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With the André Schroeder Research Prizes, the ITI annually singles out two research teams for outstanding work in advancing dental research and development. Forum Implantologicum talked to Dr. Stefan Bienz about his award-winning study “Clinical and histological comparison of the soft tissue morphology between zirconia and titanium dental implants under healthy and experimental mucositis conditions—A randomized controlled clinical trial” and his plans for the future.
Forum Implantologicum (FI): Can you give us a brief outline of your academic career so far?

Stefan Bienz (SB): After graduating in Zurich, Switzerland in 2011, I worked in the private offices of Andreas Grimm and Ueli Grunder/David Schneider. At that time, my aim was to finish my postgraduate education and return to a dental office. Then in 2015, Ronald Jung offered me a position as a research assistant at the University of Zurich. I accepted his offer, honestly without having a clue about what an opportunity I was being given. Afterwards and in combination with the research position, I did my postgraduate education under Christoph Hämmerle and then enjoyed a research stay at the University of Queensland, Australia in the department of Saso Ivanovski. Since then, I have been working in the Clinic of Reconstructive Dentistry at the University of Zurich. This encompasses patient care, aspects of undergraduate and postgraduate education, and research.

FI: How did you become interested in research and more specifically in implant dentistry research?

SB: As mentioned above, I had always seen myself as a clinician. The first steps as a research assistant aroused my curiosity for research. At the time, I was not aware of the fact that I had joined an experienced research group, this was a big piece of luck. Nowadays I am very grateful to be part of the group. At a university, you just keep on learning and this is both motivating and satisfying. There is so much knowledge available – research methodology, statistics, writing and histology, to mention just a few things. After maybe two years I started to understand that this is a wonderful part of the work, in combination with treating patients. During this time I also learned that I am more interested in the biological than in the technical aspects. Combining clinics and research has advantages and disadvantages, of course. I feel very comfortable with our setting and it makes every single day different and interesting.

FI: Would you outline the main theme of your winning study, and also give us some insight into why you chose it.

SB: This study aimed to answer the question whether zirconia performs differently on the level of the soft tissues when compared to titanium under both healthy and mucositis conditions. Zirconia implants have attracted a lot of attention in recent years, and the current level of knowledge claims that they perform similarly on the level of the bone and better on the level of the soft tissues. Therefore, we considered the soft tissue part as relevant for the study outcome. This project could have been performed with zirconia and titanium abutments on bone level implants as well. But by using two one-piece implants made from different materials, we were able to avoid biases such as a micro-gap and we had similar geometries of all parts. When looking back at this project now, our research group is very proud of the within-subject study design and also the overall scale of the project.

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Fig. 1: The André Schroeder Research Prize medallion
FI: What are the main findings of your study?

SB: In brief and within a bigger picture, titanium and zirconia performed similarly. This was actually shown by Abrahamsson and Welander earlier on, that titanium and zirconia outperformed other materials such as gold, resins and veneering ceramic in terms of soft tissue integration. While the results were relatively similar under healthy conditions, there was less plaque accumulation and also less bleeding on probing around zirconia implants under mucositis conditions. This was quite a clear clinical result. Histologically, we were not able to give such a clear answer. This would need a more detailed discussion. An interesting fact is that we did not find any differences in terms of the biological width or the length of the junctional epithelium, as indicated by preclinical studies. There were large differences between patients but not between the two types of implants.

FI: How relevant is this project to daily practice, and how do you think that its findings advance the field of implant dentistry?

SB: Considering the present study, my first preference from a biological point of view in regard to the material on the soft tissue level is zirconia. The prevalence of mucositis is relatively high. It is therefore quite likely that a patient with an implant will develop mucositis at some point. In this particular situation, zirconia could well have the edge. However, there is a technical side as well and, currently, ceramic implants or ceramic abutments on titanium implants have certain limitations. This means that for daily practice, they cannot and should not be used in every patient.

FI: As a recipient of the André Schroeder Research Prize, how do you see the significance of organizations like the ITI for research in the field of implant dentistry?

SB: What I learned in Zurich is that we should raise clinically relevant research questions. Ideally our research ideas should emerge from clinical problems in daily practice. Some of these research ideas are also in the scope of the companies which provide parts or materials and are then often funded by the industry. Others are not, and without the opportunity to apply for grants provided by foundations, these research questions could not be addressed. In addition, this also makes research more independent. This is what I consider most important. Of course, there are many other positive facts, such as education, promotion and networking for young researchers. The André Schroeder Research Prize is a wonderful acknowledgment of the hard work of our team and we are very proud of this achievement.

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Fig. 2: ITI President Charlotte Stilwell presents Stefan Bienz with the 2022 André Schroeder Research Prize for Clinical Research at the ITI Annual Conference in Rome, Italy
FI: If possible, could you share with us some details of your upcoming projects, and what you consider to be "hot topics" in the field of implant dentistry?

SB: Soft tissue integration has become an important topic in the field of implant dentistry. This is, from my perspective, connected with two areas in which we are trying to generate a better clinical understanding. This encompasses surgical soft tissue adaptions on the one hand, where we are focusing on the use of substitute materials. On the other hand, it is strongly connected to the prosthetic field, encompassing emergence profiles, materials and connections and new workflows with fewer interventions.

About the André Schroeder Research Prize

The André Schroeder Research Prizes for Preclinical and Clinical Research are awarded annually with 10,000 Swiss francs for each prize winner. The André Schroeder Research Prize is awarded to independent researchers for advancing dental research and development. The aim is to promote new scientific findings in implant dentistry, oral tissue regeneration and related fields. The award is presented in honor of the late Professor André Schroeder (1918-2004), the founding ITI President, who pioneered implant dentistry and whose lifework contributed significantly to modern dentistry.