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At least 235 records · Page 13Linked to original sources
PubMed2003

Porous polymethylmethacrylate as bone substitute in the craniofacial area.

In craniofacial surgery, alloplastic materials are used for correcting bony defects. Porous polymethylmethacrylate (PMMA) is a biocompatible and nondegradable bone cement. Porous PMMA is formed by the classic bone cement formulation of methylmethacrylate liquid and PMMA powder in which an aqueous biodegradable carboxymethylcellulose gel is dispersed to create pores in the cement when cured. Pores give bone the opportunity to grow in, resulting in a better fixation of the prostheses. We evaluated the long-term results (n = 14), up to 20 years, of augmentations and defect fillings in the craniofacial area, with special interest in possible side effects and bone ingrowth. The evaluation consisted of a questionnaire, a physical examination, and a computed tomography (CT) scan. There were no side effects that could be ascribed to the porous PMMA. Twelve CT scans showed bone ingrowth into the prostheses, proving the validity behind the concept of porous PMMA.

Biocompatible Materials↗
PubMed2004

Biodegradation and biocompatability of a calcium sulphate-hydroxyapatite bone substitute.

An injectable material consisting of calcium sulphate mixed with hydroxyapatite was investigated as a possible alternative to autograft in the restoration of bone defects. The material was studied both in vitro in simulated body fluid (SBF) and in vivo when implanted in rat muscles and into the proximal tibiae of rabbits. Variation in the strength and weight of the material during ageing in SBF was measured. Tissue response, material resorption and bone ingrowth were studied in the animal models. A good tissue response was observed in both the rat muscles and rabbit tibiae without inflammatory reactions or the presence of fibrous tissue. Ageing in SBF showed that during the first week carbonated hydroxyapatite precipitated on the surfaces of the material and this may enhance bone ingrowth.

Animals↗
PubMed2001

Coralline hydroxyapatite as bone substitute in orthopedic oncology.

We retrospectively reviewed the results of 71 consecutive patients managed with coralline hydroxyapatite (Pro-Osteon 500; Interpore Cross International) for bone defects produced as a result of surgical extirpation of bone tumors. All patients underwent a thorough physical examination and a radiographic evaluation at baseline and follow-up by the same senior surgeon (R.B.I.). Seventy-one patients were followed up for an average of 2.4 years (range, 8.1 months to 3.5 years); mean age of female patients was 39.8 years and that of male patients was 30 years. The functional status of patients at follow-up was evaluated based on comparison with preoperative functional status. Radiographic evaluation was performed and graded as follows: stage I (obvious margins), stage II (hazy margins), and stage III (obvious incorporation). The average time of return of preoperative function was 7.6 weeks. There were 3 major and 9 minor complications. We conclude that coralline hydroxyapatite graft in the form of Pro-Osteon 500 is a viable option for the management of bone defects in orthopedic oncology.

Adolescent↗
PubMed2000

Osseointegration of subperiosteal implants using bovine bone substitute and various membranes.

An earlier study revealed incomplete osseointegration of individually made titanium subperiosteal implants covered by ePTFE membranes and fixated to the rabbit tibial bone surface. In addition, the newly-formed bone was dominated by large marrow spaces. In this subsequent study, subperiosteal implants were also fixated on the bone surface of both tibia of 9 Copenhagen White rabbits. Bio-Oss particles were packed densely covering the entire implant surface. One of 3 different membranes covered the implant and the particles. The membranes used were the degradable Polyglactin 910 mesh, a degradable bilayer collagen membrane and the non-degradable ePTFE membrane. Undecalcified sections were prepared for histologic evaluation after a 12 weeks' observation period. All 18 subperiosteal implants were completely osseointegrated. In addition, the marrow spaces were reduced compared to our previous study. The Bio-Oss particles proved to be biocompatible and osteoconductive. The ePTFE membranes revealed neither signs of collapse nor adjacent infiltration of inflammatory cells. The Polyglactin 910 mesh and the bilayer collagen membranes collapsed slightly. There were signs of resorption of the surface of the newly-formed bone under the degradable membranes. The cause of resorption can not be documented.

