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Sopcak T, Medvecky L, Zagyva T, Dzupon M, Balko J, Balázsi K, Balázsi C. Characterization and adhesion strength of porous electrosprayed polymer–hydroxyapatite composite coatings. RESOLUTION AND DISCOVERY 2018. [DOI: 10.1556/2051.2018.00057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- T. Sopcak
- Institute of Technical Physics and Materials Sciences, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, 1121 Budapest, Hungary
- Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice, Slovak Republic
| | - L. Medvecky
- Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice, Slovak Republic
| | - T. Zagyva
- Institute of Technical Physics and Materials Sciences, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, 1121 Budapest, Hungary
| | - M. Dzupon
- Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice, Slovak Republic
| | - J. Balko
- Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice, Slovak Republic
| | - K. Balázsi
- Institute of Technical Physics and Materials Sciences, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, 1121 Budapest, Hungary
| | - C. Balázsi
- Institute of Technical Physics and Materials Sciences, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, 1121 Budapest, Hungary
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2
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Liu J, Zhou X, Wang H, Yang H, Ruan J. In vitro
cell response and in vivo
primary osteointegration of highly porous Ta-Nb alloys as implant materials. J Biomed Mater Res B Appl Biomater 2018; 107:573-581. [DOI: 10.1002/jbm.b.34149] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/29/2018] [Accepted: 04/17/2018] [Indexed: 11/05/2022]
Affiliation(s)
- Jue Liu
- State Key Laboratory of Powder Metallurgy; Central South University; Changsha 410083 People's Republic of China
| | - Xiongwen Zhou
- Department of Anesthesiology; The Second Xiang Ya Hospital, Central South University; Changsha 410011 People's Republic of China
| | - Huifeng Wang
- State Key Laboratory of Powder Metallurgy; Central South University; Changsha 410083 People's Republic of China
| | - Hailin Yang
- State Key Laboratory of Powder Metallurgy; Central South University; Changsha 410083 People's Republic of China
| | - Jianming Ruan
- State Key Laboratory of Powder Metallurgy; Central South University; Changsha 410083 People's Republic of China
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3
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Singh A, Singh G, Chawla V. Characterization and mechanical behaviour of reinforced hydroxyapatite coatings deposited by vacuum plasma spray on SS-316L alloy. J Mech Behav Biomed Mater 2018; 79:273-282. [PMID: 29335194 DOI: 10.1016/j.jmbbm.2018.01.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/02/2018] [Accepted: 01/09/2018] [Indexed: 12/31/2022]
Abstract
Hydroxyapatite powder reinforced individually with 10wt percentage (wt%) of Al2O3 and ZrO2 (HA + 10wt% Al2O3 and HA + 10wt% ZrO2) was thermally sprayed onto SS-316L substrate with a bond coat of Zirconia by vacuum plasma spray (VPS) technique. The resulted coatings were heat treated at 700°C for 1h to study its effects on microstructural and mechanical properties of the deposited coatings. The characterization of the coatings was carried out using scanning electron microscope, x-ray diffraction, porosity, surface roughness and crystallinity using Rietveld analysis. The results indicated that after post coating heat treatment substantial decrease in porosity was witnessed along with significant improvement in crystallinity. Besides, the hardness across the cross-section of the coatings and bond strength was considerably improved; however the hardness of top coat was reduced owing to the loosening of un-melted and partially melted particles by diffusion process which takes place during heat treatment.
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Affiliation(s)
- Amardeep Singh
- I. K. Gujral Punjab Technical University, Kapurthala 144603, India.
| | - Gurbhinder Singh
- I. K. Gujral Punjab Technical University, Kapurthala 144603, India.
| | - Vikas Chawla
- I. K. Gujral Punjab Technical University, Kapurthala 144603, India.
