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 523 records · Page 29Linked to original sources
PubMed2003

Rabbit calvarial wound healing by means of seeded Caprotite scaffolds.

Autologous bone is the most successful bone-grafting material; however, limited supply and donor site morbidity are problematic. Synthetic bone substitutes are effective, but healing is slow and unpredictable. Osseous wound healing may be enhanced if bone substitutes are combined with autologous bone marrow cells. To test this hypothesis, we created 40 calvarial defects in 20 12-week-old New Zealand White rabbits, divided into four groups: (1) unrepaired controls, (2) autologous bone grafts, (3) unseeded Caprotite (a polymer-ceramic composite) grafts, and (4) Caprotite grafts seeded with autologous bone marrow stromal cells. CT scans were obtained at 0, 6, and 12 weeks post-operatively, and defects were harvested for histology. Defects repaired with autologous bone had significantly (p < 0.05) more bone than the other three groups, although seeded Caprotite defects showed different wound-healing sequelae. Results suggest that seeded Caprotite scaffolds did not significantly enhance osseous defect healing compared with controls.

Absorbable Implants↗
PubMed2000

Biology of lumbar spine fusion and use of bone graft substitutes: present, future, and next generation.

Posterolateral lumbar spine arthrodesis is a commonly performed procedure, yet the biology of healing is poorly understood. Nonunion, or failure to achieve a solid bony fusion, occurs in up to 40% of patients. We first developed and validated a rabbit model to characterize the healing process by measuring macroscopic parameters, microscopic parameters, and gene expression. We found that presently available osteoconductive and weakly osteoinductive materials were insufficient to replace autografts, but could in some cases serve as bone graft extenders. In contrast, two osteoinductive growth factors currently in development could replace autograft in non-human primates and in humans, but may be limited by the high dose required, carrier variability, and high cost. We identified, cloned, and sequenced a novel complementary DNA (cDNA) encoding for an intracellular protein LMP-1, which is expressed during the first few hours of osteoblast differentiation. LMP-1 expression is able to induce many BMPs, their receptors, and other bone growth factors. Local implantation of bone marrow cells transfected with LMP-1 cDNA induced spine fusion in 100% of sites tested; no bone formed at the control sites without LMP-1. This strategy of local gene therapy may provide a basis for the next generation of bone graft substitutes.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Analysis of the risk of transmitting bovine spongiform encephalopathy through bone grafts derived from bovine bone.

Bone substitutes of bovine origin are widely used for treatment of bone defects in dental and orthopedic surgery. Due to the occurrence of BSE and the new variant of Creutzfeldt Jakob Disease risks of transmitting diseases through the use of such materials need to be carefully evaluated. Risk analysis can either be based on theoretical assessments or experimental evidence. Here we present a comparative study on two bovine bone substitutes (Bio-Oss and Osteograf/N) which is based on theoretical values. Furthermore, for one of these materials, i.e. Bio-Oss, the prion inactivation capacity of one of the production steps was experimentally evaluated. Theoretical and experimental data indicate that the use of these materials does not carry a risk of transmitting BSE to patients.

Animals↗
PubMed2005

Hydroxyapatite cement in pediatric craniofacial reconstruction.

The gold standard for closing small cranial defects is autogenous bone: iliac crest, rib, or split calvarial grafts. Autogenous grafts result in donor site morbidity, increased operative time, blood loss, and additional cost, and they are limited in quantity. Hydroxyapatite cements are alternative bone substitutes that eliminate these restrictions. Although the use of hydroxyapatite is well accepted in completely developed crania, its use in the growing pediatric skull is limited. The purpose of the current study was to address the safety and long-term efficacy of this bone substitute for the repair of craniofacial bone defects in the growing pediatric skull. Safety is measured dually by resistance of bone substitute to infection and its tolerability by lack of a foreign body reaction. Efficacy is evaluated as structural skull integrity, volume stability with time, aesthetic quality, and most importantly, the ability to integrate adequately into a growing cranium without subsequent deformity or complications. This is a retrospective review of all pediatric patients at the authors' institution who underwent reconstruction of cranial defects using hydroxyapatite cement between May 1997 and March 2001. Eight patients who underwent 11 operations between the ages of 25 and 100 months (mean, 55 months) were followed up between 23 and 72 months (mean, 38 months). No mortalities or significant morbidities were encountered in the study population. It has been the authors' experience that hydroxyapatite cement is both biocompatible and resistant to infection when used in sites not contiguous with sinus mucosa; and that it is a good alternative to autogenous bone in pediatric craniofacial reconstruction.

