Biomedical Engineering Reference
In-Depth Information
of ers this dei nition of a biomaterial: “a material intended to interface with
biological systems to evaluate, treat, augment, or replace any tissue, organ,
or function of the body [174].” Nanostructured metals are already i nding
use in dental implants and are being evaluated for other medical applica-
tions such as intramedullary nails, as described below. For example, the
Nanoimplant dental implant has been manufactured and marketed since
2006 by Timplant in the Czech Republic (see Section 1.2.1). h is was the
i rst medical device to be made from nanostructured titanium. One of
the next nanostructured titanium products, also a dental implant, was
manufactured and marketed by BASIC Dental Implant Systems under the
trademark Biotanium in the USA beginning in 2011. h e nanostructured
titanium for both these products was fabricated by NanoMet LLC. (Ufa,
Russia). We will examine prospective new applications in the sections
that follow.
1.2.1
Nanostructured Titanium and its Alloys
Titanium and its alloys are widely used for medical implants in trauma
surgery, orthopedic and oral medicine [3, 175, 176]. Successful incorpo-
ration of these materials in design, fabrication and application of medi-
cal devices requires that they meet several critical criteria. Of paramount
importance is their biocompatibility, as determined in part by their rela-
tive degree of reactivity with human tissues. Another criterion for medical
devices is their ability to provide sui cient mechanical strength, especially
under cyclic loading conditions. Finally the material should be machinable
and formable, thereby enabling device fabrication at an af ordable cost.
Recent studies have shown that nanostructuring of titanium and its alloys
by severe plastic deformation (SPD) opens new avenues and concepts for
medical implants, providing benei ts in multiple areas of medical device
technology. Results of processing these materials, including their proper-
ties relevant to advanced medical applications are presented below.
1.2.1.1
Commercially Pure Titanium
Numerous clinical studies of medical devices fabricated from com-
mercial purity (CP) titanium for trauma, orthopedic and oral medicine
have proven its excellent biocompatibility [3]. However, the mechanical
strength of CP titanium is relatively low compared to other metals used in
biomedical devices. Whereas the strength of this material can be increased
by either alloying or secondary processing, for example by rolling or
drawing, these enhancements normally come with some degradation in
