Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bone Substitutes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed2005

The in vitro growth and activity of sheep osteoblasts on three-dimensional scaffolds from poly(L/DL-lactide) 80/20%.

Critical-size bone defects usually require the use of autogenous bone grafts to heal. Harvesting of bone is traumatic, and results in high morbidity of donor site. A potential alternative to bone graft may be a bone substitute with adequate biocompatibility and biological properties produced from ceramics and/or bioresorbable or biodegradable polymers. In the present study, sheep osteoblasts isolated from cancellous bone chips were seeded and cultured for 1, 2, and 3 weeks on porous poly(L/DL-lactide) 80/20% scaffolds. The cell morphology was assessed from rhodamine staining and scanning electron microscopy, cell growth, and activity from the measurements of DNA, alkaline phosphatase activity, and total protein amount in the cell lysate, and mineral deposits from EDAX and van Kossa staining. The cells attached firmly to the scaffold walls, grew deeply into the pores, and exhibited morphology typical of osteoblasts. Mineralized noduli with a Ca/P ratio of 1.4 to 1.8 found in the scaffold indicated that the cells had maintained their osteoblastic phenotype. The amount of DNA, alkaline phosphatase activity, and the total amount of proteins increased with time of culturing, although at 3 weeks the cells did not yet reach the contact inhibition. These results demonstrate that three-dimensional porous poly(L/DL-lactide) 80/20% scaffolds provide a suitable substrate for the attachment and growth of primary osteoblasts, and might potentially be used as bone defect fillers and in the design of tissue-engineered bone substitutes.

Animals↗
PubMed2003

Novel bioactive materials with different mechanical properties.

Some ceramics, such as Bioglass, sintered hydroxyapatite, and glass-ceramic A-W, spontaneously bond to living bone. They are called bioactive materials and are already clinically used as important bone substitutes. However, compared with human cortical bone, they have lower fracture toughness and higher elastic moduli. Therefore, it is desirable to develop bioactive materials with improved mechanical properties. All the bioactive materials mentioned above form a bone-like apatite layer on their surfaces in the living body, and bond to bone through this apatite layer. The formation of bone-like apatite on artificial material is induced by functional groups, such as Si-OH, Ti-OH, Zr-OH, Nb-OH, Ta-OH, -COOH, and PO(4)H(2). These groups have specific structures revealing negatively charge, and induce apatite formation via formations of an amorphous calcium compound, e.g., calcium silicate, calcium titanate, and amorphous calcium phosphate. These fundamental findings provide methods for preparing new bioactive materials with different mechanical properties. Tough bioactive materials can be prepared by the chemical treatment of metals and ceramics that have high fracture toughness, e.g., by the NaOH and heat treatments of titanium metal, titanium alloys, and tantalum metal, and by H(3)PO(4) treatment of tetragonal zirconia. Soft bioactive materials can be synthesized by the sol-gel process, in which the bioactive silica or titania is polymerized with a flexible polymer, such as polydimethylsiloxane or polytetramethyloxide, at the molecular level to form an inorganic-organic nano-hybrid. The biomimetic process has been used to deposit nano-sized bone-like apatite on fine polymer fibers, which were textured into a three-dimensional knit framework. This strategy is expected to ultimately lead to bioactive composites that have a bone-like structure and, hence, bone-like mechanical properties.

Animals↗
PubMedDate not supplied

Compressive strength of calcium carbonate and hydroxyapatite implants after bone-marrow-induced osteogenesis.

