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Size Defect (size + defect)
Kinds of Size Defect Selected AbstractsA new animal model for bone atrophic nonunion: Fixation by external fixatorJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2008Katharina Kaspar Abstract A new small animal model of bone atrophic nonunion was established for investigating the process of bone regeneration by performing cauterization of the periosteum, removal of the local bone marrow, and stabilization with external fixation. The model allows the creation of an atrophic nonunion without the need for a critical size defect. Furthermore, it provides reproducible, well-defined mechanical conditions and minimized physical interference of the implant with the biological processes in the healing zone. Eighty adult Sprague-Dawley rats received an osteotomy of the left femur, stabilized with an external fixator. In half of the animals, the periosteum proximal and distal to the osteotomy was destroyed by cauterization and the adjacent bone marrow was removed (nonunion group). At 2 and 8 weeks after surgery, radiological, biomechanical, histological, and histomorphometrical analyses showed a typical physiological healing in the control group, while the nonunion group was characterized by resorption of the bone ends with some callus formation distant to the osteotomy. At both time points, the callus was composed of significantly less bone and significantly more connective tissue (p,<,0.001). In addition, the torsional strength of the osteotomized femur was significantly less in the nonunion group than in the control group, which was comparable to that of the intact femur (p,<,0.001). In conclusion, the present model allows the induction of an atrophic nonunion without the need of a critical size defect. It is reproducible, provides standardized biomechanical conditions, and allows minimized interaction of the implant with the healing zone. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] In vivo study on the healing of bone defects treated with bone marrow stromal cells, platelet-rich plasma, and freeze-dried bone allografts, alone and in combinationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2006D. Dallari Abstract The repair of confined trabecular bone defects in rabbits treated by autologous bone marrow stromal cells (BMSC), platelet-rich plasma (PRP), freeze-dried bone allografts (FDBA) alone and in combination (BMSC,+,PRP; FDBA,+,BMSC; FDBA,+,PRP; FDBA,+,PRP,+,BMSC) was compared. A critical size defect was created in the distal part of the femurs of 48 adult rabbits. Histology and histomorphometry were used in the evaluation of healing at 2, 4, and 12 weeks after surgery. The healing rate (%) was calculated by measuring the residual bone defect area. Architecture of the newly formed bone was compared with that of bone at the same distal femur area of healthy rabbits. The defect healing rate was higher in PRP,+,BMSC, FDBA,+,PRP, FDBA,+,BMSC, and FDBA,+,PRP,+,BMSC treatments, while lower values were achieved with PRP treatment at all experimental times. The highest bone-healing rate at 2 weeks was achieved with FDBA,+,PRP,+,BMSC treatment, which resulted significantly different from PRP (p,<,0.05) and BMSC (p,<,0.05) treatments. At 4 weeks, the bone-healing rate increased except for PRP treatment. Finally, the bone-healing rate of FDBA,+,PRP, FDBA,+,BMSC, and FDBA,+,PRP,+,BMSC was significantly higher than that of PRP at 12 weeks (p,<,0.05). At 12 weeks, significant differences still existed between PRP, BMSC, and FDBA groups and normal bone (p,<,0.05). These results showed that the combination of FDBA, BMSC and PRP permitted an acceleration in bone healing and bone remodeling processes. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Bone tissue engineering in a critical size defect compared to ectopic implantations in the goatJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2004Moyo C. Kruyt Abstract Since the application of the autologous bone graft, the need for an alternative has been recognized. Tissue engineering (TE) of bone by combining bone marrow stromal cells (BMSCs) with a porous scaffold, is considered a promising technique. In this study we investigated the potential of tissue engineered bone to heal a critical sized defect in the goat. Orthotopic bone formation was compared to ectopic bone formation in comparable constructs. TE constructs were prepared from goat BMSCs and porous biphasic calcium phosphate ceramic scaffolds. These constructs and scaffolds without cells were implanted paired in critical sized iliac wing defects. Comparable samples were implanted intramuscularly. After 9 (n = 7) and 12 (n = 8) weeks implantation, the samples were analyzed histomorphometrically. After 9-weeks implantation in the iliac wing defect, significantly more bone apposition was found in the TE condition. After 12 weeks, the defects were almost completely filled with bone, but no significant advantage of TE was determined anymore. This contrasted with the intramuscular samples where TE implants showed significantly more bone at both time points. In conclusion, bone TE is feasible in critical sized defects. However, when appropriate osteoconductive/inductive materials are applied the effect of cell seeding may be temporary. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Effects of various implant materials on regeneration of calvarial defects in ratsPATHOLOGY INTERNATIONAL, Issue 8 2000Sung-Chul Lim The purpose of the present study was to determine the best implant material, the best conditions to substitute absorbable membrane for non-absorbable membrane, and the factors influencing guided regeneration of critical size defects using experimental rats. An 8-mm circular transosseous calvarial bony defect was made and implant materials, such as demineralized freeze-dried bone (DFDB), absorbable membrane (BioMesh; Samyang Co., Seoul Korea), non-absorbable membrane (Millipore filter; Micro Filtration System, MA, USA) or a combination of these materials, was placed on the defect. As for the results of sequential time-based guided bone regeneration, histological, histochemical, immunohistochemical and histomorphometric aspects were observed, and a statistical comparative analysis was performed, with control group of a soft tissue flap. Bone formation was significantly enhanced when DFDB was retained within the defect with a protective absorbable membrane. Inframembranous DFDB-filling was required to prevent membrane collapse and to preserve spaces for bone regeneration. The absorbable membrane which was recommended to overcome the disadvantages of the non-absorbable membrane should remain intact for more than 5 weeks in order for it to be effective. The macrophages recruited by grafts were involved partly in decreasing bone regeneration via the sequential events of releasing fibronectin, and in chemotactic effect of the fibronectin to fibroblasts and collagen lay-down. Thus, the activity of new bone formation was dependent upon the physical barrier effect of the membrane, such as the preserving ability to secure spaces and the suppression ability of early infiltration of collagen and epithelium, inducible ability of inflammation by the implant material, and potential in guiding bone regeneration of the grafts. [source] Bone repair and augmentation using block of sintered bovine-derived anorganic bone graft in cranial bone defect modelCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2009Tania Mary Cestari Abstract Objective: To histomorphometrically investigate the repair of critical size defects (CSDs) and bone augmentation in cranial walls using block of sintered bovine-derived anorganic bone (sBDAB) graft. Material and methods: Forty guinea-pigs were divided into test (n=20) and CSD control (n=20) groups. In each animal, a full-thickness bone defect with 9.5 mm diameter was made in the frontal bone. The defects were filled with an sBDAB block soaked in blood in the test group and with blood clot in the CSD control group. The skulls were collected at 0 h (n=2) and 30, 90 and 180 days (n=6/group and period) postoperatively. The volume density and total volume of newly formed bone, sBDAB, blood vessels and connective tissue, vertical thickness of removed bone plug, sBDAB block and graft area were evaluated. Results: The vertical thickness of the adapted sBDAB block was 3.8 times higher than that of the removed bone plug and did not show significant difference between periods, filling in average 29.8% of the total graft region. The sBDAB block exhibited complete osseointegration with the borders of the defect at 90 days. At 90 and 180 days, the vertical thickness of the graft was 279% in the average, and the total volume of bone augmentation was, respectively, 78.8% and 148.5% higher compared with the removed bone plug. The defects of the CDS control group showed limited osteogenesis and filling by connective tissue plus tegument. Conclusion: The sBDAB block can be used to promote repair of CSDs and bone augmentation in the craniomaxillofacial region, due to its good osteoconductive and slow resorptive properties. [source] Does platelet-rich plasma promote remodeling of autologous bone grafts used for augmentation of the maxillary sinus floor?CLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2005Gerry M. Raghoebar Abstract: The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) on remodeling of autologous bone grafts used for augmentation of the floor of the maxillary sinus. In five edentulous patients suffering from insufficient retention of their upper denture related to a severely resorbed maxilla, the floor of both maxillary sinus was augmented with an autologous bone graft from the iliac crest. Randomly, PRP was added to the bone graft used to augment the floor of the left or right sinus (split-mouth design). Three months after the reconstruction, bone biopsies were taken with a trephine from the planned implant sites (N=30). Subsequently, three implants were placed in the left and right posterior maxilla. Microradiograms were made of all biopsies (N=30), whereafter the biopsies were processed for light microscopic examination. In addition, clinical parameters were scored. Wound healing was uneventful, clinically no difference was observed between the side treated with PRP or not. Also microradiographical and histomorphological examination of the biopsies revealed no statistical difference between the PRP- and non-PRP side. One implant placed in the PRP side of the graft was lost during the healing phase. Implant-retained overdentures were fabricated 6 months after implantation. All patients functioned well (follow-up 20.2±4.3 months). In this study, no beneficial effect of PRP on wound healing and bone remodeling was observed. It is posed that PRP has no additional value in