Home About us Contact
|
Home About us Contact | ||
|
|
||
Defect Area (defect + area)
Selected AbstractsBone healing around implants placed in a jaw defect augmented with Bio-Oss®JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2000An experimental study in dogs Abstract The present experiment was carried out to study some tissue reactions around implants that were placed in an edentulous ridge which had been augmented with deproteinized natural bovine cancellous bone mineral. In 4 male beagle dogs, the premolars in the right side of the mandible were extracted and a large buccal ridge defect was created by mechanical means. The bone plate at the lingual aspect of the defect was left intact. 5 months later, the distal 2/3 of the defect area was augmented with Bio-Oss® (Geistlich Sons Ltd, Wolhusen, Switzerland) mixed with a fibrin sealer (Tisseel®, Immuno AG, Vienna, Austria). After 3 months of healing, 3 fixtures (Astra Tech AB, Mölndal, Sweden; TiO-blast; 8×3.5 mm) were installed in the mandible; 2 were placed in the augmented portion and 1 was placed in the non-augmented portion of the defect. After a healing period of 3 months, abutment connection was performed and a plaque control period initiated. 4 months later, the dogs were sacrificed and each implant region was dissected. The tissue samples were dehydrated, embedded in plastic, sectioned in the bucco-lingual plane and examined in the light microscope. It was observed that osseointegration failed to occur to implant surfaces within an alveolar ridge portion previously augmented with Bio-Oss®. In the augmented portion of the crest, the graft particles were separated from the host tissue as well as from the implant by a well-defined connective tissue capsule. Although the lingual aspect of all fixtures (test and control) was in contact with hard tissue at the time of installation, after 4 months of function, a deep vertical bone defect frequently had formed at the lingual surface of the implants. It was concluded that in this model (i) Bio-Oss® failed to integrate with the host bone tissue and (ii) no osseointegration occurred to the implants within the augmented portion of the crest. [source] Effects of defect configuration, size, and remaining teeth on masticatory function in post-maxillectomy patientsJOURNAL OF ORAL REHABILITATION, Issue 9 2005S. KOYAMA summary, The aim of this study was to investigate the correlation between the masticatory function and the maxillary defect configuration, size, and remaining teeth in post-maxillectomy patients restored with an obturator prosthesis. Fifty consecutive post-maxillectomy patients (mean age 67·0) participated in this study. The subjects consisted of 26 dentate and 24 edentulous patients. Data were collected from the patients' clinical records, diagnostic casts, and a questionnaire on masticatory function to evaluate the defect configuration, size, and the masticatory function scores associated with wearing obturator prostheses. The defect size was evaluated by the ratio of defect area to the horizontal impression area. The defect configuration was assessed according to Aramany's classification and separated into unilateral and bilateral defects. The multiple regression analysis and the Mann,Whitney U -test (P < 0·05) were used to assess statistical significance. The Spearman's correlation coefficient by rank test was also used to detect correlation. The following conclusions were made: (i) The presence of teeth in the maxillary dentition and the different type of the defect configuration had significant correlation with the masticatory function score (r = 0·616). (ii) The masticatory function scores of the subjects differed significantly with the presence of teeth in the maxillary dentition and the different types of defect configurations (P = 0·005, P = 0·002, respectively). (iii) There was significant correlation between the masticatory function score and the size of the defect area in the edentulous group (r = ,0·648, P = 0·001). The presence of teeth, the size and configuration of the defect influenced the masticatory function of post-maxillectomy patients with obturator prostheses. [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] Effects of a cultured autologous chondrocyte-seeded type II collagen scaffold on the healing of a chondral defect in a canine modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2003C. R. Lee Using a previously established canine model for