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Native Bone (native + bone)
Selected AbstractsThe Implications of Polymer Selection in Regenerative Medicine: A Comparison of Amorphous and Semi-Crystalline Polymer for Tissue RegenerationADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Michelle D. Kofron Abstract Biodegradable polymeric scaffolds are being investigated as scaffolding materials for use in regenerative medicine. While the in vivo evaluation of various three-dimensional (3D), porous, biodegradable polymeric scaffolds has been reported, most studies are ,3 months in duration, which is typically prior to bulk polymer degradation, a critical event that may initiate an inflammatory response and inhibit tissue formation. Here, a 6,month in vitro degradation and corresponding in vivo studies that characterized scaffold changes during complete degradation of an amorphous, 3D poly(lactide- co -glycolide)(3D-PLAGA) scaffold and near-complete degradation of a semi-crystalline3D-PLAGA scaffold are reported. Using sintered microsphere matrix technology, constructs were fabricated in a tubular shape, with the longitudinal axis void and a median pore size that mimicked the architecture of native bone. Long-term quantitative measurements of molecular weight, mechanical properties, and porosity provided a basis for theorization of the scaffold degradation process. Following implantation in a critical size ulnar defect model, histological analysis and quantitative microCT indicated early solubilization of the semi-crystalline polymer created an acidic microenvironment that inhibited mineralized tissue formation. Thus, the use of amorphous over semi-crystalline PLAGA materials is advocated for applications in regenerative medicine. [source] Accelerated repair of cortical bone defects using a synthetic extracellular matrix to deliver human demineralized bone matrixJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2006Yanchun Liu Abstract Injectable hydrogel and porous sponge formulations of CarbylanÔ-GSX, a crosslinked synthetic extracellular matrix (ECM), were used to deliver human demineralized bone matrix (DBM) in a rat femoral defect model. A cortical, full-thickness 5-mm defect was created in two femurs of each rat. Six rats were assigned to each of five experimental groups (thus, 12 defects per group). The defects were either untreated or filled with CarbylanÔ-GSX hydrogel or sponges with or without 20% (w/v) DBM. Radiographs were obtained on day 1 and at weeks 2, 4, 6, and 8 postsurgery of each femur. Animals were sacrificed at week 8 postsurgery and each femur was fixed, embedded, sectioned, and processed for Masson's Trichrome staining. The bone defects were measured from radiographs and the fraction of bone healing was calculated. The average fractions of bone healing for each group were statistically different among all groups, and all treatment groups were significantly better than the control group. The CarbylanÔ-GSX sponge with DBM was superior to the sponge without DBM and to the hydrogel with DBM. Histology showed that defects treated with the CarbylanÔ-GSX sponge plus DBM were completely filled with newly generated bone tissue with a thickness comparable to native bone. CarbylanÔ-GSX sponge was an optimal delivery vehicle for human DBM to accelerate bone healing. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1454,1462, 2006 [source] Metastases and multiple myeloma generate distinct transcriptional footprints in osteocytes in vivo,THE JOURNAL OF PATHOLOGY, Issue 5 2008S Eisenberger Abstract Osteocytes are the most abundant bone cells, playing important roles in tissue maintenance. Little is known of how they react in vivo to cancer stress. Here we present a comparative study of the effect of a bone-residing tumour (myeloma) and metastases of bone-remote cancers on osteocytes. While no differences in morphology of the bone are seen, the changes in the transcriptome of osteocytes are specifically related to the tumour stress present. Screening ,22 000 genes in osteocytes prepared from cryosections of native bone using laser-supported microdissection, we observed ,1400 and ,1800 gene expression differences between osteocytes dissected from normal bone compared with those associated with metastases and multiple myeloma, respectively. The genes up-regulated due to the stress exerted by metastases were repressed by multiple myeloma and vice versa, indicating stress-specific footprints in the transcriptome of osteocytes. Functionally, the stressors seem to impose selective pressures on signalling pathways such as that of TGF,, a major player in bone biology. Our data show for the first time that the transcriptome of osteocytes in vivo becomes strongly affected by cancer stress, generating gene expression footprints which, in contrast to comparable morphological changes, appear to relate to the nature of cancer and might thus become helpful in distinguishing different bone diseases. