrificed at 2‐week intervals for up to 15 weeks after infection.Results: Plaque samples were collected at the time of sacrifice and alveolar bone loss was examined. The results indicated that P. gingivalis was recovered from the plaque samples in 95% of the infected mice after 1 week and then gradually dropped to 58% after 15 weeks of infection, whereas P. gingivalis was not isolated in either sham‐infected or control mice throughout the experimental period. The infected mice showed significant P. gingivalis‐induced bone loss at the sites where the ligature was tied weeks 13 to 15. A linear regression analysis revealed a significant positive correlation between the number of P. gingivalis recovered and alveolar bone loss at 15 weeks after infection (P <0.01).Conclusions: The use of a P. gingivalis‐adhered ligature supported a long‐lasting infection of P. gingivalis in mice, resulting in P. gingivalis‐induced alveolar bone breakdown. J Periodontol 2000;71:1167‐1173.
Ability of Deproteinized Cancellous Bovine Bone to Induce New Bone Formation
Authors: Schwartz Z. , Weesner T. , Van Dijk S. , Cochran D.L. , Mellonig J.T. , Lohmann C.H. , Carnes D.L. , Goldstein M. , Dean D.D. , Boyan B.D. 
Published: February 2005

Background: Preclinical and clinical studies indicate that deproteinized cancellous bovine bone is osteoconductive and may be osteopromotive. Previous studies using commercial preparations failed to demonstrate the presence of protein, implicating bone‐mineral composition and 3‐dimensional structure as reasons for clinical success; however, these studies did not examine whether osteoinductive factors might be present in close association with the mineral phase.Methods: Deproteinized cancellous bovine bone was decalcified and any protein present released by chaotropic solvents using the protocol described for purification of bone morphogenetic proteins (BMPs). Three extracts were obtained and tested for their ability to support osteoinduction in the calf muscle of nude mice.Results: Protein content averaged 11 µg/g based on absorbance at 280 nm using bovine serum albumin as a standard. All extracts contained material that stained positively with silver stain after sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). Western blots of these gels indicated the presence of transforming growth factor‐beta (TGF‐β) and BMP‐2. All 3 extracts were osteoinductive in the nude mouse model when combined with inactive DFDBA, and bone formation was comparable to that induced by active DFDBA. Deproteinized cancellous bovine bone by itself was not osteoinductive in the nude mouse, but in a clinical case, exhibited osteoclastic resorption with adjacent new bone formation.Conclusions: The results suggest that small amounts of protein are present in deproteinized cancellous bovine bone in close association with the mineral phase. Some of the extracted material has osteoinductive potential and may contain growth factors. This may explain the osteopromotive ability of deproteinized cancellous bovine bone clinically. J Periodontol 2000;7I:l258‐1269.
In Vitro Wound Healing Responses to Enamel Matrix Derivative
Authors: Hoang A.M. , Oates T.W. , Cochran D.L. 
Published: February 2005

