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PubMed2003

Osteoblasts response to allogenic and xenogenic solvent dehydrated cancellous bone in vitro.

The present in vitro study investigates the cellular interaction of primary human osteoblasts with human and bovine solvent dehydrated cancellous bone (SDCB) discs. These are bio-implants from solvent dehydrated, gamma-irradiated preserved human and bovine cancellous bone, pre-treated to remove all cells, genetic components and water soluble proteins. Primary human osteoblasts were harvested from cancellous chips of trauma patients undergoing osteosynthesis with bone grafting from the iliac crest. All patients provided informed consent. The present investigation tested proliferation, synthesis of phenotypic marker, and morphology of primary cultured human osteoblasts on SDCB in vitro. The total protein and collagen type 1 content could not be revealed, due to the inherent naturally occurring protein content in these two bio-implants. In conclusion, our in vitro results suggest that SDCB may be a suitable bone substitute which provides a well structured and biocompatible scaffold for ingrowing human osteoblasts.

Animals↗
PubMed1990

[The use of coral in bone surgery. Results following 4 years of utilization].

The authors have used Porites coral as a bone substitute in more than 200 patients since 1985, initially for reconstruction after craniotomy or removal of graft from the iliac crest. Encouraging results have prompted wider use. No complications have occurred. The biological properties of coral are described. It is easily available and appears to be a promising bone substitute.

Calcium Carbonate↗
PubMed2005

In vitro behavior of a porous TiO2/perlite composite and its surface modification with fibronectin.

In this study, we introduce a porous composite material, termed "Ecopore", and describe in vitro investigation of the material and its modification with fibronectin. The material is a sintered compound of rutile TiO2 and the volcanic silicate perlite with a macrostructure of interconnecting pores. It is both inexpensive and easy to manufacture. We first investigated Ecopore for corrosion and leaching of elements in physiological saline. The corrosion supernatants did not contain critical concentrations of toxic trace elements. In an in vitro model, human primary osteoblasts (HOB) were cultured directly on Ecopore. HOB grew on the composite as well as on samples of its single constituents, TiO2 and perlite glass, and remained vital, but cellular spreading was less than on tissue culture plastic. The pro-inflammatory cytokines IL-1 and TNF-alpha were below detection limits in HOB culture supernatants, whereas IL-6 was detectable on a low level. To enhance cellular attachment and growth, the surface of the composite was modified by etching, functionalization with aminosilane and coupling of fibronectin. This modification greatly enhanced the spreading of HOB, indicated by vital staining and Sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate (XTT) metabolism assays. HOB grew on the entire visible surface of porous fibronectin-modified composite, expressing alkaline phosphatase, a mature osteoblast marker. We conclude that Ecopore is non-toxic and sustains HOB growth, cellular spreading being improvable by coating with fibronectin. The composite may be usable in the field of bone substitution.

Alkaline Phosphatase↗
PubMed1977

High dose granulocyte substitution after bone marrow transplantation in a case of aplastic anaemia in childhood.

A bone marrow transplantation (BMT) was successfully carried out in a seven-year-old boy with aplastic anaemia. An HLA and MLC-identical brother served as donor. During the first 16 days after BMT between 0.55 and 7.11X10(10) granulocytes were transfused 14 times (an average of 4.03X10(10) per transfusion). The maximum increment in the peripheral blood after transfusion was over 4000 granulocytes per microliter. The course of local infections was taken as parameter for determining the clinical effectiveness of the granulocyte transfusion. Under the substitution therapy the necrotic ulcer of a fingertip and the mucous membrane ulcers in the oral cavity subsided. The presence of transfused granulocytes in the oral cavity ("orogranulocytes") could be established. There was a statistically significant relationship between the number of granulocytes in the peripheral blood and the number of orogranulocytes. It could be demonstrated that in children a temporary normalisation of the number of granulocytes in the peripheral blood can be attained by means of granulocyte substitution and that the transfused granulocytes are clinically effective.

Anemia, Aplastic↗
PubMed2006

Osteoblast response to zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate.

Calcium phosphate bioceramics, such as hydroxyapatite, have long been used as bone substitutes because of their proven biocompatibility and bone binding properties in vivo. Recently, a zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate (Zr-ACP) has been synthesized, which is more soluble than hydroxyapatite and allows for controlled release of calcium and phosphate ions. These ions have been postulated to increase osteoblast differentiation and mineralization in vitro. The focus of this work is to elucidate the physicochemical properties of Zr-ACP and to measure cell response to Zr-ACP in vitro using a MC3T3-E1 mouse calvarial-derived osteoprogenitor cell line. Cells were cultured in osteogenic medium and mineral was added to culture at different stages in cell maturation. Culture in the presence of Zr-ACP showed significant increases in cell proliferation, alkaline phosphatase activity (ALP), and osteopontin (OPN) synthesis, whereas collagen synthesis was unaffected. In addition, calcium and phosphate ion concentrations and medium pH were found to transiently increase with the addition of Zr-ACP, and are hypothesized to be responsible for the osteogenic effect of Zr-ACP.