Animals↗
PubMed2005

Clinical and histological study of a xenogenic bone substitute used as a filler in postextractive alveolus.

AIM: The development of oral implant techniques and the demand for the treatment of increasingly complex cases have drawn the attention of researchers and clinicians towards those systems and materials able to promote bone regeneration. The aim of this paper is to evaluate the clinical behavior and in particular the resorption times of the material used as a filler in postextractive alveolus with the intent of preserving the ridge volume, a prerequisite for successive insertion of osteointegrated fixtures. METHODS: A group of 12 patients, aged between 30-40 years, have been selected at the Oral Surgery Unit of the San Giovanni Calibita Hospital in Rome. They all required an endosseous implant following the loss of a dental element due to radicular fracture of periodontal pathology. The grafting material used is OsteoBiol Putty, an antigen-free bone paste composed of 80% granulated mix and 20% pure collagen. RESULTS: The results emerging from the histological analysis show that 3 months after insertion of this osteoconductive material in the receiving site it can no longer be detected in the samples collected and it has been completely substituted by trabecular bone tissue. CONCLUSIONS: The conclusion is drawn that the heterologous material used in this study shows excellent manageability allowing the operator to easily and accurately remove and shape it in the receiving site.

Adult↗
PubMed1985

Comparative study of porous hydroxyapatite and tricalcium phosphate as bone substitute.

This study was performed to quantitate the bone ingrowth and biodegradability of porous calcium phosphate. Two kinds of coralline hydroxyapatite (CHA), along with sintered tricalcium phosphate (TCP), were evaluated. All implants had totally interconnecting pores. These pores measured 260-600 mu for CHA-Goniopora (CHAG), 190-230 microns for CHA-Porites (CHAP), and 100-300 microns for TCP. Cylindrical implants (3 mm in diameter by 8 mm in length) were implanted into the diaphyses of rabbit tibias for 3 to 24 weeks. The quantity of regenerated bone, remaining implant, nonmineralized space, and the middle two quarters of the cortical area were measured by a computerized operator-assisted analysis for bone histomorphometry. At 3 weeks after implantation, 17.3% of CHAG, 11.3% of CHAP, and 7.0% of TCP were infiltrated by regenerated bone. At 24 weeks, 56.1% of CHAG, 52.7% of CHAP, and 44.7% of TCP were occupied by lamellar-type bone. Implant degradation was noted to be 46.4% for TCP and 27.5% for CHAP. In contrast, CHAG did not show appreciable degradation until 24 weeks.

Animals↗
PubMed1999

Ostrich eggshell as a bone substitute: a preliminary report of its biological behaviour in animals--a possibility in facial reconstructive surgery.

The aim of this study was to assess the biological behaviour of an implant of ostrich eggshell in various animal models of facial bone reconstruction. The implant was first bioassayed in a rat muscle pouch (n=10), and then tested as an interpositional graft in rat (n=10) and rabbit (n=5) cranial defects. It was finally used as an onlay graft on rabbit mandibles (n=5). Animals were killed after two months in the bioassay, three months in the interpositional model, and six months in the onlay model. The specimens were studied by contact radiography and standard histological techniques. All animals showed normal wound-healing. In the bioassay, the implants produced only a minimal inflammatory reaction. In the interpositional model, the implants maintained a good contour, but there was no sign of graft-remodelling. In the onlay model, the grafts were stable and partly osteointegrated. The onlay graft model gave the most promising results. Because ostrich eggshell is inexpensive and has good mechanical properties, it deserves further study. Long-term studies will clarify its possible role in maxillofacial surgery.

Animals↗
PubMed2002

Bone substitutes as carriers for transforming growth factor-beta(1) (TGF-beta(1)).

