Effect of TiO2-Ag2O additives on the formation of calcium phosphate based functionally graded bioceramics.
TL;DR: In vitro solubility study in phosphate buffer at physiological conditions shows the resorbable nature of these materials and enhanced TCP formation with reduced impurity phases was observed with TiO2-Ag2O addition.
About: This article is published in Biomaterials.The article was published on 2000-10-01. It has received 45 citations till now. The article focuses on the topics: Silver oxide.
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TL;DR: Current biomedical applications of calcium orthophosphate bioceramics include replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery.
1,019 citations
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...ested readers are advised to read the original papers [108,253,254]....
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TL;DR: A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs.
Abstract: Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs.
664 citations
Cites background from "Effect of TiO2-Ag2O additives on th..."
...[562] showed a functionally graded CaP scaffold composed of HAp, TCP, TiO2 and Ag2O in an attempt to improve the scaffold’s mechanical stability and antibacterial activity....
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...Moreover, the decomposition of HAp in the presence of TiO2 leads to the formation of CaTiO3 impurity, and therefore to high adhesion strength [562]....
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TL;DR: In this article, the vibrational spectra for polycrystalline powders of AgO and Ag2O are discussed in relation to its crystal structure, and were found to be consistent with factor group analysis predictions.
Abstract: FT-IR and Raman spectra for polycrystalline powders of silver (I, III) oxide, AgO, and silver (I) oxide, Ag2O, are reported. The vibrational spectra for each oxide are discussed in relation to its crystal structure, and were found to be consistent with factor group analysis predictions. Infrared and Raman spectroscopy, in conjunction with powder XRD, were also used to follow the thermal decomposition of AgO powder in air. Supplementary studies employing differential scanning calorimetry (DSC) and temperature programmed reaction (TPR), provided additional information relevant to the decomposition process. In agreement with mechanisms previously reported, AgO was thermally reduced to metallic silver ia two non-reversible steps, with the intermediate formation of Ag2O. The transformation of AgO to Ag2O occurred with heating in the 373–473 K region, while the product of
this reaction remained stable to temperatures in excess of 623 K. Complete thermal decomposition of the Ag2O intermediate to Ag and O2 occurred at 673 K.
397 citations
TL;DR: A review of bioceramics prepared from calcium orthophosphates can be found in this paper, which belongs to the categories of bioactive and bioresorbable compounds.
Abstract: In the late 1960s, much interest was raised in regard to biomedical applications of various ceramic materials. A little bit later, such materials were named bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30–40 years. Namely, by structural and compositional control, it became possible to choose whether calcium orthophosphate bioceramics were biologically stable once incorporated within the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics—which is able to promote regeneration of bones—was developed. Presently, calcium orthophosphate bioceramics are available in the form of particulates, blocks, cements, coatings, customized designs for specific applications and as injectable composites in a polymer carrier. Current biomedical applications include artificial replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Exploratory studies demonstrate potential applications of calcium orthophosphate bioceramics as scaffolds, drug delivery systems, as well as carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes.
212 citations
TL;DR: Current biomedical applications of CaPO4-based bioceramics include bone augmentations, artificial bone grafts, maxillofacial reconstruction, spinal fusion, periodontal disease repairs and bone fillers after tumor surgery, and future applications comprise drug delivery and tissue engineering purposes.
189 citations
Cites background from "Effect of TiO2-Ag2O additives on th..."
...The interested readers are advised to read the original papers [111, 234, 235]....
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...[234] Manjubala, I....
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References
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TL;DR: A review of the past, present, and future of the hydroxyapatite (HAp)-based biomaterials from the point of view of preparation of hard tissue replacement implants is presented in this paper.
Abstract: This paper reviews the past, present, and future of the hydroxyapatite (HAp)-based biomaterials from the point of view of preparation of hard tissue replacement implants. Properties of the hard tissues are also described. The mechanical reliability of the pure HAp ceramics is low, therefore it cannot be used as artificial teeth or bones. For these reasons, various HAp-based composites have been fabricated, but only the HAp-coated titanium alloys have found wide application. Among the others, the microstructurally controlled HAp ceramics such as fibers/whiskers-reinforced HAp, fibrous HAp-reinforced polymers, or biomimetically fabricated HAp/collagen composites seem to be the most suitable ceramic materials for the future hard tissue replacement implants.
1,892 citations
TL;DR: In this paper, a new process was described for preparing dense polycrystalline hydroxylapatite, which has close theoretical density and is free of fine pores and second phases.
Abstract: A new process is described for preparing dense, polycrystalline hydroxylapatite. This material has close to theoretical density and is free of fine pores and second phases. The best material has an average compressive strength of 917 MN m−2 (133×103 psi), and polished samples have an average tensile strength of 196 MN m−2 (28.4×103 psi). The material is highly translucent, and the degree of translucence depends upon processing conditions. The relationship between processing variables and microstructure, strength, and translucence is described. This dense hydroxylapatite has good promise for bone implants and dental applications.
803 citations
TL;DR: The bone/material interface and the events occurring in the development of this dynamic interface such as cellular response, biodegradation or bioresorption of the materials and their transformation to carbonate hydroxyapatite (CHA) were described.
483 citations
TL;DR: The bactericidal effect of Ag+ AC suggests that Ag+ dissolved out and reacted with E. coli, thus inhibiting its growth, and it was difficult to ascertain any bactericidal effects in the case of Cu2+ and Zn2+ AC.
Abstract: The antimicrobial ceramics (AC) based on hydroxyapatite (HA) were made in a wet chemical process with additions of AgNO3, Cu(NO3)2. 3H2O and Zn(NO3)2. 6H2O. The ACs were composed of metal-ion substituted hydroxyapatite and nitrate-apatite, which was identified by X-ray diffraction. The viable count and turbidity measurement was adopted to observe the antimicrobial effects of the various ACs. The aerobic Escherichia coli was used in the study. An obvious antimicrobial effect against E. coli was observed in Ag+ AC. In contrast to Ag+ AC, it was difficult to ascertain any bactericidal effect in the case of Cu2+ and Zn2+ AC. The bactericidal effect of Ag+ was observed using a dialysis tube experiment. This suggests that Ag+ dissolved out and reacted with E. coli, thus inhibiting its growth.
435 citations
TL;DR: In this article, the authors show that dense nanostructured titania, with density >99% of the theoretical maximum and an average grain size of less than 60 nm, can be prepared by sintering a titanium oxide sol gel near the anatase-rutile phase transformation temperature (about 600 °C).
Abstract: NANOPHASE materials, characterized by an ultrafine grain size, have stimulated much interest in recent years1–11 by virtue of their unusual mechanical, electrical, optical and magnetic properties. Nanophase ceramics are of particular interest because they are more ductile at elevated temperatures than are coarse-grained ceramics11—an important property for the fabrication of ceramic components. Preparing materials that are both dense and fine-grained, however, has proved difficult: the high sintering temperatures generally required to obtain high densities can also lead to exaggerated grain growth, resulting in coarse-grained, nonuni-form materials. Sintering at lower temperatures gives a much finer grain size, but does not in general result in high-density materials. We show here that dense nanostructured titania, with density >99% of the theoretical maximum and an average grain size of less than 60 nm, can be prepared by sintering a titanium oxide sol gel near the anatase–rutile phase transformation temperature (about 600 °C). The increased mobility of the atoms during the phase transformation enhances the sintering rate at lower temperatures, suggesting that this method could be used more generally to produce nanophase materials with near theoretical densities.
342 citations