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Host Bone (host + bone)
Selected AbstractsA 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] Enhancing the mechanical integrity of the implant,bone interface with BoneWelding® technology: Determination of quasi-static interfacial strength and fatigue resistanceJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2006Stephen J. Ferguson Abstract The BoneWelding® technology is an innovative bonding method, which offers new alternatives in the treatment of fractures and other degenerative disorders of the musculoskeletal system. The BoneWelding process employs ultrasonic energy to liquefy a polymeric interface between orthopaedic implants and the host bone. Polymer penetrates the pores of the surrounding bone and, following a rapid solidification, forms a strong and uniform bond between implant and bone. Biomechanical testing was performed to determine the quasi-static push-out strength and fatigue performance of 3.5-mm-diameter polymeric dowels bonded to a bone surrogate material (Sawbones solid and cellular polyurethane foam) using the BoneWelding process. Fatigue tests were conducted over 100,000 cycles of 20,100 N loading. Mechanical test results were compared with those obtained with a comparably-sized, commercial metallic fracture fixation screw. Tests in surrogate bone material of varying density demonstrated significantly superior mechanical performance of the bonded dowels in comparison to conventional bone screws (p < 0.01), with holding strengths approaching 700 N. Even in extremely porous host material, the performance of the bonded dowels was equivalent to that of the bone screws. For both cellular and solid bone analog materials, failure always occurred within the bone analog material surrounding and distant to the implant; the infiltrated interface was stronger than the surrounding bone analog material. No significant decrease in interfacial strength was observed following conditioning in a physiological saline solution for a period of 1 month prior to testing. Ultrasonically inserted implants migrated, on average, less than 20 ,m over, and interfacial stiffness remained constant the full duration of fatigue testing. With further refinement, the BoneWelding technology may offer a quicker, simpler, and more effective method for achieving strong fixation and primary stability for fracture fixation or other orthopaedic and dental implant applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Increased bone formation around coated implantsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2009Bernd Stadlinger Abstract Aim: We hypothesized that coating threaded, sandblasted acid-etched titanium implants with collagen and chondroitin sulphate (CS) increases bone formation and implant stability, compared with uncoated controls. Materials and Methods: Three different implant surface conditions were applied: (1) sandblasted acid-etched (control), (2) collagen/chondroitin sulphate (low-dose , CS1), (3) collagen/chondroitin sulphate (high-dose , CS2). Sixty 9.5 mm experimental implants were placed in the mandible of 20 minipigs. Bone,implant contact (BIC) and relative peri-implant bone-volume density (rBVD , relation to bone-volume density of the host bone) were assessed after 1 and 2 months of submerged healing. Implant stability was measured by resonance frequency analysis (RFA). Results: After 1 month, coated implants had significantly more BIC compared with controls (CS1: 68%, p<0.0001, CS2: 63%, p=0.009, control: 52%). The rBVD was lower for all surface conditions, compared with the hostbone. After 2 months, BIC increased for all surfaces. No significant differences were measured (CS1: 71%, p=0.016, CS2: 68%, p=0.67, control: 63%). The rBVD was increased for coated implants. RFA values were 71,77 at implantation, 67,73 after 1 month and 74,75 after 2 months. Differences in rBVD and RFA were not statistically significant. Conclusions: Data analysis suggests that collagen/CS has a positive influence on bone formation after 1 month of endosseous healing. [source] Lateral ridge augmentation by the use of grafts comprised of autologous bone or a biomaterial.JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 12 2002An experiment in the dog Abstract Objective: The present investigation was performed to determine if a block of Bio-Oss® used as an onlay graft can be used as a scaffold for new bone formation. Material and methods: Five mongrel dogs were used. The mandibular premolars were extracted. On both sides of the mandible, the buccal bone plate was resected and defects, about 25 mm long, 8 mm high and 5 mm wide, were produced After 3 months of healing, a second surgical procedure was performed. In the left side, a block of Bio-Oss® was adjusted to the buccal bone wall. The