Checking the shade fidelity of a crown made of VITA Press Ceramic using a shade guide

Why you can always rely on the tooth shades from the VITA press ceramic

Find out how VITA employees give their best every day so that you have a robust ceramic in the correct tooth shade.

In your dental laboratory, you work with a press ceramic that has, in theory, proven its worth for you over many years. And yet you weren't, and perhaps aren't, always 100% satisfied with the esthetic results. Perhaps you've asked yourself what the alternatives are, and have heard about VITA AMBRIA lithium disilicate press ceramic. But switching without a second thought from your ceramic to a new press ceramic – that's not something that you could consider. You want to be really sure that you can genuinely trust a new material and manufacturer. That's why we would like to invite you to take a look with us behind the scenes at VITA Zahnfabrik. Find out from dental technician and dental engineer Michael Gödiker (Project Manager Material Development, Bad Saeckingen, Germany) and engineer Michael Hackner (Division Manager Process Technology, Bad Saeckingen, Germany) how VITA handles research and production with real passion on a daily basis to bring you a lithium disilicate press ceramic that you can truly rely on.

From the original formula to a natural-looking tooth shade

Creating a press ceramic that offers excellent shade fidelity and is extremely robust during processing – that was the key goal during the development of VITA AMBRIA. "As a former dental technician, it was particularly important to me to develop a press ceramic that was both robust and esthetic. Nothing is more annoying than realizing after pressing that it hasn't worked“, says Michael Gödiker.

As a trained dental technician, I wanted to develop a lithium disilicate press ceramic that offers genuine shade fidelity and robustness.

So that all shades exactly match the VITA shade standard, over 100 tests are necessary in the technical laboratory: "As a manufacturer of dental materials, we always aim to offer a very broad range of shades“, explains Gödiker: "The shade D2 is rarely used on a daily basis in the laboratory, but if restorations must be fabricated in D2, then the shade has to be absolutely correct. "So that dental technicians can rely on a press ceramic in the correct tooth shades, we move gradually from the basic formulation with base raw materials and chromophoric oxides to the optimum shade formulations for the ceramic", says the dental engineer. In the laboratory, VITA employee Mirella Mannino weighs the different material components for the test series on a precision balance – minute quantities for a handful of prototypes. A formulation is comprised of 10 to 12 components: "You have to work very precisely. Otherwise the formulation won't be correct – and then everything can go wrong on a large scale.“

VITA employee weighing raw materials for the development of a press ceramic
Weighing the material components on the precision balance
VITA employee performing melting tests in the technical laboratory
Pouring the first press pellet prototypes in the test melting system

"So that the press ceramic is both esthetic and fracture-resistant, comprehensive test series are required“, explains Michael Gödiker. After weighing the sample so that it is exact to the last milligram, the ceramic composition is melted in the test melting furnace. Then, wearing fireresistant protective clothing, Mirella Mannino uses a tongs to remove the hot crucible from the furnace. She pours the glowing glass material into the mold that is standing by: the prototypes are then used for shade measurements and other research.

The original formula for tooth shades – one hundred years of VITA expertise

When it comes to shade matching, VITA researchers are assisted by the original VITA formula for dental tooth shades – the VITA classical A1-D4 shade standard that was developed 100 years ago by the company itself and, today, is valid worldwide.
"All tooth-colored dental materials must be matched to this yardstick", says Michael Gödiker. When developing a tooth-colored press ceramic, all of this experience is a considerable advantage: "We not only have the original samples, we also have access to the original substances in order to precisely reproduce the 16 VITA classical shades."