Natural coral and structurally similar porous hydroxyapatite (HA) have been used as bone substitutes. They are not osteoinductive but bone formation can be induced by marrow cells, even in extraosseal sites. In our previous study we induced bone formation in porous coral and HA after having implanted the materials in intramuscular pockets in rat. New bone formed only in HA or coral implants soaked with marrow cells; fibrous tissue ingrowth alone was observed in the controls (without marrow). In the present study we examined the effect of tissue ingrowth on the mechanical properties of coral and HA implants obtained in a similar process to that used before. At 12 weeks the compressive strength of HA was higher in the marrow group than in the controls; it was also higher than that of the wet unimplanted material. The HA blocks did not show resorption. Coral resorbed quickly and lost its compressive strength, which was originally higher than in HA. At three weeks the marrow group was stronger than the control specimens. After six weeks only the marrow group, but not the controls, could be tested. Bone ingrowth seemed to maintain the strength of the coral implant even if it was dissolving. The mechanical strength of both materials was comparable to that of cancellous bone.

Animals↗
PubMed2003

Enhancement of osseointegration of implants placed into extraction sockets of healthy and periodontally diseased teeth by using graft material, an ePTFE membrane, or a combination.

BACKGROUND: Advanced periodontal disease as well as failed endodontic teeth are the most common reasons for tooth removal and simultaneous implant placement. PURPOSE: To determine whether the addition of a bone substitute graft material and/or a guided bone regeneration membrane added to the site of an immediately placed implant would increase the development of lamellated bone, particularly in the presence of bone defects. MATERIALS AND METHODS: Four treatment modalities associated with the immediate placement of hydroxyapatite-coated endosteal screw implants into extraction sockets of healthy (C/H) and periodontally diseased teeth (T/PD) were tested. Five dogs with healthy teeth and five dogs with naturally occurring periodontitis were chosen for the study. Each dog received eight implants after extraction of four mandibular and four maxillary premolars. Four implants were submerged for 3 months and four for 6 months. The implants were either inserted alone (subgroup A); surrounded by a GORE-TEX membrane (subgroup B; W.L. Gore & Associates Inc., Flagstaff, AZ, USA); surrounded by PepGen P-15 (Dentsply Friadent CeraMed Dental Co. Denver, CO, USA) at coronal area (subgroup C); or surrounded by a combination of graft material and the ePTFE membrane (subgroup D). Implants in group A were osseointegrated in both C/H and T/PD groups with similar bone-implant contact ratios (BICRs). RESULTS: ePTFE membrane significantly improved the BICR of the 6-months implants, whereas graft material significantly increased the BICR at 3 months and maintained the gain thereafter. The graft material and membrane combination further improved the BICR and significantly increased lamellated bone in crestal bone of all implants. CONCLUSIONS: This study provides experimental evidence in support of use of graft material with immediately placed implants, particularly in presence of bone defects that initially reduce the BICR such as in periodontitis. Adding an ePTFE membrane to graft material resulted in a greater replacement of woven bone by lamellated bone. Clinical trials in humans are recommended as a follow-up of this experimental study.

Analysis of Variance↗
PubMed2003

Use of a resorbable hydroxyapatite-collagen chondroitin sulfate material on immediate postextraction sites: a clinical and histologic study.

This study looked at a bone-substitute biomaterial (Biostite) used to fill bone defects around immediate implants in humans. Ninety-six peri-implant bone defects were treated without the use of membranes, comparing two groups: group A = filling the defect with Biostite, and group B = no defect fill. After 4 to 6 months of healing, group A revealed higher percentages of implants covered by new, bone-like tissue (67% in group A, 34% in group B). Endochondral osteogenesis was demonstrated histologically in the regenerated tissues in alveolar sites treated, allowing the hypothesis of bone induction from the filling material used.

Absorbable Implants↗
PubMed1997

Mechanical properties of carbonated apatite bone mineral substitute: strength, fracture and fatigue behaviour.

