Materiales biocerámicos cristalinos

[EN] A strong interest in the use of ceramics for biomedical engineering applications developed in the late 1960´s. Used initially as alternatives to metallic materials in order to increase the biocompatibility of implants, bioceramics have become a diverse class of biomaterials, presently including three basic types: relatively bioinert ceramics; bioactive or surface reactive bioceramics and bioresorbable ceramics. This review will only refer to bioceramics “sensus stricto”, it is to say, those ceramic materials constituted for nonmetallic inorganic compounds, crystallines and consolidated by thermal treatments of powders to high temperatures. Leaving bioglasses, glass-ceramics and biocements apart, since, although all of them are obtained by thermal treatments to high temperatures, the first are amorphous, the second are obtained by desvitrification of a glass and in them vitreous phase normally prevails on the crystalline phases and the third are consolidated by means of a hydraulic or chemical reaction to room temperature. A review of the composition, physiochemical properties and biological behaviour of the principal types of crystalline bioceramics is given, based on the literature data and on the own experience of the authors.[ES] A finales de los años sesenta se despertó un gran interés por el uso de los materiales cerámicos para aplicaciones biomédicas. Inicialmente utilizados como una alternativa a los materiales metálicos, con el propósito de incrementar la biocompatibilidad de los implantes, las biocerámicas se han convertido en una clase diversa de biomateriales, incluyendo actualmente tres tipos: cerámicas cuasi inertes; cerámicas bioactivas o reactivas superficialmente y cerámicas reabsorbibles o biodegradables. En la presente revisión se hace referencia a las biocerámicas en sentido estricto, es decir, a aquellos materiales constitutitos por compuestos inorgánicos no metálicos, cristalinos y consolidados mediante tratamientos térmicos a altas temperaturas. Dejando aparte los biovidrios, los vitrocerámicos y los biocementos, puesto que, si bien todos ellos son obtenidos por tratamiento térmicos a altas temperaturas, los primeros son amorfos, los segundos son obtenidos por desvitrificación de un vidrio, prevaleciendo normalmente la fase vítrea sobre las fases cristalinas, y los terceros son consolidados mediante una reacción química o hidráulica a temperatura ambiente. Así pues, teniendo en cuenta la abundante bibliografía sobre el tema y la experiencia propia de los autores, se presenta una revisión de la composición, propiedades fisicoquímicas, aplicaciones y comportamiento biológico de los principales tipos de biocerámicas cristalinas.The authors thank to CICYT the financial support of the Project MAT2003-08331-C02-01-02.Peer reviewe

Vidrios y Vitrocerámicos Bioactivos

[EN] Since the late 1960´s, a great interest in the use of bioceramic materials for biomedical applications has been developed. In a previous paper, the authors reviewed crystalline bioceramic materials "sensus stricto", it is to say, those ceramic materials, constituted for non-metallic inorganic compounds, crystallines and consolidates by thermal treatment of powders at high temperature. In the present review, the authors deal with those called bioactive glasses and glassceramics. Although all of them are also obtained by thermal treatment at high temperature, the first are amorphous and the second are obtained by devitrification of a glass, although the vitreous phase normally prevails on the crystalline phases. After an introduction to the concept of bioactive materials, a short historical review of the bioactive glasses development is made. Its preparation, reactivity in physiological media, mechanism of bonding to living tissues and mechanical strength of the bone-implant interface is also reported. Next, the concept of glass-ceramic and the way of its preparation are exposed. The composition, physicochemical properties and biological behaviour of the principal types of bioactive glasses and glass-ceramic materials: Bioglass®, Ceravital®, Cerabone®, Ilmaplant® and Bioverit® are also reviewed. Finally, a short review on the bioactive-glass coatings and bioactive-composites and most common uses of bioactive-glasses and glass-ceramics are carried out too.[ES] Desde finales de los años sesenta, se ha despertado un gran interés por el uso de los materiales biocerámicos para aplicaciones biomédicas. En un trabajo previo, los autores hicieron una revisión de los denominados materiales biocerámicos cristalinos en sentido estricto, es decir, de aquellos materiales, constituidos por compuestos inorgánicos no metálicos, cristalinos y consolidados mediante tratamientos térmicos a altas temperaturas. En el presente trabajo, los autores revisan el desarrollo de los vidrios bioactivos (biovidrios) y de las vitrocerámicas bioactivas. Si bien todos ellos son obtenidos también por tratamiento térmico a altas temperaturas, los primeros son amorfos y los segundos son obtenidos por desvitrificación de un vidrio, si bien la fase vítrea normalmente predomina sobre las fases cristalinas. Después de una introducción al concepto de material bioactivo, se expone una breve revisión histórica del desarrollo de los vidrios bioactivos. A continuación se describe su obtención, reactividad en suero fisiológico artificial, mecanismo de unión al tejido vivo y resistencia mecánica de la interfaz hueso-implante. Posteriormente, se expone el concepto de material vitrocerámico y el proceso de su obtención así como también se describen los principales tipos de vidrios y vitrocerámicos bioactivos (Bioglass®, Ceravital®, Cerabone®, Ilmaplant® and Bioverit®), sus composiciones, sus propiedades físico-químicas y sus comportamientos biológicos. Finalmente, se lleva a cabo también una corta revisión de los recubrimientos con vidrios bioactivos y de los materiales compuestos (composites) bioactivos así como de los usos más comunes de los vidrios y vitrocerámicos bioactivos.The authors wish to acknowledge funding from Spain’s CICYT within the framework of Projects MAT2003-08331-C02-01-02 and MAT2006-12749-C02-01-02 and Generalitat Valenciana (GVA) ACOMP06/044.Peer reviewe

