title: Acceleration of apatite nucleation on microrough bioactive titanium for bone-replacing implants.
abstract: The viability of a new two-step method for obtaining bioactive microrough titanium surfaces for bone replacing implants has been evaluated. The method consists of (1) Grit blasting on titanium surface to roughen it; and (2) Thermo-chemical treating to obtain a bioactive surface with bone-bonding ability by means of nucleating and growing an apatite layer on the treated surface of the metal. The aim of this work is to evaluate the effect of surface roughness and chemical composition of the grit-blasting particles on the ability of the surfaces of nucleating and growing a homogeneous apatite layer. The determination and kinetics of the nucleation and growing of the apatite layer on the surfaces has mainly been studied with environmental scanning electron microscopy (ESEM) and grazing-incidence X-ray diffractometry. The results show that Al(2)O(3)-blasted and thermochemically-treated titanium surfaces accelerates nucleation of the apatite, whereas SiC-blasted and thermochemically-treated titanium surfaces inhibits apatite nucleation, compared with the well studied polished and thermochemically-treated titanium surfaces. The acceleration of the apatite nucleation on the Al(2)O(3)-blasted microrough titanium surfaces is because concave parts of the microroughness that are obtained during grit blasting provides to the rough and bioactive surfaces with a chemical- and electrostatic-favored situation for apatite nucleation. This consists of a high density of surface negative charges (also assisted by the nanoroughness of the surface obtained after the thermochemical treatment) and an increased concentration of the Ca(2+)-ions of the fluid, which have a limited mobility at the bottom of the concave parts.
authors.affiliation: Department of Materials Science and Metallurgical Engineering, E.T.S.E.I.B. Technical University of Catalonia, Avda. Diagonal 647, Barcelona 08028, Spain. conrado.aparicio@upc.edu
authors.forename: C
authors.initials: C
authors.lastname: Aparicio
authors.forename: J M
authors.initials: JM
authors.lastname: Manero
authors.forename: F
authors.initials: F
authors.lastname: Conde
authors.forename: M
authors.initials: M
authors.lastname: Pegueroles
authors.forename: J A
authors.initials: JA
authors.lastname: Planell
authors.forename: M
authors.initials: M
authors.lastname: Vallet-Regí
authors.forename: F J
authors.initials: FJ
authors.lastname: Gil
mesh_terms: D000537:Aluminum Oxide; D001031:Apatites / Q000627:therapeutic use*; D001672:Biocompatible Materials; D018786:Bone Substitutes / Q000138:chemical synthesis* / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis* / Q000737:chemistry*; D008422:Materials Testing; D013499:Surface Properties; D014025:Titanium / Q000627:therapeutic use*
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D014025:Titanium; D000537:Aluminum Oxide