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Ingrowth
Kinds of Ingrowth Selected AbstractsFabrication of Load-Bearing NiTi Scaffolds for Bone Ingrowth by Ni Foam Conversion,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Irena Gotman Highly porous NiTi scaffolds for bone ingrowth were fabricated by reactive conversion (PIRAC) of commercially available Ni foams. These open cell ,trabecular NiTi' scaffolds possess high strength and ductility and exhibit low Ni ion release. PIRAC deposition of a thin titanium nitride (TiN) layer further improves the corrosion characteristics of "trabecular NiTi" and allows for material bioactivation by alkali treatment or biomimetic Ca phosphate deposition. [source] Combined Use of Uncovered Duodenal and Covered Biliary Metallic Stent for Carcinoma of the Papilla of VaterDIGESTIVE ENDOSCOPY, Issue 4 2000Hitoshi Sano We have reported successful implantation of self-expandable metallic stents for palliative treatment in a case of an 87-year-old female patient with carcinoma of the papilla of Vater. She suffered from both duodenal and biliary stenoses, but refused surgical treatment. For the duodenal stenting, a self-expandable knitted nitinol metallic stent, for esophageal use, was inserted endoscopically. For the biliary stenting, a self-expandable metallic stent, partially polyurethane-covered on the proximal part to prevent tumor ingrowth and overgrowth, was inserted via the percutaneous transhepatic biliary drainage route. No major complications occured during these procedures. After the two stents were inserted in an end-to-side fashion, she was able to eat a normal diet adequately and suffered from no abdominal symptoms and jaundice during the follow-up period of 13 months. These stenting procedures might be less invasive and more useful than surgical treatment and provide long patency of biliary stenting and a good quality of life. [source] Fibronectin Functionalized Hydroxyapatite Coatings: Improving Dermal Fibroblast Adhesion In Vitro and In Vivo,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Catherine J. Pendegrass Skin-penetrating devices including intraosseous transcutaneous amputation prostheses (ITAP) and external fixator pins rely on a skin-implant seal to prevent infection. In this study, we assess the effectiveness of fibronectin (Fn) functionalized hydroxyapatite (HA) coatings for promoting dermal fibroblast and dermal tissue attachment and ingrowth in vitro and in vivo. By measuring the number of focal adhesions per unit cell area we have demonstrated that HA significantly promotes dermal fibroblast attachment compared with titanium alloy. Dermal fibroblast attachment is promoted further using Fn functionalized HA coatings incorporated into an implant design with 700,µm pores, which significantly increased dermal tissue ingrowth and attachment compared with non-functionalized HA and titanium alloy controls incorporating 500 or 1000,µm pores. We postulate that Fn functionalized HA coatings applied to transdermal implants may promote and sustain the skin-implant interface and assist in preventing infection long term. [source] Fabrication of Load-Bearing NiTi Scaffolds for Bone Ingrowth by Ni Foam Conversion,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Irena Gotman Highly porous NiTi scaffolds for bone ingrowth were fabricated by reactive conversion (PIRAC) of commercially available Ni foams. These open cell ,trabecular NiTi' scaffolds possess high strength and ductility and exhibit low Ni ion release. PIRAC deposition of a thin titanium nitride (TiN) layer further improves the corrosion characteristics of "trabecular NiTi" and allows for material bioactivation by alkali treatment or biomimetic Ca phosphate deposition. [source] Afferent ingrowth and onset of activity in the rat trigeminal nucleusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2000P. M. E. Waite Abstract A novel in vitro preparation, consisting of the rat brainstem with the trigeminal ganglion attached, has been used to study the anatomical and functional development of the trigeminal nucleus from embryonic day (E)13 to postnatal day (P)6. Neurobiotin injections into the trigeminal ganglion showed that primary afferents had reached the trigeminal tract by E13 and had grown simple, mainly unbranched, collaterals into all levels of the nucleus by E15. By E17, these collaterals were extensively branched, with occasional boutons present. Patches of intense neurobiotin-labelled terminals, corresponding to whisker-related patterns, were first seen at E20 and became clearer over the next few days. Terminal arbours at this stage were relatively localized and densely branched, with many boutons. Responses from the trigeminal nucleus were recorded with suction electrodes, following stimulation of the trigeminal ganglion. Recordings from the main sensory nucleus showed a postsynaptic response was first present at E15. At E16, bath application of AP5 and DNQX showed that the response contained both NMDA and AMPA components, with NMDA predominating (75%). The NMDA : AMPA ratio remained high until P1, then gradually declined to 50% by P6. The postsynaptic response was also reduced by bath application of bicuculline, indicating the presence of a GABAA -mediated excitatory component. GABAergic excitation was present at all ages but was maximal from E20 to P1, the age at which whisker-related patterns are developing. It is hypothesized that both GABAergic excitation and NMDA receptor activation play a role in the consolidation of trigeminal connections, and are thus important in the development of whisker-related patterns. [source] Effect of Silicate-Substitution on Attachment and Early Development of Human Osteoblast-Like Cells Seeded on Microporous Hydroxyapatite Discs,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Katharina Guth Hydroxyapatite (HA) is a well-established graft material used in bone repair. Silicon-substituted hydroxyapatite (SA; 0.8,wt% Si) has shown greater bone ingrowth and bone coverage than phase pure HA. To assess the effect of microporosity on sensitivity of cell