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Zhang W, Zhang X, Wang S, Xu L, Zhang M, Wang G, Jin Y, Zhang X, Jiang X. Comparison of the use of adipose tissue-derived and bone marrow-derived stem cells for rapid bone regeneration. J Dent Res 2013; 92:1136-41. [PMID: 24097853 DOI: 10.1177/0022034513507581] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Stem cell-based bone tissue engineering has been recognized as a new strategy for maxillary sinus floor elevation. More rapid bone formation may enhance this technique when simultaneous dental implant placement is desired. Adipose tissue-derived stem cells (ADSCs) and bone marrow stem cells (BMSCs) are the most well-characterized cell sources for bone regeneration, but comparative studies on the osteogenic potential of these cells have yielded conflicting conclusions. This study aimed to compare the rapid bone formation capacity of ADSCs and BMSCs in a canine sinus floor augmentation model. In in vitro studies, BMSCs had a higher proliferative ability and greater osteogenic differentiation potential at both the mRNA and protein levels. When GFP-labeled cells on calcium phosphate cement (CPC) scaffolds were implanted subcutaneously into nude mice, both ADSCs and BMSCs survived for 4 wks, but only BMSCs formed new bone. Furthermore, according to sequential fluorescence labeling results for the canine sinus, BMSCs promoted rapid and greater bone regeneration during the entire observation period. In contrast, obvious mineralization was detected starting from 3 wks after implantation in the ADSC group. These results suggest that BMSCs might be more useful than ADSCs for rapid bone regeneration for sinus augmentation with simultaneous implant placement.
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Affiliation(s)
- W Zhang
- Department of Prosthodontics, Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai 200011, China
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102
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Bose S, Fielding G, Tarafder S, Bandyopadhyay A. Understanding of dopant-induced osteogenesis and angiogenesis in calcium phosphate ceramics. Trends Biotechnol 2013; 31:594-605. [PMID: 24012308 PMCID: PMC3825404 DOI: 10.1016/j.tibtech.2013.06.005] [Citation(s) in RCA: 240] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/24/2013] [Accepted: 06/24/2013] [Indexed: 12/31/2022]
Abstract
General trends in synthetic bone grafting materials are shifting towards approaches that can illicit osteoinductive properties. Pharmacologics and biologics have been used in combination with calcium phosphate (CaP) ceramics, however, they have recently become the target of scrutiny over safety. The importance of trace elements in natural bone health is well documented. Ions, for example, lithium, zinc, magnesium, manganese, silicon, strontium, etc., have been shown to increase osteogenesis and neovascularization. Incorporation of dopants (trace metal ions) into CaPs can provide a platform for safe and efficient delivery in clinical applications where increased bone healing is favorable. This review highlights the use of trace elements in CaP biomaterials, and offers an insight into the mechanisms of how metal ions can enhance both osteogenesis and angiogenesis.
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Affiliation(s)
- Susmita Bose
- W.M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA.
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103
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Houmard M, Fu Q, Genet M, Saiz E, Tomsia AP. On the structural, mechanical, and biodegradation properties of HA/β-TCP robocast scaffolds. J Biomed Mater Res B Appl Biomater 2013; 101:1233-42. [PMID: 23650043 DOI: 10.1002/jbm.b.32935] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 02/04/2013] [Accepted: 02/18/2013] [Indexed: 11/09/2022]
Abstract
Hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) composite scaffolds have shown great potential for bone-tissue engineering applications. In this work, ceramic scaffold with different HA/β-TCP compositions (pure HA, 60HA/40β-TCP, and 20HA/80β-TCP) were fabricated by a robotic-assisted deposition (robocasting) technique using water-based hydrogel inks. A systematic study was conducted to investigate the porosity, mechanical property, and degradation of the scaffolds. Our results indicate that, at a similar volume porosity, the mechanical strength of the sintered scaffolds increased with the decreasing rod diameter. The compressive strength of the fabricated scaffolds (porosity ≈ 25-80 vol %) varied between ∼3 and ∼50 MPa, a value equal or higher than that of human cancellous bone (2-12 MPa). Although there was a slight increase of Ca and P ions in water after 5 month, no noticeable degradation of the scaffolds in SBF or water was observed. Our findings from this work indicate that composite calcium phosphate scaffolds with customer-designed chemistry and architecture may be fabricated by a robotic-assisted deposition method.
