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Bone Ingrowth (bone + 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] Locally delivered rhTGF-,2 enhances bone ingrowth and bone regeneration at local and remote sites of skeletal injuryJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2001Dr. Sumner The purposes of the present study were to determine if recombinant human transforming growth factor-beta-2 (rhTGF-,2) enhances bone ingrowth into porous-coated implants and bone regeneration in gaps between the implant and surrounding host bone. The implants were placed bilaterally for four weeks in the proximal humeri of skeletally mature, adult male dogs in the presence of a 3-mm gap. In three treatment groups of animals, the test implant was treated with hydroxyapatite/tricalcium phosphate (HA/TCP) and rhTGF-,2 in buffer at a dose per implant of 1.2 ,g (n = 6), 12 ,g (n = 7), or 120 ,g (n = 7) and placed in the left humerus. In these same animals, an internal control implant treated only with HA/TCP and buffer was placed in the right humerus. In a non-TGF-, treated external control group of animals (n = 7), one implant was treated with HA/TCP while the contralateral implant was not treated with the ceramic. In vitro analyses showed that approximately 15% of the applied dose was released within 120 h with most of the release occurring in the first 24 h. The TGF-, treated implants had significantly more bone ingrowth than the controls with the greatest effect in the 12 ,g/implant group (a 2.2-fold increase over the paired internal control (P = 0.004) and a 4-fold increase over the external control (P < 0.001)). The TGF-, treated implants had significantly more bone formation in the gap than the controls with the greatest effect in the 12 and 120 ,g groups (1.8-fold increases over the paired internal controls (P = 0.003 and P = 0.012, respectively) and 2.8-fold increases over the external controls (P < 0.001 and P = 0.001, respectively)). Compared to the external controls, the internal control implants tended to have more bone ingrowth (1.9-fold increase, P = 0.066) and had significantly more bone formation in the gap (1.7-fold increase, P = 0.008). Thus, application of rhTGF-,2 to a porous-coated implant-stimulated local bone ingrowth and gap healing in a weakly dose-dependent manner and stimulated bone regeneration in the 3-mm gap surrounding the contralateral control implant, a site remote from the local treatment with the growth factor. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Control of Crystallinity of Hydrated Products in a Calcium Phosphate CementJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2009Tao Yu A novel calcium phosphate cement (CPC) was prepared by dry-mechanochemical rout in this work. With the different crystallinity, the CPC showed the different degradation ratio after setting. The degradation ratio of CPC was characterized by the calcium ion-dissolving ratio in deionized water after different soaking time. With the increment of crystallinity, the setting times of CPC were prolonged, and the different mechanical property of CPC were obtained. This novel CPC was supposed to match the new bone ingrowth in vivo and have the potential application in orthopedic surgery for filling non-load-bearing bone defects. [source] Finite Element Modelling of Bioactive Contact in Bone-Implant InterfacePROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2008André Lutz Finite element simulation for the prediction of bone remodelling caused by implants is a powerful method to improve or to rate implant designs even before they will be evaluated in clinical studies. But the bone,implant interaction is often modelled as ideal bonding in the interface. This approach is not suitable to describe the interrelation of both parts in a physiological manner. To correct these insufficiencies a 3D bioactive contact element has been developed. This contact element describes on the one hand the pure mechanical interaction and on the other hand the mechanical stimulated bone ingrowth in porous surfaces. The benefits of the use of the bioactive contact element regarding the standard method will be presented in this contribution. A comparison of both methods based on clinic results regarding a hip prosthesis with mixed surface textures will be shown. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Canal Wall Reconstruction with Mimix Hydroxyapatite Cement: Results in an Animal Model and Case Study,THE LARYNGOSCOPE, Issue 12 2003John Dornhoffer MD Abstract Objective/Hypothesis To assess Mimix hydroxyapatite cement for its applicability in canal wall reconstruction using the gerbil as a canal wall model. A case is presented to illustrate a novel technique of canal wall reconstruction using Mimix on the basis of the findings of our animal research. Study Design This was a preclinical study. Methods Ten Mongolian gerbils were implanted with Mimix, with the left side used to simulate mastoid obliteration and the right side used to simulate canal wall reconstruction. Pre- and postsurgery auditory-evoked brainstem responses were used to assess ototoxicity, and hematoxylin-eosin staining of histologic sections was used to assess inflammatory and foreign-body response and new bone formation. Results Rapid wound healing was achieved with each of the nine animals evaluated, with no erythema, edema, or drainage. Inspection of the ear canal at the time of sacrifice revealed no signs of otitis media and no middle ear effusions. Microscopic examination showed no inflammatory response or foreign-body reaction, good mucosalization on the side of the implant facing the bulla, and minimal fibrosis adjacent to the skin. Eight of nine specimens showed new woven bone ingrowth at the bone implant interface, with active osteoblasts and viable lacunae cells. There were no apparent fractures in the implanted material. Conclusions Mimix hydroxyapatite cement is biocompatible and suitable for canal wall reconstruction in the animal model. The characteristics of this cement, namely its ability to set quickly in a moist environment, offer advantages over previously used cements for canal wall reconstruction. [source] Metaphyseal-Loading Anterolaterally-Flared Femoral Stem in Cementless Total Hip Arthroplasty: Five- to Eleven-Year Follow-Up EvaluationARTIFICIAL ORGANS, Issue 5 2010Hideo Kawahara Abstract Using a nonlinear three-dimensional finite element analysis simulating loading conditions, we designed a new type of proximal-fitting, anterolaterally-flared, arc-deposit hydroxyapatite-coated anatomical femoral stem (FMS-anatomic stem; Japan Medical Materials, Osaka, Japan) for cementless total hip arthroplasty (THA) for Japanese patients with dysplastic hip osteoarthritis. The aim of the present study was to analyze the clinical and radiographic outcomes of the new stem. We reviewed 143 consecutive patients (164 hips; 13 men, 14 hips; 130 women, 150 hips; age at surgery, 56.6 ± 7.6 years, mean ± SD, range, 30,74) who underwent cementless THA using the FMS-anatomic stem at a single institution, with a follow-up period of 7.6 ± 1.6 years (range, 5.3,11.0). Harris Hip score improved from 46.1 ± 12.6 before surgery to 90.0 ± 8.9 points post-THA. The 7.6-year survival rate of the stem was 99.0% after revision for aseptic loosening. Radiographs at follow-up confirmed the stability of the femoral stems within the femoral canal in all cases, with sufficient bone ingrowth. None of the patients had subsidence of the stem exceeding 2.0 mm within the femoral canal or changes in varus or valgus position of more than 2.0°. The FMS-anatomic stem provided excellent results in patients with dysplastic hip osteoarthritis. Our analysis confirmed reduced radiolucency around the stem in Gruen zones, minimal subsidence, appropriate stress shielding, and promising medium-term stability within the femoral canal in our patients. [source] Bone Response Inside Free-Form Fabricated Macroporous Hydroxyapatite Scaffolds with and without an Open MicroporosityCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2007Johan Malmström DDS ABSTRACT Background:, The technique of free-form fabrication enables the production of controlled macroporous geometry inside ceramic scaffolds. Using scaffolds with identical macropore design makes it possible to study a relevant biological response linked to other specific changes of the material. Purpose:, This study investigates the role of open micropores in hydroxyapatite (HA) scaffold during early bone healing to quantitatively ascertain whether microporosity in otherwise identical macroporous HA scaffolds can influence the bone response in rabbit tibia and femur at 6 weeks. Materials and Methods:, HA scaffolds (Ø: 3.8 mm) with and without microporosity were randomly installed in both cortical and trabecular bone sites of New Zealand White rabbits. The animals were sacrificed 6 weeks after surgery. Ground sections obtained from en bloc tissues containing scaffold and recipient bone were subjected to histological evaluation and histomorphometric analysis. Results:, Microscopy showed elevated amounts of bone ingrowth and bone contact inside the microporous HA (mHA) group as compared with non-mHA. Conclusion:, The current study indicates that the presence of open scaffold microporosity in HA, as determined by the fabrication process, enhances the ability of ceramic scaffolds to promote bone ingrowth and bone contact. [source] Injectable calcium phosphate cement as a filler for bone defects around oral implants: an experimental study in goatsCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2002Luca Comuzzi Abstract: The aim of this study was to evaluate the clinical applicability and