Animals↗
PubMed2005

A novel method for the simultaneous, titrant-free control of pH and calcium phosphate mass yield.

Calcium phosphate (CaP) bioceramics have long been of interest for the unique properties that they exhibit as bone substitute materials. By harnessing the unique bone-bonding capacity of CaP's, biomaterials scientists have made great strides over the past 2 decades to produce novel materials to assist in the treatments of defects caused by trauma, disease, or both. In recent years, however, it has become apparent that the traditional set of techniques used to produce calcium phosphates does not satisfy all of the requirements necessary to meet the challenges of emerging applications. In particular, recent interest in (i) the synthesis of coprecipitated CaP/bioorganic composites and (ii) the investigation of the mechanisms of biomineralization has highlighted the need for new methods to control pH and CaP mass yield.

Biocompatible Materials↗
PubMed2006

Bioactivity and mechanical properties of cellulose/carbonate hydroxyapatite composites prepared in situ through mechanochemical reaction.

Organic-inorganic composites, prepared from bone-bonding bioactive ceramics and organic polymers, are useful for novel bone substitutes having mechanical properties analogous to natural bone. We synthesized composites from cellulose and carbonate hydroxyapatite (CHAp) in situ through mechanochemical reaction. They contained B-type CHAp analogous to bone apatite. They showed a bending strengths of 10-13 MPa and Young's modulus of 1.5-2.2 GPa. We predicted their microstructure by comparing the measured density with the theoretical one. Cellulose was assumed to be distributed in the pore of CHAp at low cellulose content, and in grain boundaries of CHAp at high cellulose content. The composites formed calcium phosphate on their surfaces in simulated body fluid, meaning that they have a potential to be bioactive.

Biomechanical Phenomena↗
PubMed2003

Calcium phosphate bone cements: a comprehensive review.

Calcium phosphate cements (CPCs) augment the healing of bone following craniofacial and maxillofacial surgery. Their ability to function as bone substitutes has accelerated the healing processes from bone fractures or defects. Although CPCs all possess the same general function, small chemical composition differences in these compounds have a profound impact on their in vivo character. The main purpose of this article is to report the differences of several major CPCs. When available, specific clinical trials are referenced. The goal is to expand the knowledge base on CPCs to better inform the clinician and researcher.

Bone Cements↗
PubMedDate not supplied

Synthetic bone grafts in peri-implant bone dehiscences: histological results in humans.

This study describes the histological results found in three patients treated with osseointegrated implants and Bioplant HTR (Hard Tissue Replacement) synthetic bone graft in peri-implant dehiscences adjacent to implants. This therapy was carried out without the use of barrier membranes. Bioplant HTR is reported to act as its own barrier and prevent gingival soft tissue migration ingrowth. The histologic picture demonstrated that Bioplant HTR is osteoconductive and biocompatible, and can be used both as bone substitute and as a barrier for guided bone regeneration in implant therapy.

Adult↗
PubMedDate not supplied

Bone grafts and growth and differentiation factors for regenerative therapy: a review.

Guided bone regeneration, tissue grafts, regenerative barrier membranes, and bone substitute materials have been used to restore inadequate hard and soft tissue structures to make them conducive to proper implant placement. Polypeptide growth and development factors (GDFs) have successfully been applied exogenously to periodontal defects to attract preosteoblasts to the site and accelerate their proliferation to stimulate angiogenesis. This article provides an overview of current modalities for restoring lost bone and soft tissue during the treatment of periodontal disease.

Alveolar Ridge Augmentation↗
PubMed2006

Implant placement after marsupialization of a dentigerous cyst.

This paper presents a case of a dentigerous cyst accompanied by a history of inflammation, resorption of the roots of the first molar and the lingual aspect of the distal root of the second molar, and devitalization of the 2 premolars. The treatment option chosen was marsupialization of the cyst, extraction of the involved teeth, endodontic treatment of both premolars, and implant insertion in the area of the first mandibular molar at a later stage. Twelve months postsurgery the area of interest was almost flattened and the radiographic examination revealed total disappearance of the radiolucency. An implant of 15 x 4 mm was inserted in the area of the first mandibular molar. Despite the excellent implant stability achieved, a thin central zone of the defect remained void of bone. After complete excision of soft tissue the defect was filled with an alloplastic bone substitute. Eight months later (20 months postsurgery), the implant was uncovered and the restorative procedure completed. The implant and the crown have been functioning sign and symptom free for 48 months. Marsupialization was preferred instead of enucleation due to (1) proximity of the cyst to the mandibular canal; (2) need for apicectomy of both premolars to gain good access for enucleation; (3) refusal of the patient to undergo a second surgery for bone harvesting; (4) lower probability for postoperative contamination; (5) need of small quantity of bone substitute; (6) easier extraction of the impacted second molar due to its coronal movement. The disadvantages of the treatment were the long healing period and the discomfort of the patient at the early stages of marsupialization. It was judged that the advantages outweighed the disadvantages in this case. We discuss the findings of other authors who support the conservative approach to jaw cysts in a young population, and the concerns that exist in the literature about the ability of osseoconductive graft materials to generate vital bone and achieve implant-to-bone contact.

