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1.
Lomelino Rde O Castro-Silva II Linhares AB Alves GG Santos SR Gameiro VS Rossi AM Granjeiro JM 《Journal of materials science. Materials in medicine》2012,23(3):781-788
This work evaluates the suitability of biphasic calcium phosphate (BCP) granules (β-TCP/HA 70:30) as potential carriers for
cell-guided bone therapy. The BCP granules were obtained by synthesis in the presence of wax, thermal treatment, crushing
and sieving and characterized by scanning electron microscopy (SEM), X-ray diffraction and Fourier transform infrared spectroscopy.
The cytocompatibility of the BCP granules was confirmed by a multiparametric cytotoxicity assay. SEM analysis showed human
bone cell adhesion and migration after seeding onto the material. Rat subcutaneous xenogeneic grafting of granules associated
to human bone cells revealed a more accentuated moderate chronic inflammatory infiltrate, without signs of a strong xenoreactivity.
Histomorphometrical analysis of bone repair of defects in rat skulls (∅ = 5 mm) has shown that bone cell associated-BCP and
autograft promoted a two- and threefold increase, respectively, on new bone formation after 45 days, as compared to BCP alone
and blood clot. The increase in bone repair supports the suitability the biocompatible (70:30) BCP granules as injectable
and mouldable scaffolds for human cells in bone bioengineering. 相似文献
2.
Cell response to collagen-calcium phosphate cement scaffolds investigated for nonviral gene delivery
Perez RA Ginebra MP Spector M 《Journal of materials science. Materials in medicine》2011,22(4):887-897
Collagen-hydroxyapatite (HA) scaffolds for the non-viral delivery of a plasmid encoding the osteoinductive protein bone morphogenetic
protein (BMP)-7 were developed. The collagen-HA was obtained by the combination of calcium phosphate cement in a collagen
template. The effect on cell behavior of increasing amounts of HA in the scaffolds was evaluated. Collagen-HA scaffolds containing
13, 23 or 83 wt% HA were prepared. Cell proliferation was reduced in the 83% HA scaffold after 1 day compared to 13 and 23%
HA, but by 14 days the number of cells in 83% HA considerably increased. Alkaline phosphatase (ALP) activity was 8 times higher
for the 83% HA scaffolds. BMP-7 plasmid was incorporated into the 83% HA scaffold. The transfection was low, although significant
levels of BMP7 were expressed, associated with an increase in cell proliferation. 相似文献
3.
Yusuf M. Khan Emily K. Cushnie John K. Kelleher Cato T. Laurencin 《Journal of Materials Science》2007,42(12):4183-4190
As an alternative to current bone grafting strategies, a poly-lactide-co-glycolide/calcium phosphate composite microsphere-based scaffold has been synthesized by the direct formation of calcium
phosphate within forming microspheres. It was hypothesized that the synthesis of low crystalline calcium phosphate within
forming microspheres would provide a site-specific delivery of calcium ions to enhance calcium phosphate reprecipitation onto
the scaffold. Both polymeric and composite scaffolds were incubated in simulated body fluid (SBF) for 8 weeks, during which
time polymer molecular weight, scaffold mass, calcium ion concentration of SBF, pH of SBF, and calcium phosphate reprecipitation
was monitored. Results showed a 20% decrease in polymeric scaffold molecular weight compared to 11–14% decrease for composite
scaffolds over 8 weeks. Composite scaffold mass and SBF pH decreased for the first 2 weeks but began increasing after 2 weeks
and continued to do so up to 8 weeks, suggesting interplay between pH changes and calcium phosphate dissolution/reprecipitation.
Free calcium ion concentration of SBF containing composite scaffolds increased 20–40% over control values within 4 h of incubation
but then dropped as low as 40% below control values, suggesting an initial burst release of calcium ions followed by a reprecipitation
onto the scaffold surface. Scanning electron micrographs confirm calcium phosphate reprecipitation on the scaffold surface
after only 3 days of incubation. Results suggest the composite scaffold is capable of initiating calcium phosphate reprecipitation
which may aid in bone/implant integration. 相似文献
4.