biological behavior of a newly developed injectable calcium phosphate (Ca-P) cement as bone filler for gaps around oral implants. Twenty-four step-like implants, creating gaps of 1 and 2 mm, were inserted into the trabecular bone of the medial femoral condyles of six goats. Four different situations were tested: (1) implant + gaps; (2) implant + gaps, but covered with a polylactic acid membrane; (3) implant + gaps that were filled with Ca-P cement; and (4) implant + gaps that were filled with Ca-P cement and covered with a membrane. All implants were left in place for 12 weeks. Histological and quantitative histomorphometrical measurements demonstrated that implants + gaps had generally poor bone contact at the implant base. Furthermore, fibrous encapsulation was observed in the gap part. In contrast, the presence of a membrane promoted bone ingrowth into the gap and also the bone contact at the implant base. Injection of Ca-P cement resulted in an almost complete filling of the gaps around the implant. The cement surface was completely covered by bone. Active resorption and remodeling of cement particles was observed, suggesting a pattern of slow resorption associated with full replacement with newly formed bone. Additional use of a membrane did not result in adjunctive benefits. Bone-to-implant contact at the implant base was comparable with the implants provided only with a membrane. In conclusion, the Ca-P cement used here showed excellent clinical handling properties combined with a superior bone behavior. On the other hand, the degradation rate of the material was still very slow. This current characteristic can hamper the final clinical applicability of the material as gap filler for periimplant or periodontal defects. Résumé Le but de l'étude présente a été d'évaluer l'application clinique et le comportement biologique d'un nouveau ciment de calcium de phosphate injectable (Ca-P) comme comblement osseux pour les cavités autour des implantes dentaires. Vingt-quatre implants créant des cavités de 1 et 2 mm ont été insérés dans l'os trabéculaire des condyles fémoraux moyens de six chèvres. Quatre situations différentes ont été testées: 1) implant + cavités; 2) implant = cavités recouvertes par une membrane en acide polylactique, 3) implant + cavités comblées par le ciment Ca-P et 4) implant + cavités comblées par le ciment Ca-P et recouvertes par une membrane. Tous les implants ont été laissés in situ pendant douze semaines. Les mesures histologiques et quantitatives histomorphométriques ont démontré que les implants + cavités avaient généralement un contact osseux pauvre au niveau de la base implantaire. De plus, une encapsulation fibreuse était observée dans la partie cavité. Par contre, la présence d'une membrane favorisait la croissance osseuse dans la cavité ainsi que le contact osseux à la base de l'implant. L'injection du cément Ca-P résultait en une réparation quasi complète des cavités autour de l'implant. La surface cémentaire était complètement recouverte d'os. La résorption active et le remodelage des particules de cément étaient observés, ce qui suggérait un système de résorption lente associéà un remplacement complet par de l'os néóformé. L'usage additionnel d'une membrane ne s'accompagnait pas de bénéfice supplémentaire. Le contact os/implant à la base de l'implant était comparable à celui des implants installés seulement avec une membrane. En conclusion, le ciment Ca-P possèdait des propriétés cliniques excellentes combinées à un comportement osseux supérieur. Par contre le taux de dégradation du matériel était toujours très lent. Cette caractéristique pourrait gêner l'application clinique finale de ce matériel en tant que comblement des cavités autour des implants ou dans les lésions parodontales. Zusammenfassung Das Ziel dieser Studie war es, die klinische Anwendbarkeit und das biologische Verhalten eines neu entwickelten injizierbaren Kalziumphosphatzements (Ca-P) als Knochenfüller bei oralen Implantaten auszuwerten. Vierundzwanzig stufenförmige Implantate, welche Defekte von 1 und 2 mm kreieren, wurden in den trabekulären Knochen der medialen femoralen Kondylen von 6 Ziegen eingesetzt. Vier verschiedene Situationen wurden getestet: 1) Implantat + Defekte; 2) Implantat + Defekte, aber bedeckt mit einer Membran aus Polimilchsäure; 3) Implantat + Defekte, welche mit Ca-P-Zement gefüllt wurden; 4) Implantat + Defekte, welche mit Ca-P-Zement gefüllt und mit einer Membran bedeckt wurden. Alle implantate wurden 12 Wochen belassen. Histologische und quantitative histomorphometrische Messungen zeigten, dass Implantate + Defekte generell schlechten Knochenkontakt an der Implantatbasis aufwiesen. Ausserdem wurde eine fibröse Einkapselung im Bereich der Defekte beobachtet. Im Gegensatz dazu bewirkte die Präsenz einer Membran das Einwachsen von Knochen in die Defekte und der Knochenkontakt