repair of articular cartilage defects, this study evaluated the 15-week healing of chondral defects (i.e., to the tidemark) implanted with an autologous articular chondrocyte-seeded type II collagen scaffold that had been cultured in vitro for four weeks prior to implantation. The amount and composition of the reparative tissue were compared to results from our prior studies using the same animal model in which the following groups were analyzed: defects implanted with autologous chondrocyte-seeded collagen scaffolds that had been cultured in vitro for approximately 12 h prior to implantation, defects implanted with autologous chondrocytes alone, and untreated defects. Chondrocytes, isolated from articular cartilage harvested from the left knee joint of six adult canines, were expanded in number in monolayer for three weeks, seeded into porous type II collagen scaffolds, cultured for an additional four weeks in vitro and then implanted into chondral defects in the trochlear groove of the right knee joints. The percentages of specific tissue types filling the defects were evaluated histomorphometrically and certain mechanical properties of the repair tissue were determined. The reparative tissue filled 88 ± 6% (mean ± SEM; range 70,100%) of the cross-sectional area of the original defect, with hyaline cartilage accounting for 42 ± 10% (range 7,67%) of defect area. These values were greater than those reported previously for untreated defects and defects implanted with a type II collagen scaffold seeded with autologous chondrocytes within 12 h prior to implantation. Most striking, was the decreased amount of fibrous tissue filling the defects in the current study, 5 ± 5% (range 0,26%) as compared to previous treatments. Despite this improvement, indentation testing of the repair tissue formed in this study revealed that the compressive stiffness of the repair tissue was well below (20-fold lower stiffness) that of native articular cartilage. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Influence of interleukin-1 gene polymorphism on periodontal regeneration in intrabony defectsJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2003M. Christgau The aim of this controlled retrospective study was to evaluate the influence of an IL-1 gene polymorphism on the clinical and radiographic healing outcomes of GTR therapy. The study included 47 adult periodontitis patients with 94 deep intrabony defects treated by GTR using different membrane materials. The following clinical parameters were recorded at baseline and 12 months after surgery: papillary bleeding index (PBI), gingival recession (REC), probing pocket depth (PPD), clinical attachment level (CAL), and the vertical relative attachment gain (V-rAG). Bone changes in the defect regions due to GTR therapy were quantitatively evaluated using digital subtraction radiography (DSR). Polymorphisms of the IL-1A gene at position ,,889 and of the IL-1B gene at position +,3953 were analyzed by PCR. Statistical analysis was performed using the Mann,Whitney-U and the Wilcoxon-Signed-Rank tests (, = 0.05). The study comprised 19 IL-1 genotype positive (IL-1 +) patients and 28 IL-1 genotype negative (IL-1 ,) patients. Twelve months after GTR therapy, both patient groups revealed statistically significant PPD reductions and CAL gain [median (25/75% percentiles)]: ,PPD [IL-1 + : 4.0 (2.5/5.0) mm; IL-1- : 3.8 (3.0/4.9) mm], ,CAL [IL-1 + : 3.5 (3.0/4.8) mm; IL-1 ,: 3.0 (1, 2/4, 5) mm]. V-rAG amounted to 60.0 (47.7/78.6)% in IL-1 + patients and 53.1 (43.4/81.9)% in IL-1 , patients. Both patient groups showed significant bone density gain in 40% (IL-1 +) and 43.6% (IL-1 ,) of the initial defect area due to GTR. Neither the clinical nor the radiographic healing parameters revealed any statistically significant differences in the GTR healing outcome between IL-1 + and IL-1 , patients. In conclusion, these 12-month findings indicate that the IL-1 gene polymorphism has no influence on the clinical and radiographic regeneration results following GTR therapy. [source] Structural Analysis on Planar Defects Formed in WC Platelets in Ti-Doped WC,CoJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2006Sabine Lay Platelet-reinforced WC,Co alloys are processed by liquid-phase sintering from very fine-grained WC powders in the presence of small amounts of TiC. Large and flat WC grains develop in the material. The microstructure of these platelets is investigated by