The synthesis and properties of carbonated apatite materials have received considerable attention due to their importance for medical and dental applications. Such apatites closely resemble the mineral phase of bone, exhibiting superior osteoconductive and osteogenic properties. When formed at physiological temperature they present significant potential for bone repair and fracture fixation. The present study investigates the mechanical properties of a carbonated apatite cancellous bone cement. Flexural strength was measured in three and four point bending, and the fracture toughness and fatigue crack-growth behaviour was measured using chevron and disc-shaped compact tension specimens. The average flexural strength was found to be approximately 0.468 MPa, and the fracture toughness was approximately 0.14 MPa radical m. Fatigue crack-growth rates exhibited a power law dependence on the applied stress intensity range with a crack growth exponent m=17. The fatigue threshold value was found to be approximately 0.085 MPa radical m. The mechanical properties exhibited by the carbonated apatite were found to be similar to those of other brittle cellular foams. Toughness values and fatigue crack-growth thresholds were compared to other brittle foams, bone and ceramic materials. Implications for structural integrity and longer term reliability are discussed.

Journal Article↗
PubMed1992

Experimental study on osteoconductive properties of a chitosan-bonded hydroxyapatite self-hardening paste.

A developmental bone substitute, composed of a chitosan-bonded hydroxyapatite paste and having various possible applications in medical and dental treatments, was evaluated with regard to its osteoconductive properties. Radiographic examination revealed that a bone-like irregular radiopacity appeared in the region of the embedded paste. This was judged histopathologically as the formation of bone tissue with chondral tissue. These data suggest that the paste has osteoconductive properties, and may, therefore, prove clinically useful as a bioactive bone substitute.

Animals↗
PubMed2006

[Bridging posttraumatic bony defects. Established and new methods].

Bony defects as a result of injury or disease can be caused by a variety of conditions such as acute injury, fall fractures in osteoporotic patients or tumours and congenital malformations of the musculoskeletal system which necessitate the resection of affected parts of the bone. This results in a multitude of defects concerning localisation and specificity as well as a number of conditions involving both hard and soft tissue structures and various situations of different patients. A reasonable classification of defects which is relevant for practical purposes includes four basic types: defects of the spine, metaphyseal defects as well as partial and complete diaphyseal defects of long bones. A variety of options exists for the treatment of these conditions. The aim of all efforts is to reinstall the integrity of affected structures long-lastingly and dependably and at the same time guarantee the normal function of joints involved. In addition to classical treatment strategies which involve the use of autogenous and allogenous corticocancellous bone grafts a great number of bone substitute materials can also be used. Further options lie in complex reconstructive methods such as the transport of whole segments or the transplantation of vascularised bone grafts. The field of new regenerative strategies including tissue engineering as well as stem cell and gene therapy holds great promise for the future. The aim of this review is to derive a ranking from the evaluation of biological and mechanical characteristics for the treatment of posttraumatic defects.

Bone Morphogenetic Proteins↗
PubMed1999

Autogenous masticatory mucosal grafts in extraction socket seal procedures: a comparison between sockets grafted with demineralized freeze-dried bone and deproteinized bovine bone mineral.

Successful preservation of the edentulous ridge after extractions may eliminate or reduce the need for ridge augmentation procedures. It has been claimed that grafting fresh extraction sockets and sealing them with autogenous soft tissue grafts promote ridge preservation after tooth extraction. In this study, the survival of free autogenous connective tissue grafts sealing extraction sites was evaluated. In 24 healthy patients, 42 maxillary anterior teeth were extracted. After socket debridement, soft tissue margins of the socket orifice were carefully cut to remove epithelial debris, Sockets were filled with either demineralized freeze-dried bone allografts (DFDBA) or deproteinized natural bovine bone mineral xenograft (DBBMX) to the level of the alveolar bone crest. Circular connective tissue grafts, slightly larger in diameter than the soft tissue socket orifice, were obtained and placed on top of the filler graft material sealing the sockets. Grafts were stabilized and secured by sutures and inspected weekly for the first month. The grafts were classified into 3 groups according to clinical parameters: vital, partially vital and non-vital. After 1 week, 18 grafts were vital, 13 partially vital and 11 non-vital. When only 1 sample unit (1 site per patient) was compared between DFDBA and DBBMX grafted sockets, no significant difference in graft vitality was shown (P = 0.34 for vital; P = 0.67 for vital plus partially vital). After 1 month, all socket orifices were sealed with mucosa. Based on the present observations, it seems that connective tissue grafts sealing fresh extraction sites are mainly dependent on underlying tissue vascularization and that sealing grafted fresh extraction sockets filled with bone substitute allograft or xenograft materials may be beneficial but an unpredictable procedure.