《Advanced Powder Technology》2022,33(11):103774
The main inorganic components of clam shells are calcium carbonate and trace elements of magnesium, strontium, and zinc. Clam shells can be used as a calcium source to synthesize calcium phosphates, and these trace elements promote the growth of bone tissue and improve the performance of bioceramics. In this study, hydroxyapatite (HA) powders were synthesized from clam shells, and porous calcium phosphate granules were prepared through the gas foaming technique. In addition, the effects of a chitosan coating and cooling conditions on the strength of the porous granules were investigated. The results indicated that the samples produced under the furnace cooling condition were biphasic hydroxyapatite/β-tricalcium phosphate granules (HA/β-TCP), whereas the samples produced under the air-cooling condition were triphasic hydroxyapatite/β-tricalcium phosphate/α-tricalcium phosphate granules (HA/β-TCP/α-TCP). The compressive strength of the porous granules prepared through air cooling was 79% higher than that of the granules produced through furnace cooling. The compressive strength of the air-cooled sample after the subsequent application of the chitosan coating further increased by 21%. A degradability test revealed that the weight loss rate of the air-cooled samples was greater than that of the furnace-cooled samples, which was due to the presence of high-solubility α-TCP in the air-cooled samples. 相似文献
5.
Wilson CE van Blitterswijk CA Verbout AJ Dhert WJ de Bruijn JD 《Journal of materials science. Materials in medicine》2011,22(1):97-105
Calcium phosphate ceramics, commonly applied as bone graft substitutes, are a natural choice of scaffolding material for bone
tissue engineering. Evidence shows that the chemical composition, macroporosity and microporosity of these ceramics influences
their behavior as bone graft substitutes and bone tissue engineering scaffolds but little has been done to optimize these
parameters. One method of optimization is to place focus on a particular parameter by normalizing the influence, as much as
possible, of confounding parameters. This is difficult to accomplish with traditional fabrication techniques. In this study
we describe a design based rapid prototyping method of manufacturing scaffolds with virtually identical macroporous architectures
from different calcium phosphate ceramic compositions. Beta-tricalcium phosphate, hydroxyapatite (at two sintering temperatures)
and biphasic calcium phosphate scaffolds were manufactured. The macro- and micro-architectures of the scaffolds were characterized
as well as the influence of the manufacturing method on the chemistries of the calcium phosphate compositions. The structural
characteristics of the resulting scaffolds were remarkably similar. The manufacturing process had little influence on the
composition of the materials except for the consistent but small addition of, or increase in, a beta-tricalcium phosphate
phase. Among other applications, scaffolds produced by the method described provide a means of examining the influence of
different calcium phosphate compositions while confidently excluding the influence of the macroporous structure of the scaffolds. 相似文献
6.
Landi E Logroscino G Proietti L Tampieri A Sandri M Sprio S 《Journal of materials science. Materials in medicine》2008,19(1):239-247
The incorporation of magnesium ions (in the range 5–10 mol% in respect to Ca) into the hydroxyapatite structure, which is
of great interest for the developing of artificial bone, was performed using magnesium chloride, calcium hydroxide and phosphoric
acid, as reactants. Among the synthesized powders, the synthetic HA powder containing 5.7% Mg substituting for calcium was
selected, due to its better chemico-physical features, and transformed into granules of 400–600 μm, for biocompatibility tests
(genotoxicity, carcinogenicity, toxicity, in vitro cytotoxicity and in vivo skin irritation-sensitization tests). In vivo
tests were carried out on New Zealand White rabbits using the granulate as filling for a femoral bone defect: osteoconductivity
and resorption were found to be enhanced compared to commercial stoichiometric HA granulate, taken as control. 相似文献
7.