attachment to surface physiochemistry, microporous SA and HA discs, and control Thermanox (TMX) discs were incubated with osteoblast-like cells (5,×,104 HOS-TE85 cells) under differing tissue culture conditions. To investigate early cellular attachment, organization, and differentiation, cells were also stained for integrin,,5,1, actin, and runt-related transcription factor (RUNX-2), respectively, after incubation on HA, SA, and TMX discs for 3 days. No significant differences emerged between HA, SA, and TMX discs in mean numbers of cells attached in serum free medium (SFM) over 90,min incubation. In contrast, significantly more cells were attached to SA than HA after 180,min incubation in complete medium (C-MEM) containing fetal calf serum (p,<,0.05). Cell attachment to SA and HA discs pre-conditioned in SFM supplemented with fibronectin (FN) was lower than discs pre-conditioned in C-MEM, suggesting sensitivity of an active FN conformation to the presence of co-adsorbates. Confocal microscopy demonstrated significantly more co-localization of integrin ,5,1 and actin on SA than HA. Translocalization of RUNX-2 to the nucleus was stronger in cells incubated on SA. Microporosity did not diminish the effect of surface physiochemistry on cell adhesion, and enhanced cell attachment for SA appears to be mediated by differences in the quality of adsorbed protein rather than via direct effects of substrate chemistry. [source] Powder Metallurgical Near-Net-Shape Fabrication of Porous NiTi Shape Memory Alloys for Use as Long-Term Implants by the Combination of the Metal Injection Molding Process with the Space-Holder Technique,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Manuel Köhl Abstract A new method was developed for producing highly porous NiTi for use as an implant material. The combination of the space-holder technique with the metal injection molding process allows a net-shape fabrication of geometrically complex samples and the possibility of mass production for porous NiTi. Further, the porosity can be easily adjusted with respect to pore size, pore shape, and total porosity. The influence of the surface properties of powder metallurgical NiTi on the biocompatibility was first examined using human mesenchymal stem cells (hMSCs). It was found that pre-alloyed NiTi powders with an average particle size smaller than 45,,m led to the surface properties most suitable for the adhesion and proliferation of hMSCs. For the production of highly porous NiTi, different space-holder materials were investigated regarding low C- and O-impurity contents and the reproducibility of the process. NaCl was the most promising space-holder material compared to PMMA and saccharose and was used in subsequent studies. In these studies, the influence of the total porosity on the mechanical properties of NiTi is investigated in detail. As a result, bone-like mechanical properties were achieved by the choice of Ni-rich NiTi powder and a space-holder content of 50,vol% with a particle size fraction of 355,500,,m. Pseudoelasticity of up to 6% was achieved in compression tests at 37,°C as well as a bone-like loading stiffness of 6.5,GPa, a sufficient plateau stress ,25 of 261,MPa and a value for ,50 of 415,MPa. The first biological tests of the porous NiTi samples produced by this method showed promising results regarding proliferation and ingrowth of mesenchymal stem cells, also in the pores of the implant material. [source] Selective Electron Beam Melting of Cellular Titanium: Mechanical PropertiesADVANCED ENGINEERING MATERIALS, Issue 9 2008P. Heinl Cellular titanium seems to be a promising material for medical implant applications due to an elastic modulus comparable with human bone and an interconnected porosity which facilitates bone ingrowth. This paper reports the mechanical properties of non-stochastic cellular Ti-6Al-4V structures fabricated by Selective Electron Beam Melting depending on different unit cell sizes and varying energy input per unit length of the electron beam. [source] Biocompatibility of Lotus-type Stainless Steel and Titanium in Alveolar BoneADVANCED ENGINEERING MATERIALS, Issue 9 2006Y. Higuchi Abstract Lotus-type porous stainless steel (SUS304L) and porous titanium were fabricated by unidirectional solidification in a mixture gas of hydrogen and argon. The porous metals which were cut into 5,mm cubes (non-dehydrogenated) and 3.4,mm,,×,5,mm cylinders (dehydrogenated) were implanted into the canine mandible alveolar bone for two, four and eight weeks for animal experiments. The changes in the tissues were observed using SEM. For porous stainless steel (cylindrical; dehydrogenated) new formation of bones was observed around the sample in two weeks without any sign of bony ingrowth into the pores. The osteogenesis was found in shallow areas in the pores in four weeks and deep in the pores in eight weeks. Porous titanium, on the other hand, showed deep ingrowth of new bones in four weeks. Our observations allowed us to expect application of the porous metals as biomaterials. They maintain mechanical strength and are lighter in weight so that it is expected to be applied for dental implants and core materials of artificial bones. [source] Porous TiNi Biomaterial by Self-Propagating High-Temperature Synthesis,ADVANCED ENGINEERING MATERIALS, Issue 6 2004J.S. Kim Abstract Porous TiNi shape-memory alloy (TiNi SMA) bodies with controlled pore structure were produced from the (Ti+Ni) powder mixture by self-propagating high-temperature synthesis (SHS) method. The effect of processing variables such as the kind of starting powders, ignition temperature and preheating schedule on the behavior of combustion wave propagation, the formation of phases and pore structure was investigated. The relationship between pore structure and mechanical properties was also investigated. An in vivo test was performed to evaluate bone tissue response and histocompatibility of porous TiNi SMA using 15 New Zealand white rabbits. No apparent adverse reactions such as inflammation and foreign body reaction were noted on or around all implanted porous TiNi