Biocompatible Materials↗
PubMed1997

Repair of bone defect in primate mandible using a bone morphogenetic protein (BMP)-hydroxyapatite-collagen composite.

The purpose of this study was to evaluate a hydroxyapatite (HA)-collagen (Col)-bone morphogenetic protein (BMP) composite as an osteoinductive bone substitute. Partially-purified BMP from bovine bone was mechanically mixed with highly purified type I collagen from calf dermis and then subsequently mixed with pure synthetic hydroxyapatite granules or block. The HA-Col-BMP composite, or the HA-Col composite as a control, was implanted in a surgically-induced mandible bone defect (6 x 7 x 10 mm) in an adult Japanese monkey. The mandible was excised three months after implantation and studied histologically. The BMP-containing implant induced much more new bone than the control implant in all experimental animals of each group, with either HA granules or HA block. Newly formed bone was attached tightly to HA and infiltrated deeply into the pores of the HA of the BMP-containing implant, while fibrous tissue existed between the host bone and HA in the control implant. Thus, we conclude that an HA-Col-BMP composite could be a superior biomaterial for a bone substitute.

Animals↗
PubMed2003

Growth factor releasing porous poly (epsilon-caprolactone)-chitosan matrices for enhanced bone regenerative therapy.

Drug releasing porous poly(epsilon-caprolactone) (PCL)-chitosan matrices were fabricated for bone regenerative therapy. Porous matrices made of biodegradable polymers have been playing a crucial role as bone substitutes and as tissue-engineered scaffolds in bone regenerative therapy. The matrices provided mechanical support for the developing tissue and enhanced tissue formation by releasing active agent in controlled manner. Chitosan was employed to enhance hydrophilicity and biocompatibility of the PCL matrices. PDGF-BB was incorporated into PCL-chitosan matrices to induce enhanced bone regeneration efficacy. PCL-chitosan matrices retained a porous structure with a 100-200 microm pore diameter that was suitable for cellular migration and osteoid ingrowth. NaHCO3 as a porogen was incorporated 5% ratio to polymer weight to form highly porous scaffolds. PDGF-BB was released from PCL-chitosan matrices maintaining therapeutic concentration for 4 week. High osteoblasts attachment level and proliferation was observed from PCL-chitosan matrices. Scanning electron microscopic examination indicated that cultured osteoblasts showed round form and spread pseudopods after 1 day and showed broad cytoplasmic extension after 14 days. PCL-chitosan matrices promoted bone regeneration and PDGF-BB loaded matrices obtained enhanced bone formation in rat calvarial defect. These results suggested that the PDGF-BB releasing PCL-chitosan porous matrices may be potentially used as tissue engineering scaffolds or bone substitutes with high bone regenerative efficacy.

Animals↗
PubMed2005

MBCP biphasic calcium phosphate granules and tissucol fibrin sealant in rabbit femoral defects: the effect of fibrin on bone ingrowth.

An ageing population implies an increase in bone and dental diseases, which are in turn a source of numerous handicaps. These pathologies are an expensive burden for the European health system. As no specific bioactive materials are efficient enough to cope with this burden, we have to develop an injectable, mouldable, self-hardening bone substitute to support bone tissue reconstruction and augmentation. New, highly bioactive and suitable biomaterials have been developed to replace bone grafts in orthopedic revision and maxillofacial surgery for bone augmentation. These mouldable, self-hardening materials are based on the association of MBCP Biphasic Calcium Phosphate Granules and Tissucol Fibrin Sealant. The in vivo evaluation of ingrowth in relation to the composite was made in an experiment on rabbits. The results indicate that in the presence of fibrin sealant, newly-formed bone developed at a small distance from the surface of the calcium phosphate ceramic. Two different bone apposition processes were identified. Without the fibrin component (MBCP group), bone rested directly on the surface of the granules. This observation is commonly described as osteoconduction in calcium phosphate materials. On the contrary, the presence of the fibrinogen component seemed to modify this standard osteoconduction phenomenon: the newly-formed bone essentially grew at a distance from the surface of the granules, on the fibrillar network, and could be considered as an inductive phenomenon for osteogenic cell differentiation from mesenchymal stem cells.