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4
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Sterilization Method Using Plasma Discharge Against Biofilm-Producing Pseudomonas aeruginosa on Surface of Contact Lens. J Med Biol Eng 2015. [DOI: 10.1007/s40846-015-0080-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Choy MT, Tang CY, Chen L, Wong CT, Tsui CP. In vitro and in vivo performance of bioactive Ti6Al4V/TiC/HA implants fabricated by a rapid microwave sintering technique. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 42:746-56. [PMID: 25063176 DOI: 10.1016/j.msec.2014.06.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/03/2014] [Accepted: 06/10/2014] [Indexed: 11/16/2022]
Abstract
Failure of the bone-implant interface in a joint prosthesis is a main cause of implant loosening. The introduction of a bioactive substance, hydroxyapatite (HA), to a metallic bone-implant may enhance its fixation on human bone by encouraging direct bone bonding. Ti6Al4V/TiC/HA composites with a reproducible porous structure (porosity of 27% and pore size of 6-89 μm) were successfully fabricated by a rapid microwave sintering technique. This method allows the biocomposites to be fabricated in a short period of time under ambient conditions. Ti6Al4V/TiC/HA composites exhibited a compressive strength of 93 MPa, compressive modulus of 2.9 GPa and microhardness of 556 HV which are close to those of the human cortical bone. The in vitro preosteoblast MC3T3-E1 cells cultured on the Ti6Al4V/TiC/HA composite showed that the composite surface could provide a biocompatible environment for cell adhesion, proliferation and differentiation without any cytotoxic effects. This is among the first attempts to study the in vivo performance of load-bearing Ti6Al4V/TiC and Ti6Al4V/TiC/HA composites in a live rabbit. The results indicated that the Ti6Al4V/TiC/HA composite had a better bone-implant interface compared with the Ti6Al4V/TiC implant. Based on the microstructural features, the mechanical properties, and the in vitro and in vivo test results from this study, the Ti6Al4V/TiC/HA composites have the potential to be employed in load-bearing orthopedic applications.
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Affiliation(s)
- Man Tik Choy
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China
| | - Chak Yin Tang
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China.
| | - Ling Chen
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China
| | - Chi Tak Wong
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China
| | - Chi Pong Tsui
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China
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6
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Pineda-Vargas CA, Topic M, Ntsoane T. Micro-PIXE analysis of bioconductive hydroxyapatite coatings on titanium alloy. J Radioanal Nucl Chem 2013. [DOI: 10.1007/s10967-012-2405-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Aniket, El-Ghannam A. Electrophoretic deposition of bioactive silica-calcium phosphate nanocomposite on Ti-6Al-4V orthopedic implant. J Biomed Mater Res B Appl Biomater 2011; 99:369-79. [DOI: 10.1002/jbm.b.31908] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 04/07/2011] [Accepted: 05/25/2011] [Indexed: 11/09/2022]
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8
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Aparicio C, Rodriguez D, Gil F. Variation of roughness and adhesion strength of deposited apatite layers on titanium dental implants. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2011. [DOI: 10.1016/j.msec.2010.09.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Evaluation of corrosion behavior of surface modified Ti–6Al–4V ELI alloy in hanks solution. J APPL ELECTROCHEM 2009. [DOI: 10.1007/s10800-009-9972-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Tercero JE, Namin S, Lahiri D, Balani K, Tsoukias N, Agarwal A. Effect of carbon nanotube and aluminum oxide addition on plasma-sprayed hydroxyapatite coating's mechanical properties and biocompatibility. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2009. [DOI: 10.1016/j.msec.2009.05.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Kim MS, Ryu JJ, Sung YM. One-step approach for nano-crystalline hydroxyapatite coating on titanium via micro-arc oxidation. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.04.023] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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12
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In vitro biological, chemical and electrochemical evaluation of titania reinforced hydroxyapatite sol–gel coatings on surgical grade 316L SS. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2007. [DOI: 10.1016/j.msec.2006.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Yang CY, Lee TM, Yang CW, Chen LR, Wu MC, Lui TS. In vitro andin vivo biological responses of plasma-sprayed hydroxyapatite coatings with posthydrothermal treatment. J Biomed Mater Res A 2007; 83:263-71. [PMID: 17415765 DOI: 10.1002/jbm.a.31246] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This study was undertaken to evaluate the effect of post-hydrothermal treatment on the biological responses of the plasma-sprayed hydroxyapatite (HA)-coated Ti-6Al-4V implant system both in vitro and in vivo. After hydrothermal treatment, the HA coating (HAC) shows the high mechanical strength and indices-of-crystallinity, denser microstructure, lower concentrations of amorphous and impurity phases, when compared with the as-sprayed HAC. The in vitro cell-culture studies, using UMR106 osteoblast-like cell, demonstrated no signifiacnt cell growth on both surface of as-sprayed and hydrothermal-treated HACs during 10-day culture. The in vivo studies, using the transcortical implant model in the femora of goats, evaluated the histological responses of two coatings. After 6 week of implantation, using backscattered electron images, no substantial histological variations in the extents of new bone apposition and new bone healing between the two HACs were observed. However, the as-sprayed HAC, owing to the dissolution induced the granular particles dissociated from the HAC, showed the statically lower extent of new bone apposition than hydrothermal-treated HAC at 12 weeks. The results suggest that hydrothermal treatment could be used to improve the mechanical strength, crystallinity, and phase composition of HAC, which are important factors of long-term fixation and stability of implant. Besides, the treated HAC could also achieve the initial fixation of implant in clinical use.
