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  • 1
    Electronic Resource
    Electronic Resource
    Munksgaard : Munksgaard International Publishers
    Journal of clinical periodontology 26 (1999), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract. The purpose of this study was to compare the bovine derived xenograft (BDX) Bio-Oss® to demineralized freeze dried bone allograft (DFDBA) in human intrabony defects. 17 healthy patients with no systemic disease with moderate-severe periodontitis (7 males, 10 females; aged 34–67), were treated. Surgically, defects were included only if the intraosseous defect depth was 〉3.0 mm. Final selection included 30 defects. The sites were randomly assigned treatment with DFDBA or BDX. Soft tissue and osseous defect measurements were taken the day of surgery and 6 months post-operatively at re-entry. Average baseline PD, CAL, and surgical defect depth for the DFDBA group were not statistically different from the BDX group. No adverse healing response occurred. The results showed a statistically significant improvement in PD and AL for both materials at 6 months in 26 defects (4 defects did not respond to therapy). Soft tissue measurements for the DFDBA group included PD reduction of 2.0±1.3 mm, and AL gain of 2.6±1.6 mm, while the BDX group showed a PD reduction of 3.0±1.7 mm, and AL gain of 3.6±1.8 mm. Osseous measurements showed bone fill of 2.4 mm (46.8%) for the DFDBA group and 3.0 mm (55.8%) for the BDX group. Defect resolution was 59.4% for the DFDBA group and 77.6% for the BDX group. Statistical analysis revealed there was no statistical difference between the 2 materials in all measurements.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Journal of clinical periodontology 29 (2002), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives: To assess clinical, radiographic, and biochemical markers as diagnostic indicators of disease activity by comparing ligature-induced bone loss in the presence or absence of IL-1/TNF-α antagonist inhibition of bone loss in a primate model.Material and Methods: 6 animals with a naturally-occurring gingivitis were evaluated over a 6-week time period following the placement of silk ligatures and initiation of a soft diet. Three animals received intrapapillary injections of soluble receptors (blockers), capable of blocking the biologic activity for both IL-1 and TNF-α, and 3 animals received vehicle (control) injections. Injections were given 3× per week over the course of the study. Clinical assessments included a gingival index and quantification of gingival crevicular fluid (GCF) levels. Collected GCF samples were then used in the biochemical assessment of pyridinoline (PYD) and bone alkaline phosphatase (BAP). Radiographic assessment was made using computer-assisted subtraction radiography to measure both bone density (CADIA) values and linear changes in crestal bone height.Results: Significant (p〈0.01) changes using both radiographic measures occurred between 2 and 4 weeks following initiation of disease in this model. The use of the blockers significantly (p〈0.01) reduced the levels of radiographic bone loss by approximately 50% over that found in the control sites. Both biochemical markers showed the greatest increase during the first two weeks of the study with PYD levels increased 35-fold over baseline levels after 1 week. This difference in response was significantly (p〈0.05) greater than the levels found in the non-ligated teeth or in the ligated teeth receiving blockers injections. BAP levels showed significant increases in ligated teeth compared to non-ligated teeth, but failed to show any significant differences between animals treated with vehicle and those treated with IL-1/TNF antagonists. In contrast to these radiographic and biochemical effects, there were no significant differences detected between animals treated with antagonists and the control group for any of the clinical measures.Conclusions: The results of this study demonstrate that both subtraction radiography and PYD crevicular fluid levels can detect relative differences in periodontal disease progression, while BAP crevicular fluid levels cannot.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Journal of clinical periodontology 28 (2001), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background, aims: Connective tissue grafts are used successfully in periodontal therapy for root coverage. However, reports on the histologic interface between the root surface and the grafted tissue have been few in number. This report describes a case study in which a subepithelial connective tissue graft was placed in a 27-year-old female on the maxillary left side.Methods: The graft (15 mm long, 10 mm wide, 1.5 mm thick) included palatal periosteum and was placed with the periosteal side facing the exposed bone and root surfaces.Results: 15 weeks after grafting, the teeth presented with residual recessions of 1 mm, and buccal probing depths were approximately 1 mm. 14 months post-surgery, the 1st maxillary premolars on both sides were extracted for orthodontic therapy. Clinical parameters at the graft site remained as at 15 weeks. Histologic analysis of tooth #24 showed that the sulcular epithelium was keratinized; epithelium lining the dentin exhibited rete ridges projecting into the gingival connective tissue; and junctional epithelium extended over new cementum. New connective tissue attachment was also observed, including periodontal ligament.Conclusion: Biological width was comparable pre- and post-surgery, indicating a real gain in attachment of 3.9 mm.