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Benefits of dental implants installed during ablative tumour surgery in oral cancer patients: a prospective 5-year clinical trialCLINICAL ORAL IMPLANTS RESEARCH, Issue 9 2010Anke Korfage Abstract Objective: This prospective study assessed treatment outcome and patient satisfaction of oral cancer patients with a mandibular overdenture on implants up to 5 years after treatment. Materials and methods: At baseline, 50 consecutive edentulous oral cancer patients, in whom prosthetic problems were expected after oncological treatment, were evaluated by standardized questionnaires and clinical assessments. All implants were installed during ablative tumour surgery in native bone in the interforaminal area. About two-thirds of the patients (n=31) had radiotherapy post-surgery (dose >40 Gy in the interforaminal area). Results: At the 5-year evaluation, 26 patients had passed away and four patients had to be excluded from the analyses, because superstructures were not present, due to persistent local irritation (n=2), loss of three implants (n=1) and the impossibility of making an overdenture related to tumour and oncological surgery-driven anatomical limitations (n=1). In the remaining 20 patients, the prosthesis was still in function (76 implants). During the 5-year follow-up, total 14 implants were lost, 13 in irradiated bone (survival rate 89.4%, dose >40 Gy) and one in non-irradiated bone (survival rate 98.6%). Peri-implant tissues had a healthy appearance and remained healthy over time. Patients were satisfied with their dentures. Conclusions: It was concluded that oral cancer patients can benefit from implants installed during ablative surgery, with a high survival rate of the implants, a high percentage of rehabilitated patients and a high denture satisfaction up to 5 years after treatment. To cite this article: Korfage A, Schoen PJ, Raghoebar GM, Roodenburg JLN, Vissink A, Reintsema H. Benefits of dental implants installed during ablative tumour surgery in oral cancer patients: a prospective 5-year clinical trial. Clin. Oral Impl. Res. 21, 2010; 971,979. doi: 10.1111/j.1600-0501.2010.01930.x [source] Bone regeneration of dental implant dehiscence defects using a cultured periosteum membraneCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2008Daiki Mizuno Abstract Objectives: This study aimed to demonstrate the feasibility of a cultured periosteum (CP) membrane for use in guided bone regeneration at sites of implant dehiscence. Material and methods: Four healthy beagle dogs were used in this study. Implant dehiscence defects (4 × 4 × 3 mm) were surgically created at mandibular premolar sites where premolars had been extracted 3 months back. Dental implants (3.75 mm in diameter and 7 mm in length) with machined surfaces were placed into the defect sites (14 implants in total). Each dehiscence defective implant was randomly assigned to one of the following two groups: (1) PRP gel without cells (control) or (2) a periosteum membrane cultured on PRP gel (experimental). Dogs were killed 12 weeks after operation and nondecalcified histological sections were made for histomorphometric analyses including percent linear bone fill (LF) and bone-to-implant contact (BIC). Results: Bone regeneration in the treatment group with a CP membrane was significantly greater than that in the control group and was confirmed by LF analysis. LF values in the experimental and the control groups were 72.36±3.14% and 37.03±4.63%, respectively (P<0.05). The BIC values in both groups were not significantly different from each other. The BIC values in the experimental and the control groups were 40.76±10.30% and 30.58±9.69%, respectively (P=0.25) and were similar to native bone. Conclusion: This study demonstrated the feasibility of a CP membrane to regenerate bone at implant dehiscence defect. [source] Osseointegration of Osseotite® and machined-surfaced titanium implants in membrane-covered critical-sized defects: a histologic and histometric study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2007Alexander A. Veis Abstract: The texture of an implant's surface can influence the rate and extent of bone fixation as expressed by the amount of linear bone-to-implant contact (BIC). The purpose of this study was to compare the bone density and linear BIC between Osseotite® and machined-surface implants placed in bony defects without graft material and covered by a membrane. Thirty 2 mm diameter, 10 mm length custom implants were prepared for this study having a ,split surface,' with one side having the acid-etched surface and the opposite side having a machined surface. Defects were created in the iliac wing of three adult mongrel dogs where a 6-mm-diameter drill was used to generate a 5-mm-deep defect. The implants were inserted into the center of the defect with 5 mm secured into the bone leaving 5 mm free in the defect with a 2 mm gap between the implant and surrounding bone. Expanded polytetrafluroethelyene membranes were placed over the defect sites stabilized with Biotack® pins. The healing times were 2, 3, and 5 months. Histologic and histometric analysis showed significantly lower BIC in the defect region as compared with the portion of implant placed into native bone for both implant surfaces in all groups. There was no difference in BIC values at 2- and 5-month periods between the two surfaces in the regenerated area, while BIC values for Osseotite® surfaces were significantly higher than the machined surfaces at 3 months' healing time. Changes in bone density, observed between the three groups, affected correspondingly the BIC values in both implant surfaces, the effect being more pronounced in the Osseotite® surface. [source] | ||||||||||