high-resolution electron microscopy in order to obtain information on their formation mechanism. Inside the grains, an extended defect parallel to the basal plane is observed. It can be described by a pair of stacking faults with a shear vector equal to 1/3 ,0-110, occurring in two successive (0001) planes. At the level of the faults, the plane spacing is slightly reduced. The defect area is similar to a thin cubic layer about 0.5 nm thick at the interior of the platelet. The enhanced grain growth of the platelets is likely related to the presence of the defect area. [source] Reverse latissimus dorsi musculocutaneous flap for reconstruction of lumbar radiation ulcerTHE JOURNAL OF DERMATOLOGY, Issue 8 2007Sei-ichiro MOTEGI ABSTRACT The surgical treatment of large, deep defects on the midline of the lower back or lumbar area comprises difficult reconstructive challenges. Various flaps have been designed to reconstruct the defect area. We herein report a 70-year-old Japanese woman with a large, deep ulcer in the midline of the lower back, caused by postoperative radiation therapy for eccrine porocarcinoma. The ulcer was successfully treated with surgical debridement followed by reverse latissimus dorsi musculocutaneous flap. This flap is reliable and useful for reconstruction of a large, deep midline defect of the lower back, having large and bulky tissue with a sufficient blood supply. [source] The bone,metal interface of defect and press-fit ingrowth of microwave plasma-chemical vapor deposition implants in the rabbit modelCLINICAL ORAL IMPLANTS RESEARCH, Issue 1 2005Stephan Rupprecht Abstract Purpose: The histological differences between the defect and contact areas of the implant surface to bone were tested in 35 New Zealand White rabbits in a standardized model. Microwave plasma chemical vapor-coated implant probes were tested in control and uncoated materials. Material and methods:, In each femur of 35 rabbits, cylindrical implant rods with a planed side were inserted. Three groups, divided in coated and uncoated material at half, were observed 42, 84 and 168 days. The probes were examined histologically for bone,implant contact in the curved and plane (defect area) sides. Results: Generally the bone,implant contact seems to be nearly constant in time in the curved area of coated and uncoated probes. Here the implant was inserted in the press-fit mode. Diamond-coated probes showed similar bone,implant contact (51.9% (42 days), 62.5% (84 days), 56.1% (168 days)) compared to uncoated material (56.2%, 65.4%, 62.9%). The defect area (plane side) had no bone,implant contact at the time of insertion and showed increasing values on longer observation times with only significant differences in the 42-day group between coated (17.85%, 35.2%, 47.7%) and uncoated materials (35.5%, 40.55%, 51.81%). Conclusion: The evaluation of the curved side of the implant probe showed no great variation of bone,implant contact within the described observation times. This model simulates the usual implant insertion situation. The diamond-coated material becomes osseointegrated at a later time point. The bone,implant contact was only statistically relevant in one group in comparison to uncoated material. Résumé Les différences histologiques entre la lésion et les aires de contact de la surface implantaire à l'os ont été testées chez 35 lapins blancs de Nouvelle-Zélande dans un modèle standardisé. Des sondes implantaires recouvertes d'une vapeur chimique de plasma par micro-ondes ont été testées par rapport à du matériel non-recouvert. Dans chaque fémur des 35 lapins, des baguettes implantaires cylindriques avec un côté plat ont été insérées. Trois groupes, divisés en matériel couvert et non-couvert à moitié ont été observés après 42, 84 et 168 jours. Les sondes ont été examinées histologiquement pour le contact os-implant dans les sites courbe et plat (aire de la lésion). Généralement le contact os-implant semblait constant dans la durée dans la zone courbe des sondes couvertes et non-couvertes. Ici l'implant a été inséré par la méthode de pressé-fixé (=fit après insertion). Les sondes recouvertes de diamant montraient un contact os-implant semblable (52%à 42 J, 63%à 84 J et 56%à 168 J) comparées au matériel non-recouvert (56%, 65%, 63%). L'aire de la lésion (partie plate) n'avait pas de contact os-implant au moment de l'insertion et montrait des valeurs grandissantes avec le temps avec seulement des différences