Animals↗
PubMed2005

In vivo bone regeneration with injectable calcium phosphate biomaterial: a three-dimensional micro-computed tomographic, biomechanical and SEM study.

This in vivo study investigated the efficiency of an injectable calcium phosphate bone substitute (IBS) for bone regenerative procedures through non-destructive three-dimensional (3D) micro-tomographic (microCT) imaging, biomechanical testing with a non-destructive micro-indentation technique and 2D scanning electron microscopy (SEM) analysis. The injectable biomaterial was obtained by mixing a biphasic calcium phosphate (BCP) ceramic mineral phase and a cellulosic polymer. The BCP particles were 200-500 microm or 80-200 microm in diameter. The injectable material was implanted for 6 weeks into critical-sized bone defects at the distal end of rabbit femurs. Extensive new bone apposition was noted with both 2D and 3D techniques. Micro-CT showed that newly formed bone was in perfect continuity with the trabecular host bone structure and demonstrated the high interconnectivity of the restored bone network. For both IBS formulations, SEM and microCT gave very close measurements. The only detected significant difference concerned the amount of newly formed bone obtained with IBS 80-200 that appeared significantly higher with microCT analysis than with SEM (p=0.00007). Student t-tests did not show any significant difference in the amount of newly formed bone and remaining ceramic obtained from microCT analysis or SEM. Regression analysis showed satisfactory correlation between both the amount of newly formed bone and remaining ceramic obtained from microCT or SEM. For IBS 200-500, the newly formed bone rate inside the defect was 28.0+/-5.2% with SEM and yield strength of the samples was 18.8+/-5.4 MPa. For IBS 80-200, the newly formed bone rate inside the defect was 31.7+/-5.1% with SEM and yield strength of the samples was 26.8+/-4.5 MPa. Yield strength appeared well correlated with the amount of newly formed bone, specially observed with microCT. This study showed the ability of non-destructive techniques to investigate biological and mechanical aspects of bone replacement with injectable biomaterials.

Animals↗
PubMed2006

The modulation of gene expression in osteoblasts by thrombin coated on biphasic calcium phosphate ceramic.

For many years, fibrin sealants were associated with bone substitutes to promote bone healing. However, the osteoblastic response to fibrin sealant components remains poorly documented. In this study, MC3T3-E1 osteoblastic cells were cultured on biphasic calcium phosphate ceramic (MBCP) coated with Tissucol components (thrombin and fibrinogen). Analysis of osteoblastic differentiation markers by RT-PCR revealed that MBCP coated with Tissucol stimulated mRNA levels for osteocalcin and alkaline phosphatase (ALP). Of all the components of Tissucol, thrombin has been reported to affect osteoblastic behavior. Our results demonstrated that low thrombin concentrations (0.5-5 U/ml) stimulated mRNA levels for ALP, whereas high thrombin concentrations (50-100 U/ml) decreased mRNA levels for ALP and PTH/PTHrP receptor and also increased mRNA level for the osteoclastogenesis inhibitor OPG. As thrombin stimulated angiogenesis, we then wondered whether thrombin could influence the expression of angiogenic factors. Low thrombin concentrations were shown to up-regulate mRNA levels for VEGF-B and VEGF-R1, suggesting an autocrine/paracrine role for VEGF-B. Higher thrombin concentrations also up-regulated mRNA for VEGF-A and neuropilin-1. In conclusion, the association of MBCP with thrombin and fibrinogen appears to be a convenient scaffold for bone cell differentiation. Thrombin could also acts at the cellular level by increasing the angiogenic potential of osteoblasts as well as their responsiveness to thrombin and VEGF.

Animals↗
PubMed1999

Osteoconductive materials and their role as substitutes for autogenous bone grafts.

The term osteoconduction applies to a three-dimensional process that is observed when porous structures are implanted into or adjacent to bone. Capillaries, perivascular tissues, and osteoprogenitor cells migrate into porous spaces and incorporate the porous structure with newly formed bone. The observed process is characterized by an initial ingrowth of fibrovascular tissue that invades the porous structure followed by the later development of new bone applied directly within it. This article reviews observations of commonly used osteoconductive matrices to increase understanding of this process.

