[Mineral component of regenerated bone at various period of accretion during use of thyrocalcitonin].
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Animals↗
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Results for “BONE REGENERATION”
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[Replacement of cranial defects in dogs by regenerating bone through heterotransplantation of bone filings].
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Animals↗
[The effect of ribonucleic acid on hydroxyproline concentration in regenerating bone].
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Animals↗
[Animal experimental studies on bone regeneration following drilling of the bone].
Experiments in dogs showed that drilling at the surface of bone provokes damage which increases with the number of revolutions per minute. Polychrome sequence marking and histological tests demonstrated that filling up of bony defects started later with turbine-driven drills than with drills of 2,000 r.p.m. and has not even been completed after eight weeks. It is therefore recommended to abstain from using turbines in drilling at the surface of bone.
Animals↗
[Blood flow changes in regenerating bone tissue during electrostimulation for reparative osteogenesis].
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Animals↗
A technique for regenerating bone in residual defects at implant sites utilizing an osteotropic material.
The discovery of a residual defect at the time of surgery for dental implant placement necessitates a series of critical clinical decisions. They include closing of the site, placing the implant in the residual defect, or grafting the site. If grafting is chosen, the graft material must be selected. For the learning objective, this article presents the case for grafting the site prior to implant placement, using bovine-derived resorbable hydroxylapatite matrix.
Alveolar Ridge Augmentation↗
Spacemaking metal structures for nonresorbable membranes in guided bone regeneration around implants. Two case reports.
This article presents a surgical technique to promote bone regeneration and enlargement of localized alveolar ridge defects in the mandible. The purpose of this study was to investigate the use of spacemaking gold frames used in combination with expanded polytetrafluoroethylene Gore-Tex augmentation membranes (WL Gore) on two patients to create and maintain adequate space for the regeneration of bone. The membrane was sutured under the frame and the assembly was bent and adapted over the residual bony defect to create a dome and prevent the expanded polytetrafluoroethylene barrier membranes from collapsing into the defects. The framed membranes have also been positioned over dehisced implants. After a healing period of 12 months, a second-stage surgery procedure was performed to remove the gold frames and expanded polytetrafluoroethylene membranes and to connect the healing abutments. The gain of bone dimension was assessed by standardized measurements. On both patients the spaces created by the framed membranes were completely filled with newly regenerated bone. Biopsies from the treated sites revealed new bone formation.
Adult↗
Ultrasonographic appearance of regenerate bone in limb lengthening.
The appearance of regenerate bone during the process of limb lengthening using a mono-axial device was studied using radiographs and ultrasound scanning in nine patients. The corticotomy site initially appeared as a sonolucent area. Poorly organized echogenic foci were detectable 2 weeks after the distraction was begun. After 4 weeks, these areas became aligned. At 7-8 weeks, a clear impression of a new cortical margin was seen. The formation of a medullary canal started at this point, progressing to a radiographically evident canal. Ultrasound scanning can reduce considerably exposure to ionising radiation in patients undergoing limb lengthening. Accurate measurements are possible in the early stages, and ossification can be monitored. Axial deviation can be seen but not evaluated. The maturity of the regenerate bone still has to be assessed clinically.
Bone Lengthening↗
[Quantitative and qualitative comparison of the maxillary bone regeneration after beta-tricalcium phosphate and autogenous bone implantation].
Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared. In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry. Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4 +/- 10.9% and 34.7 +/- 11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than on the control side. The TBPf value was lower on the control side than on the experimental side (-0.53 +/- 1.7 mm(-1) and -0.11 +/- 1.4 mm(-1), respectively); but this difference was not significant. Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.
Adult↗
Clinical evaluation of guided bone regeneration at exposed parts of Brånemark dental implants with and without bone allograft.
This investigation evaluated guided bone regeneration with a polytetrafluoroethylene barrier membrane at exposed parts of Brånemark dental implants with and without concomitant use of decalcified freeze-dried bone allograft. Density of the regenerated tissue was also determined using a No. 23 probe at a pressure of 25 g and was graded from 1 to 5. The higher index was associated with a higher resistance of newly formed tissue to the pressure of the probe. In 19 patients, 23 defects were treated by barrier membrane alone and 11 defects by bone allograft with barrier membrane. The width and the depth of the defects were determined at the time of the implant placement and at the second-stage implant surgery. When success was defined as 0 mm of residual defect, the mean success rate was 68% for the membrane group and 90% for the membrane group with bone allograft, with no statistically significant difference between the two treatment groups. The two groups did not demonstrate a significant difference in median density index. There was a significant positive relationship between time of membrane coverage and density index. A density index of 4 was only recorded after 7 months of membrane coverage. The present findings suggest beneficial clinical effect with the use of membrane alone and freeze-dried bone allograft with membrane for guided bone regeneration. This study proposed the use of a novel density index for clinical evaluation of regenerated tissue.