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Affiliation(s)
- C Y Yang
- Department of Orthopaedics, National Cheng Kung University, Tainan 701, Taiwan
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14
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Wang F, Lee HP, Lu C. Thermal–mechanical study of functionally graded dental implants with the finite element method. J Biomed Mater Res A 2007; 80:146-58. [PMID: 17001649 DOI: 10.1002/jbm.a.30855] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This article investigates the thermal-mechanical performance of hydroxyapatite/titanium (HA/Ti) functionally graded (FG) dental implants with the three-dimensional finite element method. The stresses induced by occlusal force for the present HA/Ti FG implant are calculated to compare with the corresponding stresses for the titanium dental implant. Thermal-mechanical effect of temperature variation due to daily oral activity is also studied. The HA/Ti FG dental implant performance is evaluated against the maximum von Mises stress, which is the general performance indicator, the first principal/tensile stress for mechanical failure of implant-bone-bond and the third principal/compressive stress for bone absorption. Simulation results indicate that under the influence of occlusal force only, the FG implants with different HA fraction along the implant length perform almost equally well, while the titanium implant sustains much higher von Mises stress. However, when thermal stress is also considered, the FG implant having HA fraction exponential index of m = 2 with temperature decrease of 20 degrees C yields the highest first principal and von Mises stresses among all the FG and titanium implants.
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Affiliation(s)
- F Wang
- Institute of High Performance Computing, 1 Science Park Road, No 01-01 The Capricorn, Singapore Science Park II, Singapore 117528, Singapore.
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15
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Yang CW, Lee TM, Lui TS, Chang E. Effect of post vacuum heating on the microstructural feature and bonding strength of plasma-sprayed hydroxyapatite coatings. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2006. [DOI: 10.1016/j.msec.2005.08.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Low Temperature Crystallization and Structural Modification of Plasma-Sprayed Hydroxyapatite Coating with Hydrothermal Treatment. ACTA ACUST UNITED AC 2006. [DOI: 10.4028/www.scientific.net/amr.15-17.147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of autoclaving hydrothermal treatment on the characteristics of plasma-sprayed hydroxyapatite (HA) coatings on the Ti-6Al-4V substrate was investigated. The heating temperatures were 100°C, 150°C and 200°C with ambient saturated steam pressure in an autoclave. On the basis of quantitative analysis of crystallinity using x-ray diffraction (XRD), hydrothermal treatment was found to be effective for increasing the crystallinity and phase purity of the HA coatings. The prominent and sharp OH− and PO4 3− peaks detected from x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra demonstrate a superior crystallized integrity of hydrothermal-treated HA coatings through the incorporation of water vapor. Moreover, the significant presence of OH− peak in XPS spectra represents a replenishment of water molecules which tends to reduce the dehydroxylation state of as-sprayed HA coatings. From the observation of microstructures, crystallized HA was found to diminish the spraying defects of hydrothermal HA coating layers, and finely-crystallized HA crystals, with a Ca/P atomic ratio of 1.67, were observed through transmission electron microscopy (TEM). Hydrothermal treatment could induce a low-temperature crystallization process, and the saturated steam pressure is thought to be a factor which reduces the activation energy and accelerates the HA crystallization. Experimental evidence confirmed that the ambient saturated steam pressure plays an important role in lowering heating temperatures and promoting HA crystallization.