significatives dans les groupes à 42 jours entre le matériel recouvert (18%, 35% et 48%) et le non-recouvert (36%, 41% et 52%). L'évaluation du côté arrondi de la sonde implantaire ne montrait pas de grande variation dans le contact os-implant dans les temps d'observation décrits. Ce modèle simule la situation d'insertion implantaire usuelle. Le matériel recouvert de diamant devient ostéoïntégré plus tardivement. Le contact os-implant n'était statistiquement valable que dans un groupe en comparaison avec le matériel non-recouvert. Zusammenfassung Ziel: Mit einem standartisierten Modell untersuchte man an 35 weissen New Zealand Kaninchen die histologischen Unterschiede zwischen in direktem Kontakt mit dem Implantat stehendem Knochen und Defektstellen. Testimplantate, die mit Diamant beschichtet worden sind, verglich man mit unbeschichtetem Material als Kontrolle. Material und Methode: In jeden Femur der 35 Kaninchen inserierte man zylindrische Implantate, die auf einer Seite abgeplattet waren. Man beobachtete drei Gruppen, je hälftig unterteilt in beschichtete und unbeschichtete Implantate, während 42, 84 und 168 Tagen. Die Blockbiopsien wurden in der runden und abgeflachten (Defektzone) Region histologisch auf ihren Implantat-Knochen-Kontakt hin untersucht. Resultate: Allgemein stellte man fest, dass der Knochen-Implantat-Kontakt während der ganzen Beobachtungszeit in der runden Region der beschichteten und unbeschichteten Implantate ziemlich konstant zu bleiben scheint. Die Implantate sind eingeklopft worden. Die diamantbeschichteten Prüfkörper zeigten einen ähnlichen Knochen-Implantat-Kontakt (51.9% (42d), 62.5% (84d), 56.1% (168d)) wie die unbeschichteten Prüfkörper (56.2%, 65.4%, 62.9%). Die Defektzonen (abgeflechte Stellen) hatten zum Zeitpunkt der Implantation natürlich keinen Kontakt zum Knochen, zeigten aber während der Beobachtungszeit zunehmend Kontakt. Einzig nach 42 Tagen zeigten sich zwischen den beschichteten (17.85%, 35.2%, 47.7%) und den unbeschichteten Implantaten (35.5%, 40.55%, 51.81%) signifikante Unterschiede. Zusammenfassung: Innerhalb der umschriebenen Beobachtungszeit zeigte die Untersuchung der runden Seite der Implantate keine grossen Unterschiede bei der Ausdehnung der Kontaktflächen zum Knochen. Dieses Modell empfindet die übliche Implantationssituation nach. Das mit Diamant beschichtete Material wird zu einem etwas späteren Zeitpunkt osseointegriert. Die Unterschiede im Knochen-Implantat-Kontakt waren im Vergleich mit dem unbeschichteten Material nur in einer Gruppe statistisch gesehen von Bedeutung. Resumen Propósito: Se probaron las diferencias histológicas entre los defectos y las áreas de contacto de la superficie del implante al hueso en 35 conejos blancos de Nueva Zelanda en un modelo estandarizado. Se investigaron implantes de prueba cubiertos de plasma de vapor químico de microonda frente a material sin cubierta como control. Material y Métodos: Se insertaron en cada fémur de 35 conejos barras cilíndricas de implantes con un lado plano. Se observaron tres grupos divididos en material cubierto y no cubierto a la mitad durante 42, 84 y 168 días. Las pruebas se examinaron histológicamente para contacto hueso-implante en los lados curvado y plano (área de defecto). Resultados: Generalmente el contacto hueso implante suele ser constante en el tiempo en el área curvada de las pruebas cubiertas y no cubiertas. Aquí el implante se insertó en el modo press-fit. Las pruebas cubiertas de diamantes mostraron un contacto hueso implante similar (51.9% (42d), 62.5% (84d), 56.1% (168)) comparados con el material no cubierto (56.2%, 65.4%, 62.9%). El área de defecto (lado plano) no tuvo contacto hueso implante en el momento de la inserción y mostró valores crecientes en periodos mas largos de observación con solo diferencias significativas en el grupo del día 42 entre materiales cubiertos (17.85, 32.2%, 47%) y no cubiertos (35.5%, 40.55%, 51.81%). Conclusión: La evaluación del lado curvado del implante de prueba no mostró una gran variación del contacto hueso implante dentro de los tiempos de observación descritos. Este modelo simula la situación usual de inserción del implante. El material cubierto de diamante se osteointegra en un momento posterior. El contacto hueso implante fue solo estadísticamente relevante en un grupo en comparación con el material no cubierto. [source] Histological assessment of augmented jaw bone utilizing a new collagen barrier membrane compared