The editors invited me to do it. They felt that the field, which was very much out of the mainstream of the ceramic industry, needed representation to stimulate the interest of the whole ceramics community. In the United States, there were very few manufacturers that were willing to take on bioceramics. In fact, the pioneering work on the inert bioceramics for use in total hip prosthesis has been here in Europe. It's only been in the last year or two that the FDA has approved ceramics for that application, despite 25 years of clinical data on successful use of aluminum oxide hip prostheses in France.

  What is the greatest challenge you've encountered in pursuing bioceramics research?

The greatest challenges are still there today, and those are the commercialization steps: the technology transfer from university labs through the regulatory processes, the capitalization, the clinical trials, and then, subsequently—even when that's all done—the marketing and the acceptance of new materials and new concepts into the clinic.

  Why is it so hard to go from the lab to the clinic?

Well, the pathway has a lot of steps, and the actual value of the material that is put into the patient is such a small fraction of the whole cost so that the returns on investment are often too small to support aggressive commercial action. The existing products have most of the market share, and the big companies have so much invested in them, that it is very difficult to get new materials accepted. Although the total volume of the biomaterials market worldwide is really quite large, the incremental component of it with each new material is quite small. And it tends to get divided up into a lot of little niche products and markets. Here in the UK, for example, there was a survey done of orthopedic surgeons treating National Health Service patients in a population of, say, 10 million people in the Midlands and they were using 40 different types of hip prosthesis over a five-year period of time.

Moreover, the market itself has a host of mine fields that make it even more difficult to get a new material accepted: a product like zirconium oxide ceramic heads, for instance, comes onto the marketplace, and a manufacturing problem occurs and there's a serious problem in a small group of patients, and then manufacturers have to recall all 20,000 of the zirconium oxide heads made in the same period of time. The media then correctly presents this as a problem, that there is a recall and that all these people are affected and so on and so forth. And neither the consumer, who is the patient, or the surgeon, or the hospital administrator doing the ordering understands the difference between, say, standard aluminum oxide ceramics and the new zirconium oxide ceramics. A lot of professional materials people don’t really understand the subtle difference when it involves use in the body. The technology behind it is very complicated. And so if you ask the average orthopedic surgeon, what do you want to use, he'll say the standard prosthesis because he's comfortable with it.

  Was there a single most difficult moment in the course of your research over the years?

In the context of what we were talking about, I think the single most difficult thing was when a former student informed me that a U.S. patent had been issued to two German engineers assigned to a German company, and when I read the patent it was almost a carbon copy of our results from our first few years of research. This was work we had already published in the open literature. It had never entered our minds that there was patentability potential and then we found our work had been essentially pirated into a patent by another company, by engineers who had visited our lab. That was a big shock. This has been a major stumbling block ever since. Any time we tried to bring our new materials into the clinical arena, we had to compare it to this patented German material that hasn't even been used for the past 10 years.

  What important results have emerged in bioceramics since your 1993 review?

Well, I think the most important was work we just recently published. Ever since we discovered these special compositions of glasses in 1969, the first man-made materials to bond to living tissues, we've been trying to understand how and why the biological system is able to incorporate these materials within the living host tissues and not reject them as being foreign. And this last year we discovered the answer to why that happens. It turns out that the glasses slowly dissolve and the dissolution products, the soluble silicon and soluble calcium, actually activate six families of genes in old bone cells that then form new bone cells. These genes stimulate cell division and the synthesis of growth factors that lead to the new bone cells. These cells not only expand in number but also generate collagen and other extracellular matrix proteins that mineralize and form new bone. So we've gone from the late 1960s, when it was generally believed that all materials implanted in the body would be isolated by scar tissue, through the mid-1980s, when it became accepted that a class of materials, called bioactive materials, will form a bond to bone and soft tissues, to this new millennium, when we recognize that certain of those compositions actually work at a genetic level.

  Where was this new work published?

Those new results are what I think are important. And the reason is because they offer a potential pathway for prevention. We are at a time in history when the current approaches toward maintaining the quality of life of an aging population can no longer be afforded, and the numbers of people that are suffering through revision prosthesis in all fields are growing at a critical rate. We need a completely new approach, and the genomic revolution provides us the means of tackling that problem. Now we believe from our results that we will eventually be able to design a way to activate the genes and the stem cells present even in aging people to proliferate and repair tissues. If we can do that, it also means we might be able to get those biological stimuli on a daily basis through appropriate foodstuffs, or additives to foods. So we may actually be able to slow down the deterioration of all our connective tissues. All we need to do to prevent the breakdown of our cardiovascular and skeletal systems is slow deterioration down by about 20% a year; we don’t have to stop it all together. That’s the message. Every talk I give nowadays, I finish on that note: we must work today toward prevention.

Professor L.L. Hench, Ph.D.
Imperial College of Science, Technology, and Medicine
University of London
London, England