M. Schumacher F. Uhl R. Detsch U. Deisinger G. Ziegler 《Journal of materials science. Materials in medicine》2010,21(11):3039-3048
The adequate regeneration of large bone defects is still a major problem in orthopaedic surgery. Synthetic bone substitute
materials have to be biocompatible, biodegradable, osteoconductive and processable into macroporous scaffolds tailored to
the patient specific defect. Hydroxyapatite (HA) and tricalcium phosphate (TCP) as well as mixtures of both phases, biphasic
calcium phosphate ceramics (BCP), meet all these requirements and are considered to be optimal synthetic bone substitute materials.
Rapid prototyping (RP) can be applied to manufacture scaffolds, meeting the criteria required to ensure bone ingrowth such
as high porosity and defined pore characteristics. Such scaffolds can be used for bone tissue engineering (BTE), a concept
based on the cultivation of osteogenic cells on osteoconductive scaffolds. In this study, scaffolds with interconnecting macroporosity
were manufactured from HA, TCP and BCP (60 wt% HA) using an indirect rapid prototyping technique involving wax ink-jet printing.
ST-2 bone marrow stromal cells (BMSCs) were seeded onto the scaffolds and cultivated for 17 days under either static or dynamic
culture conditions and osteogenic stimulation. While cell number within the scaffold pore system decreased in case of static
conditions, dynamic cultivation allowed homogeneous cell growth even within deep pores of large (1,440 mm3) scaffolds. Osteogenic cell differentiation was most advanced on BCP scaffolds in both culture systems, while cells cultured
under perfusion conditions were generally more differentiated after 17 days. Therefore, scaffolds manufactured from BCP ceramic
and seeded with BMSCs using a dynamic culture system are the method of choice for bone tissue engineering. 相似文献
8.
Tong WANG Qing LI Gui-feng ZHANG Gang ZHOU Xin YU Jing ZHANG Xiu-mei WANG Zhi-hui TANG 《材料科学前沿(英文版)》2016,10(2):122-133
Bone scaffolds are critical in current implant and periodontal regeneration approaches. In this study, we prepared a novel composite type-I collagen and hydroxyapatite (HA)/β-tricaleium phosphate (TCP) scaffold (CHTS) by incorporating type-I collagen and bovine calcined bone granules, prepared as a mixture of 50% HA and 50% TCP, by freeze drying. We then characterized the CHTS and determined its cytotoxic effects. Additionally, ridge preservation experiments were carried out to evaluate the clinical effects of the CHTS. The results demonstrated that the composite scaffolds had good surface morphology and no cytotoxicity. Additionally, an in vivo experiment in an animal model showed that the CHTS performed equally as well as Bio-Oss Collagen, a widely used bone graft in ridge preservation. These findings revealed that the CHTS, which contained natural constituents of bone, could be used as a scaffold for bone regeneration and clinical use. 相似文献
9.
Hermes S. Costa Alexandra A. P. Mansur Edel F. Barbosa-Stancioli Marivalda M. Pereira Herman S. Mansur 《Journal of Materials Science》2008,43(2):510-524
In bone tissue engineering, a highly porous artificial extracellular matrix or scaffold is required to accommodate cells and
guide the tissue regeneration in three-dimension. Calcium phosphate (CaP) ceramics are widely used for bone substitution and
repair due to their biocompatibility, bioactivity, and osteoconduction. However, compared to alumina ceramics, either in the
dense or porous form, the mechanical strength achieved for calcium phosphates is generally lower. In the present work, the
major goal was to develop a tri-dimensional macroporous alumina scaffold with a biocompatible PVA/calcium phosphate coating
to be potentially used as bone tissue substitute. This approach aims to combine the high mechanical strength of the alumina
scaffold with the biocompatibility of calcium phosphate based materials. Hence, the porous alumina scaffolds were produced
by the polymer foam replication procedure. Then, these scaffolds were submitted to two different coating methods: the biomimetic
and the immersion in a calcium phosphate/polyvinyl alcohol (CaP/PVA) slurry. The microstructure, morphology and crystallinity
of the macroporous alumina scaffolds samples and coated with CaP/PVA were characterized by X-ray diffraction (XRD), Fourier
Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDX) analysis. Also, specific surface area was
assessed by BET nitrogen adsorption method and mechanical behavior was evaluated by axial compression tests. Finally, biocompatibility
and cytotoxicity were evaluated by VERO cell spreading and attachment assays under SEM. The morphological analysis obtained
from SEM photomicrograph results has indicated that 3D macroporous alumina scaffolds were successfully produced, with estimated
porosity of over 65% in a highly interconnected network. In addition, the mechanical test results have indicated that porous
alumina scaffolds with ultimate compressive strength of over 3.0 MPa were produced. Concerning to the calcium phosphate coatings,
the results have showed that the biomimetic method was not efficient on producing a detectable layer onto the alumina scaffolds.