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17
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Yildirim OS, Aksakal B, Celik H, Vangolu Y, Okur A. An investigation of the effects of hydroxyapatite coatings on the fixation strength of cortical screws. Med Eng Phys 2005; 27:221-8. [PMID: 15694605 DOI: 10.1016/j.medengphy.2004.10.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Revised: 09/28/2004] [Accepted: 10/25/2004] [Indexed: 11/25/2022]
Abstract
Hydroxyapatite (HA) are commonly applied to orthopaedic implants for acceleration of osteointegration and so overcoming the loosening problems such as in cortical screws. Electrophoretic deposition (EPD) of hydroxyapatite was applied for coating of cortical screws in this work. The effects of hydroxyapatite-coated and uncoated cortical screws on insertion and extraction torque were investigated through in vivo experiments. Three groups of screws were undertaken: first group with no coating, second group coated with HA and the third group coated with HA+interlayer, a synthetic calcium silicate compound. Five sheep were operated, and 60 cortical (20 x 3) screws from those of groups were implanted in cortical femurs to observe the effect of HA and interlayer on screws. Results show that as an alternative to plasma spray coating method, the EPD process enables to produce a quick, easy, cheap and uniform adjustable coating layer. Also from biomechanical and SEM examinations, HA coating by EPD method of cortical screws resulted in extremely improved fixation with reduced risk of loosening problem.
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Affiliation(s)
- O S Yildirim
- Department of Orthopaedic, Faculty of Medicine, Atatürk University, Erzurum, Turkey
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18
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Affiliation(s)
- Bashir A Zikria
- Department of Orthopaedic Surgery, Lenox Hill Hospital, 100 East 77th Street, New York, NY 10021, USA
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19
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Nogueras-Bayona J, Gil FJ, Salsench J, Martinez-Gomis J. Roughness and bonding strength of bioactive apatite layer on dental implants. IMPLANT DENT 2004; 13:185-9. [PMID: 15179096 DOI: 10.1097/01.id.0000127523.91195.bd] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study examined the roughness and bonding strength of the chemical-made apatite layer in comparison with the titanium surface and the plasma-sprayed apatite. Commercially pure titanium plates were heated and chemically treated to deposit crystalline apatite on their surface. The roughness of the titanium surface of the original samples and the apatite surface was analyzed by a roughness surface tester. A scratch test was used to compare the adhesion of the chemical apatite layer to the titanium with the adhesion of a plasma-sprayed layer. A dense bone-like apatite layer was formed on the surface of the titanium by a simple chemical method. The surface roughness test showed that the chemical apatite coating increased the roughness of the samples. The scratch test showed that the bonding strength of the chemical-made apatite coatings to the titanium substrate was higher than the plasma-sprayed apatite coatings. The apatite layer produced by chemical treatment did not show a lower roughness than the titanium substrate. This chemical apatite layer also bonded tighter to the titanium than the plasma-sprayed apatite. This chemically made apatite coating is expected to provide a long-term implant-bone fixation.
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20
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Khor KA, Li H, Cheang P. Significance of melt-fraction in HVOF sprayed hydroxyapatite particles, splats and coatings. Biomaterials 2004; 25:1177-86. [PMID: 14643591 DOI: 10.1016/j.biomaterials.2003.08.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Microstructure characterization and property evaluation of high velocity oxy-fuel (HVOF) sprayed hydroxyapatite (HA) splats and coatings were conducted in the present study as a function of the proportion of melting that occurred in HA particles during HVOF spray. In vitro behavior of single and folded HA splats in simulated body fluid was also investigated. Results showed that phase composition of as-sprayed HA coatings was influenced significantly by the melt fraction in HVOF sprayed particles. Melt fraction of the HA powders were experimentally determined from particle morphology analysis. It was found that the spray parameters and starting powder size influenced the melt fraction of the particles. In vitro investigation of individual HA splats made from different HA particles revealed decisive role of local phase composition in influencing their dissolution/precipitation behavior during the test. Furthermore, Raman spectroscopy qualitative inspection on the sprayed HA particles (partial melted) revealed that thermal decomposition occurred within the melted part rather than the unmelted zone. Young's modulus and micro-hardness of the as-sprayed particles and coatings were determined using nano-indentation technique. The resolidified zone of the sprayed HA particles exhibited an average Young's modulus value of 41.25 GPa. The measured values ranged from 23.1 to 65.3 GPa. The unmelted part of the HA powders showed a markedly narrower range. Young's modulus value of 83.9 GPa (+/-9.4 GPa) was recorded for this region. This succinctly highlight the difference between the unmelted region and melted regions of a HA particle. Young's moduli values measured on HVOF coatings were found to mirror the trend found in the spheroidised particles and splats with apt fidelity.