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study compared osteoblast proliferation, differentiation, and protein synthesis on new and used titanium (Ti) disks to test the hypothesis that cleaning and resterilization of previously used Ti disks does not alter cell response to a particular surface. Ti disks of varying roughness were prepared by one of five different treatment regimens. Standard tissue culture plastic was used as a control. Human osteoblast-like cells (MG63) were cultured on the Ti disks and cell proliferation, cell differentiation, RNA synthesis and matrix production (collagen and noncollagen protein; proteoglycans) measured. After their first use, the disks were cleaned, re-sterilized by autoclaving. and MG63 cells cultured on them as before. At confluence, the same parameters were measured and cell behaviour on new and used disks compared. When confluent cultures of cells on plastic were compared to those cultured on new Ti surfaces, cell number was reduced on the roughest surfaces and equivalent to plastic on the other surfaces. Cell number was further reduced when disks with the roughest surfaces were re-used; no differences in cell number could be discerned after cleaning and re-sterilization. Cell proliferation was inversely related to surface roughness and was less than seen on tissue culture plastic. Re-use of the Ti disks resulted in no change in cell proliferation rate. Alkaline phosphatase specific activity in isolated cells was lowest on the rougher surfaces; no differences between new and used disks were observed. Similarly, enzyme activity in the cell layer was decreased in cultures grown on rougher surfaces, with no effect of prior disk use being noted. RNA synthesis was decreased with respect to plastic in cultures on smoother surfaces and increased on rougher surfaces; prior disk use did not alter RNA synthesis. Collagen production by the cells was decreased on smoother surfaces, but was comparable to tissue culture plastic when grown on rougher surfaces. Non-collagen protein production was unaffected by culture surface and whether or not the disk had been previously used. Proteoglycan synthesis by cells was decreased on all surfaces studied and comparable on both new and used disks. The results of this study indicate that Ti implant surfaces are unaffected by cleaning and resterilization, although rougher surfaces may require more extensive cleaning than smoother ones. This suggests the possibility that implants, in the same patient, could be safely reused. In vivo studies in animals, however, need to be performed before clinical application can be considered.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Previous studies have demonstrated in short-term experiments that a sandblasted and acid-etched (SLA) titanium implant had a greater bone-to-implant contact than a titanium plasma-sprayed (TPS) implant in non-oral bone. In the present study, an SLA implant was compared radiographically to a TPS implant under unloaded and loaded conditions in the canine mandible for up to 15 months. 69 implants were placed in 6 foxhounds. Standardized radiographs were taken at baseline, preload, 3, 6, 9, and 12 months of loading. Loaded implants were restored with gold crowns similar to the natural dentition. Radiographic assessment of the bone response to the implants was carried out by measuring the distance between the implant shoulder and the most coronal bone-to-implant contact (DIB) and by evaluation of bone density changes using computer-assisted densitometric image analysis (CADIA). 5 different areas-of-interest (AOI) were defined coronally and apically along the implant. DIB measurements revealed that SLA implants had significantly less bone height loss (0.52mm) than TPS implants (0.69mm) at the preload evaluation (p=0.0142) as well as at 3 months of loading (0.73mm/1.06mm: p=0.0337). This difference was maintained between the implant types during the 1-year follow-up period. The same trend was also evident for CADIA measurements with SLA implants showing higher crestal bone density values when comparing preload to baseline data (p=0.0890) and 3 months to baseline data (p=0.0912). No measurable bone density changes were apparent in the apical areas of either implant. These results suggest that SLA implants are superior to TPS implants as measured radiographically in oral bone under unloaded and loaded conditions.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth factors PDGF-AA and PDGF-BB have previously been shown to be potent mitogens for human periodontal ligament (hPDL) cells in vitro. Additionally, the mitogenic response to PDGF-AA has been shown to be specifically inhibited by TGF-β. The purpose of the present investigation was to examine the binding of PDGF-AA and PDGF-BB, and the modulation of PDGF binding by TGF-β, in hPDL cells. Scatchard analysis identified an average of 32,000 PDGF-AA high-affinity binding sites per cell with a dissociation constant (Kd) of 0.66 nM and an average of 36,000 PDGF-BB binding sites per cell with a dissociation constant (kd) of 0.44 nM. After treatment with TGF-β, the receptor number for PDGF-AA was found to specifically decrease by approximately 50%, with no change in binding affinity. This reduced number of binding sites was shown to correlate with both a decrease in levels of receptor tyrosine phosphorylation and a decreased number of α receptor subunits. Northern blot analysis identified the TGF-β-mediated decrease in PDGF α receptor subunit mRNA levels. PDGF-BB showed little change in the number of binding sites or in the binding affinity with TGF-β treatment, and the data were consistent with an increase in the number of β receptor subunits. These results demonstrate nearly equivalent numbers of receptors for both PDGF-AA and PDGF-BB in hPDL cells. Also, modulation of PDGF binding, by TFG-β, was shown to result in a reduced number of α receptor subunits with an increase in the number of β receptor subunits. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 7