On the other hand, a uniform and adherent inorganic–organic coating was effectively formed onto alumina macroporous scaffold
by the immersion of the porous structure into the CaP/PVA suspension. Viable VERO cells were verified onto the surface of
alumina porous scaffold samples coated with PVA–calcium phosphate. In conclusion, a new method was developed to produce alumina
with tri-dimensional porous structure and uniformly covered with a biocompatible coating of calcium phosphate/PVA. Such system
has high potential to be used in bone tissue engineering. 相似文献
10.
S. Teixeira L. Yang P. J. Dijkstra M. P. Ferraz F. J. Monteiro 《Journal of materials science. Materials in medicine》2010,21(8):2385-2392
Currently, in bone tissue engineering research, the development of appropriate biomaterials for the regeneration of bony tissues
is a major concern. Bone tissue is composed of a structural protein, collagen type I, on which calcium phosphate crystals
are enclosed. For tissue engineering, one of the most applied strategies consists on the development and application of three
dimensional porous scaffolds with similar composition to the bone. In this way, they can provide a physical support for cell
attachment, proliferation, nutrient transport and new bone tissue infiltration. Hydroxyapatite is a calcium phosphate with
a similar composition of bone and widely applied in several medical/dentistry fields. Therefore, in this study, hydroxyapatite
three dimensional porous scaffolds were produced using the polymer replication method. Next, the porous scaffolds were homogeneously
coated with a film of collagen type I by applying vacuum force. Yet, due to collagen degradability properties, it was necessary
to perform an adequate crosslinking method. As a result, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) was employed as an efficient and non-toxic crosslinking method in this research. The composites
were characterized by means of SEM, DSC and TNBS. Furthermore, heparin was incorporated in order to accomplish sustained delivery
of a growth factor of interest namely, bone morphogenetic proteins (BMP-2). BMP-2 binding and release of non-heparinized and
heparinized scaffolds was evaluated at specific time points. The incorporation of heparin leads to a reduced initial burst
phase when compared to the non heparinized materials. The results show a beneficial effect with the incorporation of heparin
and its potential as a localized drug delivery system for the sustained release of growth factors. 相似文献
11.
Natkrita Wongsupa Thongchai Nuntanaranont Suttatip Kamolmattayakul Nuttawut Thuaksuban 《Journal of materials science. Materials in medicine》2017,28(2):25
Craniofacial bone defects such as alveolar cleft affect the esthetics and functions that need bone reconstruction. The advanced techniques of biomaterials combined with stem cells have been a challenging role for maxillofacial surgeons and scientists. PCL-coated biphasic calcium phosphate (PCL-BCP) scaffolds were created with the modified melt stretching and multilayer deposition (mMSMD) technique and merged with human dental pulp stem cells (hDPSCs) to fulfill the component of tissue engineering for bone substitution. In the present study, the objective was to test the biocompatibility and biofunctionalities that included cell proliferation, cell viability, alkaline phosphatase activity, osteocalcin, alizarin red staining for mineralization, and histological analysis. The results showed that mMSMD PCL-BCP scaffolds were suitable for hDPSCs viability since the cells attached and spread onto the scaffold. Furthermore, the constructs of induced hDPSCs and scaffolds performed ALP activity and produced osteocalcin and mineralized nodules. The results indicated that mMSMD PCL-BCP scaffolds with hDPSCs showed promise in bone regeneration for treatment of osseous defects. 相似文献
12.