promoting healing of grafted non-critical size defects. Résumé Le but de cette étude a été d'évaluer l'effet du plasma riche en plaquettes sur le remodelage de greffons osseux autogènes utilisés pour l'épaississement du plancher sinusal. Chez cinq patients édentés souffrant d'une rétention insuffisante de leur prothèse supérieure en relation avec un maxillaire sévèrement résorbé, les planchers sinusaux des deux maxillaires ont étéépaissis avec un greffon d'os autogène provenant de la crête iliaque. Au hasard, du plasma riche en plaquettes (PRP) a été ajouté au greffon osseux utilisé pour épaissir le plancher du sinus gauche ou droit (modèle de bouche divisée). Trois mois après la reconstruction, des biopsies osseuses ont été obtenues avec un trépan des sites planifiés pour placer des implants (N=30). Ensuite, trois implants ont été placés dans les parties maxillaires gauches et droites. Des microradiogrammes des 30 biopsies ont été effectuées, ces dernières ont ensuite été utilisées pour l'examen au microscope optique. De plus, des paramètres cliniques ont été enregistrés. La guérison a été parfaite, cliniquement aucune différence n'a été observée entre les sites traités avec PRP ou sans. L'examen microradiographique et histomorphologique des biopsies n'a révélé aucune différence significative entre les sites PRP et non-PRP. Un implant placé dans le site PRP du greffon a été perdu durant la phase de guérison. Des prothèses retenues sur implants ont été fabriquées six mois après l'insertion des implants. Tous les patients ont une mise en fonction excellente après un suivi de 20±4,3 mois. Dans cette étude, aucun effet bénéfique additionnel du PRP sur la guérison et le remodelage osseux n'a été observé. Le PRP n'aurait aucune valeur supplémentaire à promouvoir la guérison dans ce type d'opération. Zusammenfassung Das Ziel dieser Studie war, den Einfluss von plättchenreichem Plasma auf die Remodellierung von autologen Knochentransplantaten, welche für die Augmentation des Sinusbodens vom Sinus maxillaris verwendet wurden, auszuwerten. Bei 5 zahnlosen Patienten, welche aufgrund einer stark resorbierten Maxilla über einen ungenügenden Halt der Oberkieferprothese klagten, wurde der Sinus maxillaris mit autologem Knochen vom Beckenkamm augmentiert. Zufällig wurde dem Knochen, der zur Augmentation des rechten oder linken Sinusbodens verwendet wurde, plättchenreiches Plasma (PRP) hinzugefügt (unterschiedlich behandelte Seiten). Drei Monate nach der Augmentation wurden mittels Hohlfräsen Biopsien an den geplanten Implantatlokalisationen entnommen (N=30). Danach wurden je drei Implantate in die rechte und linke posteriore Maxilla eingesetzt. Von allen Biopsien wurde Mikroröntgenbilder angefertigt (N=30), danach wurden die Biopsien für die lichtmikroskopische Untersuchung aufgearbeitet. Zusätzlich wurden klinische Parameter aufgenommen. Die Wundheilung war unauffällig. Klinisch konnten keine Unterschiede zwischen den mit und ohne PRP behandelten Seiten beobachtet werden. Ebenso ergab die mikroradiographische und histomorphometrische Untersuchung der Biopsien keine statistisch signifikanten zwischen der PRP und nicht-PRP Seite. Ein Implantat, welches in eine PRP Seite eingesetzt worden war, ging während der Einheilphase verloren. Die implantatgetragenen Hybridprothesen wurden 6 Monate nach Implantation angefertigt. Alle Patienten funktionierten problemlos (Beobachtungszeit bis 20.2±4.3 Monate). In dieser Studie konnte kein positiver Einfluss des PRP auf die Wundheilung und die Knochenremodellierung beobachtet werden. Es wird vermutet, dass PRP keinen zusätzlichen Effekt bei der Förderung der Heilung von Transplantaten in Defekten mit nicht-kritischer Grösse hat. Resumen La intención de este estudio fue evaluar el efecto del plasma rico en plaquetas en el remodelado de injertos de hueso autólogo usado para aumento del suelo del seno maxilar. Se aumentó el suelo de ambos senos maxilares con injertos de hueso autólogo de la cresta iliaca en 5 pacientes edéntulos que padecían de insuficiente retención de su dentadura superior relacionada con un maxilar severamente reabsorbido. Aleatoriamente, se añadió plasma rico en plaquetas (PRP) al injerto óseo usado para aumentar el suelo del seno derecho o izquierdo (diseño de boca partida). Tres meses tras la reconstrucción, se tomaron biopsias de hueso con un trépano de los lugares de implantes planificados (N=30). Subsecuentemente se colocaron tres implantes en el maxilar posterior derecho e izquierdo. Se hicieron microrradiogramas de todas las biopsias (N=30), posteriormente las biopsias se procesaron para microscopía óptica. Además se tomaron parámetros clínicos. La cicatrización de la herida tuvo lugar sin incidentes. Clínicamente no se observó diferencia alguna entre el lado tratado con PRP o no. Tampoco el examen microrradiográfico e histomorfológico de las biopsias revelaron diferencias estadísticamente significativas entre los lados con o sin PRP. Un implante colocado en el lado del PRP se perdió durante la cicatrización. Las dentaduras implantorretenidas se fabricaron a los seis meses de la implantación. Todos los pacientes funcionaron bien (seguimiento de 20.2±4.3 meses). En este estudio no se observó ningún efecto beneficioso del PRP sobre la cicatrización y sobre el remodelado óseo. Se plantea que el PRP no tiene ningún valor adicional en promover la cicatrización de defectos no críticos injertados. [source] | ||||||||||