Titanium in Medicine: A Look Forward in Alloys, Manufacturing and Distribution
Over the past 50 years, titanium has achieved an impressive record of success in a range of medical products and applications used to improve and extend people’s lives. Mechanical characteristics that have driven it to become the metal of choice in medicine include high strength-to-weight ratio, low modulus, corrosion immunity, low risk of allergic reaction and biocompatibility. Today, the metal and its alloys are used extensively in total joint replacements, dental implants, orthopedic and trauma devices, prosthetics and surgical instruments.
However, the relatively long history of alloy and manufacturing innovations that enabled creation of these multiple product forms now raises the question of what future advances might still be realized and what direction they will take. Hans Schmotzer, of SigmaRC, a technical expert and management consultant in medical new product development, observes, “You have to admit if you look at these fields – devices, hardware products – from a general market and also an investor financial perspective, the market in the developed countries is in a very, very mature state.
“Senior executives in many of the device companies have basically cut R&D spending because they say there’s not much to gain in the foreseeable future with traditional device innovation,” he continues. Schmotzer is one of three experts who weighed in on the outlook for medical titanium during Titanium Europe 2013, sponsored by the International Titanium Association in March, 2013.
Francisco Faoro, of Institut Straumann AG, a leading manufacturer of dental products targeted to premium markets, points out that alloy research and development, on the other hand, remains strong, at least at his firm. The focus remains on titanium, he explains, because biocompatibility and osseointegration requirements limit the selection of materials. “Roxolid™, our new titanium/zirconium implant alloy, took many years to develop, but at the end we have a superior material which has both higher strength and the topography for excellent osseointegration. It’s a combination nobody else has.” Roxolid™ is formulated for small diameter implants in narrow interdental spaces where the tooth must endure high chewing forces.
A leading titanium distributor, Andre Hempel, of Hempel Special Metals, sees changes coming in the specifications required for materials used in manufacturing devices and implants. “What is going to change might be tolerances, surfaces, mainly because of equipment that’s changed. Machinery may require tighter tolerances for automation.” Mergers, especially within a segment, can also lead to feedstock specification modifications, such as in bar lengths used in different manufacturing methods for the same product. Both situations may require additional work at the service center that may influence prices. “You have to take every single piece and put it into a machine. Is it worth the effort? I can’t answer that… I’m not an implant producer.”
Schmotzer says he anticipates “development taking place more in manufacturing technology.” Today, he says, some 80% to 90% of products are still machined from stock, as they have been for 40 years. “I see the manufacturing landscape making evolutionary changes to move to powder-based materials.
“With the development of rapid prototyping and injection molding technologies, I think powder metallurgy is becoming more and more the focus area,” Schmotzer continues. “You are still producing the same devices, but from powder rather than stock. These are simple processes that generate less material waste and allow designs you can’t manufacture cost-effectively from solid material.”
The new powder manufacturing processes also enable creation of custom shapes, fueling a trend toward individualized medicine, according to Schmotzer. “Dental is already highly patient specific and similar trends are taking place, while not to the same degree, in orthopedics.” Additive processes like laser and EB sintering allow greater manufacturing flexibility and hollow or porous structures for example. Metal injection molding can achieve more complex shapes.
Hempel says the next generation of medical titanium product improvements may also require cutting or processing standard mill product materials to specific shapes or profiles. “What we see is innovation comes from design of the product, not chemical composition. Design impacts the shape the OEM needs. They come to us, we go to the mill. Can we provide the profile at a competitive price? We are the go-between, especially if the mill is in the U.S. and the OEM is here in Europe.”
This critical role of the distributor as the mill-OEM go-between reinforces another recent trend Hempel observes for the future: OEMs concentrating their business with fewer distributors, to increase their volumes, control their prices and receive complementary service.
Faoro sees additional future application potential in Straumann’s Roxolid™. “It could be used in fracture care and orthopedics, such as hip or knee replacement. Roxolid™ is biocompatible and has such excellent in-growth capabilities, that it might have potential everywhere this behavior is required.”
Beyond powder technologies, Schmotzer looks for promise in products that separate themselves as unique. For example, he says, titanium has many positive aspects and a single significant drawback: “That is low wear resistance. Wear produces particles with a negative biologic response. Today, processes like anodizing have resolved some of the issues, but if technologies were available that could eliminate the particles, it would open up new applications for titanium.”
“But is that realistic?” he continues. “In some applications you have to live with the limitations. But it would certainly lead to product differentiation. And in a mature market, if you can’t drive fundamental innovation, you need to drive a differentiation campaign by delivering added benefits.”
The representatives of all three medical titanium supplier segments – Francisco Faoro addressing alloy research and development, Andre Hempel speaking about mill product distribution and Hans Schmotzer discussing device manufacturing – expressed optimism regarding the titanium industry’s role in medicine today and in the future, while acknowledging they must recognize the trends in each of their respective customer bases to enjoy continued success.