Gauthier O Goyenvalle E Bouler JM Guicheux J Pilet P Weiss P Daculsi G 《Journal of materials science. Materials in medicine》2001,12(5):385-390
Macroporous biphasic calcium phosphate ceramics (MBCP) and a calcium phosphate injectable bone substitute (IBS), obtained by the association of biphasic calcium phosphate (BCP) ceramic granules and an aqueous solution of a cellulosic polymer, were compared in the same animal model. The two tested biomaterials were implanted in distal femoral osseous defects in rabbits. Qualitative and quantitative histological evaluation was performed three and eight weeks after implantation to investigate bone colonization and ceramic biodegradation associated with the two bone substitutes.Both biomaterials expressed osteoconduction properties and supported the apposition of a well-mineralized lamellar newly-formed bone. Bone colonization occurred much earlier and faster for IBS than for MBCP implants, although the respective rates of newly-formed bone after eight weeks of implantation did not differ significantly. For both biomaterials, ceramic resorption occurred regularly throughout the implantation period, though to a greater extent with IBS than with MBCP implants.The associated polymer in IBS produced intergranular spaces allowing body fluids to reach each BCP ceramic granule immediately after implantation, which may have favored osteoblastic activity, new bone formation and ceramic resorption. This completely interconnected open macroporosity could account for the earlier and more satisfactory bone substitution achieved with IBS. © 2001 Kluwer Academic Publishers 相似文献
13.
Marcia S. Sader Virginia C.A. Martins Santiago Gomez Racquel Z. LeGeros Gloria A. Soares 《Materials science & engineering. C, Materials for biological applications》2013,33(7):4188-4196
3D porous scaffolds are relevant biomaterials to bone engineering as they can be used as templates to tissue reconstruction. The aim of the present study was to produce and characterize in vitro 3D magnesium-carbonate apatite/collagen (MCA/col) scaffolds. They were prepared by using biomimetic approach, followed by cross-linking with 0.25% glutaraldehyde solution (GA) and liofilization. Results obtained with Fourier-transform infrared spectroscopy (FT-IR) confirmed the type-B carbonate substitution, while by X-ray diffraction (XRD), a crystallite size of ~ 10 nm was obtained. Optical and electron microscopy showed that the cylindrical samples exhibited an open-porous morphology, with apatite nanocrystals precipitated on collagen fibrils. The cross-linked 3D scaffolds showed integrity when immersed in culture medium up to 14 days. Also, the immersion of such samples into an acid buffer solution, to mimic the osteoclastic resorption environment, promotes the release of important ions for bone repair, such as calcium, phosphorus and magnesium. Bone cells (SaOs2) adhered, and proliferated on the 3D composite scaffolds, showing that synthesis and the cross-linking processes did not induce cytotoxicity. 相似文献
14.
以掺锶β-磷酸三钙/硫酸钙为原料,利用搅拌喷雾干燥法制备出掺锶β-磷酸三钙/硫酸钙复合小球,再将硅胶与制备的复合小球复合,通过在模具中堆垛聚集的方法,制备出硅胶/掺锶β-磷酸三钙/硫酸钙复合生物支架。采用XRD,SEM,FT-IR等方法分析制得复合多孔支架的成分、形貌以及结构特征,并研究复合生物支架的降解性、孔隙率、力学性能和细胞毒性等。结果表明:该复合多孔生物支架具有一定的不规则孔洞结构,小球与小球之间的孔隙约为0.2~1mm,而每个小球上也有大量的微孔,孔径在50~200μm之间,且平均孔隙率达到62%,基本能满足骨组织工程支架对孔隙率的要求;该复合多孔支架无细胞毒性,其降解周期约为80天,抗压强度约为0.1MPa,因此该支架在非承重骨组织修复方面具有良好的应用前景。 相似文献
15.