Biocompatible Materials↗
PubMed2003

Treatment of angular bone defects with a composite bone grafting material in combination with a collagen membrane.

BACKGROUND: The purpose of this study was to evaluate the effect of a bioabsorbable collagen barrier (CB) in combination with a composite bone substitute (deproteinized bovine bone mineral with collagen, DBBM + C) in periodontal regeneration of angular bone defects in humans using a new application technique. METHODS: Twelve patients participated, each contributing at least 1 defect site, which exhibited a probing depth (PD) of > or = 5 mm, a clinical attachment level (CAL) of > or = 6 mm, and was positive for bleeding on probing (BOP) following initial therapy. Twenty-two angular bone defects were filled with DBBM + C. A hole was placed in the membrane, which was then pulled over the tooth. The observation period was 2 years and included measurements of plaque, gingivitis, tooth mobility, PD, CAL, soft tissue recession, and bone level as assessed from standardized radiographs. RESULTS: The residual PD and CAL were reduced to 3.3 mm (PD) and 5.6 mm (CAL) with a CAL gain of 3.2 mm at 24 months. The radiographic defect reduction (bone fill) was 4.0 mm after surgery and 2.2 mm at 24 months. The changes measured clinically and radiographically were more pronounced in sites with a deep intrabony defect component than in sites with shallow ones. CONCLUSIONS: These findings indicate that angular bone defects can be successfully treated with DBBM + C in combination with CB. A degradation of the filler material seems to occur particularly during the first 6 months, but without affecting the clinical parameters, which improved consistently.

Absorbable Implants↗
PubMed2001

[Experimental study in rabbit on repair of radial bone defect by bioactive degradable polymer].

OBJECTIVE: To investigate the availability of bone defect repair by degradable porous polycaprolactam (PCL) as the carrier of bone morphogenetic protein (BMP). METHODS: Three different kinds of bone substitutes, including decalcified bone matrix, PCL-BMP compounds and simple PCL, were implanted into the radial bone defects in 36 rabbits, and in the other 12 rabbits the bone defects were left untreated as control. X-ray examination, X-ray morphometry, histological and electron microscopic observation were performed at different time after operation. RESULTS: The quantity of new bone formation in PCL-BMP group was prior to that in simple PCL group. The pattern and speed of bone defect repair in PCL-BMP group were similar to those in decalcified bone matrix. Electron microscopic observation showed that the PCL-BMP group degraded faster than simple PCL group, which was more suitable for bone repair. CONCLUSION: PCL is a good carrier of BMP with potential for clinical use.

Animals↗
PubMed1996

Formation of apatite-collagen complexes.

An apatite-collagen complex was prepared in calcium beta-glycerophosphate solutions at pH 9.0 and 37 degrees C with the purpose of developing new bone substitutes that more closely resemble bone than currently available materials. Reconstituted type I collagen as well as sheet collagen were crosslinked in the presence of alkaline phosphatase and egg-yolk phosvitin. The crosslinked collagens were immersed in daily-renewed calcium beta-glycerophosphate solutions for 2 and 4 weeks to induce the deposition of apatite on the collagen fibers. After 2 weeks of reaction, for example, apatites deposited approximately two times the crosslinked collagen in weight. With reconstituted collagen, the complex showed some elasticity but no apatite was visually observed to detach under deformation with fingers and forceps. The complex, moreover, did not disintegrate when immersed in saline or animal blood. Nevertheless, the complex resorbed with no evidence of cytotoxicity when implanted in muscle tissues. These findings suggest that the apatite-collagen complex prepared would be useful as bone substitutes, especially for periodontal osseous lesion repair and alveolar ridge augmentation.

Alkaline Phosphatase↗
PubMed1988

Madreporic coral: a new bone graft substitute for cranial surgery.

Since 1985, the authors have been using madreporic coral fragments (genera Porites) as a bone graft substitute. Of the 167 coral grafts implanted, 150 were coral "corks" used to obliterate burr holes (diameter 10 mm), five were large implants (length 20 to 40 mm) to repair skull defects, and 12 were coral blocks to reconstruct the floor of the anterior cranial fossa. Previous experimental studies suggested that coral grafts would be well tolerated and become partially reossified as the calcific skeleton was resorbed. The authors describe their experience and detail the main biological properties of these materials, which appear to be very promising for use in cranial reconstructive surgery.

Animals↗