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Rabbit Tibia (rabbit + tibia)
Selected AbstractsStudies on dentin grafts to bone defects in rabbit tibia and mandible; development of an experimental modelDENTAL TRAUMATOLOGY, Issue 1 2009Lars Andersson This property may possibly be used as an alternative or supplement to bone grafting to defective areas after trauma prior to treatment with osseointegrated implants. Hence, the objective of this study was to investigate if dentin can be used as a graft in bone defects in an experimental rabbit model. Materials and Methods:, Eight New Zealand White Rabbits were used to prepare bone cavities either in the angle of the mandible or tibia. Six of the eight tibial and six of the eight mandibular bone defects were filled with dentin blocks from human premolars which were extracted for orthodontic treatment. Two mandibular and two tibial bone cavities were used as controls and all the rabbits were sacrificed after 3 months. Radiographic and histological examinations were performed. Results:, There was a difference in healing pattern between the mandibular and tibial defects. In the mandible, the dentin blocks were resorbed to a larger extent and more often surrounded by fibrous tissue, probably due to the fact that the dentin blocks were mobile because of the thin mandibles and muscular activity in that area. Only some dentin blocks were ankylosed with the mandibular bone. In the tibia however, all dentin blocks were fused to bone over a large area. Osseous replacement resorption was seen. In control cavities, bone formation was seen but was never complete. No signs of inflammatory changes were seen in any fused grafts. Conclusions:, Dentin grafts have a potential to be incorporated in bone without inflammation and can be used as bone inducer and later replaced by bone. Thus, rabbit tibia served as a better model for further studies of this phenomenon when compared to the mandible. [source] Generation of tendon-to-bone interface "enthesis" with use of recombinant BMP-2 in a rabbit modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2007Yusuke Hashimoto Abstract The anatomical structure at bone-tendon and bone-ligament interfaces is called the enthesis. Histologically, the enthesis is characterized by a transitional series of tissue layers from the end of the tendon to bone, including tendon, fibrocartilage, calcified fibrocartilage, and bone. This arrangement yields stronger direct connection of the soft tissues to bone. In surgical repair, the enthesis has proven difficult to reproduce, and the success of ligament-bone bonding has depended on the fibrous attachment that forms after any ligament reconstructions. In this study, we attempted to generate a direct-insertion enthesis in two stages. First, recombinant human bone morphogenetic protein-2 (rhBMP-2) was injected into the flexor digitorum communis tendon in the rabbit hind limb to induce ectopic ossicle formation. In a second step, the resultant tendon/ossicle complex was then surgically transferred onto the surface of the rabbit tibia to generate a stable tendon-bone junction. One month following surgery, histomorphological examination confirmed direct insertion of tendon-bone structures in the proximal tibia of the rabbit. Ultimate failure loads of the BMP-2-generated tendon-bone junction were significantly higher than in the control group (p,<,0.01). These findings suggest that it is possible to successfully regenerate a direct tendon-to-bone enthesis. Use of this approach may enable successful reconstruction of joints rendered unstable after ligamentous rupture or laxity after anterior cruciate ligament injury. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1415,1424, 2007 [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] Resonance frequency measurements in vivo and related surface properties of magnesium-incorporated, micropatterned and magnesium-incorporated TiUnite®, Osseotite®, SLA® and TiOblast® implantsCLINICAL ORAL IMPLANTS RESEARCH, Issue 10 2009Young-Taeg Sul Abstract Objective: To investigate implant stability using resonance frequency measurements of topographically changed and/or surface chemistry-modified implants in rabbit bone. Material and methods: Six groups of microstructured, screw-shaped titanium implants: two oxidized, cation-incorporated experimental implants [Mg implants and MgMp implants with micropatterned thread flanges (80,150 ,m wide and 60,70 ,m deep)] and four commercially available clinical implants (TiUnite®, Osseotite®, SLA®, and