In tissue engineering technology, polymer–ceramics or polymer–polymer composites have been considered as advanced scaffolds having mechanical stability, biocompatibility, cell proliferation, and easy processability. However, the relationship between the mechanical properties and the cell proliferation behavior of such composite scaffolds has not been clarified yet. In this study, two types of composite scaffolds, poly(ethylene terephthalate) (PET) fiber/collagen and β-tricalcium phosphate (β-TCP)/gelatin scaffolds, were investigated. MC3T3-E1 cells were cultured in these scaffolds under appropriate conditions. Compression tests were then periodically conducted to evaluate the compressive elastic modulus. It was found that the modulus of the scaffolds containing cells increased with the cell culture period. It is noted that the modulus of the β-TCP/gelatin with cells was approximately seven times larger than that of the PET fiber/collagen with cells. 相似文献
16.
Masanobu Kamitakahara Ryohei Imai Koji Ioku 《Materials science & engineering. C, Materials for biological applications》2013,33(4):2446-2450
Spherical Ca-deficient hydroxyapatite (HA) granules are expected to be useful drug carriers in bony sites because of their bone regeneration and adsorption ability. In order to control drug loading and release ability of the granules, a controlled surface microstructure was constructed. Spherical Ca-deficient granules composed of micron-sized rod-shaped particles were prepared by hydrothermal treatment of α-tricalcium phosphate (α-TCP) granules, and then, submicron HA particles were precipitated on the obtained granules by immersion in a supersaturated calcium phosphate (CP) solution. When bovine serum albumin was used as a drug model, precipitation of submicron particles causes the loading capability to increase and the release rate to decrease. The spherical Ca-deficient HA granules with the controlled surface microstructure are expected to be useful drug carriers that can act as scaffolds for bone repair. 相似文献
17.
Strontium substituted calcium phosphate biphasic ceramics obtained by a powder precipitation method 总被引:3,自引:0,他引:3
Kim HW Koh YH Kong YM Kang JG Kim HE 《Journal of materials science. Materials in medicine》2004,15(10):1129-1134
Strontium (Sr) substituted calcium phosphate ceramics were fabricated using a powder precipitation method. The Sr ions were added up to 8 mol % to replace the Ca ions during the powder preparation. Composition analysis showed that the added Sr was not fully incorporated within the as-precipitated apatite structure, presumably being washed out during the powder preparation. After calcination, the Sr containing powders were crystallized into apatite and tricalcium phosphate (TCP), that is, biphasic calcium phosphates were formed. The amount of TCP increased with increasing the Sr addition. The lattice parameters of the calcined powders increased gradually with Sr substitution in both the a- and c-axis. However, the obtained values deviated slightly from the calculated ones at higher Sr additions (>4%) due to the partial substitution of Sr ions. The microstructure of the sintered bodies changed with the Sr addition due to the formation of TCP. The Vickers hardness increased slightly from 5.2 to 5.5 MPa with increasing Sr addition, which was driven by the HA+TCP biphasic formation. The osteoblast-like cells cultured on the Sr-substituted biphasic sample spread and grew actively. The proliferation rate of the cells was higher in the samples containing more Sr. The alkaline phosphate activity of the cells was expressed to a higher degree with increasing Sr addition. These observations confirmed the enhanced cell viability and differentiation of the Sr-substituted biphasic calcium phosphate ceramics. 相似文献
18.
