Hydroxyapatite (HA) plays an important role in orthopedics and dentistry due to its excellent bioactivity. However, the thermal decomposition and the poor corrosion resistance in an acid environment have restricted the applications of HA. In this study, several fluorine-substituted hydroxyapatite (FHA) ceramics with the general chemical formula Ca10(PO4)6(OH)(2-2x)F2x, where x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, were prepared. Thermogravimetric analysis in the temperature range from 25 degrees C to 1400 degrees C showed that the FHA ceramics with x > 0.4 had remarkably improved thermal stability as compared to pure HA. X-ray diffraction of the FHA ceramics sintered at 1300 degrees C for 1 h further confirmed the thermal stability. Dilatometer analysis showed that the fluorine addition substantially increased the onset sintering temperature of the FHA ceramics. Density measurements showed that the fluorine addition into the HA matrices slightly retarded the densification of the FHA ceramics. Corrosion testing on the polished surfaces of the FHA ceramics using a 2.5 wt% citric acid solution indicated that the FHA ceramics with x > or = 0.4 had substantially improved corrosion resistance.
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http://dx.doi.org/10.1016/j.biomaterials.2004.04.027 | DOI Listing |
J Mech Behav Biomed Mater
January 2022
Orthopaedic and Plastic Surgery Research Laboratory, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, 84148, USA; Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT, 84112, USA. Electronic address:
Purpose: Hydroxyapatite (HA) scaffolds are common replacement materials used in the clinical management of critical-sized bone defects. This study was undertaken to examine the potential benefits of fluoridated derivatives of hydroxyapatite, fluorapatite (FA), and fluorohydroxyapatite (FHA) as bone scaffolds in conjunction with adipose-derived stem cells (ADSCs). If FHA and FA surfaces could drive the differentiation of stem cells to an osteogenic phenotype, the combination of these ceramic scaffolds with ADSCs could produce materials with mechanical strength and remodeling potential comparable to autologous bone.
View Article and Find Full Text PDFJ Mater Chem B
June 2021
Institute of Science and Technology for Ceramics (ISTEC), National Research Council (CNR), Via Granarolo 64, 48018 Faenza, Italy.
Amorphous calcium phosphate (ACP) is a material of high interest for dentistry, orthopedics, and other biomedical sectors. Being intrinsically metastable, the process of transformation of ACP into a crystalline phase upon heating is of high relevance for the development of innovative bioceramics. Here we have first studied the thermal behavior of a citrate-stabilized ACP (Cit-ACP) also doped with fluoride ions (Cit-FACP) prepared at three different nominal Cit/Ca ratios (i.
View Article and Find Full Text PDFMaterials (Basel)
February 2021
Department of Prosthodontics, Faculty of Dentistry, Ataturk University, 25030 Erzurum, Turkey.
J Nanosci Nanotechnol
June 2018
School of Materials Science and Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of Thin Film and Coatings, Hohhot 010051, Inner Mongolia, China.
Hydroxyapatite (HA) ceramics have important biomedical applications as hard tissue replacements. However, the mechanical properties and chemical stability of HA ceramics in physiological environments need to be tailored for specific applications. To improve the mechanical properties of HA ceramics, carbon nanotubes (CNTs) are introduced into HA matrix materials by an in-situ chemical synthesis method.
View Article and Find Full Text PDFJ Prosthet Dent
December 2016
Full Professor, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea. Electronic address:
Statement Of Problem: Fit is an important factor influencing the success or failure of restorations. Recently, there has been increasing use of a newly developed pre-sintered soft alloy for use in computer-aided design and computer-aided manufacturing (CAD-CAM) of cobalt-chromium alloys for the fabrication of metal ceramic restorations. However, almost no studies are available on the fit of restorations fabricated in this way.
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