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PubMed2006

Osteogenic potential using a malleable, biodegradable composite added traditional Chinese medicine: in vitro and in vivo evaluations.

The purpose of this investigation was to prepare and evaluate the feasibility and biocompatibility of a new composite as a large defect bone substitute. The new GTGG was mainly composed of tricalcium phosphate ceramic particles and glutaraldehyde crosslinked gelatin in which Gui-Lu-Jiao was added (a mixture of Cervi Colla Cornus and Colla Plastri Testudinis). In the in vitro study, rat's calvaria osteoblasts were used to study bone characteristics upon exposure to different concentrations of the Gui-Lu-Jiao solution. In the in vivo study, GTGG composites were implanted into the defects of calvarial bones in mature New Zealand rabbits to test their osteogenerative characteristics. As a result, we found that Gui-Lu-Jiao added to the culture could promote the proliferation of osteoblasts. In addition, GTGG could induce a large amount of new bone growth in the rabbit's calvarial bone defect. Therefore, the GTGG composite might be a potential bone substitute.

Alkaline Phosphatase↗
PubMed1999

Osteogenic potential in vitro of human bone marrow cells cultured on macroporous biphasic calcium phosphate ceramic.

Calcium phosphate ceramics are synthetic bone substitutes that promote bone formation by osteoconduction. However, they have shown an osteogenic potential in vivo in animal models when associated with bone marrow cells. In order to develop an osteogenic human "hybrid material," we studied the in vitro osteogenic potential of human bone marrow cells cultured on macroporous biphasic calcium phosphate (BCP) pellets in the presence of dexamethasone with or without 1alpha,25 dihydroxyvitamin D3. We were examining, in particular, their mesenchymal stem cell proliferation and hematopoietic potential. Osteogenic differentiation was evaluated in terms of alkaline phosphatase activity and immunological characterization of the extracellular matrix formed by these cells. The specimens were observed by scanning and transmission electron microscopy. Human mesenchymal stem cells proliferated on macroporous BCP ceramic, with a doubling time delayed at the beginning of the culture as compared to the cultures realized on plastic. These cells maintained a hematopoietic activity identical to that of cultures performed in plastic wells. The proliferating mesenchymal stem cells expressed an osteoblastic phenotype, as shown by alkaline phosphatase activity and the synthesis in ceramic macropores of an extracellular matrix composed of fibronectin, osteocalcin, and collagen I (but not collagen III). In addition, numerous microcrystals of apatite precipitated on the extracellular matrix, producing a mineralized fibrillar network within the ceramic not observed with cell cultures realized on plastic. These results demonstrate that human mesenchymal stem cells cultured on macroporous BCP ceramic express and conserve their osteoblastic phenotype even after one month of culture and that these osteogenic cells are able to form new bone matrix in a BCP ceramic in vitro.

Biocompatible Materials↗
PubMed2005

The vertebral interbody grafting site's low concentration in osteogenic progenitors can greatly benefit from addition of iliac crest bone marrow.

The ability of bone substitutes to promote bone fusion is contingent upon the presence of osteoinductive factors in the bone environment at the fusion site. Osteoblast progenitor cells are among these environmental osteoinductive factors, and one of the most abundant and available sources of osteoblastic cells is the bone marrow. As far as biological conditions are concerned, the vertebral interbody space appears as a favorable site for fusion, as it is surrounded by spongy bone, theoretically rich in osteogenic cells. This site may, however, not be as rich in osteogenic precursor cells especially at the time of grafting, because decortication of the vertebral end plates during the grafting process may modify cell content of the surrounding spongy bone. We tested this hypothesis by comparing the abundance of human osteogenic precursor cells in bone marrow derived from the iliac crest, the vertebral body, and the decorticated intervertebral body space. The number of potential osteoblast progenitors in each site was estimated by counting the alkaline phosphatase-expressing colony-forming units (CFU-AP). The results, however, demonstrate that the vertebral interbody space is actually poorer in osteoprogenitor cells than the iliac crest (P<0.001) and vertebral body (P<0.01), especially at the time of graft implantation. In light of our results, we advocate addition of iliac crest bone marrow aspirate to increase the success rate of vertebral interbody fusion.

Adult↗
PubMed1999

Bone banking. Update on methods and materials.

Bone allografts are being used in increasing numbers by orthopedic surgeons, yet many surgeons are unfamiliar with their preparation and processing, as well as their use as safe and effective transplants. This article reviews current sources of bone allografts, new methods of processing to achieve optimal results, the biology of incorporation of allografts, and new bone substitutes.

Biology↗
PubMed2001

Treatment of the unstable distal radius fracture with external fixation and a hydroxyapatite spacer.