SMA blocks. Bone ingrowth was found in the pore space of all implanted blocks. [source] A Computational Approach on the Osseointegration of Bone Implants Based on a Bio-Active Interface TheoryGAMM - MITTEILUNGEN, Issue 2 2009André Lutz Abstract In this presentation an integrated approach on the simulation of osseointegration in the boneimplant interface is outlined. Besides the consistent combination of computational bone remodelling simulation and established medical imaging techniques, a new model refinement in terms of a bioactive interface theory is introduced, which enables the simulation of bone ingrowth in rough coated uncemented implants. Under consideration of seven physiological loads of daily motion the bone-implant relative micromotion in a soft tissue region around the endoprosthesis is investigated. As the micromotions are an important factor for osseointegration, because excessive micromotion leads to apposition of fibrous tissue, they are considered for the simulation of osseointegration. Results for different parameter constellations, regarding thickness and stiffness of bone-implant interface layer, are compared and the ingrowth for different configurations is predicted. With these results conclusions can be made about the stability of prosthesis in the host bone, which is an important factor for the clinical success of the treatment (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Peptide-coated vascular grafts: An in vivo study in sheepHEMODIALYSIS INTERNATIONAL, Issue 4 2004Cheng Li Abstract The data on function and patency of prosthetic vascular grafts in various clinical settings are limited. The purpose of this in vivo study was to compare the function and patency of P15-coated expanded polytetrafluoroethylene (ePTFE) vascular grafts to uncoated ePTFE grafts in sheep. The P15 cell-binding peptide was covalently immobilized onto the surface of ePTFE grafts by a novel atmospheric plasma coating method. We evaluated the amount of neointimal tissue ingrowth present at the arterial and venous sides of the anastomoses and the degree of endothelial cell resurfacing of the luminal surface of the graft. Four P15-coated grafts and two control grafts were implanted as arteriovenous grafts between the femoral artery and vein and the carotid artery and jugular vein in two sheep (n = 6). One animal was euthanized after 14 days and the other after 28 days. The study showed the intimal ingrowth was significantly less. The average intimal thickness of P15-coated grafts (658 µm) was approximately two and a half times less than that of uncoated samples (1657 µm). The newly formed endothelial cell lining was thicker and its coverage was more uniform for P15-coated grafts compared to the uncoated controls. [source] Three-Dimensional Microstructural Characterization of Porous Hydroxyapatite Using Confocal Laser Scanning MicroscopyINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 3 2005Fei Ren The characterization of porosity is crucial in the development and commercialization of ceramic bone replacement technology, since the pore size and interconnectivity play a central role in both biological function (bone ingrowth and nutrient flow) as well as mechanical properties of bone scaffolds. The ability of confocal laser scanning microscopy (CLSM) to image three-dimensional (3-D) structures with large vertical depths (,2 mm) and fine vertical resolution (,1 ,m) is utilized in this article to characterize the 3-D microstructures of hydroxyapatite (HA) bone scaffold specimens with porosity ranging from roughly 60,70 vol%. Various CLSM techniques are applied to image and interpret the HA pore structure, including Z -series stacking, topographic profiling, and Phi- Z scanning and contour mapping. [source] Bladder wall grafting in rats using salt-modified and collagen-coated polycaprolactone scaffolds: Preliminary reportINTERNATIONAL JOURNAL OF UROLOGY, Issue 10 2007Dah-Shyong Yu Aim: A rat model was used for the evaluation of collagen-coated and salt-modified polycaprolactone (PCL) scaffolds for bladder grafting after hemicystectomy. Methods: SD rats underwent partial cystectomy and cystoplasty with collagen-coated and salt-modified polycaprolactone scaffolds. The grafts of the regenerated bladder wall were harvested at different intervals and tissue regeneration was evaluated microscopically. Anatomic and functional characters were evaluated by cystography and urodynamics. Results: At harvesting, after 1 and 2 months, we found good preservation of the bladder shape and volume in all 16 rats receiving PCL cystorrhaphy. No stone formation was observed. Good epithelialization and ingrowth of smooth muscle cells were seen after 2 months grafting. Collagen-coated PCL scaffolds showed considerable encrustation, which appeared to be absorbed and disappear with time. The cystographic and urodynamic examinations revealed intact contour and a well-accommodated bladder with reservoir volume and contractility. Conclusions: In the rat model, we have successfully demonstrated the applicability of collagen coated and salt-modified PCL in reconstruction of the partial cystectomized bladder. [source] Re-utilization of Schwann cells during ingrowth of ventral root afferents in perinatal kittensJOURNAL OF ANATOMY, Issue 2 2008A. Ingela M. Nilsson Remahl Abstract Ventral roots in all mammalian species, including humans, contain significant numbers of unmyelinated axons, many of them afferents transmitting nociceptive signals from receptive fields in skin, viscera, muscles and joints. Observations in cats indicate that these afferents do not enter the spinal cord via the ventral root, but rather turn distally and enter the dorsal root. Some unmyelinated axons are postganglionic autonomic efferents that innervate blood vessels of the root and the pia mater. In the feline L7 segment, a substantial proportion of unmyelinated axons are not detectable until late in perinatal development. The mechanisms inducing this late ingrowth, and the recruitment of Schwann cells (indispensable, at this stage, for axonal survival and sustenance), are