We studied the suitability of three different hydroxyapatite materials (Endobone, Bio-Oss and Algipore) as carriers for the bone growth promoting factor TGF-beta(1). The hydroxyapatite materials either were incubated for 24 h or directly loaded with hrTGF-beta(1) (Diagnostic Products Corporation, DPC) at a concentration of 10 ng hrTGF-beta(1)/mg. For the release experiment the hydroxyapatite materials covered with hrTGF-beta(1) were either suspended in pure phosphate buffered saline (PBS) or human serum albumin (HSA). The concentration of hrTGF-beta(1) was measured every 6 h the first day and then daily at the 2nd, 7th, 14th and 28th day. With Bio-Oss and Endobone the release of growth factor in HSA showed a two-phase kinetics. TGF-beta(1) reached a maximum concentration within the first 24 h and decreased almost linearly until day 28. With Algipore the concentration of growth factor reached a maximum after 12 h and showed a rapid decline until day 2. From day 2 the TGF-beta(1) concentrations remained low. Significantly, more TGF-beta(1) was released into HSA than into PBS. Our study suggests that the hydroxyapatite materials are suitable as TGF-beta(1) carriers.

Biocompatible Materials↗
PubMed2002

[Gel derived bioactive ceramic as bone substitute--an in vivo study].

The paper presents the histopathological and radiological study performed on a series of male, mixed-race rabbits. All rabbits had a 20 x 4 x 4 mm-bone fragment extracted from the radial bone according to a modified technique by Scmitt and Weller. In the right radius bone the bone defect was filled with approximately 0.5 cm3 bioglass S2. In the left rius, which served as control, allogenic bone graft (the size of the defect) collected from the tibia and femur was implanted. Rabbits were sacrificed 3, 6 and 12 weeks after the procedure and histopathological and radiological studies were performed. These studies revealed a heterogeneous increase of new bone regeneration in all three phases of the study. The S2 biomaterial both stimulated and accelerated bone regeneration in the rabbits.

Animals↗
PubMedDate not supplied

[The impact of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF) on osseointegration, degradation and biomechanical properties of a synthetic bone substitute].

INTRODUCTION: It was the purpose of this investigation to test the osteointegrative capacity and the degradation rate of a neutralized glass ceramic within an animal model after loading with different growth factors. MATERIALS AND METHODS: The glass ceramic GB9N was implanted in the medial tibial head of mature merino sheep (n = 48) after being loaded with either Bone Morphogenetic Protein-2 (BMP-2, 100 micro g/100 micro l), Vascular Endothelial Growth Factor (VEGF, 100 micro g/100 micro l), basic Fibroblast Growth Factor (b-FGF, 60 micro g/100 micro l) or unloaded. At 4 weeks (n = 24) and 9 months (n = 24) after operation histomorphological, histomorphometrical and biomechanical investigations were performed. RESULTS: The amount of newly formed bone was different within the study groups after 4 weeks. BMP-2 induced a significant increase in bone formation and a significant decrease of residual substitute. b-FGF and VEGF induced no such effects in comparison to the controls. Biomechanical investigations could only demonstrate slight increases of the maximal fracture load in the BMP-2 group after 4 weeks in comparison to the others. At 9 months after operation no differences concerning newly formed bone could be found in the study groups comparing to the controls. Only the amount of residual substitute was still significantly lower in the BMP-2 group. Biomechanical data could demonstrate maximal fracture loads of all study samples achieving the level of the controls. CONCLUSION: This investigation has demonstrated that by combining synthetic bone substitutes with growth factors certain parameters of the bone remodelling process can intitially be influenced in a positive way.

Animals↗
PubMed1994

Bone substitute with osteoinductive biomaterials--current and future clinical applications.

In craniomaxillofacial surgery, possible indications for the use of osteo-inductive biomaterials are interposition in intraosseous defects, contour augmentation, and reconstruction of segmental defects. The experimental results in the field of bone morphogenetic protein (BMP) research within the last few years have shown that it is possible to combine osteoinductive proteins with suitable carrier materials to obtain new composite osteoinductive biomaterials. These carrier materials function as slow-delivery systems for BMP. By combination of BMP with different carrier materials such as various types of calcium phosphate ceramics, collagen or inactive collagenous bone matrix, and other organic and inorganic carriers, the biomaterial can be adapted to clinical demands in a wide range. In several experimental animal studies, we investigated nine different calcium phosphate ceramics and inactive rat bone matrix for their use as BMP carrier. All materials tested seem to be suitable carriers for BMP. The first clinical applications are discussed.

Animals↗