Metal implants
Inventors
Pickford, Martin Edward Lee • Lewis, David Richard • Turner, Andrew Derek
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-9011665-B2
Publication Date
2015-04-21
Expiration Date
Abstract
A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer is grown by anodizing at a voltage between 50 and 150 V, and the biocidal material incorporated in it by ion exchange. This produces a significantly harder surface than anodizing at low voltage, and generates pits containing ion-absorbing material.
Core Innovation
The invention concerns a titanium metal implant for use in a surgical procedure that has an integral mirror finish surface layer with a hard anodized layer including pits. The hard layer has a thickness between 0.07 microns and 0.7 microns and a coloured appearance determined by the thickness. The pits have a diameter about 5 microns and occupy between 15 and 20% of the surface area of the surface layer.
The pits extend through the hard layer into the metal substrate and are filled with a softer and more porous material than the hard layer. The softer and more porous material comprises hydrous titanium dioxide. The softer and more porous material in the pits absorbs biocidal metal material to a larger extent than the hard layer.
The surface layer comprises a surface area and includes ion exchange so that the hard layer and the pits include ions of a biocidal metal material. In addition, a phosphate matrix is present at the surface layer of the metal substrate, and the phosphate matrix comprises biocidal metal ions. The implant thereby provides a surface layer in which the biocidal metal material is incorporated in both the hard layer and the phosphate matrix and is preferentially absorbed in the porous hydrous titanium dioxide present in the pits.
Claims Coverage
The patent includes two independent claims: one directed to a titanium metal implant having a specific integral anodized, pitted, phosphate-matrix surface structure with ion-exchanged biocidal metal, and another directed to a method for forming such a surface layer and incorporating biocidal metal by ion exchange. Across the independent claims, the inventive features focus on the mirror finish anodized hard layer with defined pit morphology, hydrous titanium dioxide-filled pits, phosphate matrix containing biocidal metal ions, and preferential absorption of biocidal metal in the porous pit material.
Mirror-finish pitted anodized hard layer with hydrous titanium dioxide-filled pits
A titanium metal implant for use in a surgical procedure having a mirror finish surface layer integral with the metal substrate, wherein the surface layer is an anodized hard layer including pits extending through the hard layer into the metal substrate, the hard layer having a thickness between 0.07 microns and 0.7 microns, the pits being of a diameter about 5 microns and occupying between 15 and 20% of the surface area, and the pits being filled with hydrous titanium dioxide that is softer and more porous than the hard layer.
Preferential absorption and ion exchange of biocidal metal into pit material and hard layer with phosphate matrix
An implant in which the hard layer and the pits include ions of a biocidal metal material as a result of ion exchange, with the more porous material in the pits absorbing biocidal metal material to a larger extent than the hard layer, and wherein a phosphate matrix is present at the surface layer comprising biocidal metal ions.
Method of polishing, phosphoric-acid anodising to retain mirror finish, pit generation, and ion exchange
A method of treating a titanium metal implant comprised of a metal substrate for use in a surgical procedure, including polishing to obtain a mirror finish, anodising the implant for forming a surface layer integral with the metal substrate, rinsing, and performing ion exchange to incorporate ions of a biocidal metal into the surface layer, wherein anodising comprises applying a voltage between 50 volts and 150 volts to the surface of the implant in an electrolyte comprising phosphoric acid of concentration between 5% and 20% by weight, for a period of more than 30 minutes, while the surface retains a mirror finish after the anodising step, and the anodising is performed for sufficient time to initially generate a dense hard surface layer and then generate shallow pits filled with hydrous titanium dioxide that is somewhat softer and more porous.
Defined pit morphology and preferential biocidal uptake during ion exchange
A method in which the surface layer includes pits of a diameter about 5 microns occupying between 15% and 20% of the surface area, the pits extend through the hard layer into the metal substrate, and in the ion exchange step the more porous material in the pits absorbs biocidal metal to a larger extent than the hard layer.
The independent claims cover a titanium surgical implant having an integral mirror-finish anodized hard layer with hydrous titanium dioxide-filled pits and a phosphate matrix containing biocidal metal ions, where pits preferentially absorb biocidal metal, and a corresponding method using polishing, phosphoric-acid anodising with defined conditions to retain a mirror finish while generating dense hard layer and hydrous titanium dioxide-filled pits, followed by ion exchange to incorporate biocidal metal with preferential uptake into the porous pit material.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Titanium metal implant for use in a surgical procedure.
Treating a titanium metal implant for use in a surgical procedure by polishing, anodising, rinsing, and ion exchange to incorporate biocidal metal into the surface layer.
Interested in licensing this patent?