title: Optimizing thickness of ceramic coatings on plastic components for orthopedic applications: A finite element analysis.
abstract: Realizing hard ceramic coatings on the plastic component of a joint prosthesis can be strategic for the mechanical preservation of the whole implant and to extend its lifetime. Recently, thanks to the Plasma Pulsed Deposition (PPD) method, zirconia coatings on ultra-high molecular weight polyethylene (UHMWPE) substrates resulted in a feasible outcome. Focusing on both the highly specific requirements defined by the biomedical application and the effective possibilities given by the deposition method in the perspectives of technological transfer, it is mandatory to optimize the coating in terms of load bearing capacity. The main goal of this study was to identify through Finite Element Analysis (FEA) the optimal coating thickness that would be able to minimize UHMWPE strain, possible insurgence of cracks within the coating and stresses at coating-substrate interface. Simulations of nanoindentation and microindentation tests were specifically carried out. FEA findings demonstrated that, in general, thickening the zirconia coating strongly reduced the strains in the UHMWPE substrate, although the 1 μm thickness value was identified as critical for the presence of high stresses within the coating and at the interface with the substrate. Therefore, the optimal thickness resulted to be highly dependent on the specific loading condition and final applications.
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy. Electronic address: g.marchiori@biomec.ior.it.
authors.forename: G
authors.initials: G
authors.lastname: Marchiori
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy; Dipartimento di Ingegneria dell'Informazione, Università degli Studi di Brescia, via Branze 38, Brescia, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Lopomo
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Boi
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Berni
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bianchi
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Gambardella
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Visani
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Russo
authors.affiliation: Laboratorio di NanoBiotecnologie - NaBi, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy; Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, via di Barbiano 1/10, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D020342:Finite Element Analysis; D008422:Materials Testing; D009985:Orthopedics / Q000379:methods*; D010969:Plastics / Q000737:chemistry*; D011095:Polyethylenes; D013314:Stress, Mechanical; D015040:Zirconium / Q000737:chemistry
chemical_list: D020099:Coated Materials, Biocompatible; D010969:Plastics; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D015040:Zirconium; C028541:zirconium oxide
keywords: Ceramic coating; Finite element analysis; Indentation; Joint prosthesis; Stress; UHMWPE