| industry Ceramics come of age Prof. Stefan Holst, Switzerland Zirconia has been used in dental applications for de- cades—sometimes successfully, sometimes less so. The first zirconia implants were introduced on an exper- imental basis well before the turn of the century.1 Sys- tems have come and gone. Review the literature or visit a clinic today, and you’ll find that most of the early-phase implants are associated with complications. We’ve seen a range of problems, including fractures during surgery, fractures after loading, mobility, infection, pain, bone loss, and a lack of osseointegration.2 On the mi- crolevel, inconsistent material quality, less-than- optimal manufacturing processes and surface mod- ifications may bear part of the blame. On the macro level, design flaws have led to unfavourable loading conditions. remembering: Zirconia At the heart of this apparent co- nundrum lies a simple fact, well worth is not a metal. Zirconia is a ceramic; and we need to respect the unique properties of this material. Because manufacturing flaws—even minute imperfections—in the production and surface treatment of the zirconia im- plant may compromise strength, great care must be taken with the materials to ensure clinical predictably and favour- able long-term results.2 Consequently, when processing zirconia, it is essential to select the appropriate zirconia powder, the proper powder particles, how to best com- pact these powders, the ideal postprocessing methods, and so on. Choosing the wrong mix of variables can eas- ily lead to early degradation and failure over time. Flaws may not manifest themselves immediately, but micro- and macro- flaws with lag times of three to five years have led to the failure of many zirconia implants. In short, directly applying what we have learned from over 40 years of experience with titanium implants to zirconia does not provide a suitable path forward. In the devel- opment of NobelPearl, we have discovered, for instance, that the implant connection design of a zirconia implant cannot be copied one-to-one from existing titanium im- plants. We’ve also learned a great deal more about the material over recent years. More than ten years ago, Nobel Biocare sponsored clinical trials of a potential product that was not brought to market. Those trials generated neither the data nor the clinical outcomes we require.3 But over the interceding decade our body of knowledge has grown substantially and researchers with whom we collaborate have now reached the point where we can provide a zir- conia implant that is designed to work reliably. Serious challenges to meeting patient demand Looking at the zirconia market from a patient perspec- tive, you see increasing demand. Projected growth in- dicates that although zirconia is very unlikely to re- place titanium as the base material for implants anytime soon—if ever—it is already becoming an alternative wor- thy of attention in certain clinical situa- tions. The intrinsic aesthetic attributes of this material are well known. Per- haps less well-known is the fact that this material manifests beneficial soft- tissue-friendly biological properties.4 Zirconia, as an implant material, has provided some serious challenges to in- novators over the years. Because it is a brittle material, early attempts to make it stronger involved increasing the vol- ume of the product. As a result, early zir- conia implants were predominantly one-piece designs. Unfortunately, such designs have an untoward impact on restorability, placement and intraoral adjustment. No one wants to face these issues on a day-to-day basis with their patients. Development consequently began on two-piece zirconia implants. They were not easy to han- dle and attempts at intraoral cementation of the abut- ment at bone level did not provide the predictable, long- term solution patients deserve. At least one drawback, however, has been associated with the use of the alter- nate choice for retention, screws. When patients ask for a metal-free solution, for instance, and you offer them a two-piece zirconia product, can you in good conscience connect the two pieces with a titanium screw? We at Nobel Biocare don’t think so. Science first Nobel Biocare has invested in fundamentally under- standing the material properties of zirconia and the de- 28 implants 1 2019