to a standard barrier membrane to protect a granular bone substitute materialCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2002A randomized clinical trial Abstract: Successful bone augmentation requires predictable space maintenance and adequate exclusion of those cells that lack osteogenetic potential from the defect area. Natural bone mineral is considered to be osteoconductive and is used as space maker in combination with membrane barrier techniques. The aim of this study was to compare qualitative histological results achieved by using deproteinized bovine bone mineral (DBBM) as a space maintainer and a new collagen barrier (OssixÔ, test group) vs. the same bone substitute and the standard e-PTFE membrane (Gore-Tex®, control group). Twenty-eight patients were randomly assigned to the test or the control group. Seven months after augmentation procedures, biopsies were obtained at reentry and were analysed histomorphometrically. In all, 14 specimens of group I (test group, OssixÔ) and 13 specimens of group II (controls, PTFE-membranes) showed close qualitative similarity of their histologies. Histomorphometrically, total mineralized bone area was 42% ± 18% in group I vs. 39% ± 15% in group II. The unmineralized tissue area was 44% ± 15% vs. 46% ± 12% and the area of DBBM remnants 14% ± 9% and 15% ± 12%, respectively. The differences were statistically nonsignificant (Mann,Whitney test). The occurrence of barrier exposure did not interfere with the histological outcome either in the test or in the control group. The new collagen barrier combined with the DBBM provided qualitative bone regeneration comparable to the standard e-PTFE material combined with the same mineral. [source] Noggin Inhibits Postoperative Resynostosis in Craniosynostotic Rabbits,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2007Gregory M Cooper PhD Abstract Inhibition of bone formation after surgery to correct craniosynostosis would alleviate the need for secondary surgeries and decrease morbidity and mortality. This study used a single dose of Noggin protein to prevent resynostosis and improve postoperative outcomes in a rabbit model of craniosynostosis. Introduction: Craniosynostosis is defined as the premature fusion of one or more of the cranial sutures, which causes secondary deformations of the cranial vault, cranial base, and brain. Current surgical intervention involves extirpation of the fused suture to allow unrestricted brain growth. However, resynostosis of the extirpated regions often occurs. Several bone morphogenetic proteins (BMPs), well-described inducers of ossification, are involved in bone healing. This study tested the hypothesis that a postoperative treatment with Noggin, an extracellular BMP inhibitor, can inhibit resynostosis in a rabbit model of human familial nonsyndromic craniosynostosis. Materials and Methods: Thirty-one New Zealand white rabbits with bilateral coronal suture synostosis were divided into three groups: (1) suturectomy controls (n = 13); (2) suturectomy with BSA in a slow-resorbing collagen vehicle, (n = 8); and (3) suturectomy with Noggin in a slow-resorbing collagen vehicle (n = 10). At 10 days of age, a 3 × 15-mm coronal suturectomy was performed. The sites in groups 2 and 3 were immediately filled with BSA-loaded gel or Noggin-loaded gel, respectively. Serial 3D-CT scan reconstructions of the defects and standard radiographs were obtained at 10, 25, 42, and 84 days of age, and the sutures were harvested for histological analysis. Results: Radiographic analysis revealed that Noggin-treated animals had significantly greater coronal suture marker separation by 25 days and significantly greater craniofacial length at 84 days of age compared with controls. 3D-CT analysis revealed that Noggin treatment led to significantly greater defect areas through 84 days and to increased intracranial volumes at 84 days of age compared with other groups. Histological analysis supported CT data, showing that the untreated and BSA-treated groups had significant healing of the suturectomy site, whereas the Noggin-treated group had incomplete wound healing. Conclusions: These data support our hypothesis that inhibition of BMP activity using Noggin may prevent postoperative resynostosis in this rabbit model. These findings also suggest that Noggin therapy may have potential clinical use to prevent postoperative resynostosis in infants with craniosynostosis. [source] | ||||||||||