an der Implantatbasis wurde gefördert. Die Injektion von Ca-P-Zement resultierte in einer fast kompletten Auffüllung der Defekte um die Implantate. Die Zementoberfläche war völlig mit Knochen bedeckt. Es konnte eine aktive Resorption und eine Remodellierung der Zementpartikel beobachtet werden. Dies lässt ein Muster mit langsamer Resorption assoziiert mit komplettem Ersatz durch neugebildeten Knochen vermuten. Die zusätzliche Verwendung einer Membran brachte keine weiteren Vorteile. Der Knochen-/Implantat-Kontakt an der Implantatbasis war vergleichbar mit den Implantaten, die nur mit einer Membran abgedeckt worden waren. Zusammenfassend kann festgehalten werden, dass der verwendete Ca-P-Zement eine exzellente Handhabung kombiniert mit ausserodentlichem Knochenverhalten zeigte. Andererseits war die Zersetzungsrate des Materials immer noch sehr Gering. Diese momentanen Eigenschaften können letztendlich die klinische Anwendbarkeit des Materials als Defektfüller bei periimplantären und parodontalen Defekten behindern. Resumen La intención del presente estudio fue evaluar la aplicabilidad clínica y el comportamiento biológico de un cemento recientemente desarrollado de fosfato de calcio (Ca-P) como relleno óseo para huecos alrededor de los implantes orales. Se insertaron veinticuatro implantes del tipo escalón creando huecos de 1 y 2 mm en el hueso trabecular de los cóndilos femorales mediales de 6 cabras. Se probaron cuatro situaciones diferentes: 1) implantes + huecos; 2) implantes + huecos, pero cubiertos con una membrana de ácido poliláctico; 3) implantes + huecos que se rellenaron con cemento de Ca-P; y 4) + huecos que se rellenaron con cemento de Ca-P y se cubrieron con una membrana. Todos los implantes se dejaron en su lugar durante 12 semanas. las mediciones histológicas e histomorfométricas cuantitativas demonstraron que los implantes + huecos tuvieron generalmente un contacto óseo pobre en la base del implante. Posteriormente, se observó una encapsulación fibrosa en la parte del hueco. En contraste, la presencia de la membrana promocionó el crecimiento óseo hacia el hueco y también el contacto óseo en la base del implante. La inyección de cemento Ca-P resultó en un casi completo relleno de los huecos alrededor del implante. La superficie del cemento se cubrió completamente de hueso. La reabsorción activa y la remodelación de las partículas de cemento fueron observadas, lo cual sugiere un patrón de reabsorción lenta asociada con una completa sustitución con hueso neoformado. El uso adicional de la membrana no resultó en beneficios adicionales. El contacto hueso implante en la base del implante fue comparable con los implantes que solo tenían la membrana. En conclusión, el uso de cemento de Ca-P mostró excelentes propiedades de manejo clínico combinado con un superior comportamiento óseo. Por otro lado, el índice de degradación del material fue muy lento. Estas características actuales pueden estorbar la aplicabilidad clínica final del material como rellenador de huecos alrededor de defectos periodontales o perimplantarios. [source] Development, characterization, and validation of porous carbonated hydroxyapatite bone cementJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Pei-Fu Tang Abstract Carbonated hydroxyapatite (CHA) bone cement is capable of self-setting and forming structures similar to mineralized bone. Conventional CHA leaves little room for new bone formation and delays remodeling. The purposes of this study were to develop porous CHA (PCHA) bone cement and to investigate its physicochemical properties, biocompatibility, biodegradation, and in vivo bone repair potential. Vesicants were added to modify CHA, and the solidification time, porosity, and pore size of the PCHA cements were examined. The cytotoxicity and bone repair potential of PCHA were tested in a rabbit bone defect model and assessed by x-ray, histological examination, and mechanical testing. The porosity of the modified PCHA was 36%; 90.23% of the pores were greater than 70 ,m, with a calcium/phosphate ratio of 1.64 and a solidification time of 15 minutes. The PCHA did not affect bone cell growth in vitro, and the degrading time of the PCHA was two and four times faster in vitro and in vivo when compared to CHA. In the bone defect model, the amount of new bone formation in the PCHA-treated group was eight times greater than that of the CHA group; the compressive strength of the PCHA setting was relatively weak in the first weeks but increased significantly at 8 to 16 weeks compared to the CHA group. The PCHA has stable physicochemical properties and excellent biocompatibility; it degrades faster than CHA, provides more porous spaces for new bone ingrowths, and may be a new form of bone cement for the management of bone defects. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009 [source] | |||||||||||||