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Affiliation(s)
- Manuel Houmard
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG 31270-901, Brazil
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Bougas K, Stenport VF, Currie F, Wennerberg A. Laminin Coating Promotes Calcium Phosphate Precipitation on Titanium Discs in vitro. J Oral Maxillofac Res 2012; 2:e5. [PMID: 24422002 PMCID: PMC3886082 DOI: 10.5037/jomr.2011.2405] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 09/16/2011] [Indexed: 01/01/2023]
Abstract
Objectives The objective of this study was to investigate the effect of a laminin
coating on calcium phosphate precipitation on three potentially bioactive
titanium surfaces in simulated body fluid. Material and Methods Blasted titanium discs were prepared by alkali and heat treatment (AH),
anodic oxidation (AO) or hydroxyapatite coating (HA) and subsequently coated
with laminin. A laminin coated blasted surface (B) served as a positive
control while a blasted non coated (B-) served as a negative control.
Surface morphology was examined by Scanning Electron Microscopy (SEM). The
analysis of the precipitated calcium and phosphorous was performed by Energy
Dispersive X-ray Spectroscopy (EDX). Results The thickness of the laminin coating was estimated at 26 Å by ellipsometry.
Interferometry revealed that the coating process did not affect any of the
tested topographical parameters on µm level when comparing B to B-. After 2
weeks of incubation in SBF, the alkali-heat treated discs displayed the
highest calcium phosphate deposition and the B group showed higher levels of
calcium phosphate than the B- group. Conclusions Our results suggest that laminin may have the potential to be used as a
coating agent in order to enhance the osseoinductive performance of
biomaterial surfaces, with the protein molecules possibly functioning as
nucleation centres for apatite formation. Nevertheless, in vivo studies are
required in order to clarify the longevity of the coating and its
performance in the complex biological environment.
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Affiliation(s)
- Kostas Bougas
- Department of Prosthodontics, Faculty of Odontology, Malmö University Malmö Sweden. ; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden
| | - Victoria Franke Stenport
- Department of Prosthodontics, Faculty of Odontology, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden. ; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden
| | | | - Ann Wennerberg
- Department of Prosthodontics, Faculty of Odontology, Malmö University Malmö Sweden. ; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden
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105
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Bougas K, Stenport VF, Currie F, Wennerberg A. In vitro Evaluation of Calcium Phosphate Precipitation on Possibly Bioactive Titanium Surfaces in the Presence of Laminin. J Oral Maxillofac Res 2011; 2:e3. [PMID: 24421995 PMCID: PMC3886075 DOI: 10.5037/jomr.2011.2303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Accepted: 07/19/2011] [Indexed: 11/30/2022]
Abstract
Objectives The aim of the present study was to evaluate calcium phosphate precipitation
and the amount of precipitated protein on three potentially bioactive
surfaces when adding laminin in simulated body fluid. Material and Methods Blasted titanium discs were prepared by three different techniques claimed to
provide bioactivity: alkali and heat treatment (AH), anodic oxidation (AO)
or hydroxyapatite coating (HA). A blasted surface incubated in
laminin-containing simulated body fuid served as a positive control (B)
while a blasted surface incubated in non laminin-containing simulated body
fuid served as a negative control (B-). The immersion time was 1 hour, 24
hours, 72 hours and 1 week. Surface topography was investigated by
interferometry and morphology by Scanning Electron Microscopy (SEM).
Analysis of the precipitated calcium and phosphorous was performed by Energy
Dispersive X-ray Spectroscopy (EDX) and the adsorbed laminin was quantified
by iodine (125I) labeling. Results SEM demonstrated that all specimens except for the negative control were
totally covered with calcium phosphate (CaP) after 1 week. EDX revealed that
B- demonstrated lower sum of Ca and P levels compared to the other groups
after 1 week. Iodine labeling demonstrated that laminin precipitated in a
similar manner on the possibly bioactive surfaces as on the positive control
surface. Conclusions Our results indicate that laminin precipitates equally on all tested titanium
surfaces and may function as a nucleation center thus locally elevating the
calcium concentration. Nevertheless further studies are required to clarify
the role of laminin in the interaction of biomaterials with the host bone
tissue.