Adolescent↗
PubMed1991

Interaction of allogeneic demineralized bone matrix and porous hydroxyapatite bioceramics in lumbar interbody fusion in rabbits.

Bone repair by autograft is effective in clinical practice. However, serious problems arise when a considerable volume of transplant is needed, as with spinal fusion procedures. The use of bone substitutes combined with osteoinductive agents may contribute to the solution of such problems. In this study, the effectiveness of such a procedure was tested in an experimental model of interbody fusion in rabbits in which the incorporation of a porous hydroxyapatite block (HA) was enhanced by the addition of allogeneic demineralized bone matrix (DBM). The latter was used as a delivery system for the osteoinductive activity of the bone morphogenetic protein contained in the matrix. A group implanted with combined HA + DBM showed significantly earlier stabilization of the fusion when compared to groups implanted with DBM alone, HA alone, and bone autografts. On the other hand, the general results of the fusion with HA + DBM were superimposable on those of autografts. With further research, the combination of a bone substitute and an osteoinductive agent may constitute an alternative to the use of bone autografts.

Animals↗
PubMed2006

Quantitative assessment of growth factors in reaming aspirate, iliac crest, and platelet preparation.

Large bony defects and non-unions are still a complication in trauma and orthopedic surgery. Treatment strategies include the use of autogenous materials (iliac crest), allogenic bone, bone substitutes, and currently stimulation with growth factors such as BMP-2, BMP-7 or the growth factors containing platelet-rich plasma (PRP). Another source of bone graft material might be the cuttings produced during intramedullary reaming. The aim of this study was to compare the quantity of various growth factors found within iliac crest, bony reaming debris, reaming irrigation fluid, and platelet-rich plasma. Iliac crest and reaming debris and irrigation samples were harvested during surgery. PRP was prepared from blood. The growth factors in the bony materials (iliac crest or reaming debris) and of the liquid materials (platelet-poor plasma (PPP), platelet-rich plasma (PRP) or reaming irrigation) were compared. Elevated levels of FGFa, PDGF, IGF-I, TGF-beta1 and BMP-2 were measured in the reaming debris as compared to iliac crest curettings. However, VEGF and FGFb were significantly lower in the reaming debris than from iliac crest samples. In comparing PRP and PPP all detectable growth factors, except IGF-I, were enhanced in the platelet-rich plasma. In the reaming irrigation FGFa (no measurable value in the PRP) and FGFb were higher, but VEGF, PDGF, IGF-I, TGF-beta1 and BMP-2 were lower compared to PRP. BMP-4 was not measurable in any sample. The bony reaming debris is a rich source of growth factors with a content comparable to that from iliac crest. The irrigation fluid from the reaming also contains growth factors.

Adult↗
PubMed1998

Morphology of peri-implant regenerated bone, in sheep's tibia, by means of guided tissue regeneration.