Background: Enamel matrix derivative (EMD) contains a variety of hydrophobic enamel matrix proteins and is extracted from developing embryonal enamel of porcine origin. EMD has been associated with the formation of acellular cementum and it has been found to stimulate periodontal regeneration. The present study was established to investigate the influence of EMD on human periodontal ligament (PDL) cells, gingival fibroblasts (GF), and osteosarcoma (MG‐63) cells on wound‐fill rates using an in vitro wound model.Methods: Wounds were created by making 3 mm incisions in cell monolayers across the length of tissue culture plates. The wounded PDL, GF, and MG‐63 cell monolayers were treated with media containing EMD over a concentration range of 5 to 100 µg/ml, platelet‐derived growth factor (PDGF‐BB) at 20 ng/ml as a positive control and insulin‐like growth factor (IGFI) at 100 ng/ml as a negative control. PDL cell wounded monolayers also were treated in EMD coated tissue culture plates. After an incubation period (up to 9 days), the cells were fixed and stained and cellular fill was measured across the width of the wound by computer‐assisted histomorphometry.Results: When PDL, GF, and MG‐63 cells were exposed to EMD in culture medium, an enhanced wound‐fill was observed for all cells compared to untreated conditions. At early time points, PDL wound‐fill rates in the presence of EMD were statistically greater than the rates of GF and MG‐63 treated with EMD (P <0.001). There were no significant differences in wound‐fill rates of PDL cells treated with EMD in medium versus EMD coated on culture plates. At days 3 and 6 post‐wounding, PDL cells showed a significantly greater response to EMD than to PDGF‐BB (P <0.001). EMD also had a greater effect on GF wound‐fill rates than PDGF‐BB at days 6 and 9. MG‐63 cells were less responsive to PDGF‐BB and EMD than PDL cells and GF. All 3 cell types treated with IGF‐I showed no significant increase of wound‐fill rates.Conclusion: The present data support the concept that clinical application of enamel matrix derivative may enhance periodontal wound regeneration by specifically modifying periodontal ligament cell proliferation and migration. J Periodontol 2000;71:1270‐1277.
Porcine Fetal Enamel Matrix Derivative Enhances Bone Formation Induced by Demineralized Freeze Dried Bone Allograft In Vivo
Authors: Boyan B.D. , Weesner T.C. , Lohmann C.H. , Andreacchio D. , Carnes D.L. , Dean D.D. , Cochran D.L. , Schwartz Z. 
Published: February 2005

Background: Embryonic enamel matrix proteins are involved in the formation of acellular cementum during development of the periodontal attachment apparatus, suggesting that these proteins might be used clinically to promote periodontal regeneration. At present, it is unknown if these proteins are osteoinductive, osteoconductive, or osteopromotive. To address this question, we examined the ability of a commercially prepared embryonic porcine enamel matrix derivative to induce new bone formation in nude mouse calf muscle, or to enhance the bone induction ability of a demineralized freeze‐dried bone allograft (DFDBA).Methods: Porcine fetal enamel matrix derivative (EMD) was implanted bilaterally in the calf muscle of 4 male Nu/Nu mice per treatment group (N = 8 implants): 2 mg EMD alone; 4 mg EMD alone; inactive human DFDBA alone; inactive DFDBA + 2 mg EMD; inactive DFDBA + 4 mg EMD; active DFDBA alone; active DFDBA + 2 mg EMD; and active DFDBA + 4 mg EMD. Implants were harvested after 56 days and examined histologically for bone induction using a semi‐quantitative score and histomorphometrically for area of new bone, cortical bone, bone marrow, and residual DFDBA.Results: Implants containing inactive DFDBA, 2 mg EMD, 4 mg EMD, and inactive DFDBA + 2 or 4 mg EMD did not induce new bone. Active DFDBA and active DFDBA + 2 mg EMD induced new bone to a similar extent. In contrast, active DFDBA + 4 mg EMD resulted in enhanced bone induction, area of new bone, and cortical bone. Residual DFDBA was also increased in this group.Conclusions: EMD is not osteoinductive. However, it is osteopromotive, due in part to its osteoconductive properties, but a threshold concentration is required. J Periodontol 2000;71:1278‐1286.
Porcine Fetal Enamel Matrix Derivative Stimulates Proliferation But Not Differentiation of Pre‐Osteoblastic 2T9 Cells, Inhibits Proliferation and Stimulates Differentiation of Osteoblast‐Like MG63 Cells, and Increases Proliferation and Differentiation of Normal Human Osteoblast NHOst Cells
Authors: Schwartz Z. , Carnes D.L. , Pulliam R. , Lohmann C.H. , Sylvia V.L. , Liu Y. , Dean D.D. , Cochran D.L. , Boyan B.D. 
Published: February 2005