graft had the shape of a cylinder and was retained with a miniscrew and covered with a collagen membrane. In the contra-lateral side of the mandible, a block biopsy was first obtained from the ascending ramus. This bone graft had the shape of a cylinder that was 8 mm in diameter and 3 mm thick. The graft was transferred to the experimental site, adjusted to the buccal wall, retained with a miniscrew, and covered with a membrane. The flaps were repositioned and closed with sutures to ensure a complete coverage of the experimental sites. After 6 months of healing, the dogs were sacrificed and the experimental sites dissected. The biopsies were processed for ground sectioning. The sections were stained in toluidine blue, examined in the microscope, and a number of histo- and morphometric assessments made. Results: The study demonstrated that cortical bone used as an onlay graft in the lateral aspect of the alveolar ridge, during a 6-month period of healing integrated with the host bone but underwent marked peripheral resorption. Thus, close to 30% of the height and 50% of the length of the graft was replaced with connective tissue. It was further observed that while the dimensions of a graft which contained a scaffold of cancellous bovine bone mineral remained unchanged, only moderate amounts of new bone formed at the base of this graft. Conclusion: Grafts of autologous cortical bone, placed on the surface of a one-wall defect, may undergo marked resorption during healing. A similar graft of Bio-Oss® may retain its dimension, and limited amounts of new bone will form within the biomaterial. [source] Mechanical characteristics of the bone,graft,cement interface after impaction allograftingJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2005Hanspeter Frei Impaction allografting is an attractive procedure for the treatment of failed total hip replacements. The graft,cement,host bone interface after impaction allografting has not been characterized, although it is a potential site of subsidence for this type of revision total hip reconstruction. In six human cadaveric femurs, the cancellous bone was removed proximally and local diaphyseal lytic defects were simulated. After the impaction grafting procedure, the specimens were sectioned in 6 mm transverse sections and pushout tests were performed. From the adjacent sections the percentage cement contact of the PMMA cement with the endosteal bone surface was determined. The host bone interface mechanical properties varied significantly along the femur largely due to different interface morphologies. The apparent host bone interface shear strength was highest around the lesser trochanter and lowest around the tip of the stem. A significant positive correlation was found between the percentage cement contact and the apparent host bone interface shear strength (r2 = 0.52). The sections failed in 69% of the cases through a pure host bone interface failure without cement or allograft failure, 19% failed with local cement failure, and 12% with a local allograft failure. The apparent host bone interface strength was on average 89% lower than values reported for primary total hip replacements and were similar to cemented revisions proximally and lower distally. This study showed that cement penetration to the endosteal surface enhanced the host bone,graft interface. © 2004 Orthopaedic Research Society. Published by Elsevier 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] Effects of Screw Eccentricity on the Initial Stability of the Acetabular Cup in Artificial Foam Bone of Different QualitiesARTIFICIAL ORGANS, Issue 1 2010Jui-Ting Hsu Abstract Acetabular cup loosening is one of the major failure models of total hip replacement (THR), which is mostly due to insufficient initial stability of the cup. Previous studies have demonstrated that cup stability is affected by the quality of the host bone and the surgical skill when inserting screws. The purpose of this study was to determine the effects on the initial stability of the acetabular cup of eccentric screws in bone of different qualities. In this study, hemispherical cups were fixed into bone specimens constructed from artificial foam with three elastic moduli using one to three screws. The effects of two types of screw eccentricity (offset and angular) on the stability of the acetabular cup were also evaluated. The experimental results indicate that in the presence of ideal screwing, the cup was stable in bone specimens constructed from foam with the highest elastic modulus. In addition, increasing the number of ideal screws enhanced the cup stability, especially in bone specimens constructed from soft foam. Moreover, the cup stability was most affected by offset eccentric screw(s) in the hard-foam bone specimens and by angular eccentric