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Affiliation(s)
- Kostas Bougas
- Department of Prosthodontics, Faculty of Odontology, Malmö University Malmö Sweden. ; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden
| | - Victoria Franke Stenport
- Department of Prosthodontics, Faculty of Odontology, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden. ; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden
| | | | - Ann Wennerberg
- Department of Prosthodontics, Faculty of Odontology, Malmö University Malmö Sweden. ; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg Sweden
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106
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Martinez A, Franco J, Saiz E, Guitian F. Maxillary sinus floor augmentation on humans: Packing simulations and 8 months histomorphometric comparative study of anorganic bone matrix and β-tricalcium phosphate particles as grafting materials. Mater Sci Eng C Mater Biol Appl 2010; 30:763-769. [PMID: 21625341 PMCID: PMC3103085 DOI: 10.1016/j.msec.2010.03.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study compares the behaviour of an anorganic bone matrix material and a synthetic β-Tricalcium phosphate employed as grafting materials in a sinus floor augmentation two step protocol in humans. In order to estimate the initial occupation level for the two materials, an 'in vitro' simulation has been performed to analyse macroporosity created due to particle packing in terms of porosity and interparticle distances. Grafting in the sinus floor augmentation was performed by filling the defects only with pure grafting materials without autogenous bone addition. The new-bone generated is 100% based on the osteoconductive properties of the grafted materials in contact with physiological fluids. The implants were placed 8 months after the grafting procedure. All the implanted positions were biopsied and embedded in methacrylate resin. Histomorphometric analyses were done over thin film undecalcified sections. Packing simulations allow establishing a comparison of the resorbed volumes related to the initial occupancy of the grafting materials inside the defect. The nature of this interconnected pore network is very alike for either material so new-bone generated was similar (~35 vol.%).
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Affiliation(s)
- A. Martinez
- Facultad de Medicina y Odontología, University of Santiago de Compostela, Rua San Francisco s/n; 15782 Santiago de Compostela, Spain
| | - J. Franco
- Lawrence Berkeley National Laboratory, 1 Cyclotron Rd Mail stop 62R0203 Berkeley, CA 94720, USA
| | - E. Saiz
- Lawrence Berkeley National Laboratory, 1 Cyclotron Rd Mail stop 62R0203 Berkeley, CA 94720, USA
| | - F. Guitian
- Instituto de Ceramica de Galicia, Av Mestre Mateo s/n, 15782 Santiago de Compostela, Spain
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107
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Fatimi A, Tassin JF, Axelos MAV, Weiss P. The stability mechanisms of an injectable calcium phosphate ceramic suspension. J Mater Sci Mater Med 2010; 21:1799-809. [PMID: 20229185 PMCID: PMC3118935 DOI: 10.1007/s10856-010-4047-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 03/01/2010] [Indexed: 05/22/2023]
Abstract
Calcium phosphate ceramics are widely used as bone substitutes in dentistry and orthopedic applications. For minimally invasive surgery an injectable calcium phosphate ceramic suspension (ICPCS) was developed. It consists in a biopolymer (hydroxypropylmethylcellulose: HPMC) as matrix and bioactive calcium phosphate ceramics (biphasic calcium phosphate: BCP) as fillers. The stability of the suspension is essential to this generation of "ready to use" injectable biomaterial. But, during storage, the particles settle down. The engineering sciences have long been interested in models describing the settling (or sedimentation) of particles in viscous fluids. Our work is dedicated to the comprehension of the effect of the formulation on the stability of calcium phosphate suspension before and after steam sterilization. The rheological characterization revealed the macromolecular behavior of the suspending medium. The investigations of settling kinetics showed the influence of the BCP particle size and the HPMC concentration on the settling velocity and sediment compactness before and after sterilization. To decrease the sedimentation process, the granule size has to be smaller and the polymer concentration has to increase. A much lower sedimentation velocity, as compared to Stokes law, is observed and interpreted in terms of interactions between the polymer network in solution and the particles. This experimentation highlights the granules spacer property of hydrophilic macromolecules that is a key issue for interconnection control, one of the better ways to improve osteoconduction and bioactivity.