unknown. We have counted axons and Schwann cells in both ends of the L7 ventral root in young kittens and made the following observations. (1) The total number of axons detectable in the root increased throughout the range of investigated ages. (2) The number of myelinated axons was similar in the root's proximal and distal ends. The increased number of unmyelinated axons with age is thus due to increased numbers of small unmyelinated axons. (3) The number of separated large probably promyelin axons was about the same in the proximal and distal ends of the root. (4) Schwann cells appeared to undergo redistribution, from myelinated to unmyelinated axons. (5) During redistribution of Schwann cells they first appear as aberrant Schwann cells and then become endoneurial X-cells temporarily free of axonal contact. We hypothesize that unmyelinated axons invade the ventral root from its distal end, that this ingrowth is particularly intense during the first postnatal month and that disengaged Schwann cells, eliminated from myelinated motoneuron axons, provide the ingrowing axons with structural and trophic support. [source] The characterization and optimization of injectable silicone resin particles in conjunction with dermal fibroblasts and growth factors: An in vitro studyJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2010Robert M. Crews Abstract Minimally invasive subdermal injection of liquid silicone has been used clinically to augment the soft tissue of the foot to mitigate high pressures that cause diabetic foot ulcers. However, implant migration has been a clinical issue. The objective of this study was to assess the effects of three specific concentrations of silicone resin particles (12 ,m average diameter) in conjunction with either platelet-derived growth factor (PDGF-BB) or basic fibroblast growth factor (bFGF) on fibroblast cell proliferation, collagen synthesis, cell morphology, and migration through in vitro assays and a monolayer scratch wound model. PDGF and bFGF enhanced the proliferation of fibroblasts 5.7-fold and fivefold, respectively, while the addition of silicone particles had no significant effect on proliferation. Collagen production was increased approximately twofold with the addition of bFGF and the medium concentration of particles over bFGF without particles and the PDGF groups. The addition of silicone particles had no significant effect on collagen production compared with control groups without particles. Fibroblast migration was enhanced by the addition of both PDGF and bFGF compared to controls, although slower scratch wound closure rates were observed in the presence of particles compared to controls without particles. Cell morphology suggested that particles induced cellular aggregation encircling silicone particles postwounding as well as migration into the wound area. These results suggest that silicone particles in combination with a growth factor might enhance fibroblast aggregation and implant stability, and could promote connective tissue ingrowth and implant encapsulation in the soft tissue of the diabetic foot. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [source] Use of stereolithography to manufacture critical-sized 3D biodegradable scaffolds for bone ingrowth,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2003Malcolm N. Cooke Abstract A novel approach to the manufacture of biodegradable polymeric scaffolds for tissue-engineering utilizing stereolithography (SLA) is presented. SLA is a three-dimensional (3D) printing method that uses an ultraviolet laser to photo-crosslink a liquid polymer substrate. The current generation of SLA devices provide a 3D printing resolution of 0.1 mm. The experiments utilized a biodegradable resin mixture of diethyl fumarate (DEF), poly(propylene fumarate) (PPF), and a photoinitiator, bisacylphosphine oxide (BAPO). The PPF is crosslinked with the use of the SLA's UV laser (325-nm wavelength). An SLA device was retrofitted with a custom fixture build tank enclosing an elevator-driven build table. A 3D prototype model testing the manufacturing control this device provides was created in a computer-aided-design package. The resulting geometric data were used to drive the SLA process, and a DEF/PPF prototype part was successfully manufactured. These scaffolds have application in the tissue engineering of bony substrates. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 64B: 65,69, 2002 [source] Evaluation of blood vessel ingrowth in fibrin gel subject to type and concentration of growth factorsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 9a 2009A. Arkudas Abstract Our aim was to quantitatively assess the angiogenetic effects of VEGF and bFGF immobilized in a fibrin-based drug delivery system in a suitable subcutaneous rat model. After evaluation of a suitable implantation technique (6 rats), four teflon isolation chambers containing fibrin gel matrices were implanted subcutaneously in an upside-down fashion on the back of 30 Lewis rats. The matrices consisted of 500 ,l fibrin gel with two different fibrinogen concentrations (10 mg/ml or 40 mg/ml fibrinogen) and 2 I.U./ml thrombin and contained VEGF and bFGF in five different concentrations (0 to 250 ng/ml each). At 3, 7 and 14 days after implantation, matrices were explanted and subjected to histological and morphometrical analysis. At 1 week, the volume of the fibrin clots was significantly smaller in the 100 and 250 ng/ml VEGF and bFGF groups in comparison to lower concentrated growth factors. At 1 and 2 weeks, the use of growth factors in low concentrations (25 ng/ml VEGF and bFGF) significantly increased the amount of fibrovascular tissue, average fraction of blood vessels and number of blood vessels at the matrix,host interface in comparison to growth factor-free controls. Higher concentrations were neither associated with further increase of tissue formation nor with increased sprouting of blood vessels in this model. This study demonstrates that fibrin gel-immobilized angioinductive growth factors efficiently stimulate generation of fibrovascular tissue and sprouting