screw(s) in the soft-foam bone specimens. The reported results indicate that the presence of screw eccentricity affects the initial stability of the acetabular cup. Surgeons should keep this in mind when performing screw insertions in THR. However, care is necessary when translating these results to the intraoperative situation due to the experiments being conducted under laboratory conditions, and hence, future studies should attempt to replicate the results reported here in vivo. [source] Sinus augmentation analysis revised: the gradient of graft consolidationCLINICAL ORAL IMPLANTS RESEARCH, Issue 10 2009Dieter Busenlechner Abstract Objective: Graft consolidation follows a gradient that reflects the properties of bone substitutes at sites of sinus augmentation. Here we present an analytical method to investigate the process of graft consolidation taking the distance from the maxillary host bone into account. Material and methods: We therefore evaluated histological specimens, 6 and 12 weeks after the sinus of minipigs was augmented with Bio-Oss®, a deproteinized bovine bone mineral, and Ostim®, an aqueous paste of synthetic nanoparticular hydroxyapatite. A curve was drawn that represents the changes in histomorphometric parameters within a given distance from the maxillary host bone. Results: Based on this curve, three regions of interest were defined: R1 (0,1 mm) the bridging distance where new bone is laid onto the host bone, R2 (2,3 mm) a region of osteoconduction where new bone exclusively grows on the biomaterial, R3 (4,5 mm) and a region of osteoconduction where bone formation has reached its maximal extension. Qualitative and quantitative analysis of the three regions can reveal differences in graft consolidation, depending on the bone substitutes and the observation period [Bone volume (BV) per tissue volume after 6 weeks: R1: 19±8.4% for Bio-Oss® and 42.9±13.2% for Ostim® (P=0.03), R2: 3±2.4% for Bio-Oss® and 14.7±9.5% for Ostim® (P=0.03), R3: 5±4.1% for Bio-Oss® and 5.3±5.3% for Ostim® (P=0.86). BV per tissue volume after 12 weeks: R1: 38.0±13.3% for Bio-Oss® and 53.3±6.6 for Ostim® (P=0.04), R2: 14±12.2 for Bio-Oss® and 26.4±11 for Ostim® (P=0.18), R3: 6.6±7 for Bio-Oss® and 10.7±5.8 for Ostim® (P=0.32) after 12 weeks]. Conclusion: Based on the graft consolidation gradient, the impact of bone substitutes to modulate the process of bone formation and the kinetic of degradation within a distinct region of the augmented sinus can be investigated. [source] Bone formation following sinus grafting with autogenous bone-derived cells and bovine bone mineral in minipigs: preliminary findingsCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2004Gabor Fuerst Abstract: Bone formation in a sinus grafted with a cell-free scaffold requires the presence of local progenitor cells that differentiate into osteoblasts. The purpose of this study was to examine the effect of culture expanded autogenous bone-derived cells (ABC) with bovine bone mineral (BBM) on bone formation after single-stage sinus grafting in minipigs. Bone biopsies from the iliac crest were harvested 4 weeks prior to sinus grafting and ABC were culture expanded in vitro. The sinuses of five adult minipigs were grafted. In one sinus of each minipig the space between Schneider's membrane (SM) and the sinus wall was grafted with ABC (325,000 cells per sinus, on average) and BBM. In the other sinus, BBM alone was used. The animals were sacrificed after 12 weeks. One block of each grafted area was prepared by saw cutting and the amount of newly formed bone was analysed by micro-computed tomography (,-CT). The addition of ABC to BBM significantly increased the amount of newly formed bone compared with BBM alone on ,-CT analysis (ABC+BBM: 29.86±6.45% vs. BBM: 22.51±7.28% (P=0.016)). Bone formation was increased near SM (ABC+BBM: 20.7±4.5% vs. BBM: 15.43±3.62% (P=0.009)) and in the middle zone of the grafting material (ABC+BBM: 31.63±7.74% vs. BBM: 22.5±7.91% (P=0.001)), but not near the local host bone (ABC+BBM: 37.23±8.23% vs. BBM: 28.42±12.54% (P=0.15)). These preliminary findings indicate that supplementation of cell-free grafting material with culture expanded ABC can stimulate bone formation in areas with low bone-forming capacity. Résumé La néoformation osseuse dans un sinus grefféà l'aide d'un échafaudage acellulaire requiert la présence de cellules progénitrices locales qui se différencient en ostéoblastes. Le but de cette étude a été d'examiner l'effet de cellules dérivées de l'os autogène (ABC) avec expansion par culture avec un minéral osseux bovin (BBM) sur la formation osseuse après une greffe sinusale en une étape chez le mini-porc. Des biopsies osseuses de la crête iliaque ont été prélevées quatre semaines avant la greffe sinusale et les ABC ont été placées en culture