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Affiliation(s)
- K A Khor
- School of Mechanical and Production Engineering, Advanced Materials Research Centre, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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Kuroda S, Virdi AS, Li P, Healy KE, Sumner DR. A low-temperature biomimetic calcium phosphate surface enhances early implant fixation in a rat model. ACTA ACUST UNITED AC 2004; 70:66-73. [PMID: 15174110 DOI: 10.1002/jbm.a.30062] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The present study demonstrates increased early mechanical fixation of titanium implants coated with a new biomimetic apatite surface in a rat model. Male Sprague-Dawley rats received unilateral femoral medullary implants for periods of 1-4 weeks. The strength of fixation of the implant to the host bone increased more rapidly in the group receiving apatite-treated implants compared with the control group as evidenced by the apatite group's 21-fold greater fixation strength at 1 week (p = 0.009), 4-fold greater fixation strength at 2 weeks (p = 0.041), and 2-fold greater fixation strength at 4 weeks (p = 0.093) compared with the control. Fixation strength was correlated with bone-implant contact as determined from micro computed tomography assessment of the specimens (r2 = 0.338, p = 0.011 in the control group and r2 = 0.543, p < 0.001 in the apatite group). Furthermore, for a given amount of bone-implant contact, the fixation strength was higher in the apatite group than in the control group (p = 0.011), suggesting that the bone formed a stronger bond to the apatite coating than to the titanium. This difference in bonding strength accounted for the difference in mechanical behavior.
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Affiliation(s)
- S Kuroda
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois 60612, USA
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22
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Schmidmaier G, Wildemann B, Schwabe P, Stange R, Hoffmann J, Südkamp NP, Haas NP, Raschke M. A new electrochemically graded hydroxyapatite coating for osteosynthetic implants promotes implant osteointegration in a rat model. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2003; 63:168-72. [PMID: 11870650 DOI: 10.1002/jbm.10130] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hydroxyapatite (HAP) is widely used as an osteoconductive coating for orthopedic implants. So far standard coating methods like plasma spraying produce a relatively thick coating layer (>30 microm). In addition, the chemical structure of the HAP may be altered because of the heating throughout the coating process. This may have negative effects on the coating stability, implant fixation, and induction of bone formation. The relatively thick layer may detach from the implant with the risk of wear debris. In the present study the potential of a newly developed HAP coating of implants on osteointegration was investigated in a rat model. The coating method, based on an electrochemical process, is applied in a graded manner and results in a biodegradable HAP coating with a thickness of approximately 2 mum. Coated versus uncoated titanium Kirschner wires (1.4-mm diameter) were inserted into the medullary cavity of the right femora of 5-month old female Sprague Dawley rats (n=36) in a retrograde fashion. Throughout an experimental period of 2 months the osteointegration was traced radiologically. After this time the animals were sacrificed and the implant integration was tested biomechanically with the use of a push-out test. To analyze the bone-implant interface, histological sections (80 mum) were investigated with an image analyzing system. The biomechanical testing revealed a significantly higher implant fixation in the group treated with the HAP-coated implant (shear strength: 27.8 +/- 6.7 MPa) compared to control (shear strength: 8.08 +/- 3.4 MPa). The histological analyses demonstrated a better ingrowth of the implants in the HAP group with significantly more direct bone-implant contacts compared to the control group. The results demonstrate that the HAP coating promotes implant osteointegration in a rat model.
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Affiliation(s)
- G Schmidmaier
- Department of Trauma and Reconstructive Surgery, Charité, Humboldt--University of Berlin, Germany.