BACKGROUND: No data on the resistance to functional loads of bone regenerated by means of guided tissue regeneration, can be found. In this paper the new-formed bone is analyzed, in cases that see the surgical creation of defects in testing animals. The morphological aspects of perimplant bone, regenerated by means of bone substitutes or not, were evaluated. METHODS: A coronal defect was created by means of a counter-sink bur. The following step provided for osseointegrated fixtures, with a machined or blasted (TiOblast) surface, to be installed. Some bone defects were filled with Bio-Oss, and covered with resorbable membrane (Vycril), others were left unfilled. The animals were sacrificed after different periods of time (24 and 45 days). Some thick sections (200 microns) underwent then microradiography and were examined with a microscope, under transmitted and polarized light. Other sections, thin (5 microns), were coloured with toluidine blue, Gomori's Stain and Solochrome Cyanine/Congo red. RESULTS: Data confirm the excellent behaviour of bovine bone and of TiO blasted fixtures. The experimental results bring into evidence that, in cases of Guided Bone Regeneration (GBR) by means of membrane, the use of fixtures with a blasted surface (TiOblast), and of Bio-Oss as bone substitute, made osseointegration easier. CONCLUSIONS: Results, moreover, suggest that in case of implant surgery with GBR, in order to allow the maturation of regenerated bone, it's healing time must be prolonged.

Animals↗
PubMed2005

[Bone harvesting from the iliac crest].

BACKGROUND: Autogenous bone grafts from the iliac crest are frequently harvested for autologous bone transplantation. Although an autologous bone transplant does improve the local bone healing potency, significant donor site morbidity must be considered. METHODS: In this study we elucidate special bone harvesting techniques from the iliac crest and review the literature related to clinical significance of donor site morbidity. Furthermore, our own experiences are compared and discussed critically with relevant data of other investigators. RESULTS: The increasing number of scientific publications which focus on bone harvesting techniques and related complications in recent years indicate the high interest and relevance of this issue. There is a tendency to alternatives such as biomaterials as bone substitutes, whereas the role of growth factors and cell therapeutics in the treatment of bony defects are still being evaluated in clinical studies. CONCLUSION: Although autologous, heterotopic bone transplantation is still the gold standard in the treatment of bony defects, there is a tendency towards the application of biomaterials, stem cells, and growth factors. Conscientious observation of relevant anatomic considerations during bone harvesting procedures may help to avoid complications.

Adolescent↗
PubMed2004

Metallic materials stimulating bone formation.

Metallic materials implanted into bone defects are generally encapsulated by a fibrous tissue. Some metallic materials such as titanium and tantalum, however, have been revealed to bond to the living bone without forming the fibrous tissue, when they were subjected to NaOH solution and heat treatments. Thus treated metals form bone tissue around them even in muscle, when they take a porous form. This kind of osteoconductive and osteoinductive properties are attributed to sodium titanate or tantalate layer on their surfaces formed by the NaOH and heat treatments. These layers induce the deposition of bonelike apatite on the surface of the metals in the living body. This kind of bioactive metals are useful as bone substitutes even highly loaded portions, such as hip joint, spine and tooth root.

Alloys↗
PubMed2005

Rabbit pilot study on the resorbability of three-dimensional bioactive glass fibre scaffolds.

Bioactive glass composed of Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2 is used in this study to manufacture three-dimensional glass fibre scaffolds for a synthetic bone filler material for the treatment of bone defects. The glass is characterized by a large working range, which is the temperature interval at which forming of glass can take place. A preliminary in vivo study on New Zealand skeletally mature rabbit's tibia is reported here. Bone defects were prepared in the medial surfaces of the diaphyses of the tibia. For the first time melt derived three-dimensional bioactive glass fibre constructs were used to fill the cavities. The different implants investigated here were a scaffold with a porosity of 45-50%, scaffold with a porosity of 55-60% and morsels with a porosity of 55-60%. The implanted bone substitutes were dissected after 6 months and evaluated by histological and synchrotron radiation micro tomography analysis. PerioGlas and empty defects were used as positive and negative controls, respectively. The result was that the surgically created tibial defects were healed and new bone formation was found in the medullary cavities. Despite the intrinsic limitations of a pilot study, the preliminary results indicate that in 6 months the glass fibre scaffolds are completely resorbed and that the osteoconductive properties of the filling material are strictly correlated with the structural and morphological characteristics of the bone substitute.