of blood vessels in a newly developed subcutaneous upside-down isolation chamber model with an optimum between 25 and 100 ng/ml. [source] Spatial and temporal patterns of bone formation in ectopically pre-fabricated, autologous cell-based engineered bone flaps in rabbitsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2008Oliver Scheufler Abstract Biological substitutes for autologous bone flaps could be generated by combining flap pre-fabrication and bone tissue engineering concepts. Here, we investigated the pattern of neotissue formation within large pre-fabricated engineered bone flaps in rabbits. Bone marrow stromal cells from 12 New Zealand White rabbits were expanded and uniformly seeded in porous hydroxyapatite scaffolds (tapered cylinders, 10,20 mm diameter, 30 mm height) using a perfusion bioreactor. Autologous cell-scaffold constructs were wrapped in a panniculus carnosus flap, covered by a semipermeable membrane and ectopically implanted. Histological analysis, substantiated by magnetic resonance imaging (MRI) and micro-computerized tomography scans, indicated three distinct zones: an outer one, including bone tissue; a middle zone, formed by fibrous connective tissue; and a central zone, essentially necrotic. The depths of connective tissue and of bone ingrowth were consistent at different construct diameters and significantly increased from respectively 3.1 ± 0.7 mm and 1.0 ± 0.4 mm at 8 weeks to 3.7± 0.6 mm and 1.4 ± 0.6 mm at 12 weeks. Bone formation was found at a maximum depth of 1.8 mm after 12 weeks. Our findings indicate the feasibility of ectopic pre-fabrication of large cell-based engineered bone flaps and prompt for the implementation of strategies to improve construct vascularization, in order to possibly accelerate bone formation towards the core of the grafts. [source] Generalized cervical root resorption associated with periodontal diseaseJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2001Wouter Beertsen Abstract Background and description of case: The etiology and pathogenesis of generalized cervical root resorptions is not well understood. In the present report, a case of severe cervical root resorption involving 24 anterior and posterior teeth is presented. The lesions developed within a period of 2 years after the patient had changed to an acid-enriched diet. They extended far into the coronal dentin and were associated with gingival inflammation and crestal bone resorption. However, no generalized clinical attachment loss had occurred. Culturing of subgingival plaque revealed the presence of several putative periodontal pathogens among which Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Treatment consisted of mechanical debridement supported by systemic antibiotics (amoxycillin plus metronidazole) and dietary advice. Results: Within 1 year after the onset of treatment, all resorptive lesions had repaired by ingrowth of a radio-opaque mineralized tissue. The crestal areas showed radiological evidence of bone repair. 3 years after the onset of therapy, one premolar was extracted and examined histologically. It appeared that irregularly-shaped masses of woven bone-like tissue had invaded into the domain of the resorbed coronal dentin and were bordered by thin layers of acellular cementum. Conclusion: It is concluded that, in this patient, the cervical resorptions were likely the result of an osteoclastic response extending into the roots because the root-protective role of the junctional epithelium did not develop. We hypothesize that this was due to the combined effects of a periodontopathogenic microflora and a dietary confounding factor. Zusammenfassung Hintergrund und Beschreibung des Falls: Die Ätiologie und die Pathogenese der generalisierten Wurzelresorptionen ist nicht besonders bekannt. In der vorliegenden Fallpräsentation wird ein schwerer Fall von Wurzelresorption gezeigt, die 24 anteriore und posteriore Zähne einbezog. Die Läsionen entwickelten sich innerhalb einer Periode von 2 Jahren, nachdem der Patient zu einer Säure-angereicherten Diät gewechselt hatte. Die Läsionen dehnten sich in das koronale Dentin aus und waren mit gingivaler Entzündung und krestaler Knochenresorption verbunden. Jedoch wurde kein generalisierter Attachmentverlust beobachtet. Die Kultur der subgingivalen Plaque erbrachte das Vorhandensein von verschiedenen putativen parodontalen Pathogenen, unter ihnen Actinobacillus actinomycetemcomitans und Porphyromonas gingivalis. Die Behandlung bestand in der mechanischen Reinigung unterstützt mit systemischen Antibiotika (Amoxicillin und Metronidazol) und Diätanweisungen. Ergebnisse: Innerhalb eines Jahres nach dem Beginn der Therapie waren alle Resorptionsläsionen repariert durch das Einwachsen von röntgenopakem mineralisierten Gewebe. Die krestalen Regionen zeigten radiologisch nachgewiesene Knochenreparatur. 3 Jahre nach Therapiebeginn wurde ein Prämolar extrahiert und histologisch untersucht. Es schien, daß irreguläre geformte Massen von verflochtenem knochen-ähnlichen Gewebe in den Hauptteil des resorbierten koronalen Dentins hineingelangt sind und von dünnen Schichten azellulären Zementes begrenzt wurden. Zusammenfassung: Es wird geschlußfolgert, daß bei diesem Patient die zervikalen Resorptionen wahrscheinlich das Ergebnis einer osteoklastischen Reaktion waren, bis in die Wurzeln ausgedehnt, weil sich die wurzelschützende Rolle des Verbindungsepithels nich entwickelt hatte. Wir nehmen an, daß dies in der Folge eines kombinierten Effektes von parodontopathogenen Keimen und eines verwirrenden diätetischen Faktors geschah. Résumé Origine: L'étiologie et la pathogenèse des résorptions radiculaires cervicales généralisées ne sont pas suffisamment connues. Dans le rapport présent, un cas de résorption radiculaire cervicale sévère se rapportant à 24 dents antérieures et postérieures est présenté. Les lésions s'étaint développées durant les 2 années qui ont suivi le changement de régime alimentaire du patient vers un régime plus acide. Elles s'étendaient profondément dans la dentine coronaire et étaient associées à une inflammation gingivale et une résorption osseuse crestale. Cependant, aucune perte d'attache clinique généralisée n'est apparue. La culture de la plaque dentaire sous-gingivale a révélé la présence de plusieurs pathogènes parodontaux putatifs parmi lesquels l'Actinobaccilus actinomycetemcomitans et le Porphyromonas gingivalis. Le traitement a consisté en un nettoyage mécanique associéà l'utilisation d'antibiotiques par voie systémique (amoxycilline + métronidazole) et un conseil diététique. Résultats. Dans l'année qui a suivi ce traitement, toutes les lésions de résorption ont été guéries par la croissance d'un tissu minéralisé radio-opaque. Les zones crestales montraient une évidence radiologique de réparation osseuse. 