Maria Helena Santos Luis Guilherme Dias Heneine Herman Sander Mansur 《Materials science & engineering. C, Materials for biological applications》2008,28(4):563-571
Composites were developed using calcium phosphate (CaP)/collagen (COL) doped with Zn+2 to attempt the materials association with adequate properties for biological applications in the recovery of the bone tissue by trauma or pathogenies. Hydroxyapatite (HAP) and hydroxyapatite-βtricalcium phosphate (HAPβTCP) were synthesized and doped with zinc nitrate. High purity grade type I collagen was extracted and purified from bovine pericardium. CaP doped and undoped with Zn+2 were produced with COL and the composites were developed using a simple mixture process. All samples were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD. In addition, biocompatibility and cell viability were assessed by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) using osteoblast cell culture. The results have indicated that both morphological and structural features and chemical composition of the composites were very similar to their precursors, collagen and calcium phosphate components. Also, the biocomposites presented a homogeneous aspect with the calcium phosphate particles aggregated to the collagen fibers. The biological evaluation of the composites in vitro showed cellular viability, presenting proliferation of the osteoblasts compared to the control cells (P < 0.05). The composites showed appropriate physical and biological properties creating more biologically active scaffolds that may support bone growth. Therefore, the novel developed biocomposites have high potential to be used for rebuilding small lesions in bone tissue engineering. 相似文献
19.
Boix D Weiss P Gauthier O Guicheux J Bouler JM Pilet P Daculsi G Grimandi G 《Journal of materials science. Materials in medicine》2006,17(11):1145-1152
The aim of the present study was to assess the efficacy of a ready-to-use injectable bone substitute on the prevention of
alveolar ridge resorption after tooth extraction. Maxillary and mandibular premolars were extracted from 3 Beagle dogs with
preservation of alveolar bone. Thereafter, distal sockets were filled with an injectable bone substitute (IBS), obtained by
combining a polymer solution and granules of a biphasic calcium phosphate (BCP) ceramic. As a control, the mesial sockets
were left unfilled. After a 3 months healing period, specimens were removed and prepared for histomorphometric evaluation
with image analysis. Histomorphometric study allowed to measure the mean and the maximal heights of alveolar crest modifications.
Results always showed an alveolar bone resorption in unfilled sockets. Resorption in filled maxillary sites was significantly
lower than in control sites. Interestingly, an alveolar ridge augmentation was measured in mandibular filled sockets including
30% of newly-formed bone. It was concluded that an injectable bone substitute composed of a polymeric carrier and calcium
phosphate can significantly increase alveolar ridge preservation after tooth extraction. 相似文献
20.
S. Schaefer R. Detsch F. Uhl U. Deisinger G. Ziegler 《Advanced Engineering Materials》2011,13(4):342-350
The chemical composition of calcium phosphate (CaP) materials for the regenerative therapy of large bone defects is similar to that of bone. Additionally, calcium phosphates show an excellent biocompatibility. Besides the support of defect healing calcium phosphate implants should be completely degraded within an adequate time period to be replaced by newly formed bone. Although degradation of CaP‐implants occurs mainly by dissolution of the material, it is important to characterize the osteoclastic resorption as well, which is involved in native bone remodeling. The degradation of bone substitutes made of calcium phosphate ceramics is influenced by various parameters, such as defect size and localization, the general health situation, and age of the patient, but also material properties are important. Especially, the calcium phosphate composition is crucial for the degradation behavior of a calcium phosphate material. Additionally, at the cellular level the micro‐ and macroporosity, including interconnecting pores, influences both, the dissolution and the osteoclastic resorption. In our study, three different calcium phosphate materials (hydroxyapatite, tricalcium phosphate, and a biphasic calcium phosphate) and two different geometries (dense 2D samples and porous 3D scaffolds) are compared regarding their dissolution and resorption behavior. The results show, that the dissolution of CaP‐ceramics, as examined by the incubation in a degradation solution, depends mainly on the calcium phosphate phase but also on the porosity of the implant. Regarding the resorption, cell proliferation and differentiation of a monocytic cell line as well as the formation of resorption lacunas are analyzed. Cell proliferation is comparable on all phase compositions. Cell differentiation and resorption, however, are influenced by the calcium phosphate phase composition and by the implant porosity as well. By understanding these two mechanisms of degradation, bone substitute materials and, as a result, the bone regeneration of large bone defects using CaP‐ceramics can be improved. 相似文献