Interview with dental engineer Michael Gödiker

Exact reproduction of A3 calls for precise measurement technology and a lot of experience

How is the shade fidelity of a press ceramic determined? What procedures and methods does this require? "The first step in achieving correct tooth shading is precise shade measurement", explains Michael Gödiker. In order to ensure that A3 really is always A3, Gödiker follows a sophisticated, standardized test procedure. The interplay between the human being and measurement technology is critical here. "The tooth shade is always also a personal sensory impression, but we want to be sure", emphasizes the developer. That's why at VITA, every material sample is precisely measured and evaluated. Firstly using optical measuring devices, but also ultimately by many different people. "First of all, we develop various test series and test the shade effect of oxides in graduated concentrations", says VITA employee Ewa Moll. She places the samples in her measuring device and verifies the results of the analysis on the screen: "Does the result match the shade standard? Is the translucency correct?" Precision is extremely important here, says this metrologist. The toothcolored press ceramic is only approved for production when human beings and technology no longer question the precision of the result. After all, we want you, the dental technician, to obtain ideal results directly out of the press furnace – without the need for time-consuming reworking or perhaps even repeating fabrication from scratch, says the developer Michael Gödiker.

We want you, the dental technician, to obtain ideal results directly out of the press furnace – without the need for time-consuming reworking or perhaps even repeating fabrication from scratch.

A shade sample made of press ceramic is calibrated by a VITA employee
Putting the press ceramic to the test. Every shade sample is precisely measured.

Exact to the last milligram: the exact press ceramic composition

Precision is also top priority in the production of VITA AMBRIA – so that you as a dental technician really do get pellets that meet the highest quality standards. "The exact ceramic composition is extremely important for the final result. The complicated process begins in the mixing area", explains the engineer Michael Hackner: "Here, we weigh the raw materials so that they are exact to the last milligram. This is essential for precise, reproducible shade reproduction of the ceramic in the dental laboratory." Dirk Scheffelmaier has worked for VITA for over 30 years and is responsible for weighing the ceramic composition so that it is exact to the last milligram. Scheffelmaier carefully mixes the various raw materials with each other in powder form, including oxide pigments or rare earth elements. The exact ceramic mixture determines the shading, but also the crystalline structure and the final strength of the VITA AMBRIA press ceramic: "The important thing is to work in an absolutely clean and precise fashion. Even small deviations will be visible in the final product. If something were to go wrong here, an entire batch would be wasted."

The exact ceramic mixture determines the shading, but also the crystalline structure and the final strength of a press ceramic.

Raw materials for true-to-shade press ceramic are weighed out by a VITA employee
Weighed sample of the composition for a product that offers shade fidelity and high strength.

Quality takes time: from the ceramic melt to the pellet

So would you like to know how a VITA AMBRIA press ceramic pellet is manufactured? The ceramic melt and crystallization take two whole days: "Glass is very sensitive", says Michele Pischitello, who is responsible for the multistage melting process. Once again, precision is required. "All steps must take place exactly according to plan, otherwise the shade and the translucency won't be correct later on." It takes eight hours until the material is melted, and it isn't cast until the following day. The hot pellets fall into a collection container. Michele Pischitello uses fire-resistant gloves to protect himself from burns: the temperature of the 6-gram VITA AMBRIA pellets is still around 350  C. Once they have cooled down, they are carefully checked and sorted before the final production step: crystallization.

Lithium disilicate is a crystal that requires a very specific chemical composition for crystallization. "And crystallization requires precise temperatures. Every degree Celsius counts.", reports Michael Hackner, engineer. A difficult process: the required temperature must be maintained exactly. "If there are even the smallest deviations in temperature, we would not achieve our goal: a reliably repeatable result with strength and translucency."

VITA employees with VITA AMBRIA Press Ceramic pellets after crystallization
The opalescent pellets after crystallization

Interview with Michael Hackner, engineer

4 reasons why you can trust the VITA press ceramic

    1. Brillant play of shade and light.
    2. Excellent fracture resistance. Robust ceramic composition for daily laboratory use.

    3. Simple processing – developed by dental technicians for dental technicians.

    4. "Made in Germany" – 100% German dental engineering skill.

    Report: 05/2021

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