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24
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Manero JM, Salsench J, Nogueras J, Aparicio C, Padrós A, Balcells M, Gil FJ, Planell JA. Growth of bioactive surfaces on dental implants. IMPLANT DENT 2002; 11:170-5. [PMID: 12078600 DOI: 10.1097/00008505-200204000-00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Some metallic materials, such as pure titanium, Ti-6Al-4V, are used for dental and orthopedic implants under load-bearing conditions. However, they do not form a chemical bond with bone, which would achieve a good implant-bone fixation in service. In recent works, it has been demonstrated that an in vitro, chemically deposited, bone-like apatite layer with bone-bonding ability could be induced on a titanium surface. By reproducing that chemical procedure, in this work, a dense bone-like apatite layer was formed on the surface of the titanium in simulated body fluid. In addition, the different steps and kinetics of the layer-formation have been studied, because the observation of the samples in the wet state by means of the environmental scanning electron microscope has allowed the observation in situ of the apatite deposition process over a number of days. One of the most important features of the present study is that it can be carried out on a single titanium sample and the process is not interrupted at any stage. One of the main drawbacks of this chemical method is that the samples covered with apatite are susceptible to contamination by bacteria. The behavior of different types of antibiotics used to avoid this contamination has also been studied using the environmental scanning electron microscope. Finally, osteoblast cells have been cultured on the apatite-coated titanium samples to assess their biocompatibility.
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Affiliation(s)
- J M Manero
- Department of Materials Science and Metallurgy, ETSEIB, Technical University of Catalonia, Barcelona, Spain
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25
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Growth of bioactive surfaces on titanium and its alloys for orthopaedic and dental implants. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2002. [DOI: 10.1016/s0928-4931(01)00389-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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26
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Kweh SWK, Khor KA, Cheang P. An in vitro investigation of plasma sprayed hydroxyapatite (HA) coatings produced with flame-spheroidized feedstock. Biomaterials 2002; 23:775-85. [PMID: 11774849 DOI: 10.1016/s0142-9612(01)00183-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The in vitro behaviour and characteristics of plasma sprayed hydroxyapatite (HA) coatings using flame-spheroidized HA feedstock powder on titanium alloy (Ti-6Al-4V) substrates were investigated in a simulated physiological environment as an attempt to reflect the actual incubational condition of an implant in a human body system. As-sprayed and heat-treated HA coatings were immersed in a simulated body fluid with ionic concentrations comparable to that of human blood plasma for time intervals 2, 4, 6, 8 and 10 weeks. Rapid dissolution of calcium phosphate was found to occur within the first 4 weeks, and after the 5th week a retarding rate of 4.1 mM week(-1) was observed where precipitation, nucleation, and, growth of a carbonate-containing, poorly crystallized or amorphous calcium phosphate layer on the as-sprayed coatings were noted. The heat-treated coatings showed minimal or no precipitation on the surface except for the presence of calcite minerals that is due to carbonation effect. Complete dissolution of other calcium phosphate phases such as tetracalcium phosphate, tricalcium phosphate and calcium oxide was also noted after 2 weeks of immersion due to higher ionic solubility relative to HA. A declining trend in respective microhardness and elastic modulus of the as-sprayed HA coatings from 207.06 +/- 3.2 H(k300) to 131.8 +/- 5.2 H(k300) and from 31.37 +/- 1.4 to 19.81 +/- 1.6 GPa was observed after 10 weeks of immersion. Tensile bond strength of both types of coatings showed similar declining trend, with an average dip from 24.5 +/- 2.4 to 7.9 +/- 2.6 MPa. Nevertheless. the heat-treated samples showed rather reasonable mechanical stability and structural integrity of 26.7 +/-1.4 GPa in elastic modulus after soaking.
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Affiliation(s)
- S W K Kweh
- School of Mechanical and Production Engineering, Nanyang Technological University, Singapore, Singapore
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Lee TM, Wang BC, Yang YC, Chang E, Yang CY. Comparison of plasma-sprayed hydroxyapatite coatings and hydroxyapatite/tricalcium phosphate composite coatings: in vivo study. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2001; 55:360-7. [PMID: 11255189 DOI: 10.1002/1097-4636(20010605)55:3<360::aid-jbm1040>3.0.co;2-q] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study aimed to compare biological properties, including osteoconduction, osseointegration, and shear strength, between plasma-sprayed hydroxyapatite (HA) and HA/tricalcium phosphate (TCP) coatings, using a transcortical implant model in the femora of canines. After 3 and 12 weeks of implantation, the implants with surrounding bone were assessed histologically in undecalcified sections in backscattered electron images (BEIs) under a scanning electron microscope (SEM). After short-term (3 week) follow-up, both coatings conducted new bone formation and revealed direct bone-to-coating contact. The HA/TCP coating could not enhance early host-to-coating responses. At 12 weeks, serious dissolution of the HA/TCP coatings evidently occurred. By the new bone healing index (NBHI) and apposition index (AI), we found no significant difference between HA/TCP-coated implants and HA-coated implants throughout all implant periods. At 12 weeks of implantation, some particles dissociated from the HA/TCP coating were found within the remodeling canal. After push-out measurements, the shear strength and failure mode of HA/TCP-coated implants were similar to those of HA-coated implants, and no statistical differences were found between either coating. Consequently, this study indicates that HA/TCP coatings have excellent biological response and may be considered suitable bioactive ceramic coatings for short-term clinical use.