Animals↗
PubMed2002

Mechanical and chemical characteristics of mineral produced by basic fibroblast growth factor-treated bone marrow stromal cells in vitro.

It has been shown that various organ and cell cultures exhibit increased mineral formation with the addition of basic fibroblast growth factor (bFGF) and phosphate ions in the medium. However, to date there has been no attempt to relate the chemical composition of mineral formed in vitro to a measure of its mechanical properties. This information is important for understanding the in vivo mineralization process, the development of in vitro models, and the design of tissue-engineered bone substitutes. In this study we examined the reduced modulus; hardness; and mineral-to-matrix, crystallinity, carbonate-to-mineral, and calcium-to-phosphorus ratios of mineral formed by bFGF-treated rat-derived bone marrow stromal cells in vitro. The cells were treated with 1 or 3 mM beta-glycerophosphate for 3 and 4 weeks. Both mechanical parameters, reduced modulus and hardness, increased with increasing beta-glycerophosphate concentration. The only chemical measure of the mineral composition that exhibited the same dependency was the mineral-to-matrix ratio. The values of crystallinity and carbonate fraction were similar to those for intact cortical bone, but the calcium-to-phosphorus ratio was substantially lower than that of normal bone. These data indicate that the mineral formed by bFGF-treated bone cells is mechanically and chemically different from naturally formed lamellar bone tissue after 4 weeks in culture. These results can be used to improve in vitro models of mineral formation as well as enhance the design of tissue-engineered bone substitutes.

Animals↗
PubMed2004

Effect of rapidly resorbable calcium phosphates and a calcium phosphate bone cement on the expression of bone-related genes and proteins in vitro.

The use of biodegradable bone substitutes is advantageous for alveolar ridge augmentation because it avoids second-site surgery for autograft harvesting. This study examines the effect of novel, rapidly resorbable calcium phosphates and a calcium phosphate bone cement on the expression of bone-related genes and proteins by human bone-derived cells (HBDCs) and compares this behavior to that of tricalciumphosphate (TCP). Test materials were alpha-TCP, two materials with a crystalline phase Ca(2)KNa(PO(4))(2) and with a small amorphous portion containing either magnesium potassium phosphate (material denominated GB14) or silica phosphate (material denominated GB9), and a calcium phosphate bone cement (material denominated Biocement D). HBDCs were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for various mRNAs and proteins (type I collagen, osteocalcin, osteopontin, osteonectin, alkaline phosphatase, and bone sialoprotein). All substrates supported continuous cellular growth for 21 days. In the presence of GB14 and Biocement D specimens cell proliferation was reduced and cell differentiation increased. At day 21, the greatest number of cells was found on GB9 expressing significantly higher levels of bone-related proteins than cells grown on all other surfaces. Because all novel materials facilitated the expression of the osteoblastic phenotype at least as much as TCP and the polystyrene control, these biomaterials can be regarded as excellent candidate bone substitute materials. GB9 induced the highest proliferation and cellular differentiation after 21 days of incubation, suggesting that this material may possess a higher potency for enhancing osteogenesis than TCP.

Adolescent↗
PubMed2000

Secondary craniofacial surgery for trauma.

Injuries to the face may leave long-term defects with both aesthetic and functional consequences. This holds true especially when treatment is delayed, inadequate, or absent altogether. The wide spectrum of posttraumatic deformities leaves the surgeon with a formidable challenge of reestablishing harmonious facial contour and proper function of each craniofacial unit. Camouflage techniques may be used to correct minor deformities whereas osteotomies and repositioning of segments are needed for more complex problems. Bone replacement is often required as part of the treatment. Although autograft bone is the gold standard, bone substitutes can provide acceptable results. This article focuses on posttraumatic defects of the fronto-orbital region as well as those involving occlusion. Basic principles applying to facial harmony, bone healing and grafting, dental occlusion, and surgical correction specific to each region are discussed.

Bone Substitutes↗