Adolescent↗
PubMed2003

An injectable calcium phosphate cement as a bone-graft substitute in the treatment of displaced lateral tibial plateau fractures.

In the treatment of displaced tibial plateau fractures, filling the resultant metaphyseal defect is essential for maintaining reduction. This study reports on 14 patients with an average age of 53 (range 34-63) years who sustained such a fracture and whose tibial defect was augmented with an injectable calcium phosphate cement under arthroscopic and fluoroscopic control. Eight fractures were treated with subcortical percutaneous screw fixation, plates were used in four cases and two fractures were treated with bone cement only. Full weight-bearing was allowed after 6-12 weeks. At the last follow-up which averaged 28 (range 18-47) months, the reduction achieved at the index operation was not altered in any of the patients except one. Most patients recorded little or no pain with an average VAS score of 1.2 (0-3.4). Ten patients had no limitation of their walking distance. Patient satisfaction was good or excellent in 12 cases. Flexion averaged 140 degrees (range 130-150 degrees ) and extension was unlimited in 13 patients. The Lysholm knee score averaged 80 and the Knee Society score 180 (range 127-195). In our opinion the injectable calcium phosphate cement used here is a promising alternative for filling metaphyseal defects in the treatment of displaced tibial plateau fractures.

Adult↗
PubMed2006

Ectopic bone formation using an injectable biphasic calcium phosphate/Si-HPMC hydrogel composite loaded with undifferentiated bone marrow stromal cells.

We have used a new synthetic injectable composite constituted of hydroxyapatite/tricalcium phosphate (HA/TCP) particles in suspension in a self-hardening Si-hydroxypropylmethylcellulose (HPMC) hydrogel. The aim of this study was to evaluate in vivo the biocompatibility and the new bone formation efficacy of this scaffold loaded with undifferentiated bone marrow stromal cells (BMSCs). This biomaterial was mixed extemporaneously with BMSCs prepared from C57BL/6 mice, injected in subcutaneous and intramuscular sites and retrieved 4 and 8 weeks after implantation. Dissection of the implants revealed a hard consistency and the absence of a fibrous capsule reflecting a good integration into the host tissues. Histological analysis showed mineralized woven bone in the granule inter-space with numerous active osteoclasts attached to the particles as assessed by the presence of multinucleated cells positively stained for TRAP activity and for the a3 subunit of the V-ATPase. Small vessels were homogenously distributed in the whole implants. Similar results were obtained in SC and IM sites and no bone formation was observed in the control groups when cell-free and particle-free transplants were injected. These results indicate that this injectable biphasic calcium phosphate-hydrogel composite mixed with undifferentiated BMSCs is a new promising osteoinductive bone substitute. It also provides with an original in vivo model of osteoclast differentiation and function.

Animals↗
PubMed1986

Porous hydroxyapatite as a bone-graft substitute in metaphyseal defects. A histometric study.

Porous hydroxyapatite (Interpore 500) formed by conversion of the Porites goniopora coral exoskeleton has pores averaging 600 micrometers and pore interconnections averaging 260 micrometers in diameter. In the proximal tibial metaphysis of eight dogs, a defect one cubic centimeter in size was created unilaterally and was fitted with a block of Interpore 500. Both proximal tibial metaphyses were retrieved at two, four, six, and twelve months. Stained undecalcified sections were examined by light microscopy and quantitated by histometric methods. The implant-side specimens contained compact bone along the external surface and trabecular bone interiorly. The interior of these specimens was composed of 51.9 +/- 1.3 per cent soft tissue, 13.0 +/- 1.2 per cent bone, and 35.1 +/- 1.2 per cent Interpore 500 (mean and standard error). The interior of the normal specimens was composed of 79.7 +/- 1.4 per cent soft tissue and 20.2 +/- 1.4 per cent bone. The allocation of implant pore space between bone and soft tissue was proportional to that of bone and soft tissue in the normal tibiae. The stereological distribution of regenerated bone in the porous hydroxyapatite was also the same as in the normal tibiae. The appositional process of incorporation of the implant was confirmed by the finding that 66.5 per cent of the surface of the Interpore 500 was covered with bone ingrowth at twelve months.

Animals↗
PubMed1994

Surgical technique of onlay bone grafting.