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Affiliation(s)
- T M Lee
- Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan, ROC.
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Yang YC, Chan E, Hwang BH, Lee SY. Biaxial residual stress states of plasma-sprayed hydroxyapatite coatings on titanium alloy substrate. Biomaterials 2000; 21:1327-37. [PMID: 10850926 DOI: 10.1016/s0142-9612(99)00272-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Biaxial residual stress states of plasma-sprayed hydroxyapatite coatings (HACs) on titanium alloy substrate as a function of plasma power, powder feed rate and coating thickness were studied by X-ray 'sin2 psi' method. The Young's modulus of hydroxyapatite (HA), required for the stress analysis, was measured from the separated free coating by three-point bending test method. It was found that the directions of principal stresses were in proximity to and perpendicular to the spraying direction. The measured Young's moduli of HACs were much lower than the theoretical value reported. The denser, well-melted HAC exhibited a higher residual stress, as compared with the less dense, poor-melting HAC. The denser coatings could be effected by higher plasma power and lower powder feed rate. Significantly, the thicker 200 microm HAC exhibited higher residual stress than that of the thinner 50 microm HAC. The implications of residual stress in HAC for biomaterials are discussed in detail.
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Affiliation(s)
- Y C Yang
- Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan
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Kweh SW, Khor KA, Cheang P. Plasma-sprayed hydroxyapatite (HA) coatings with flame-spheroidized feedstock: microstructure and mechanical properties. Biomaterials 2000; 21:1223-34. [PMID: 10811304 DOI: 10.1016/s0142-9612(99)00275-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Flame-spheroidized feedstock, with excellent known heat transfer and consistent melting capabilities, were used to produce hydroxyapatite (HA) coatings via plasma spraying. The characteristics and inherent mechanical properties of the coatings have been investigated and were found to have direct and impacting relationship with the feedstock characteristics, processing parameters as well as microstructural deformities. Processing parameters such as particle sizes (SHA: 20-45, 45-75 and 75-125 microm) and spray distances (10, 12 and 14 cm) have been systematically varied in the present study. It was found that the increase of particle sizes and spray distances weakened the mechanical properties (microhardness, modulus, fracture toughness and bond strength) and structural stability of the coatings. The presence of inter- and intralamellar thermal microcracks, voids and porosities with limited true contact between lamellae were also found to degrade the mechanical characteristics of the coatings, especially in coatings produced from large-sized HA particles. An effort was made to correlate the effects of microstructural defects with the resultant mechanical properties and structural integrity of the plasma-sprayed hydroxyapatite (HA) coatings. The effects of different heat treatment temperatures (600, 800 and 900 degrees C) on the mechanical properties of the coatings were also studied. It was found that a heat treatment temperature of 800 degrees C does enhance the microhardness and elastic modulus of the coatings significantly (P < 0.05) whereas a further increment in heat treatment temperature to 900 degrees C did not show any discernable improvements (P > 0.1). The elastic response behaviour and fracture toughness of both the as-sprayed and heat-treated HA coatings using Knoop and Vickers indentations at different loadings have been investigated. Results have shown that the mechanical properties of the coatings have improved significantly despite increasing crack density after heat treatment in air. Coatings produced from the spheroidized feedstock of 20-45 microm (SHA 20-45 microm) sprayed at a stand-off distance of 10 cm were found to possess the most favourable mechanical properties.
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Affiliation(s)
- S W Kweh
- School of Mechanical & Production Engineering, Nanyang Technological University, Singapore, Singapore
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