Adult↗
Guided bone regeneration for dental implants.
The application of barrier membranes to promote bone regeneration was first described by Hurley et al. (J Bone Joint Surg 1959, 41A:1243-1254) in orthopedic research. However, the clinical potential of this membrane technique was recognized in the early 1980s for periodontal regeneration. Based on promising results in periodontology, researchers started to evaluate the potential of this technique--often called guided bone regeneration (GBR)--to regenerate bone defects in the alveolar process. This review describes the current knowledge of GBR in implant dentistry. Emphasis is placed on the scientific basis of GBR and the various surgical factors necessary to achieve predictable results with GBR procedures. In addition, unanswered questions that require future research are addressed including long-term success rates of dental implants placed in combination with barrier membranes, evaluation of resorbable membranes, and use of bone substitutes or growth factors to enhance bone regeneration in membrane-protected defects.
Alveolar Bone Loss↗
Initial attachment of osteoblasts to various guided bone regeneration membranes: an in vitro study.
OBJECTIVE AND BACKGROUND: Guided bone regeneration (GBR) has proved to be a suitable and somehow predictable technique for promoting bone regeneration. A variety of synthetic and naturally derived GBR barriers have been used in clinics to facilitate bone regeneration. These barriers may differ in composition and structure and these may affect the outcomes of GBR. Therefore, the present study was undertaken to evaluate the in vitro ability of osteoblasts (MC3T3-E1) to attach to various GBR membranes. MATERIALS AND METHODS: Six GBR/GTR (guided tissue regeneration) membranes [BioMend (BM), Resolut (RL), Guidor (GD), EpiGuide (EG), Gore-Tex (GT) and Millipore filter (MP)] were tested. For controls, cells were directly plated on culture dishes (CD). Each test membrane was secured to the bottom of a culture dish with a double-sided adhesive tape. All samples were triplicate. At 1.5 and 24 h after plating of 2 ml (5 x 10(4) cells/ml) of MC3T3-E1 (passage 7) cells, the specimens were rinsed with phosphate-buffered saline to wash out any unattached cells and then fixed with a 10% buffered formalin solution for 1 d. After washing with distilled water, the cells were stained with hematoxylin. The number of attached cells was counted under a light microscope equipped with an ocular-micrometer in a unit area of 0.25 mm(2) (five areas on each membrane). In addition, cell morphology attached to the membranes was evaluated under scanning electron microscope. RESULTS: Data were presented as mean +/- standard error and analyzed for statistical difference using a generalized Wilcoxon's test. Cell attachment at 1.5 h was as follows: MP (27.5 +/- 2.1) > RL (17.0 +/- 1.4) approximately equals BM (14.5 +/- 1.4) approximately equals EG (11.4 +/- 1.0) > GD (5.2 +/- 0.8) approximately equals GT (3.1 +/- 0.6); and at 24 h was: MP (67.6 +/- 3.6) > RL (35.8 +/- 1.8) > BM (15.4 +/- 0.9) approximately equals EG (13.3 +/- 1.3) > GD (5.9 +/- 0.7) approximately equals GT (5.6 +/- 1.3). At 24 h, the scanning electron microscope finding revealed that cells attached on MP, RL, BM and EG were flatter in shape, like cells on CD, than cells on GD and GT, where cells were rather round. CONCLUSIONS: Results from this study suggested that MP, BM, RL and EG enhanced the early osteoblast attachment. However, the true benefit of this observation in clinic remains to be determined.
3T3 Cells↗
[Effect of direct current on bone regeneration].
The data on bone biocurrent and on the bone regenerating effect of low intensity direct current are discussed. The stimulator constructed by the authors is described. With its help an improved callus formation could be achieved on the osteotanised femur of the rabbit.
Animals↗
Three-dimensional evaluation for augmented bone using guided bone regeneration.
OBJECTIVE: This study evaluated new bone regeneration beyond the skeletal envelope within an occlusive titanium cap on rabbit calvaria using microfocus computed tomography images. METHODS: In 10 rabbits, the calvaria was exposed and a circular groove was prepared. After penetrating the marrow, a standard hemispherical titanium cap was placed in the groove and covered with a cutaneous flap. After 1 or 3 months, the animals were killed and the calvariae and titanium caps were dissected. After taking microfocus computed tomography images of the specimens, histological sections were made. The specimens were observed using three-dimensional images constructed from the microfocus computed tomography images, and the histological sections were examined to compute bone parameters. RESULTS: The three-dimensional images and histological specimens showed that new bone formed in flat, cup-like, and dome shapes. The bone parameters trabecular thickness and the proportion of marrow space to the capacity of the titanium cap increased, whereas bone density decreased, and there were significant differences between the 1- and 3-month groups. DISCUSSION: First, a cylinder of new bone formed from the existing bone. Gradually, bone formed along the cap wall and the new tissue formed in a crater indented centrally. Finally, the new tissue formed in the shape of a dome. CONCLUSION: Trabecular bone formed along the wall of the titanium cap, and bone filled the inside of the cap within 3 months.