A prospective study was performed on 25 patients (15 women, 10 men) with unstable fractures of the distal radius selectively treated with a dynamic type of external fixation combined with a hydroxyapatite spacer. The fractures ranged from type VI to type VIII according to Frykman's classification. The patients' mean age at surgery was 49 years (range, 19-75 years). The mean follow-up period was 2.5 years, and overall outcome was assessed using Gartland and Werley's demerit point system as modified by Sarmiento. Radial inclination was 26 degrees +/- 4 degrees at the time of reduction and 26 degrees +/- 5 degrees at follow-up, palmar tilt was 9 degrees +/- 2 degrees at reduction and 8 degrees +/- 3 degrees at follow-up, and ulnar variance was 1.4 +/- 0.6 mm at reduction and 2.1 +/- 0.9 mm at follow-up. The mean range of motion at follow-up was 80 degrees +/- 10 degrees in flexion, 80 degrees +/- 10 degrees in extension, 85 degrees +/- 10 degrees in supination, and 80 degrees +/- 5 degrees in pronation. The outcome in 24 of 25 patients was evaluated as excellent. In the surgical treatment of unstable fractures of the distal radius using external fixator, the fracture reduction should be supported with bone graft or a bone substitute, and a hydroxyapatite spacer was considered to be a useful substitute for a bone graft.

Adult↗
PubMed1996

Complications of iliac crest bone graft harvesting.

Autologous bone grafts harvested from the iliac crest are commonly used in reconstructive orthopaedic surgery. Autologous bone is used to help promote bone healing in fractures and to provide structural support for reconstructive surgery. The results of autologous bone grafting are more predictable than the use of xenografts, cadaveric allografts, or synthetic bone substitutes because autologous bone grafts provide osteoinductive and osteoconductive properties, are not immunogenic, and are usually well incorporated into the graft site. In a retrospective review of 414 consecutive cases of iliac crest bone graft procedures performed at Brooke Army Medical Center from 1983 to 1993, 41 (10%) minor and 24 (5.8%) major complications were identified. Minor complications included superficial infections, superficial seromas, and minor hematomas. Major complications included herniation of abdominal contents through massive bone graft donor sites, vascular injuries, deep infections at the donor site, neurologic injuries, deep hematoma formation requiring surgical intervention, and iliac wing fractures. Harvesting of iliac crest bone graft can be associated with significant morbidity. However, with adequate preoperative planning and proper surgical technique, the incidence of these complications can be reduced.

Blood Vessels↗
PubMed1993

[In vitro toxicity tests of bioceramics and bone transplants in fibroblast culture].

Prior to the clinical use of synthetic bone substitutes and allogenic bone transplants, potential toxicity resulting from various different manufacturing, storage, and sterilisation techniques should be excluded. In order to develop a reliable and reproducible in vitro model for the investigation of possible tissue reactions after implantation of biomaterials, we modified an established animal fibroblast culture technique used to test chemical agents for acute unspecific cytotoxicity. Subcultivation of human fibroblasts produces stable monolayer cultures with the aid of which, standardised, accurate and reproducible evaluation of toxic effects, as well as the direct visualisation of fibroblast ingrowth into porous implant material, is possible. Gamma-irradiated synthetic implants and bovine hydroxyapatite failed to show any substantial cytotoxicity. In contrast, ethylene oxide sterilised implant material, as well as fresh untreated trabecular bone showed a significant toxic effect in comparison with cryopreserved and autoclaved trabecular bone.

Animals↗
PubMed2005

Basic reactions of osteoblasts on structured material surfaces.

In order to assess how bone substitute materials determine bone formation in vivo it is useful to understand the mechanisms of the material surface/tissue interaction on a cellular level. Artificial materials are used in two applications, as biomaterials alone or as a scaffold for osteoblasts in a tissue engineering approach. Recently, many efforts have been undertaken to improve bone regeneration by the use of structured material surfaces. In vitro studies of bone cell responses to artificial materials are the basic tool to determine these interactions. Surface properties of materials surfaces as well as biophysical constraints at the biomaterial surface are of major importance since these features will direct the cell responses. Studies on osteoblastlike cell reactivity towards materials will have to focus on the different steps of protein and cell reactions towards defined surface properties. The introduction of new techniques allows nowadays the fabrication of materials with ordered surface structures. This paper gives a review of present knowledge on the various stages of osteoblast reactions on material surfaces, focused on basic cell events under in vitro conditions. Special emphasis is given to cellular reactions towards ordered nano-sized topographies.

Biocompatible Materials↗
PubMed1994

Experimental investigation of bone regeneration using Pyrost in animals.

A study was undertaken to investigate bone regeneration in guinea pig mandibles implanted with Pyrost in comparison with artificial bone defects as controls. Bone defects were prepared in the angles of mandibles of 30 guinea pigs. The findings demonstrated that this bone substitute material stimulated bone healing, i.e. bone regeneration, in comparison with empty control cavities. Bone regeneration and new bone formation were found to be more extensive in Pyrost-implanted areas than in controls.