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Affiliation(s)
- Ahmed Fatimi
- LIOAD, Laboratoire d'ingénierie osteo-articulaire et dentaire
INSERM : U791IFR26Université de NantesFaculte de Chirurgie Dentaire 1, Place Alexis Ricordeau 44042 NANTES CEDEX 1,FR
| | - Jean-François Tassin
- polymères, colloïdes, interfaces
CNRS : UMR6120Université du MaineUniversité du Maine, 1 Avenue Olivier Messiaen, 72085 Le Mans cedex 9,FR
| | - Monique A. V. Axelos
- BIA, Unité de recherche sur les Biopolymères, Interactions Assemblages
INRA : UR1268BP71627, 44316 Nantes Cedex, FR
| | - Pierre Weiss
- LIOAD, Laboratoire d'ingénierie osteo-articulaire et dentaire
INSERM : U791IFR26Université de NantesFaculte de Chirurgie Dentaire 1, Place Alexis Ricordeau 44042 NANTES CEDEX 1,FR
- * Correspondence should be adressed to: Pierre Weiss
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108
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Boix D, Weiss P, Gauthier O, Guicheux J, Bouler JM, Pilet P, Daculsi G, Grimandi G. Injectable bone substitute to preserve alveolar ridge resorption after tooth extraction: a study in dog. J Mater Sci Mater Med 2006; 17:1145-52. [PMID: 17122930 PMCID: PMC2042990 DOI: 10.1007/s10856-006-0542-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 03/01/2006] [Indexed: 05/12/2023]
Abstract
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.
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Affiliation(s)
- Damien Boix
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
| | - Pierre Weiss
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
| | - Olivier Gauthier
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
- Département de chirurgie
Ecole Nationale Vétérinaire de Nantes44307 Nantes,FR
| | - Jérôme Guicheux
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
| | - Jean-Michel Bouler
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
| | - Paul Pilet
- Centre de microscopie électronique
CHU NantesUniversité de Nantes1 place Alexis Ricordeau
44042 Nantes,FR
| | - Guy Daculsi
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
| | - Gaël Grimandi
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculté de chirurgie dentaire
1 place Alexis Ricordeau BP84215
44042 Nantes,FR
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109
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Abstract
Structural features of some calcium phosphates of biological interest are described. Structure of hydroxyapatite (OHAp), considered as the prototype for the inorganic component of bones and teeth is discussed with respect to the kinds and locations of ionic substitutions. Octacalcium phosphate (OCP), is a probable precursor in biological mineralization. OCP has a layer type structure, with one layer quite similar to that of OHAp and the other, a hydrated layer consisting of more widely spaced Ca, and PO4 ions and the water molecules. The closeness of fit in the apatitic layers of OCP and OHAp accounts for the epitaxial, interlayered mixtures formed by these compounds and the in situ conversion of OCP to OHAp. Possible roles of OCP in biological mineralization are discussed.
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Affiliation(s)
- Mathai Mathew
- American Dental Association Health Foundation, Paffenbarger Research Center, National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
USA
| | - Shozo Takagi
- American Dental Association Health Foundation, Paffenbarger Research Center, National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
USA
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110
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Bourges X, Schmitt M, Amouriq Y, Daculsi G, Legeay G, Weiss P. Interaction between hydroxypropyl methylcellulose and biphasic calcium phosphate after steam sterilisation: capillary gas chromatography studies. J Biomater Sci Polym Ed 2001; 12:573-9. [PMID: 11556737 PMCID: PMC2211382 DOI: 10.1163/156856201316883412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to check the chemical stability of an injectable bone substitute (IBS) composed of a 50/50 w/w mixture of 2.92% hydroxypropyl methylcellulose (HPMC) solution in deionized water containing biphasic calcium phosphate (BCP) granules (60% hydroxyapatite/40% beta-tricalcium phosphate w/w). After separation of the organic and mineral phases, capillary gas chromatography (GC) was used to study the possible modification of HPMC due to the contact with BCP granules following steam sterilisation and 32 days storage at room temperature. HPMC was extracted from IBS in aqueous medium, and a dialytic method was then used to extract calcium phosphate salts from the HPMC. The percentage of HPMC extracted from BCP was 98.5%+/-0.5%, as measured by UV. GC showed no chemical modifications after steam sterilisation and storage.
