Dr. Alessandro Alan Porporati: ‘Transition to ceramic materials in implant dentistry is a matter of time’
Image: Dr. Alessandro Alan Porporati
This interview was first published on frag-pip.de.
About the expert
Dr. Alessandro Alan Porporati is a distinguished expert in zirconia-based materials and has extensive expertise in the field of hip arthroplasty. He has been involved in the development and clinical application of high-performance ceramics for orthopaedic and dental implants for over two decades. He currently works as Director of Medical and Scientific Affairs in the medical products department of the CeramTec Group in Plochingen, Germany.
In your lecture at the DEGUZ annual meeting, you pointed out that the transition to ceramic materials in implant dentistry is a matter of time given the trend towards the use of ceramics in hip arthroplasty over the last two decades. Could you explain it in detail?
Dr. Alessandro Alan Porporati: Indeed, I believe that the transition to ceramics is just a matter of time – mainly because we’ve already experienced this shift in hip arthroplasty. At the beginning of total hip arthroplasty (THA) surgery in the early 2000s, CoCr and stainless steel were the materials of choice for implants, but in the last two decades there has been a clear and steady move towards ceramic materials. This shift to ceramics is clearly reflected in the registry data. In Germany, according to the EPRD (Endoprothesenregister Deutschland), over 90% of femoral heads used in primary total hip replacements in 2023 were ceramic, making ceramic by far the dominant material. In the UK, the National Joint Registry reported that about 59% of femoral heads in 2023 were ceramic, making them the clear majority choice. In the United States, recent registry data show that more than 80% of femoral heads in primary hip replacements are now ceramic – a significant and consistent preference. Not only are the registry data convincing, but long-term clinical and scientific evidence also shows that orthopaedic surgeons are increasingly choosing ceramic components because they are more wear-resistant, biocompatible, and they reduce metal-related complications such as adverse local tissue reactions. Moreover, over the last decade, a growing body of evidence has shown that ceramic bearings reduce the risk of revision due to infection. These same advantages can also be applied to dental implants. In implant dentistry, we’re following the path that orthopaedic surgery has already paved. The materials have matured, the clinical results are convincing, and as more data come in, the confidence in ceramics keeps growing. So yes, as in hip arthroplasty, I think it’s only a matter of time before ceramics share the dental implant market with titanium.
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So, while both applications rely on high-performance materials, dental implants place even greater demands on corrosion resistance, immunological profile, and appearance – which is exactly why advanced ceramics such as monolithic zirconia and alumina-toughened zirconia (ATZ) are becoming so important in this field.
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What are the key requirements for materials used in dental implants compared to those used in hip replacements?
Dr. Alessandro Alan Porporati: That’s an important question, because while hip and dental implants might seem very different, the materials used share a lot of performance requirements, although weighted differently – but also diverge in some key areas. Both applications demand materials with excellent biocompatibility, fracture strength and toughness, and chemical stability. These are the foundation and key material properties for long-term performance under load and in contact with living tissue. But in implant dentistry, the challenges go even further. The oral cavity is a much more hostile environment – it’s constantly exposed to saliva, fluctuating pH levels, and temperature changes, and it’s subject to bacterial colonization. Corrosion resistance is, therefore, the most important prerequisite for success as a dental material in comparison to the hip, where wear resistance is the most important property of the bearing material. Another point is aesthetics. This is a requirement in which zirconia outperforms titanium. For dental implants, the material’s colour and translucency really matter, especially in visible areas such as the front teeth. That’s not something we think about with hip implants. In contrast to the hip, dental implants are in direct contact with the bone and therefore require an optimized surface modification, which supports osseointegration.
So, while both applications rely on high-performance materials, dental implants place even greater demands on corrosion resistance, immunological profile, and appearance – which is exactly why advanced ceramics such as monolithic zirconia and alumina-toughened zirconia (ATZ) are becoming so important in this field.
To what extent is corrosion resistance as part of the biocompatibility concept important when it comes to long-term implant success?
Dr. Alessandro Alan Porporati: The term ‘biocompatibility’ was first defined in 1985 and described ‘the ability of a material to show an appropriate host response in a specific application’. However, with socio-cultural developments in the last decades, the requirements and demands on the materials have also changed. So, the aspect of function of the definition stating “the ability to perform its desired function” has become critical to improve patient satisfaction. Biocompatibility isn’t just about a material not being toxic – it’s about how well the material interacts with the body over time. In the case of dental implants, a biocompatible material needs to perform its medical function without causing any harmful local or systemic effects. It should support the healing process, promote osseointegration, and avoid triggering any undesired and uncontrolled inflammatory response. This means that the body accepts them, integrates them and essentially treats them as part of itself, while also being aesthetically pleasing. Biocompatibility is not just a technical requirement – it’s fundamental to long-term implant success. But in the mouth, biocompatibility is really put to the test because the oral environment is extremely hostile: implant materials are constantly bathed in saliva, exposed to pH fluctuations (which can drop to around 2 under plaque), and face mechanical forces of up to 1,000 N during chewing. All of this means that corrosion resistance becomes one of the main prerequisites for biocompatibility.
In your presentation, you said that ceramics in implant dentistry are now considered ‘mature’. What exactly do you mean by that?