Animals↗
PubMed1992

New developments in synthetic bone replacement materials.

Synthetic bone replacement materials continue to be much discussed in the current periodontal literature. Numerous reports have shown their clinical use in the treatment of intraosseous defects. Periodontal treatment aims also include regeneration of a new functional attachment. Although histologic studies have shown that most of the synthetic bone substitutes can enhance bone formation, they are not able to promote new attachment of periodontal tissues to the root surface previously exposed. Future studies are needed to assess whether these materials could be of use together with growth factors in composite grafts or in conjunction with guided tissue regeneration techniques.

Alveolar Bone Loss↗
PubMed1997

Long-term outcome of extensive skull reconstruction using demineralized perforated bone in Siamese twins joined at the skull vertex.

The successful use of cortical demineralized perforated bone in the treatment of extensive skeletal defects in children is exemplified by this case involving Siamese twins joined at the skull vertex. Four years following extensive skull reconstruction using demineralized perforated bone, an examination revealed successful calvarial reconstruction in one twin. The other twin required additional implants of demineralized perforated bone to fill in defects. However, a histologic examination taken following this additional procedure revealed that these implants neither caused tissue reaction over a 4-year period, nor showed signs of resorption. Bony remodeling and new bone formation were in progress. Compared with other bone substitutes, demineralized perforated bone has proven to be effective in the treatment of large skull defects in children.

Bone Demineralization Technique↗
PubMed1996

In vitro backscattering from implant materials during radiotherapy.

It is a certainty that many of the patients now receiving dental implants will one day require radiotherapy if they have head and neck cancer. The purpose of this study was to examine the dose enhancement form backscattered radiation at implant/bone interfaces irradiated with high-energy 6 MV and 10 MV x-rays. Three commonly used implant materials, pure titanium, Ti-6A1-4V alloy, and a high gold content implant material of various thicknesses, were used to measure the dose enhancement caused by backscattered radiation. The relative ionization charges at implant/bone interfaces were measured at distances of 0, 1, 2, and 3 mm away from the implant material by insertion of 0, 1, 2, and 3 mm thick bone substitute disks between the implant material and an ionization chamber. The results indicated that the highest dose enhancement occurred at a distance of 0 mm from the implant/bone interface for all the materials studied. The Au-Cu-Ag implant material had more average relative dose than pure titanium or Ti-6A1-4V alloy. The backscattered electrons decreased as the thickness of the bone substitute (distance between the implant material and the ionization chamber) increased.

Alloys↗
PubMed1989

Porous hydroxyapatite as an onlay bone-graft substitute for maxillofacial surgery.

This paper chronicles 3 years of a continuing study comparing porous hydroxyapatite to autogenous bone grafts as onlays in maxillofacial surgery. Twenty-five patients, seen from June of 1984 to May of 1985, underwent onlay augmentation on various maxillary and mandibular locations. A total of 68 onlay augmentation sites comparing Interpore porous hydroxyapatite and autogenous bone were followed for 2 years or more. This long-term study compares these substances in radiologic longevity, histologic incorporation, clinical function, and aesthetic appearance.

Adolescent↗
PubMed1998

[Powdered eggshell in the repair of cystic cavities of the jaw. Preliminary study].

This paper is a clinical report on the use of eggshell as a bone substitute in oral surgery. Five volunteers who presented with a cystic cavity of the jaw with a mean size of 2 x 1 cm, were enrolled in the study. After enucleation of the cyst, the cavity was packed with eggshell powder. The results were assessed by clinical examination and repeated radiological examination at 2, 4, and 6 weeks. Two operative sites were checked at 2 months for histological examination. Clinically, the eggshell implants were very well tolerated. In 3 out of 5 patients, a progressive opacification of the cavities with a centripetal ossification occurred within 6 weeks. In one patient, a generalized resorption was noticed. Histological examination confirmed that eggshell powder was not osteoinductive, but it enhanced the bone regeneration from the margins. In conclusions, eggshell powder is a worth-while bone substitute because it is a safe and easily available material. However, only a modest beneficial effect can be expected on bone regeneration.

Adult↗
PubMed2002

[Tibial valgus osteotomy using a tricalcium phosphate medial wedge: a minimally invasive technique].