in vitro. Les sinus de cinq mini-porcs adultes ont été greffés. Dans un sinus de chaque mini-porc l'espace entre la membrane de Schneider et la paroi sinusale a été greffé avec les ABC (en moyenne 325 000 cellules/sinus) et BBM. Dans l'autre sinus, BBM seul a été utilisé. Les animaux ont été euthanasiés après douze semaines. Un bloc de chaque aire greffée a été scié et la quantité d'os néoformé a été analysée par tomographie par micro-ordinateur (,-CT). L'addition d'ABC au BBM augmentait significativement la quantité d'os néoformé comparée à l'utilisation du BBM seul lors de l'analyse micro-CT [ABC+BBM : 29,9±6,5% vs BBM : 22,5±7,3% (P=0,016)]. La formation osseuse était augmentée près de la membrane de Schneiderian [ABC+BBM : 20,7±4,5 vs BBM : 15,4±3,6% (P=0,009)] et dans la zone moyenne du matériel greffé [ABC+BBM : 31,6±7,7% vs BBM : 22,5±7,9 (P=0,001)], mais pas dans la région proche de l'hôte (ABC+BBM : 37,2±8,2% vs BBM : 28,4±12,5% (P=0,150). Ces découvertes préliminaires indiquent que l'addition à un matériau acellulaire de ABC en culture d'expansion pouvait stimuler la formation osseuse dans des zones avec des faibles capacités de formation osseuse. Zusammenfassung Knochenformation nach Sinusaugmentation mit autologen Zellen knöchernen Ursprungs und bovinem Knochenmineral in Minipigs: erste Ergebnisse Die Bildung von neuem Knochen im augmentierten Sinus mit einer zellfreien Matrix benötigt lokale Progenitorzellen, welche sich in Osteoblasten differenzieren können. Das Ziel dieser Studie war, den Effekt von in Kultur gezüchteten autologen Zellen knöchernen Ursprungs (ABC) mit bovinem Knochenmineral (BBM) auf die Knochenbildung nach Sinusaugmentation in Minipigs zu untersuchen. Knochenbiopsien vom Beckenkamm wurden 4 Wochen vor der Sinusaugmentation entnommen und die ABC in vitro in einer Kultur vermehrt. Die Kieferhöhlen von 5 ausgewachsenen Minipigs wurden augmentiert. Bei einer Kieferhöhle jedes Minipigs wurde der Raum zwischen der Schneider'schen Membran und der Sinuswand mit ABC (325,000 Zellen pro Sinus in Durchschnitt) und BBM aufgefüllt. In der anderen Kieferhöhle wurde BBM allein verwendet. Die Tiere wurden nach 12 Wochen geopfert. Von jeder augmentierten Region wurde mittels Sägeschnitt ein Block präpariert und die Menge an neu gebildetem Knochen wurde durch Mikro-Computertomographie (,-CT) analysiert. Die Zugabe von ABC zu BBM bewirkte in der ,-CT Analyse eine signifikante Zunahme des neu gebildeten Knochens im Vergleich zu BBM allein (ABC+BBM: 29.86±6.45% gegenüber BBM. 22.51±7.28% (P=0.016)). Die Knochenbildung hatte im Bereich der Schneider'schen Membran (ABC+BBM: 20.7±4.5% gegenüber BBM: 15.43±3.62%(P=0.009)) und in der Mittelzone des Transplantatmaterials (ABC+BBM: 31.63±7.74% gegenüber BBM: 22.5±7.91% (P=0.001)) zugenommen, aber nicht in der Nähe des lokalen Wirtsknochens (ABC+BBM: 37.23±8.23% gegenüber BBM: 28.42±12.54% (P=0.15)). Diese ersten Resultate zeigen, dass der Zusatz von in Kultur gezüchteten ABC zu zellfreien Transplantatmaterialien die Knochenbildung in Regionen mit niedriger Knochenbildungskapazität stimulieren kann. Resumen La formación de nuevo hueso en un seno injertado con una estructura libre de células requiere la presencia de células progenitoras que se diferencien en osteoblastos. El propósito de este estudio fue examinar el efecto de células autógenas derivadas de hueso de cultivo expandido (ABC) con mineral de hueso bovino (BBM) en la formación de hueso tras un injerto del seno en una sola fase en minicerdos. Se tomaron biopsias de hueso de la cresta iliaca 4 semanas antes del injerto del seno y se cultivaron expandidamente las células ABC in vitro. Se injertaron los senos de 5 minicerdos. En un seno de cada minicerdo el espacio entre la membrana de Schneider y la pared del seno se injertó con ABC (325,000 células por seno, de media) y BBM. En el otro seno se uso BBM únicamente. Los animales se sacrificaron tras 12 semanas. Se preparó un bloque de cada área injertada por medio de una sierra y se analizó la cantidad de hueso neoformado por medio de micro tomografía computarizada (,-CT). La adición de ABC a BBM incrementó significativamente la cantidad de hueso neoformado comparado con BBM solo en el análisis de ,-CT [ABC+BBM: 29.86±6.45% vs. BBM: 22.51±7.28% (P=0.016)]. La formación del hueso se incrementó cerca de la membrana de Schneider [ABC+BBM: 20.7±4.5% vs. BBM: 15.43±3.62% (P=0.009)] y en la zona media de del material de injerto [ABC+BBM: 31.63±7.74% vs. BBM: 22.5±7.91% (P=0.001], pero no cerca del hueso huésped local [ABC+BBM: 37.23±8.23% vs. BBM: 28.42±12.54% (P=0.15)]. Estos hallazgos preliminares indican que la suplementación de injertos sin células con ABC de cultivo expandido puede estimular la formación de hueso en áreas con baja capacidad de formación de hueso. [source] | ||||||||||