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Although it is well accepted that implant success is dependent on various surface properties, little is known about the effect of surface roughness on cell metabolism or differentiation, or whether the effects vary with the maturational state of the cells interacting with the implant. In the current study, we examined the effect of titanium (Ti) surface roughness on chondrocyte proliferation, differentiation, and matrix synthesis using cells derived from known stages of endochondral development. Chondrocytes derived from the resting zone (RCs) and growth zone (GCs) of rat costochondral cartilage were cultured on Ti disks that were prepared as follows: HF-HNO3-treated and washed (PT); PT-treated and electropolished (EP); fine sand-blasted, HCl-H2SO4-etched, and washed (FA); coarse sand-blasted, HCl-H2SO4-etched, and washed (CA); or Ti plasma-sprayed (TPS). Based on surface analysis, the Ti surfaces were ranked from smoothest to roughest: EP, PT, FA, CA, and TPS. Cell proliferation was assessed by cell number and [3H]-thymidine incorporation, and RNA synthesis was assessed by [3H]-uridine incorporation. Differentiation was determined by alkaline phosphatase specific activity (AL-Pase). Matrix production was measured by [3H]-proline incorporation into collagenase-digestible (CDP) and noncollagenase-digestible (NCP) protein and by [35S]-sulfate incorporation into proteoglycan. GCs required two trypsinizations for complete removal from the culture disks; the number of cells released by the first trypsinization was generally decreased with increasing surface roughness while that released by the second trypsinization was increased. In RC cultures, cell number was similarly decreased on the rougher surfaces; only minimal numbers of RCs were released by a second trypsinization. [3H]-thymidine incorporation by RCs decreased with increasing surface roughness while that by GCs was increased. [3H]-Uridine incorporation by both GCs and RCs was greater on rough surfaces. Conversely, ALPase in the cell layer and isolated cells of both cell types was significantly decreased. GC CDP and NCP production was significantly decreased on rough surfaces while CDP production by RC cells was significantly decreased on smooth surfaces. [35S]-sulfate incorporation by RCs and GCs was decreased on all surfaces compared to tissue culture plastic. The results of this study indicate that surface roughness affects chondrocyte proliferation, differentiation, and matrix synthesis, and that this regulation is cell maturation dependent. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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  • 8
    ISSN: 0021-9304
    Keywords: implant ; titanium ; osteoblasts ; surface roughness ; 1α,25- (OH)2D3 ; differentiation ; local factor ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Surface roughness has been shown to affect differentiation and local factor production of MG63 osteoblast-like cells. This study examined whether surface roughness alters cellular response to circulating hormones such as 1α,25-(OH)2D3. Unalloyed titanium (Ti) disks were pretreated with HF/HNO3 (PT) and then were machined and acid-etched (MA). Ti disks also were sandblasted (SB), sandblasted and acid etched (CA), or plasma sprayed with Ti particles (PS). The surfaces, from smoothest to roughest, were: PT, MA, CA, SB, and PS. MG63 cells were cultured to confluence on standard tissue culture polystyrene (plastic) or the Ti surfaces and then treated for 24 h with either 10-8M or 10-7M 1α,25-(OH)2D3 or vehicle (control). Cellular response was measured by assaying cell number, cell layer alkaline phosphatase specific-activity, and the production of osteocalcin, latent (L) TGFβ, and PGE2. Alkaline phosphatase activity was affected by surface roughness; as the surface became rougher, the cells showed a significant increase in alkaline phosphatase activity. Addition of 1α,25-(OH)2D3 to the cultures caused a dose-dependent stimulation of alkaline phosphatase activity that was synergistic with the effect caused by surface roughness alone. 1α,25-(OH)2D3 also caused a synergistic increase in osteocalcin production as well as local factor (LTGFβ and PGE2) production on the rougher CA, SB, and PS surfaces, but it had no effect on the production on smooth surfaces. The inhibitory effect of surface roughness on cell number was not affected by 1α,25-(OH)2D3 except on the SB surface. 1α,25-(OH)2D3 decreased cell number, increased alkaline phosphatase activity and osteocalcin production, and had no effect on LTGFβ or PGE2 production by MG63 cells grown on tissue culture polystyrene. These data suggest that bone cell response to systemic hormones is modified by surface roughness and that surface roughness increases the responsiveness of MG63 cells to 1α,25-(OH)2D3. They also suggest that the endocrine system is actively involved in normal bone healing around implants. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 77-85, 1998.