TiOblast®) were installed in 10 rabbit tibia for 6 weeks. The surface properties of the implants were characterized in detail using several analytical techniques. Implant stability was measured using a resonance frequency analyzer (OsstellÔ). Results: Surface characterization of the implants revealed microstructured, moderately rough implant surfaces varying 0.7,1.4 ,m in Sa (mean height deviation), but with clear differences in surface chemistry. After 6 weeks, all implants showed statistically significantly higher increases in implant stability. When compared with one another, MgMp implants showed the most significant mean implant stability quotient (ISQ) value relative to the others (P,0.016). In terms of increment (,ISQ) in implant stability, MgMp implants showed a significantly greater value as compared with Osseotite® (P,0.005), TiOblast® (P,0.005), TiUnite® (P,0.005), SLA® (P,0.007), and Mg implants (P,0.012). In addition, transducer direction dependence of resonance frequency analysis (RFA) measurements was observed such that the differences in the mean ISQ values between longitudinal and perpendicular measurements were significant at implant placement (P,0.004) and after 6 weeks (P,0). Conclusion: The present study found that implant surface properties influence RFA measurements of implant stability. Surface chemistry-modified titanium implants showed higher mean ISQ values than did topographically changed implants. In particular, cation (magnesium)-incorporated micropatterns in MgMp implants may play a primary role in ,ISQ. [source] Effect of cell-based VEGF gene therapy on healing of a segmental bone defectJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2009Ru Li Fracture healing requires coordinated coupling between osteogenesis and angiogenesis in which vascular endothelial growth factor (VEGF) plays a key role. We hypothesized that targeted over-expression of angiogenic and osteogenic factors within the fracture would promote bone healing by inducing development of new blood vessels and stimulating/affecting proliferation, survival, and activity of skeletal cells. Using a cell-based method of gene transfer, without viral vector, 5.0,×,106 fibroblasts transfected with VEGF were delivered to a 10-mm bone defect in rabbit tibiae (Group 1) (n,=,9); control groups were treated with fibroblasts (Group 2) (n,=,7), or saline (Group 3) (n,=,7) only. After 12 weeks, eight tibial fractures healed in Group 1, compared to four each in Groups 2 and 3. In Group 1, ossification was seen across the entire defect; in Groups 2 and 3, the defects were fibrous and sparsely ossified. Group 1 had more positively stained (CD31) vessels than Groups 2 and 3. MicroCT 3-D showed complete bridging of the new bone for Group 1, but incomplete healing for Groups 2 and 3. MicroCT bone structural parameters showed significant differences between VEGF treatment and control groups (p,<,0.05). These results indicate that the cell-based VEGF gene therapy has significant angiogenic and osteogenic effects to enhance healing of a segmental defect in the long bone of rabbits. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:8,14, 2009 [source] Low intensity pulsed ultrasound accelerated bone remodeling during consolidation stage of distraction osteogenesisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2006Chun Wai Chan Abstract Bone regeneration in distraction osteogenesis occurs under tensile stress with axial rhythmic distraction after osteotomy. In this study, we evaluated if the low intensity pulsed ultrasound (LIPUS) was also effective on enhancement of bone remodeling during consolidation stage of distraction osteogenesis. Open osteotomy of seventeen 18-week-old female New Zealand rabbit tibiae were performed. The distraction was applied with the rate of 1 mm per day. LIPUS (30 mW/cm2, 1.5 MHz) was delivered for 20 min per day during 4-week consolidation stage (n,=,10). The animals without treatment served as sham group (n,=,7). Plain X-ray, peripheral quantitative computational tomography (pQCT), and torsional test were performed. Results showed that smaller radiolucent interzone of LIPUS treatment group was gradually occupied by calcified tissue in plain X-ray at week 2. The bone mineral density (BMD) measured on radiographs increased by 9.18% in the LIPUS group. Bone mineral content (BMC), hard callus volume, and bone strength index (BSI) measured by pQCT were 83%, 116%, and 94%, respectively, in LIPUS group that were significantly greater than those of the controls. At the 4th week, LIPUS-treated callus showed the development of neocorticalization in the proximal and distal region. The BMC, hard callus volume, and BSI of LIPUS group decreased and was not significantly different from control. This was also confirmed by the maximum torque of LIPUS-treated callus (1424.2,±,457.3 N,·,mm) obtained at week 4, which did not differ from that of the sham group (1968.8,±,895.1 N,·,mm). In conclusion, the effective period of LIPUS treatment was at the initial stage of consolidation, with accelerated bone formation and remodeling. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Bone healing performance of electrophoretically deposited apatite,wollastonite/chitosan coating on titanium implants in rabbit tibiaeJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 7 2009Smriti Sharma Abstract Bone healing of tibial defect in rabbit model was used to evaluate a composite coating of apatite,wollastonite/chitosan on titanium implant. This coating has been developed to overcome the shortcomings, such as implant loosening and lack of adherence, of uncoated titanium implant. An electrophoretic deposition technique was used to coat apatite,wollastonite/chitosan on titanium implants. The present study was designed to evaluate the bone response of coated as compared to uncoated titanium implants in an animal model. After an implantation period of 14 (group A), 21 (group B), 35 (group C) and 42 days (group D), the bone,implant interfaces and defect site healing was evaluated using radiography, scintigraphy, histopathology, fluorescence labeling and haematology. Radiography of defect sites treated with coated implants suggested expedited healing. Scintigraphy of coated implant sites indicated faster bone metabolism than uncoated implant sites. Histopathological examination and fluorescence labeling of bone from coated implant sites revealed higher osteoblastic activity and faster mineralization. Faster bone healing in the case of coated implant sites is attributed to higher cell adhesion on electrostatically charged chitosan surfaces and apatite,wollastonite-assisted mineralization at bone,implant interfaces. Haematological studies showed no significant differences in haemoglobin, total erythrocyte and leukocyte counts, done using one way-ANOVA, during the entire study period. Our results show that AW/chitosan-coated implants have the advantages of faster bone healing, increased mechanical strength and good bone,implant bonding. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of a novel calcium titanate coating on the osseointegration of blasted endosseous implants in rabbit tibiaeCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2007Jo-Young Suh Abstract Objective: The purpose of this study was to investigate the effects of a nanostructured calcium coating on the surfaces of blasted Ti implants on peri-implant bone formation in the rabbit tibiae. Material and methods: Threaded implants (3.75 mm in diameter, 6 mm in length) were roughened by hydroxyapatite (HA) blasting (control; blasted implants). The implants were then hydrothermally treated in a Ca-containing solution for 24 h to prepare Ca-incorporated Ti surfaces (experimental; blasted/Ca implants). Surface characterizations were performed by scanning electron microscopy and stylus profilometry before and after Ca coating. Forty-two implants (21 control and 21 experimental) were placed in the proximal tibiae of seven New Zealand White rabbits. Each rabbit received six implants. To evaluate the effects of the nanostructured Ca coating on the peri-implant bone-healing response, removal torque tests and histomorphometric analyses were performed 6 weeks after surgery. Results: The Ca coating did not significantly change the surface properties produced by blasting at the micron level. Histologically, active bone apposition was observed in the blasted/Ca implants in the marrow space. Compared with the blasted implants, the blasted/Ca implants showed significantly increased bone-to-implant contact over the total implant length (P<0.01) and greater mean removal torque values (P<0.05). Discussion and conclusion: The nanostructured, Ca-incorporated surface significantly enhanced the peri-implant bone-healing response of HA-blasted Ti implants. It may be concluded that the use of nanostructured, Ca-coated surfaces may have synergic effects in enhancing osseointegration of blasted Ti implants due to their micron-scaled surface properties and biologically active surface chemistry. [source] | ||||||||||