PURPOSE OF THE STUDY: We present a minimally invasive technique for tibial valgus osteotomy using a medial wedge composed of tricalcium phosphate. MATERIAL AND METHODS: The bone substitute is composed of slowly resorbable tricalcium phosphate material shaped to the desired form and having mechanical properties allowing stable osteotomy via a short incision and staple fixation. Intraoperative fluoroscopy enables a reliable and reproducible technique. A lateral fixation staple is required because there is a risk the lateral hinge could break. This technique was used for 58 knees in 55 patients (mean age 47 years). According to the Ahlback classification of femorotibial degeneration, there were 43 grade I knees, 12 grade II, and 3 grade III. RESULTS: The implant was well tolerated in all cases. Bone healing was achieved in most cases without loss of the osteotomy angle. Complications were: rupture of the lateral hinge in four cases leading to nonunion in one, one low-grade infection. Implant resorption at mid term was significant: among the 22 patients with a follow-up of more than 5 years, the implant was barely visible in 18. DISCUSSION: This technique provides an easy way to achieve tibial valgus osteotomy without compromising future intervention. The technique can be considered to be minimally invasive because of the size of the incision, the minimal fixation required, and the bone sparing effect of the bone substitute.

Adult↗
PubMed2004

A biomimetic gelatin-calcium phosphate bone cement.

The interest in new bone substitutes is rapidly increasing in the field of orthopedic surgery. A variety of calcium phosphate bone cement has been developed and different additives have been used to improve their biocompatibility and bioactivity. Following a biomimetic strategy aimed at reproducing bone characteristics, this study investigates the biological properties of a new gelatin enriched calcium phosphate cement (GEL-CP) that exhibits improved mechanical properties with respect to cement prepared without gelatin (C-CP). Human osteoblast MG63 were cultured on the surfaces of GEL-CP and were compared to cells cultured on C-CP samples, and on polystyrene of plate culture as control (C). Cell attachment, proliferation and differentiation were evaluated up to 21 days. SEM revealed that osteoblasts grown on GEL-CP showed a normal morphology and biological tests demonstrated very good rate of proliferation and viability in every experimental time. The presence of gelatin stimulated alkaline phosphatase activity, collagen and transforming growth factor 31 production. The data indicate that the new cement GEL-CP favors osteoblast proliferation, activation of their metabolism and differentiation. The remarkable improvement of the setting properties of the calcium phosphate cement due to the presence of gelatin suggest that the biomimetic composite material could be successfully applied as bone substitute.

Alkaline Phosphatase↗
PubMed1992

Fibrillar collagen-biphasic calcium phosphate composite as a bone graft substitute for spinal fusion.

The osteoconductive capacity of fibrillar collagen-biphasic calcium phosphate composition was compared to autogenous bone in a canine spinal fusion model. All animals underwent a standard intervertebral body fusion (L2-L4) with rigid internal fixation and received either autogenous bone alone or a mixture of the ceramic and autogenous bone (3:1) as the graft material. Animals were followed for 12 months and the quality of fusion in each animal assessed by biomechanical testing and histological analysis. The fused L2-L4 segment of each dog was embedded in bone cement and mounted in a specially designed mechanical tester for testing in flexion, extension, and side bending. Overall, the mean rigidity of the fusion mass was not significantly different between the two groups [10.5 +/- 4.1 (SD) for autogenous bone vs. 11.3 +/- 1.7 for the ceramic plus autogenous bone, p greater than 0.05]. Similar findings were obtained for mean bending moment, compressive load, angular deformation, and energy absorbed for the two groups. Histological analysis was performed on transverse nondecalcified specimens. Quantitation of bone ingrowth using back-scattered electron imaging disclosed no significant differences in the amount of new bone formed at the graft site between autogenous bone and the ceramic plus autogenous bone recipients (23.4 +/- 10% vs. 25.8 +/- 8.8%) when correction for the autogenous bone volumes was performed. Light microscopic analysis of toluidine blue-stained transverse sections demonstrated new bone growth around and through the ceramic bone graft material. These results suggest that use of a collagen-biphasic calcium phosphate ceramic and autogenous bone mixture (3:1) provides a suitable osteoconductive alternative to the use of autogenous bone and results in the formation of a mechanically competent fusion mass not significantly different from that obtained with autogenous bone alone.

Animals↗
PubMed2001

Immunoglobulin enhances the bioactive-glass-induced chemiluminescence response of human polymorphonuclear leukocytes.

Bioactive glasses are bone substitutes that chemically bind to bone. Implanted materials always elicit a response from surrounding tissues and thereby can activate inflammatory cells, with subsequent release of biomaterial and tissue-damaging agents. Bioactive glasses can activate polymorphonuclear leukocytes (PMNL) and induce a release of reactive oxygen metabolites (ROM). Adsorption of proteins on the surface of the implanted material may influence the subsequent inflammatory cell response. The effect of Sandoglobulin(R) (SG) and albumin on the ROM release by PMNLs induced by a bioactive glass was studied by a chemiluminescence (CL) assay. An enhanced effect for SG and inhibitory effect for albumin on the CL response of PMNLs was observable. The CL response of the PMNLs was dependent on the incubation time of the glass in solution.

Bone Substitutes↗