Appeal 2007-1526
Application 11/035,534
the implant with a hydrofluoric acid solution of a concentration between
0.01% and 0.5%.
The Examiner found that Haruyuki discloses, inter alia, that treating a
metallic bone implant made of titanium or titanium alloy with hydrofluoric
acid at a concentration of 1% to 6% improves adhesion of the implant to
bone tissue (Answer 4). Haruyuki reports that the HF treatment, at the
above-noted concentration levels, forms “a large number of irregularly
shaped microscopic depressions with an average diameter of 1 to 10 µm and
an average depth of 0.5 to 5 µm” (Haruyuki 4, left column, ll. 3-6).
Haruyuki teaches that “sharp edges and spines” due to this treatment can be
smoothed by a post treatment of the implant with a hydrogen peroxide and
hydrofluoric acid mixed aqueous solution (Haruyuki 4, right column, ll. 5-
9). Haruyuki discloses that it is known to roughen the surface of titanium
implants to improve adhesion of the implant to bone and that even “the
formation of ultrafine, 10 nm to 1,000nm (0.01 µm to 1 µm) pores in the
surface of metal repair members” are known, albeit “the bonding force with
cells is still not always adequate” (Haruyuki 3, left col., ll. 17-23).
The Examiner maintains that it would have been obvious to one of
ordinary skill in the art at the time of the invention to modify the HF
treatment process of Haruyuki by using a concentration of HF in the treating
solution, as called for in representative claim 79, to improve the adhesion of
an implant to bone (Answer 3 and 4). In this regard, Haruyuki teaches that
the concentration of the HF in the treating solution and the treatment time
are result-effective variables in treating implants (Haruyuki 4, left col., ll. 6-
9). The Examiner is basically asserting that an ordinarily skilled artisan
would have recognized using lower concentrations of HF acid was a
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