In today’s environment of new information, materials and techniques, it is easy to be completely overwhelmed and lost. I personally love the constant innovation and the challenge that comes with adapting. I want to share with you the principle of “Light Performance”, and how it can help you understand what your material will need to have a successful delivery.
We are moving into a world of more complex composition in ZrO2, and it requires us to advance our understanding. I get asked over and over “why do you use Prime”, “are you getting paid to use Prime”, “have you tried”. My answer is always, “I try my best to investigate everything, and if I find something I like more than Prime, I will use it”.
[All case images provided by Dr. Dagmara, Mike Archibald and Jed Archibald]
From white zirconia to multicolored materials
We have moved far from the old pure white 3Y zirconia frameworks, to multicolored and multi-value (multi translucent) zirconia. And with all the new and cool zirconias hitting the market, also comes an assault of marketing names. Unfortunately, this just make things worse. The greatest example and ultimate plague of our industry is the label “Multilayer” and how it was used for multicolor ZrO2’s. Looking at the figure below you can see three examples to help explain. And for those who are not familiar with the term “value” we often use it as another term for translucency.
The sample one on the left, is what most companies will call Multilayer. Referring to layers of color/chroma, but it is one single composition of ZrO2 type. These sample is probably the most used in the US, and doesn’t look bad on the bench. In terms of light performance though, this is just different colors of dentine value material (all 4Y). Giving you one single value or one single type of light performance.
The sample in the middle has layers of color, and actual layer types of ZrO2. It has a base of dentine value (4Y) and enamel value (5Y), with a mixed layer between them. Brands will range from 2-4 different stacked layers. Even though the sample in the middle has better light performance over the sample on the left, the stacked layers (like Neapolitan ice cream) of ZrO2 type does have some struggles. There will be some minimal coefficient thermal expansion (CTE) changes in the layers, telling us that large bridges and layering porcelain is less stable. The stacked layers are non-visible in real life, and we know from our history with ZirCAD® MT Multi, that this type of ZrO2 composition is a major aesthetic improvement over any Multicolor 4Y. Why? Because it has better light performance in the mouth.
The third sample is ZirCAD Prime Esthetic, which is layers of color, and a true gradient/ blending of ZrO2 powders. Prime Esthetic is a base of dentine value (4Y) that has seamless blend to enamel (5Y) using unique Gradient Technology. Prime Esthetic is the next generation of compositions, giving you a seamless blend, and gradual CTE that allows us to use the material in a wider variety of techniques. And Prime, the big brother to Prime Esthetic is a 3Y base with Gradient Technology to 5Y. Giving you a stronger option for more intense large cases.
Now, let's see why this is more challenging to visualize the value of these new compositions in the lab. See the picture below , here I have taken Prime Esthetic and popular types of multicolor. Then simply stained and glazed to an A2 without making them look better than or worse than, I tried to be realistic and fair on what is done in most labs I have seen. On the bench they all look fairly similar, aside from inter-proximal contacts.
Now see the picture below . This tells you how much a multi composition material will help in natural light performance. Yes, you can use stains and techniques to help give the illusion of translucent effects, but stain is actually opaque. It may have some glaze mixed in to make it appear more translucent. But it’s still opaque suspended in a very micro space. So, the more you cake on, the less translucent your crown gets. Yes, I know there is MiYo and it's a great technique. And I teach in my Master Classes how to make your own MiYo out of any ceramic you have and like to use. But this is still working with illusion and not real translucency. Fake light performance is not as good as real light performance.
Even if you look at pictures below (Bridges fabricated with regular Prime on top and Multicolor 4Y on the bottom) you can see how it is hard to visualize the benefit from the bench, they look almost identical to the eye. Prime is a 3Y to 5Y blend, aka opaque dentine to enamel. And Prime has a much more realistic light performance. Some fall for the trap of the softer general appearance of all 4Y on the big ones, but that is just not natural. BTW, notice how light sees stains as opaque!
This is a map of what value types you may find in real teeth. And the values of ceramic you need to have if you wish to try and mimic nature. From this example, you can easily see why there is an average of 7-12 different values of porcelain in any system sold. No ceramist in the world would layer a tooth with different colors of just dentine, they would instantly lose their job. One of the best ceramists is known for saying “color is easy, but value is hard” Willi Geller.