Dr. Alessandro Alan Porporati: What I meant is that ceramics have gone through the full innovation cycle. If you look at the evolution of ceramic materials in implant dentistry – especially zirconia and its composites such as ATZ – they’ve moved beyond the early hype and uncertainty. In the beginning, there were very high expectations, but also scepticism due to issues with earlier materials, which didn’t perform well enough in dental applications. That was followed by a period of disillusionment, where adoption slowed as limitations became clearer. But over time, with better manufacturing processes and clinical validation, we’ve reached what we might call the “plateau of productivity”. Today, dental implants made of high-performance ceramics are no longer experimental – they’re supported, for instance, by 10-year clinical evidence showing over 95% survival rates. We now know how to work with these materials, and they meet both functional and biological demands. So, in short, ceramics in implant dentistry are a reliable and mature option, ready for clinical use. However, one should always bear in mind that the production of advanced ceramics requires a high level of know-how, which means that zirconia composites that appear identical can exhibit completely different performance characteristics.
Are there other factors that have been significant in the evolution of dental systems and contributed to a wider usage of ceramic implants?
Dr. Alessandro Alan Porporati: Looking back, there are definitely a few key milestones that really shaped the evolution of dental implants. One of the earliest was in 1962, when Dr. Sami Sandhaus patented the crystalline bone screw system made of alumina – that was the CBS system. That laid the groundwork for ceramics in dental use. It is worth mentioning that that implant made of Degussit was produced by Rosenthal Technik AG, a distant cousin in the CeramTec world. In 1965, Prof. Per-Ingvar Brånemark introduced the first titanium implant in a human, which became the gold standard for decades and brought the concept of osseointegration into clinical practice. In 1972, oral surgeons in Japan started using synthetic sapphire in clinical dental settings, and by 1977, Brånemark's osseointegrated titanium fixture had shown real clinical success. Another big step came in 1985, when Dr. Sandhaus developed the SIGMA implant made from zirconia, which was a major breakthrough for ceramic-based systems. Then in the early 1990s, research by Miani and Akagawa demonstrated that zirconia implants could also successfully osseointegrate, which helped build clinical confidence in zirconia-based ceramics as a real alternative to metals. So overall, it’s been a gradual shift – from metals to more biocompatible and aesthetic materials such as ceramics – but each of those milestones helped push the use of ceramic implants forward, as ceramic technology was improving in tandem with implant design.
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So, when you put it all together – better cell compatibility, higher osteogenic differentiation, and better bacterial resistance – zirconia and ATZ aren’t just an alternative to titanium. In many ways, it’s a clinically more advanced solution for modern implant dentistry.
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Given the growing interest in ceramic implant materials, particularly zirconia composites, how do they compare to titanium in terms of biological performance?
Alessandro Alan Porporati: Titanium is a widely accepted material in implant dentistry. At the same time, zirconia composites such as alumina-toughened zirconia (ATZ) and zirconia, are slowly proving themselves to perform equally or better in all three areas – cytocompatibility, bone regeneration, and bacterial resistance. Preliminary scientific data show that zirconia and ATZ surfaces support osteoblast adhesion and metabolic activity, comparable to titanium Grade 4. That means that bone-forming cells interact with and adhere to zirconia and ATZ surfaces, which confirms their cytocompatibility and which is also key for successful osseointegration. At the same time, zirconia and ATZ show lower cytotoxicity in comparison to TiGr4, providing a safe and stable environment for surrounding tissues. Another crucial factor is the osteogenic potential. Preliminary data from an ongoing study show significantly increased expression of key osteogenic differentiation markers – ALP, COL1A, and OCN – on zirconia and ATZ surfaces compared to titanium, confirming the osteogenic potential of zirconia and ATZ. And finally, perhaps most importantly in clinical practice, zirconia and ATZ have a strong bacteriostatic effect. Ongoing in vitro studies show reduced bacterial activity and viability of periodontal pathogens such as P. gingivalis and A. actinomycetemcomitans on ATZ and zirconia surfaces. These are two of the main periodontal bacterial strains involved in peri-implantitis, which can lead to implant failure. Titanium, on the other hand, showed higher levels of bacterial colonization. So, when you put it all together – better cell compatibility, higher osteogenic differentiation, and better bacterial resistance – zirconia and ATZ aren’t just an alternative to titanium. In many ways, it’s a clinically more advanced solution for modern implant dentistry.
You stated that hip arthroplasty teaches us that transition to ceramic implants is a matter of time. How does that relate to the future of ceramics in implant dentistry?
Dr. Alessandro Alan Porporati: That statement reflects the pattern we’ve seen in both fields. In hip arthroplasty, alumina ceramics were the first to gain acceptance. Over time, alumina-based composites such as ZTA matured and became standard because of their superior performance. It didn’t happen overnight – it took decades of development, data collection, and clinical refinement. Now, if we look at implant dentistry, it’s almost a mirror image, just offset in time. Zirconia and ATZ are now where ZTA was in orthopaedics about 15–20 years ago – clinically proven, safe, and ready for broader adoption. It’s the material evolution repeating itself in a different field. So, ceramics are successful when the technology and clinical understanding catch up. However, it should be emphasized that the real-world data provided by arthroplasty registries have significantly contributed to improving medical decision-making and to demonstrating the superior long-term performance of ceramic bearings compared to metal bearings. In implant dentistry, that time is now.
So exciting. Thank you very much for this conversation, Dr. Porporati.
Thank you too.