3 ans après le démarrage de ce traitement, une prémolaire a été avulsée et examinée histologiquement. Il est apparu que des masses de formes irrégulières de tissus ressemblant à de l'os ouaté avaient envahi le domaine de dentine coronaire résorbé et étaient entourées par de fines couches de cément acellulaire. Conclusions: Chez ce patient, les résorptions cervicales étaient vraisemblablement dûes à une réponse ostéoclastique s'étendant dans les racines parce que le rôle de protection radiculaire de l'épithélium de jonction ne s'étaient pas développé. Cette situation était vraisemblablement dûe à des effets combinés de la microflore parodonto-pathogène et d'un facteur diététique. [source] Dynamics of mucosal dimensions after root coverage with a bioresorbable membraneJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 1 2000Hans-Peter Müller Abstract Background: So far, the clinical effects of the placement of a resorbable membrane for guided tissue regeneration have not been studied in humans in great detail. The dynamics of the resorptive processes, in particular, appear to be rather speculative. In the present longitudinal study, specific alterations of the dimensions of the dentogingival mucosa were explored after surgical root coverage by using a bioresorbable membrane and a coronally-repositioned flap. Methods: The study population consisted of 14 patients with a total of 31 predominantly shallow, Miller class I, II or III recessions. The thickness of the masticatory and lining mucosa before and after surgical intervention was measured with an ultrasonic device. Results: Mean (±sd) recession depth and width were 2.85±1.29 and 4.46±1.14 mm, respectively. After 12 months, 51±29% of the recession depth (p<0.001) and 13±35% of its width (n.s.) were covered. Root coverage seems to be rather defect-type sensitive with best results obtained at canines with relatively shallow recessions. Mucosal thickness was considerably increased after surgery with a gradual decrease during the following 9 months. Thus, thickness of the marginal tissue rose from 0.82±0.27 mm to 1.49±0.54 mm 3 months after placement of the membrane (p<0.001). After 12 months, a mean thickness of 1.03±0.40 mm was observed (p<0.001). Even more pronounced alterations were noted for the alveolar lining mucosa with a threefold increase of thickness 3 months after surgery and a gradual decrease to about 1 mm after 12 months. Conclusions: The present results point to the considerable space making capacity of the bioresorbable membrane which probably allows for the ingrowth of a granulation tissue derived from the underlying structures. The gradual decline in mucosal thickness between months 6 and 9 after surgery may be paralleled by the maturation of the granulation tissue while complete resorption of the membrane had been accomplished. [source] Gastrointestinal and biliary stentsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2010Hoon Jai Chun Abstract Advances in stent design have led to a substantial increase in the use of stents for a variety of malignant and benign strictures in the gastrointestinal tract and biliary system. Whereas early stents were mostly composed of plastic, the majority of contemporary stents are self-expanding metal stents that are composed of either nitinol or stainless steel. These stents are able to exert an adequate expansile force and, at the same time, are highly flexible and biocompatible. Covered stents have been introduced to minimize tumor ingrowth through the metal mesh but are associated with higher rates for spontaneous migration. This has led to the development of covered stents with uncovered ends and stents with both covered and uncovered layers. Drug-eluting and biodegradable stents are also likely to become available in the near future. Although stents appear to be the preferred form of palliation for some patients with advanced cancer, many patients will benefit from a multidisciplinary approach that usually includes surgeons and oncologists. [source] A New Biological Matrix for Septal OcclusionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2003CHRISTIAN JUX, M.D. The ideal septal occluder scaffold should promote the healthiest and most complete healing response possible while eventually facilitating the full resorption of the material, leaving "native" tissue behind. An excellent biocompatibility of the scaffold tissue is a prerequisite for quick, complete, and firm ingrowth of the device, optimizing outcomes and minimizing the potential for complications. Intestinal collagen layer (ICL) is a highly purified (acellular) bioengineered type-1 collagen derived from porcine submucosa. It is gradually resorbed by the host organism and subsequently replaced by the host tissue. CardioSEAL® occluders were modified by substituting the conventional polyester fabric for an intestinal collagen layer (ICL). Percutaneous transcatheter closure of interventionally created atrial septal defects was performed in lambs using these modified occluders. A complete pathomorphological investigation including histology was carried out after 2, 4, and 12 weeks follow-up. Standard CardioSEAL implants served as a control group. After 2 weeks in vivo the devices were already covered completely by neo-endothelium. Compared with the conventional synthetic scaffold, ICL devices showed a quicker endothelialization, decreased thrombogenicity, and