Influence of Sterilization Techniques on the In Vitro Bioactivity of Pseudowollastonite

The purpose of this study was to investigate the effect of four sterilization methods (Steam autoclave, Hydrogen peroxide plasma, Ethylene oxide, and Gamma sterilization) on the surface chemistry and in vitro bioactivity of polycrystalline pseudowollastonite (psW). psW samples obtained by solid-state reaction sintering were sterilized and soaked in Kokubo et al.’s proposed simulated body fluid (SBF) up to 30 days. The sterilization procedure was found to result in no significant chemical changes in the surface of the samples. On the other hand, a Ca/P layer, of different thickness, identified as hydroxyapatite (HA) like, was developed on all the samples after soaking, although the Ethylene oxide-sterilized samples present a non-homogeneous and B68% thinner HA layer. The psW samples before soaking were analyzed by X-ray diffraction, raman spectroscopy, and scanning electron microscopy (SEM). The interfacial reaction product was examined by SEM fitted with an energy-dispersive X-ray analyzer. Additionally, changes in ionic concentrations at the psW/SBF interface were measuredPeer reviewe

Preparation, characterization and in vitro behavior of a new eutectoidbioceramic.

2014AbstractA new type of bioceramic has been designed and obtained within the sub-system Ca2SiO4–7CaOP2O52SiO2. The selected composition wasthat corresponding to the eutectoid point 69 wt% dicalcium silicate–31 wt% tricalcium phosphate. Sintering behavior, phase evolution andmicrostructural changes were analyzed by XRD and SEM. Bio-reactivity was determined by immersion of materials in simulated body fluid forseveral periods of time as well as studies in human adipose stem cells (hASC). The investigated materials are bio-acceptable since no toxic or otherharmful evidence was detected. A carbonated hydroxyapatite was formed on the surface of the 31R material within 3 days. Cell attachment assayshowed that the ceramics supported the hASC cells adhesion and spreading, and the cells established close contacts with the ceramics after 24 h ofculture. The influence of the microstructure (porosity, grain size and phase composition) on the in vitro behavior of the obtained bioceramics wasalso examined

In Situ Bone-Like Apatite Formation From a Bioeutectic SBF Dynamic Flow

In a previous study, a new ceramic material (Bioeutectic s ), prepared by slow solidification through the eutectic temperaturecomposition region of the wollastonite–tricalcium phosphate system, was found to be bioactive in static-simulated body fluid. The eutectic material reacts by dissolving the pseudowollastonite phase and forming a hydroxyapatite-like porous structure by a pseudomorphic transformation of the tricalcium phosphate lamellae, which in turn mimics porous bone. Later, a hydroxyapatite- like layer is formed by precipitation on the surface of the material. In the present study, the bioactivity of the Bioeutectic s material was assessed in dynamic simulated body fluid in order to improve the ingrowth of new bone into implants (osteointegration). Samples of the material were soaked for 2 weeks in a dynamic simulated body fluid (1 mL/min) at 371C. The experiment showed that there is no precipitation of hydroxyapatitelike layer on the surface of a the material. Otherwise, a complete transformation of the eutectic material takes place, giving rise to a hydroxyapatite artificial porous bone. The dynamic model used in this study may be better than the usual static immersion model in imitating the physiological condition of bone-like apatite formation.Peer reviewe

Human mesenchymalstemcellviability,proliferationanddifferentiation potential inresponsetoceramicchemistryandsurfaceroughness

We investigatedtheeffectoftheceramicchemistryandsurfaceroughnessofpure α-tricalcium phosphate,andalso αTCP dopedwitheither 1.5 wt%or3.0wt%ofdicalciumsilicate(C2S), ontheresponseofadulthumanmesenchymalstemcells(ahMSCs). AhMSCs wereplatedonto ceramic discs,preparedbyasolid-statereaction.Afterbeingsintered,somesampleswerepolishedupto1 μm, whileotherswerekeptas manufactured, whichresultedintwosurfaceroughnessgrades.Viability,proliferationandosteoinductivecapacityweredeterminedfollowing various incubationperiods. The resultsshowedanon-cytotoxiceffectafteranindirectapoptosistest.Celladhesionandproliferationweresurfaceroughness-sensitiveand increased proportionallytotheroughnessofmaterials.Theseobservationsbecamemoreevidentintheunpolished αTCP ceramicdopedwith 1.5 wt%C2S, whichinducedosteoblasticdifferentiationasaresultoftheroughnessandincreasedconcentrationoftheC2S solidsolution in αTCP