Intrabone implants represent artificial supports for teeth and jaw system and locomotor apparatus, which are made of biocompatible materials, mostly titanium alloys. Numerous experimental and clinical investiga tions in Russia and abroad showed that bioceramic calcium-phosphate coatings on the surface of metal implants most actively stimulate their osteointegration (engraftment), thus offering an effective solution of the problem of intrabone structure rejection. Of course, the implant coatings must occur in a required structural phase state and possess a definite combina tion of properties, including high mechanical strength and developed morphological heterogeneity (in par ticular, on a nanometer scale).The implant base is most frequently made of a metal (e.g., titanium and its alloys) and then coated by spraying calcium-phosphate materials such as hydroxyapatite (HA) and tricalcium phosphate. These coatings, supported on metal implants with a proper surface microrelief, actively stimulate osteogenesis. The rate of implant engraftment is determined by its chemical and phase composition and depends on the dimensions of fine structure elements in the surface layer of coatings (in particular, on the presence of nan odimensional grains) [1]. Indeed, it is commonly accepted that the interaction between a biocompatible coating material and biological structures of the organism takes place on a nanometer scale level of col lagen fibrils. The data of atomic force microscopy for the surface of bone trabeculae show that their struc tural components (collagen fibrils) are covered by mineral (HA) plates of medium size (30-200 nm) [2]. Compatibility with biostructures of the bone bed is determined by the characteristics of developed mor phological heterogeneity, in particular, the average grain diameter. In this context, it is a topical task to establish the influence of the regime of preliminary induction heat treatment (IHT) of the titanium base on the average grain size D in plasma sprayed bio ceramic HA coatings, which in turn affects the rate of splat cooling and the character of crystallization.Well known disadvantages of coatings obtained by the traditional thermal spraying include a significant spread of the dimensions of nanograins relative to the average value, high degree of amorphization, and the related nonuniformity of the physical properties. In many cases, the underestimation of these factors leads to a significant decrease in the quality of coatings, which is manifested by insufficient reliability and working life of intrabone implants [3].One of the most important properties of thermally deposited coatings on intrabone implants is the devel oped morphological heterogeneity (i.e., combination of the surface structure elements with a large number of dimensional modes) and uniformity of the distribu tion of nanodimensional grains. It should be noted that the essential elements do not include dusty parti cles of the uppermost surface layer with weak cohe sion. The plasma spraying of HA coatings involves struct...
The article describes prospective composite biocompatible titania coatings modified with hydroxyapatite nanoparticles and obtained on intraosseous implants fabricated from commercially pure titanium. Consistency changes of morphological characteristics and crystalline structure, mechanical properties and biocompatibility of experimental titanium implant coatings obtained by the combination of oxidation and surface modification with hydroxyapatite during induction heat treatment are defined.
The article describes prospective composite biocompatible titania coatings modified with hydroxyapatite nanoparticles and obtained on intraosseous implants fabricated from commercially pure titanium VT1-00. Consistency changes of morphological characteristics, crystalline structure, physical and mechanical properties and biocompatibility of experimental titanium implant coatings obtained by the combination of oxidation and surface modification with hydroxyapatite during induction heat treatment are defined.
The study focuses on the prospective nanostructured plasma-spraying and oxide coatings obtained on commercially pure titanium. Consistency changes of morphological characteristics and crystalline structure, physical, mechanical properties and biocompatibility of titania/hydroxyapatite coatings obtained by the combination of plasma spraying and induction heat treatment are defined.Titanium is widely used in the manufacture of intraosseous implants. Particular attention is paid to obtaining on their surface of biofunctional layer, which stimulates fusion with the bone. The metal substrate of the implant provides resistance to mechanical distributed loads. However, when the implant is installed into the bone bed significant shear stresses occur in the surface layer and abrasion with scratching by hard cortical bone takes place. Considering the above mentioned problem the aim of this work is to develop a technology enabling to obtain biocompatible mechanically durable coatings with increased morphology of micro-and nanostructure on cptitanium using a new method of oxidation by induction heat treatment (IHT) and plasma spraying (PS) of hydroxyapatite (HAp) powder.The samples were prepared from commercially pure (cp) titanium VT1-00. Onto its surface HA coatings were plasma sprayed in air from a distance of 90. . . 130 mm using an electric power of 16 kW, a plasmatron arc current of 540 A, gas (argon) consumption 50 l/min and HAp powder with particle sizes within 90 µm. The substrates were subjected to preliminary IHT at a temperature varied from 20 to 1000°C [1]. The dependence of the average size of nanograins in the plasma sprayed coating on the IHT temperature has been studied.
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