Background: Embryonic enamel matrix proteins are hypothesized to be involved in the formation of acellular cementum during tooth development, suggesting that these proteins can be used to regenerate periodontal tissues. Enamel matrix protein derived from embryonic porcine tooth germs is used clinically, but the mechanisms by which it promotes the formation of cementum, periodontal ligament, and bone are not well understood.Methods: This study examined the response of osteoblasts at 3 stages of osteogenic maturation to porcine fetal enamel matrix derivative (EMD). Proliferation (cell number and [3H]‐thymidine incorporation), differentiation (alkaline phosphatase and osteocalcin), matrix synthesis ([35S]‐sulfate incorporation; percentage of collagen production), and local factor production (prostaglandin E2 [PGE2] and transforming growth factor beta 1 [TGF‐β1]) were measured in cultures of 2T9 cells (pre‐osteoblasts which exhibit osteogenesis in response to bone morphogenetic protein‐2 [BMP‐2]), MG63 human osteoblast‐like osteosarcoma cells, and normal human osteoblasts (NHOst cells).Results: EMD regulated osteoblast proliferation and differentiation, but the effects were cell‐specific. In 2T9 cell cultures, EMD increased proliferation but had no effect on alkaline phosphatase‐specific activity. EMD decreased proliferation of MG63 cells and increased cellular alkaline phosphatase and osteocalcin production. There was no effect on collagen synthesis, proteoglycan sulfation, or PGE2 production; however, TGF‐β1 content of the conditioned media was increased. There was a 60‐fold increase in cell number in third passage NHOst cells cultured for 35 days in the presence of EMD. EMD also caused a biphasic increase in alkaline phosphatase that was maximal at day 14.Conclusions: EMD affects early states of osteoblastic maturation by stimulating proliferation, but as cells mature in the lineage, EMD enhances differentiation. J Periodontol 2000;71:1287‐1296.
Acellular Dermal Matrix Allografts to Achieve Increased Attached Gingiva. Part 1. A Clinical Study
Authors: Wei Pein‐Chi , Laurell Lars , Geivelis Milton , Lingen Mark W. , Maddalozzo Donna 
Published: February 2005

Background: Freeze‐dried acellular dermal matrix (ADM) allograft, originally used for full‐thickness burn wounds, was recently introduced as an alternative to the autogenous free gingival graft (FGG) in achieving increased attached keratinized tissue. The aim of part 1 of this study was to investigate the clinical efficacy of the ADM allograft for this particular purpose.Methods: Twelve patients, 7 males and 5 females, with attached gingiva ≤1 mm on the facial aspect of mandibular anterior teeth demonstrating a tendency of progressive marginal tissue recession, were randomly assigned to either test or control treatment. Six patients received ADM graft (test) and 6 patients received an autogenous FGG harvested from the hard palate (control). Clinical variables including plaque index (PI), gingival index (GI), probing depth (PD), attached tissue width (AT), and gingival recession (GR) were recorded immediately before surgery and at the 6‐month postoperative visit. Patients were seen at 2, 4, 6, 8, and 12 weeks to monitor wound healing and oral hygiene performance (PI and GI). Graft width was also measured, in corono‐apical direction, on individually involved teeth during the surgery.Results: When values between baseline and 6 months were compared in both groups, there was no statistically significant difference in changes of PI, GI, PD, and GR (P >0.05) with the exception of PD in the FGG group (1.01 ± 0.03 versus 1.27 ± 0.20 mm, P = 0.042). There was a statistically significant (P <0.05) increase in AT in both groups. Although the ADM group received wider grafts than the FGG group (8.81 ± 0.46 versus 6.70 ± 0.89 mm), the AT gain was significantly smaller (2.59 ± 0.92 versus 5.57 ± 0.44 mm) and the graft shrinkage significantly greater (71 ± 10% versus 16 ± 12%) in the ADM group than in the FGG group (P <0.01).Conclusions: The results of this study suggest that in procedures aiming at increasing the width of attached gingiva: 1) the ADM allograft was less effective and less predictable than the autogenous FGG in terms of increasing attached keratinized tissue due to considerable shrinkage and inconsistent quality of the attached tissue gained and 2) the esthetic results using the ADM allograft might be better than those using the autogenous FGG. J Periodontol 2000;71:1297‐1305.