superior biocompatibility with no significant cellular infiltration observed in the histology of explants with ICL fabrics. After 3 months in vivo the collagen layer remained mechanically intact, but began to show the first histological signs of mild disintegration, gradual resorption, and remodeling. In conclusion, short-term results from preliminary in vivo experiments using a bioengineered collagen matrix as the occluder tissue scaffold showed excellent biocompatibility. This resulted in superior overall results: quicker endothelialization, a decreased thrombogenicity, and decreased immunological host response. (J Interven Cardiol 2003;16:149,152) [source] Paracrine effect of transplanted rib chondrocyte spheroids supports formation of secondary cartilage repair tissue,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 9 2009Kolja Gelse Abstract The study's objective was to investigate if transplanted chondrocyte or periosteal cell spheroids have influence on ingrowing bone marrow-derived cells in a novel cartilage repair approach in miniature pigs. Autologous rib chondrocytes or periosteal cells were cultured as spheroids and press-fitted into cavities that were milled into large, superficial chondral lesions of the patellar joint surface. Within the milled cavities, the subchondral bone plate was either penetrated or left intact (full-thickness or partial-thickness cavities). The transplantation of chondrocyte spheroids into full-thickness cavities induced the formation of additional secondary repair cartilage that exceeded the original volume of the transplanted spheroids. The resulting continuous tissue was rich in proteoglycans and stained positive for type II collagen. Cell labeling revealed that secondarily invading repair cells did not originate from transplanted spheroids, but rather from arroded bone marrow. However, secondary invasion of repair cells was less pronounced following transplantation of periosteal cells and absent in partial-thickness cavities. According to in vitro analyses, these observations could be ascribed to the ability of chondrocyte spheroids to secrete relevant amounts of bone morphogenetic protein-2, which was not detected for periosteal cells. Transplanted chondrocyte spheroids exert a dual function: they provide cells for the repair tissue and have a stimulatory paracrine activity, which promotes ingrowth and chondrogenesis of bone marrow-derived cells. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Fixation of hydroxyapatite-coated revision implants is improved by the surgical technique of cracking the sclerotic bone rimJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2009Brian Elmengaard Abstract Revision joint replacement has poorer outcomes that have been associated with poorer mechanical fixation. We investigate a new bone-sparing surgical technique that locally cracks the sclerotic bone rim formed during aseptic loosening. We inserted 16 hydroxyapatite-coated implants bilaterally in the distal femur of eight dogs, using a controlled weight-bearing experimental model that replicates important features of a typical revision setting. At 8 weeks, a control revision procedure and a crack revision procedure were performed on contralateral implants. The crack procedure used a splined tool to perform a systematic local perforation of the sclerotic bone rim of the revision cavity. After 4 weeks, the hydroxyapatite-coated implants were evaluated for mechanical fixation by a push-out test and for tissue distribution by histomorphometry. The cracking revision procedure resulted in significantly improved mechanical fixation, significantly more bone ongrowth and bone volume in the gap, and reduced fibrous tissue compared to the control revision procedure. The study demonstrates that the sclerotic bone rim prevents bone ingrowth and promotes fixation by fibrous tissue. The effect of the cracking technique may be due to improved access to the vascular compartment of the bone. The cracking technique is a simple surgical method that potentially can improve the fixation of revision implants in sclerotic regions important for obtaining the fixation critical for overall implant stability. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 996,1001, 2009 [source] Covalently-linked hyaluronan promotes bone formation around Ti implants in a rabbit modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2009Marco Morra Abstract The goal of this study was the in vivo evaluation of nanoporous titanium (Ti) implants bearing a covalently linked surface hyaluronan (HA) layer. Implant surface topography and surface chemistry were previously evaluated by scanning electron micorscopy and X-ray photoelectron spectroscopy. Results showed that the surface modification process did not affect surface topography, yielding a homogeneously HA-coated nanotextured implant surface. In vivo evaluation of implants in both cortical and trabecular bone of rabbit femurs showed a significant improvement of both bone-to-implant contact and bone ingrowth at HA-bearing implant interfaces at 4 weeks. The improvement in osteointegration rate was particularly evident in the marrow-rich trabecular bone (bone-to-implant contact: control 22.5%; HA-coated 69.0%, p,<,0.01). Mechanical testing (push-out test) and evaluation of interfacial bone microhardness confirmed a faster bone maturation around HA-coated implants (Bone Maturation Index: control 79.1%; HA-coated 90.6%, p,<,0.05). Suggestions based on the biochemical role of HA are presented to account for the observed behavior. Published by Wiley Periodicals, Inc. J Orthop Res 27: 657,663, 2009 [source] In vivo release of the antimicrobial peptide hLF1-11 from calcium phosphate cement,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2008Hein P. Stallmann Abstract We studied the release of human lactoferrin 1-11 (hLF1-11), a potent antimicrobial peptide, in an animal model. Calcium phosphate cement with 50 mg/g hLF1-11 was injected into the femoral canal of 12 rabbits. One, 3, and 7 days later, four animals were terminated, and the femora excised. Sections of bone and cement were removed for histological analysis. We used liquid chromatography-mass spectrometry/mass spectrometry for semiquantitative determination of the hLF1-11 concentration. Blood samples were drawn for leukocyte count and differentiation to identify a potential immunomodulating effect of hLF1-11. After an initial burst release, the hLF1-11 concentration in cement and bone decreased steadily. This in vivo release profile is consistent with earlier in vitro studies. Tissue ingrowth into the cement, without signs of inflammation or necrosis, was observed. Leukocytosis or a shift in leukocyte differentiation did not occur. The carrier released over 99% of the hLF1-11, resulting in peak concentrations at the cement,bone interface. This indicates that hLF1-11 could become a valuable prophylactic agent in osteomyelitis treatment. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:531,538, 2008 [source] Physical activity modulates nerve plasticity and stimulates repair after achilles tendon ruptureJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2007Daniel K-I. Abstract In a rat model of tendon rupture using semiquantitative methodology, healing was assessed according to the diameter of newly organized collagen and the occurrence of the sensory neuropeptides (SP, CGRP) in relation to different levels of physical activity. Normally, innervation of the Achilles tendon is confined to the paratenon. After rupture new nerve fibers grow into the tendon proper, but disappear after healing. In a first experiment to establish peak tissue and nerve regeneration after rupture, tendon tissues from freely moving rats were collected consecutively over 16 weeks. A peak increase in organized collagen and nerve ingrowth was observed between week 2 to 4 post rupture. Therefore, in a second experiment week 4 was chosen to assess the effect of physical activity on tendon healing in three groups of rats, that is, wheel running, plaster treated, and freely moving (controls). In the wheel-running group, the diameter of newly organized collagen was 94% (,p,=,0.001) greater than that in the plaster-treated group and 48% (,p,=,0.02) greater than that in the controls. Inversely, the neuronal occurrence of CGRP in the tendon proper was 57% (,p,=,0.02) lower in the wheel-running group than that in the plaster-treated group and 53% (,p,=,0.02) lower than that in the controls, suggesting an earlier neuronal in-growth and disappearance in the more active group. Physical activity speeds up tendon healing, which may prove to be linked to accelerated neuronal plasticity. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:164,172, 2007 [source] Self-hardening calcium phosphate composite scaffold for bone tissue engineering,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2004Hockin H. K. Xu Abstract Calcium phosphate cement (CPC) sets in situ to form solid hydroxyapatite, can conform to complex cavity shapes without machining, has excellent osteoconductivity, and is able to be resorbed and replaced by new bone. Therefore, CPC is promising for craniofacial and orthopaedic repairs. However, its low strength and lack of macroporosity limit its use. This study investigated CPC reinforcement with absorbable fibers, the effects of fiber volume fraction on mechanical properties and macroporosity, and the cytotoxicity of CPC,fiber composite. The rationale was that large-diameter absorbable fibers would initially strengthen the CPC graft, then dissolve to form long cylindrical macropores for colonization by osteoblasts. Flexural strength, work-of-fracture (toughness), and elastic modulus were measured vs. fiber volume fraction from 0% (CPC Control without fibers) to 60%. Cell culture was performed with osteoblast-like cells, and cell viability was quantified using an enzymatic assay. Flexural strength (mean ± SD; n == 6) of CPC with 60% fibers was 13.5 ± 4.4 MPa, three times higher than 3.9 ± 0.5 MPa of CPC Control. Work-of-fracture was increased by 182 times. Long cylindrical macropores 293 ± 46 ,m in diameter were created in CPC after fiber dissolution, and the CPC,fiber scaffold reached a macroporosity of 55% and a total porosity of 81%. The new CPC,fiber formulation supported cell adhesion, proliferation and viability. The method of using large-diameter absorbable fibers in bone graft for mechanical properties and formation of long cylindrical macropores for bone ingrowth may be applicable to other tissue engineering materials. Published by Elsevier Ltd. on behalf of Orthopuedic Research Society. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] A resorbable porous ceramic composite bone graft substitute in a rabbit metaphyseal defect modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2003W. R. Walsh The success of converted corals as a bone graft substitute relies on a complex sequence of events of vascular ingrowth, differentiation of osteoprogenitor cells, bone remodeling and graft resorption occurring together with host bone ingrowth into and onto the porous coralline microstructure or voids left behind during resorption. This study examined the resorption rates and bone infiltration into a family of resorbable porous ceramic placed bilaterally in critical sized defects in the tibial metaphyseal,diaphyseal of rabbits. The ceramics are made resorbable by partially converting the calcium carbonate of corals to form a hydroxyapatite (HA) layer on all surfaces. Attempts have been made to control the resorption rate of the implant by varying the HA thickness. New bone was observed at the periosteal and endosteal cortices, which flowed into the centre of the defect supporting the osteoconductive nature of partially converted corals. The combination of an HA layer and calcium carbonate core provides a composite bone graft substitute for new tissue integration. The HA-calcium carbonate composite demonstrated an initial resorption of the inner calcium carbonate phase but the overall implant resorption and bone ingrowth behaviour did not differ with HA thickness. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] | ||||||||||||||||||||||||||||||||||