Now, if you are a fantastic ceramist, you may think “I don’t need super fancy core materials, it’s just going to get covered up”. But I strongly urge you to change your mindset. With a better core material, that seamlessly goes from dentine to enamel, you can microlayer, and dramatically increase your productivity without giving up your art. The time it takes to teach and make more ceramists is dramatically reduced. You can work smarter with smart materials, and not lose what makes you great.
Have you ever had a crown look perfect in the chair, then get the call “hi…when I look in the mirror my crown looks weird”? Or “when I was with my friends, they could see my crown didn’t match”. We all have had this, and it's when we don’t mimic the light performance of the natural teeth next to our crown. This is why you would not layer with all dentine porcelain and the reason why a clinician would not use only one resin composite on a Class 4 filling.
Archibald Digital is an outsourcing service to high-end and smaller labs, who need help moving into the digital market. I have lots of cool equipment due to my passion for education, and it's easy to let others have access to the best tools, materials and handling. However, when I travel for courses and R&D projects, it would sometimes throw a wrench into other’s schedules. Sometimes they need to outsource somewhere else, and the comment every single time is consistent “my doctor called me after a seating and said that they noticed a change for the worse, and I have to go back to using what I was using before”. Translation… the doctors became accustomed to the light performance of MultiValue ZrO2 and noticed a dramatic change when reverting to a MultiColor 4Y crown.
You may say “why do I not see more Prime and Prime Esthetic being offered if it’s so great then?” To be honest, either a milling center will not use a MultiValue because of cost, or they might not have the knowledge to use it correctly “I’m sorry, not sorry” Demi Lovato.
With more advanced materials, we must be more advanced in our handling. Not only do we need to make sure nesting (positioning) is handled perfectly for milling, but each type of ZrO2 is different in the way they react to sintering processes.
See the image above, the misfired sample on the left, is the result of going 2°c too fast in the wrong part of the sintering cycle - just 2°c! Therefore, little missteps in sintering can have very negative results. But handled correctly with just a little care, and the payoff is huge.
My brother Mike has done incredible cases with Prime and Prime Esthetic over the years. I know because I do the design and milling for him. Our relationship is one where a box of cases will show up, and a note “just do what is best”. He has allowed me to help dial in sinter programs and infiltration techniques, by giving me a second opinion without knowing exactly what I did. He has two perfect examples of light performance I want to share, but how he made them amazing can only be told by him.
This is a full mouth rehab, on a beautiful young girl. There is a combination of minimal preps, full preps and bridges, the kind of case we all have to do. I used Prime BL2 to keep the value a little higher and fired on my MT S11600 program.
[Image below Disclaimer: These programs are what I used and have been approved in the S1 and S1 oven. These same values in other ovens may damage your oven or the restorations]
Mike and Dr. Dagmara did everything they could to deliver a fantastic result. And as you can see, there is a whole lecture on planning, preparation, artistry, and delivery with this case. But in terms of light performance, the change in value from cervical to incisal keeps even a bright bleach shade from looking fake. And we all have to do a “I want white teeth” smile. Had we used any form of single composition, this case looks like every hockey puck you see on billboards today. All fantastic work by Mike and Dr. Dagmara at West Lafayette Dental Studio.
For the second patient I used Prime Esthetic A1, fired on my MT program as well. Here you can see a beautiful match to natural teeth. When Mike showed me a picture, I couldn’t believe it was the same 7-13 case I designed. As good as my designs, materials, and custom programs may be, it still takes a trained and talented human to make it look like this. When you do a whole mouth, you have the leeway and freedom to make your own rules of light performance, but, when you are seating crowns next to real teeth in the anterior region, light performance must be respected. You place a single composition material next to a real tooth in the anterior, and it will only look good from one angle - if you’re lucky. This is not new information; this is old ceramist information. This is a fantastic work by Mike and Dr. Dagmara at West Lafayette Dental Studio.
All in all, we are in a new phase of advanced composition ZrO2’s. And it's going to be really fun watching marketing teams come up with names, because we are just starting a whole new product line of multi-composition ZrO2’s. Anyone who knows me knows my doors are open for you to send a case and see if something can be improved in your handling or workflow. Or you can order a Prime Esthetic “Raw” shade guide as an ultimate control tool. I don’t try to horde or hide information from anyone.
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