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Affiliation(s)
- Xavier Bourges
- DMCTT, Département Matériaux
Centre de Transfert de Technologie du Mans20 rue Thalès de Milet
72000 LE MANS,FR
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculte de Chirurgie Dentaire
1, Place Alexis Ricordeau
44042 NANTES CEDEX 1,FR
| | - Michel Schmitt
- DMCTT, Département Matériaux
Centre de Transfert de Technologie du Mans20 rue Thalès de Milet
72000 LE MANS,FR
| | - Yves Amouriq
- DMCTT, Département Matériaux
Centre de Transfert de Technologie du Mans20 rue Thalès de Milet
72000 LE MANS,FR
| | - Guy Daculsi
- DMCTT, Département Matériaux
Centre de Transfert de Technologie du Mans20 rue Thalès de Milet
72000 LE MANS,FR
| | - Gilbert Legeay
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculte de Chirurgie Dentaire
1, Place Alexis Ricordeau
44042 NANTES CEDEX 1,FR
| | - Pierre Weiss
- DMCTT, Département Matériaux
Centre de Transfert de Technologie du Mans20 rue Thalès de Milet
72000 LE MANS,FR
- Matériaux d'intérêt biologique
INSERM : EPI9903Université de NantesFaculte de Chirurgie Dentaire
1, Place Alexis Ricordeau
44042 NANTES CEDEX 1,FR
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111
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Abstract
The purpose of this study was to develop an injectable bone substitute (IBS) for percutaneous orthopedic surgery. The multiphasic material used was composed of a 2% aqueous solution of methylhydroxypropylcellulose (MHPC) and biphasic calcium phosphate (BCP, 60% hydroxyapatite and 40% beta-tricalcium phosphate) in which MHPC served as the carrier for 80-200 microm of BCP granules. The best BCP/polymer ratio was determined by the rheological properties and higher BCP content of the material. Steam sterilization was more effective than gamma irradiation in maintaining the stability of the mixture and conserving its physiochemical and mechanical properties. The in vitro biocompatibility of the composite was checked by direct-contact cytotoxicity and cell-proliferation assays. A preliminary in vivo test was performed in the rabbit using intraosseous implantations in the femoral epiphysis. Histological analysis was done after 1, 2, 4, and 10 weeks. Bone ingrowth into the IBS, in close association with BCP granules, was observed after 1 week and increased regularly from the surface inward at 2, 4, and 10 weeks. At the same time, smaller BCP granules (less than 80 microns in diameter) were degraded and resorbed. This injectable biomaterial proved suitable for cavity filling. The water solubility and viscosity of the polymer allow cells to recolonize, with in situ bonding of the mineral phase.
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Affiliation(s)
- Gaël Grimandi
- Centre de Recherche sur les Matériaux d'Intérêt Biologique
Université de NantesUPRES EA 2159Faculté de Chirurgie Dentaire 1 Place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1
| | - Pierre Weiss
- Centre de Recherche sur les Matériaux d'Intérêt Biologique
Université de NantesUPRES EA 2159Faculté de Chirurgie Dentaire 1 Place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1
- * Correspondence should be addressed to Pierre Weiss
| | - F. Millot
- Centre de Recherche sur les Matériaux d'Intérêt Biologique
Université de NantesUPRES EA 2159Faculté de Chirurgie Dentaire 1 Place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1
| | - Guy Daculsi
- Centre de Recherche sur les Matériaux d'Intérêt Biologique
Université de NantesUPRES EA 2159Faculté de Chirurgie Dentaire 1 Place Alexis Ricordeau, BP 84215, 44042 Nantes Cedex 1
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112
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Abstract
Two portions of a synthetic hydroxyapatite (HA), Ca5OH(PO4)3, fully characterized by x-ray, infrared, petrographic, and chemical analyses, were heated at 1,000 °C in air and steam atmospheres, respectively. Solubility isotherms for these two samples in the system Ca(OH)2-H3PO4-H2O were determined in the pH range 5 to 7 by equilibrating the solids with dilute H3PO4 solutions. Both samples of HA dissolved stoichiometrically. The activity products( Ca + + ) 5 ( OH - ) ( PO 4 ≡ ) 3 and their standard errors-obtained by a least squares adjustment of the measurements (Ca and P concentrations and pH of the saturated solutions) subject to the conditions of electroneutrality, constancy of the activity product, and stoichiometric dissolution - were 3.73 ± 0.5 × 10-58 for the steam-heated HA and 2.51 ± 0.4 × 10-55 for the air-heated HA. Allowance was made in the calculations for the presence of the ion pairs [CaHPO4]0 and [CaH2PO4]+. The higher solubility product for the air-heated HA is ascribed either to a change in the heat of formation brought about by partial dehydration or to a state of fine subdivision resulting from a disproportionation reaction. The solubility product constants were used to calculate the points of intersection (i.e., singular points) of the two HA solubility isotherms with the isotherms of CaHPO4 · 2H2O and CaHPO4; it was found that the pH's of the singular points for the air-heated HA were a full unit higher than those of the steam-heated preparation. Conditions are described for the precipitation of HA crystals suitable for solubility measurements.
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Affiliation(s)
- E C Moreno
- Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234
| | - T M Gregory
- Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234
| | - W E Brown
- Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234
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