    Additional Material: 6 Ill.
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  • 9
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Titanium (Ti) surface roughness affects proliferation, differentiation, and matrix production of MG-63 osteoblast-like cells. Cytokines and growth factors produced in the milieu surrounding an implant may also be influenced by its surface, thereby modulating the healing process. This study examined the effect of surface roughness on the production of two factors known to have potent effects on bone, prostaglandin E2 (PGE2) and transforming growth factor β1 (TGF-β1). MG-63 cells were cultured on Ti disks of varying roughness. The surfaces were ranked from smoothest to roughest: electropolished (EP), pretreated with hydrofluoric acid-nitric acid (PT), fine sand-blasted, etched with HCl and H2SO4, and washed (EA), coarse sand-blasted, etched with HCl and H2SO4, and washed (CA), and Ti plasma-sprayed (TPS). Cells were cultured in 24-well polystyrene (plastic) dishes as controls and to determine when confluence was achieved. Media were collected and cell number determined 24 h postconfluence. PGE2 and TGF-β1 levels in the conditioned media were determined using commercial radioimmunoassay and enzyme-linked immunosorbent assay kits, respectively. There was an inverse relationship between cell number and Ti surface roughness. Total PGE2 content in the media of cultures grown on the three roughest surfaces (FA, CA, and TPS) was significantly increased 1.5-4.0 times over that found in media of cultures grown on plastic or smooth surfaces. When PGE2 production was expressed per cell number, CA and TPS cultures exhibited six- to eightfold increases compared to cultures on plastic and smooth surfaces. There was a direct relationship between TGF-β1 production and surface roughness, both in terms of total TGF-β1 per culture and when normalized for cell number. TGF-β1 production on rough surfaces (CA and TPS) was three to five times higher than on plastic. These studies indicate that substrate surface roughness affects cytokine and growth factor production by MG-63 cells, suggesting that surface roughness may modulate the activity of cells interacting with an implant, and thereby affect tissue healing and implant success. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 10
    ISSN: 0021-9304
    Keywords: surface characteristics ; titanium implants ; osseointegration ; bone response ; loaded implants ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Many dental clinical implant studies have focused on the success of endosseous implants with a variety of surface characteristics. Most of the surface alterations have been aimed at achieving greater bone-to-implant contact as determined histometrically at the light microscopic level. A previous investigation in non-oral bone under short-term healing periods (3 and 6 weeks) indicated that a sandblasted and acid-etched titanium (SLA) implant had a greater bone-to-implant contact than did a comparably-shaped implant with a titanium plasma-sprayed (TPS) surface. In this canine mandible study, nonsubmerged implants with a SLA surface were compared to TPS-coated implants under loaded and nonloaded conditions for up to 15 months. Six foxhound dogs had 69 implants placed in an alternating pattern with six implants placed bilaterally in each dog. Gold crowns that mimicked the natural occlusion were fabricated for four dogs. Histometric analysis of bone contact with the implants was made for two dogs after 3 months of healing (unloaded group), 6 months of healing (3 months loaded), and after 15 months of healing (12 months loaded). The SLA implants had a significantly higher (p 〈 0.001) percentage of bone-to-implant contact than did the TPS implants after 3 months of healing (72.33 ± 7.16 versus 52.15 ± 9.19; mean ± SD). After 3 months of loading (6 months of healing) no significant difference was found between the SLA and TPS surfaced implants (68.21 ± 10.44 and 78.18 ± 6.81, respectively). After 12 months of loading (15 months of healing) the SLA implants had a significantly greater percentage (p 〈 0.001) of bone-to-implant contact than did the TPS implants (71.68 ± 6.64 and 58.88 ± 4.62, respectively). No qualitative differences in bone tissue were observed between the two groups of implants nor was there any difference between the implants at the clinical level. These results are consistent with earlier studies on SLA implants and suggest that this surface promotes greater osseous contact at earlier time points compared to TPS-coated implants. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 1-11, 1998.
    Additional Material: 11 Ill.
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