The press technique turns 30 – the beginnings of an esthetic revolution – Part 1

“He scorched his hands and he had burn blisters. The room would be filled with smoke, because he had tried out something new.” Thirty years ago, the press technique was in its infancy and things were not always easy. It took a long time to refine until it fully met the requirements of dental technicians and patients alike. But how exactly did the press system from Ivoclar Vivadent come into existence and how did it evolve into what it is today? We invite you to join us on a trip into the past to learn more about how the system was developed and how its success story proceeded to unfold.

The beginnings of pressed ceramics and the hot-pressing technique from Ivoclar Vivadent date back to the 1980s. Arnold Wohlwend felt that it should be possible to produce restorations that are metal-free and so he started exploring possibilities at the University of Zurich. This is how pressed ceramics came into being 30 years ago. Since this time, Ivoclar Vivadent has played an active part in further developing this technology.

“We were able to harness the synergistic effects and develop a successful solution as a team.”

Marcel Schweiger, the current Director R&D Inorganic Chemistry at Ivoclar Vivadent, explains which factors played a pivotal role in the development of the press technique: “Our development work was mainly driven by the demand from patients for fully-fledged, esthetic restorations in the anterior region in particular. Dental professionals from outside the company provided us with a clear indication of the user needs that we would have to address. We joined forces with them to come up with new ideas. The knowledge and experience of many different individuals was gathered in the process. We were able to draw on Ivoclar Vivadent’s expertise in the development of materials and furnaces and on the clinical know-how of our external partners and on the technical laboratory know-how. We harnessed all these synergistic effects to develop a successful solution together.” The excellent collaboration between the experts from Ivoclar Vivadent and the dental technicians and dentists of the University of Zurich was instrumental to the successful development of the press system. Dr med. dent. Urs Brodbeck was a key member of the University of Zurich team and a staunch supporter of the project.

Failed all-ceramic products prior to 1991: “High-risk products just for show”

Urs Brodbeck remembers the first all-ceramic products that appeared on the market: “Before Ivoclar Vivadent launched its press technique, all-ceramic restorations were high-risk products just for show purposes. There were people who would exhibit only their most sophisticated cases and everyone would be in awe of them. Nevertheless, when we all got together at the bar in the evening and I would on occasion ask why we were not shown any follow-up photos, I would be told that half of the restorations had failed. This motivated us to develop a reliable product that would satisfy patients for a long time and deliver exceptional performance even behind the scenes.”

As emphasized by Urs Brodbeck the main challenges in the development of all-ceramics was to ensure the high strength and durability of the material. It was very difficult to produce a material that could replicate the properties of existing restoratives and withstand intraoral forces. Therefore, the invention of the first all-ceramic material was a tremendous breakthrough in esthetic dentistry. Urs Brodbeck experienced the development process first hand in the dental laboratory of Arnold Wohlwend at the University of Zurich: “I always said to Arnold that he reminds me of Gyro Gearloose. The genius inventor would scorch his hands, and he had burn blisters. The room would be filled with smoke, because he had tried out something new. Then in 1988 Arnold showed us his first press ingots. Unbelievably, there were two types: T1 and T2!” These two press ingots would become the cornerstone of today’s press system. They were composed of leucite-reinforced glass. Due to their specific properties, they were primarily used to produce anterior teeth. In order to develop even stronger materials, the collaboration with Ivoclar Vivadent continued, culminating with the creation of a pressable lithium disilicate ceramic.

“International studies right from the beginning”

The longevity and strength of the lithium disilicate ceramic has been scientifically studied since the material’s beginnings. The excellent clinical reliability^[1] of the material gives patients peace of mind, because they can depend on their restorations to last a long time. Marcel Schweiger is pleased about the strong performance of the material and remembers the initial studies conducted on press ceramics: “Our clinical data, which we have been compiling right from the beginning, that is, since 2002/2003, show that the press technique is responsible for very high survival rates – well above 90 % over the years^[2]. The clinical performance of the product system is quite impressive.” It is monitored by various international study centres in Europe, the US and Asia. The material itself and the life span of restorations made with it have been analyzed and verified over many years.^[2]

“A part of a complete system”

The press ceramics are not the sole components of the system. Marcel Schweiger explains: “It was extremely important to think through the entire process from the beginning to the end. What do users want? What do dental technicians, dental practitioners and ultimately patients need? All their requirements had to be fulfilled. It all started with the press ingots. However, they are by far not the final dental restorations. They are a part of a complete system. The furnace, for example, is an instrumental component because it is required for shaping the material into the restorations. For the dental practitioner and the patient, it is important for the restorations to accommodate adhesive cementation in order to achieve a sound bond to the natural tooth structure”. And so, the press technique gradually evolved into what it is today: a comprehensive and coordinated system.

Thirty years ago, the hot-pressing technique marked the advent of an esthetic revolution. Ivoclar Vivadent developed this system together with experts from the dental field. Meeting the needs of patients was always at the forefront of the development efforts. Before the system could be properly launched, however, Ivoclar Vivadent had to overcome certain challenges. Part 2 describes the difficulties that arose, the relevance of the press technique today and how the success story is expected to unfold in the future.