Animals↗
Comparison of BMP-2 and -4 for rat mandibular bone regeneration at various doses.
OBJECTIVE: To compare mandibular bone regeneration with bone morphogenetic proteins-2 and -4 (BMP-2 and -4) at varying doses. STUDY DESIGN: Defects were created in the left hemi-mandibles of 82 Sprague-Dawley rats. The defects were filled with a hyaluronic acid polymer loaded with 0.01, 0.1, 1, or 10 microg of BMP-2 or -4. Control groups consisted of animals with unfilled defects, or with defects filled with the hyaluronic acid sponges loaded with growth factor dilution buffer. Animals were killed after 8 weeks, and the hemi-mandibles were analyzed histologically using stereologic techniques. RESULTS: Mandibles implanted with carriers containing 10 microg of BMP-2 or -4 differed significantly from controls in terms of new bone area (p = 0.01 and p = 0.0001, respectively). Marrow space development occurred in a dose-dependent fashion (p < 0.0001 for both growth factors), and this effect was more pronounced for BMP-2 at larger doses (p < 0.0001 at 1 and 10 microg doses). New bone areas and volumes did not differ significantly between the growth factors. While defects implanted with BMP-4 tended to have thicker cortical bone and more trabecular bone, at least partial defect bridging was achieved in a greater number of defects implanted with BMP-2 (47%) than with BMP-4 (35%). CONCLUSION: Although similar areas and volumes of new bone were induced with BMP-2 and -4, differences were noted in the quality of bone generated with each growth factor. The results indicate a threshold dose for acute administration between 1 and 10 mug BMP-2 for bony union in this model, and > or =10 microg for BMP-4. SIGNIFICANCE: These findings suggest that differences in bone growth factor osteogenic potential deserve further study and may have an impact on the translation of osteoinductive protein therapy into clinical practice.
Analysis of Variance↗
Critical aspects of tissue-engineered therapy for bone regeneration.
Recent advances in bone tissue engineering are established on the understanding of an engineered scaffold, the molecular milieu within the osteogenic site, and the cell(s) predisposed to an osteogenic lineage. Advances in the incorporation of a generative vehicle into a skeletal defect require temporal and spatial distribution of the scaffold, growth factor, and cell compatible with enhanced bone healing. Monitoring events culminating in osteogenesis has focused on phenotypic and intracellular indicators. Phenotypic and intracellular indicators include the presence of receptors and intracellular signals that enable cell proliferation and differentiation. Progress in the areas of scaffold design, growth factor utilization, bone cell lineage, and intracellular signaling are reviewed.
Animals↗
Presence of interleukin-4-producing cells for human bone regeneration after application of guided tissue regeneration membranes.
To study the process of bone regeneration we examined three samples of periapical regenerative tissue obtained from two patients under a guided tissue regeneration treatment in endodontic surgery by the immunohistochemical and enzyme histochemical methods. The regenerative tissue consisted of a large number of fibroblast-like cells and a small number of mononuclear cells. Fibroblast-like cells stained positively for alkaline phosphatase and osteopontin, whereas mononuclear cells stained positively for CD4. Interleukin-4-producing cells could be detected in adjacent sections. However, interferon-y-producing cells could not be detected. These findings suggest that interleukin-4-producing cells may be one of the elements associated with success in the human bone regeneration process in vivo.
Adult↗
Bone regeneration with resorbable polymeric membranes. III. Effect of poly(L-lactide) membrane pore size on the bone healing process in large defects.
Poly(L-lactide) membranes of various pore sizes: microporous, medium pore size (10-20 microns), and large pore size (20-200 microns) were implanted in 15 mature New Zealand female rabbits to cover a 10-mm diaphyseal defect created in the radius. Five rabbits were implanted with each membrane. No internal fixation was used, as it was assumed that the intact ulna splints the radius adequately. Postoperative radiographs revealed the formation of hematoma within the bone defect. At the 2nd week after surgery, the hematoma was resorbed and the formation of new bone was noted radiologically either at the ends of the bone fragments or as osteophytes on the proximal and distal edges of the membrane. At 4 weeks, the newly formed bone was growing centripetally from the fragment ends. The bone regeneration took place in the majority of the cases under investigation, regardless of the pore size of the polymeric membranes used. There were, however, some differences in the intensity of the bone regeneration process. Although at 2 weeks after surgery bone formation was seen radiographically in all animals, at 6 months five rabbits of five, four rabbits of five, and three rabbits of five implanted respectively with microporous membrane, medium pore-size membrane, and large pore-size membrane showed complete regeneration of bone within the defects. It is suggested that the primary function of the membrane used to cover bone defects is to preserve the osteogenic components present in the space under the membrane from escaping and support the growth of cells within the "medullary cavity" formed by the tubular implant.
Animals↗