Different forms of bone grafting materials are alluded to in this paper. Autogenous graft is superior to other bone grafting materials but is many times not available or the patient is not willing to utilize cranial or iliac crest bone. Allografts, Xenografts and bone substitute materials are the most widely used today in dentistry and especially those patients wishing to use dental implants as abutment support. The technique discussed utilizing surgical tissue design, tissue closure over the graft material and the tissue barrier can be used to produce a successful final result using a graft material of choice. It is quite certain that in the near future, the use of bone graft enhancement materials (bone morphogenic protein-like substances) will be used to enhance a quicker result. It is anticipated that growth factors, stimulating factors, bone morphogenetic proteins, and osteogenetic proteins will cause a bone graft to vascularize, solidify, incorporate, and function optimally in a shorter period of time. These materials will reduce the disability time and enhance the outcome of bone grafting in the dental profession. It is also anticipated that advanced tissue surgical techniques will give better vascularization to the new graft. The described technique is predictable and should give the operator the desired result.

Alveolar Ridge Augmentation↗
PubMed2001

Immediate functional loading of immediate implants in edentulous arches: two-year results.

The purpose of this study was to evaluate the clinical success of immediate functional loading of immediate implants in edentulous arches. Five maxillary and five mandibular jaws were treated, and a total of 91 implants were placed; 66 of these implants were placed immediately after tooth extraction, and 25 were placed in healed sites. No bone substitutes or barrier membranes were used. Within 24 hours, fixed temporary restorations were inserted in all cases. During the entire 6-month healing time, all fixed temporary restorations were in normal function, after which the final fixed implant-supported restorations were inserted. After 24 months, the overall success rate of the implants was 92.31% (87.50% for the maxillary implants and 97.26% for the mandibular implants). The bone level measured mesially and distally was in 93.40% of all cases between the implant shoulder and the first thread. The present study shows that the immediate functional loading of immediate implants without the use of any bone substitutes or barrier membranes for fixed complete-arch reconstructions can be successful over a 2-year period.

Adult↗
PubMed1989

[Comparative study of bioactive calcium phosphate ceramics after implantation in spongy bone in dogs. Histologic, ultrastructural and electron probe microanalysis].

An experimental model of posterior spine arthrodesis in dogs was created using 3 types of calcium phosphate biomaterials already known for their applications as bone substitutes, namely: hydroxyapatite (HA), which is not readily resorbable; highly resorbable tricalcium phosphate (TCP); and a mixture of HA and TCP (BCP), the resorbability of which depends on the proportion of HA and TCP. The BCP implants had a macroporous structure, whilst the HA and TCP implants were used in dense form. The creation of macropores increases the surface exchange area, thus enabling the osseous colonization processes. By carefully removing the posterior articular facets it was possible to remove the articular surfaces and to fit into each appropriate location a block a few millimeters in diameter. The anatomopathological assessment was performed using histological methods, transmission electron microscopy, and energy dispersion microprobe analysis. Our results indicate that calcium phosphate ceramics may be used as bone substitutes for carrying out arthrodeses, provided (1) immediate immobilization using a spine containment technique is effected; (2) their chemical composition is sufficiently stable over time; (3) they are sufficiently bioactive so as to allow their colonization and replacement by bone.

Animals↗
PubMed1987

Porous hydroxylapatite as a bone graft substitute in mandibular contour augmentation: a histometric study.

The buccal contour of the mandible was augmented in 17 dogs with 5 X 7.5 X 20 mm blocks of porous hydroxylapatite (HA) on one side and two-layered split rib autografts on the other. Both specimens were retrieved at three, six, 12, 24, and 48 months. Undecalcified sections were prepared for microradiography, light and UV microscopy, and histometry. A transmitted light video image digitizing system was used to trace implant and graft perimeters and calculate cross sectional areas. This system was also used to measure graft density and calculate bone and soft tissue compositions. The HA matrix, bone and soft tissue compositions of implant specimens were measured with a backscattered scanning electron microscope imaging digitizing system. All grafts became increasingly resorbed with time whereas all implants remained intact. Mature osteotonic bone ingrowth was present in all implants except one which failed to unite with the mandibular cortex. The mean graft areas decreased from 30.8 mm2 at three months to 0.7 mm2 at 48 months, while the implant areas averaged 35.5 mm2 and remained stable. The graft specimens were composed of 46.6% bone and 53.4% soft tissue or fluid space. The implant specimens were composed of 34.5% HA matrix, 28.6% bone, and 33.9% soft tissue. The HA matrix had a surface area of 9.8 mm2/mm3 that was 61.9% covered with bone ingrowth and 38.1% covered with soft tissue or fluid space. In contrast to the rapid resorption of graft onlays, the porous HA matrix demonstrated a long-term permanence with maintenance of contour and osseous incorporation over the four-year duration of this study.

Animals↗