Towards long lasting zirconia-based composites for dental implants. Part I: innovative synthesis, microstructural characterization and in vitro stability.
In order to fulfill the clinical requirements for strong, tough and stable ceramics used in dental applications, we designed and developed innovative zirconia-based composites, in which equiaxial α-Al2O3 and elongated SrAl12O19 phases are dispersed in a ceria-stabilized zirconia matrix. The composite powders were prepared by an innovative surface coating route, in which commercial zirconia powders were coated by inorganic precursors of the second phases, which crystallize on the zirconia particles surface under proper thermal treatment. Samples containing four different ceria contents (in the range 10.0-11.5 mol%) were prepared by carefully tailoring the amount of the cerium precursor during the elaboration process. Slip cast green bodies were sintered at 1450 °C for 1 h, leading to fully dense materials. Characterization of composites by SEM and TEM analyses showed highly homogeneous microstructures with an even distribution of both equiaxial and elongated-shape grains inside a very fine zirconia matrix. Ce content plays a major role on aging kinetics, and should be carefully controlled: sample with 10 mol% of ceria were transformable, whereas above 10.5 mol% there is negligible or no transformation during autoclave treatment. Thus, in this paper we show the potential of the innovative surface coating route, which allows a perfect tailoring of the microstructural, morphological and compositional features of the composites; moreover, its processing costs and environmental impacts are limited, which is beneficial for further scale-up and real use in the biomedical field.
Department of Applied Science and Technology, INSTM R.U. PoliTO, LINCE Lab., Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy. Electronic address: paola.palmero@polito.it.
Paola
P
Palmero
Department of Applied Science and Technology, INSTM R.U. PoliTO, LINCE Lab., Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy.
Marta
M
Fornabaio
Department of Applied Science and Technology, INSTM R.U. PoliTO, LINCE Lab., Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy.
Laura
L
Montanaro
Université de Lyon, INSA de Lyon, MATEIS CNRS UMR5510, 20 Avenue Albert Einstein, F-69621 Villeurbanne Cedex, France.
Helen
H
Reveron
Université de Lyon, INSA de Lyon, MATEIS CNRS UMR5510, 20 Avenue Albert Einstein, F-69621 Villeurbanne Cedex, France.
Claude
C
Esnouf
Université de Lyon, INSA de Lyon, MATEIS CNRS UMR5510, 20 Avenue Albert Einstein, F-69621 Villeurbanne Cedex, France; Institut Universitaire de France, 103 bd Saint-Michel, Paris 75005, France.
Jérôme
J
Chevalier
D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry*; D015921:Dental Implants; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D011208:Powders; D013052:Spectrometry, X-Ray Emission; D013818:Thermogravimetry; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
D001672:Biocompatible Materials; D015921:Dental Implants; D011208:Powders; D015040:Zirconium; C028541:zirconium oxide
Ageing; Alumina; Composite; Dental implant; Microstructure; Zirconia