Episode 420: A Simplified Workflow for Highly-Esthetic Lithium Disilicate Restorations

You're listening to The Dr. Phil Klein Dental Podcast from Viva Learning.com.
Welcome to the show. I'm Dr. Phil Klein. Today we'll be discussing the benefits of using a fully
crystallized lithium disilicate CAD-CAM block to create durable and highly aesthetic indirect
restorations. This material provides high strength without the need to fire and apparently saves a
clinician up to 40% of the time required versus comparable systems. Our guest is Dr.
Paresh Shah, who maintains a private practice in Winnipeg, Canada, with a focus on implant cosmetic
and interdisciplinary care. He is currently an instructor at the University of Manitoba Dental
School in the Department of Fixed Prosthodontics and is on the editorial board for several dental
journals. He is co-founder and co-director of a Seattle Study Club affiliate in Winnipeg.
Dr. Shah, it's a pleasure to have you on Dental Talk. Hey, thanks for having me, Phil. I appreciate
it. Yeah, so you've been doing dentistry for a while. You have a lot of experience, so we're happy
to talk to you about this new lithium disilicate block, which apparently is a highly crystallized
block. In fact, GC America, who manufactures it under the name of GC Initial Lisi,
refers to it as a fully crystallized lithium disilicate block. And that's why we're interested in
hearing from you, because I know you've had some experience with it. So tell us how a fully
crystallized... block like this can save time in the practice because that's what dentists are
interested in doing is is obviously making their workflow more efficient and by saving the time as
it purportedly does does the dentist sacrifice anything as far as performance or aesthetics well
that's a loaded question a little bit uh no those are all fair questions i think uh you know one of
the things that dentists want as you said is if you can save time at certainly goes to the bottom
line at the same time you you don't want to compromise quality and longevity of a restoration and
so uh you know those you know both parts have to play a good role and i and i do feel that this
particular product has fit in well in my in my practice and from a fully crystallized point of view
it allows us the ability to not have to uh crystallize it in a furnace and that saves time with uh
with some of the other lithium disilicate cad cam blocks out there you have to actually fire it to
crystallize and depending on the furnace depending on the block depending on the workflow i mean
that can run anywhere from 10 minutes to like over 30 minutes and so if you can save that amount of
time uh certainly that Time is worth money. Right. So the fully crystallization of the block
precludes the firing, but that fully crystallized block is strong enough where it doesn't need the
firing, apparently. Is that correct? Sure. Yeah. Yeah. When you look at strengths of a lot of the
lithium disilicate materials that are out there right now. The range in terms of megapascals is a
bit of a range in the high 300s up to 500. The key is making sure that you have proper prep design,
proper bonding protocols, proper material thickness. And if you have all of that and it's bonded to
healthy tooth structure, it works really well clinically. We don't need to fire this material.
That's a big plus. Are there any other differences? that you want to talk about regarding this
lithium disilicate block? The reason I actually chose to start using it is because I used to have a
CAD-CAM system. I kind of got rid of it. I still do a lot of digital stuff for years and was using
a lab. And then I reintroduced a new mill and furnace and everything. And I hadn't had the furnace
set up. And so it was like, okay, well, how do I... use you know i want to use lithium bisilicate
for some of my procedures what can i use this was one that i looked into i liked the reputation of
gc they have some great products and great research and so when i saw it i tried out these blocks
and why i did that was it was going to save me time because i didn't have a furnace ready to go i
needed to set up my lab in such a way with a vacuum and everything and so it was actually going to
save me time it was actually going to save me cost of getting everything set up with a furnace so
it was kind of twofold and uh serendipity i just i really liked the results that i was getting yeah
have you seen any compromise in the aesthetics not having to fire the block no i don't think it has
anything to do with that i think it has to do in my in my hands at least clinically uh you know
it's the amount of time that you're spending polishing it finishing it just you know making it uh
worthy of being bonded in to to the patient's mouth and so you know it's just spending the time
doing that and that you know i'm going to do that depending on any of the other restorations as
well now the fact that it's fully crystallized and that's the important differentiating factor with
this block is it tougher on your milling burrs i haven't seen any data to support that it has like
you know long-term data what i what i can tell you anecdotally is in my practice with all the
different blocks that i've been using in the mill that i have um and mine is an open system mill by
a company called vhf and it's called z4 so i can have a like multitude of blocks that i can use I
haven't noticed, and I've done a fair amount of the leasing blocks over the past year. I have not
noticed that I've had to change the burrs over any faster than what is a normal cycle for those
burrs for my nail. Okay. Well, that's a good thing. Which has been a good thing. Yeah, it is a good
thing. Because the longevity is basically following what the recommendations of that.
specific mill have gone and it hasn't been faster which i was curious about you never know like
some of the mills and some companies will say hey our burr will be good for this or that and so far
it's reached optimal capacity every all the time basically you know you could mill and polish this
and place the restoration and save time versus the other systems yes um are there any are there any
options to characterize the restoration if need be yeah absolutely so there's a couple of ways one
is in my opinion better than the other but one is a quick way simple you're using a resin it's
called uh you know optic glaze and it works great it's a gc product as well but you can use it use
on a composite as well the downside of that is that it can possibly lose uh some of that glaze over
time just through you know uh toothbrush and toothpaste abrasion through some function and through
you know types of foods and that but you know if it's on the facial area i mean except for the
toothbrush operation it might it'll probably last a little longer so that's a quick and easy way
the other way which is more definitive but will require some firing in a furnace is to use lustre
paste it's a ceramic and you can use porcelain stains and glazes And the thing is with the
porcelain stains and glazes, you do have to fire it. But it's not adding a significant amount of
time to it. Because if you were using uncrystallized lithium disilicate materials that you had to
fire, sometimes when you have to stain and glaze it more, you still have to put it back in the
furnace. to do that, especially if you have to do some revisions. So it'll add a little bit of time
to it, but you have the flexibility of doing that with the leasing blocks. It seems to me if you
could achieve outstanding restorative results, fixed restorative results with this block without
having to fire it, isn't that kind of a game changer? And why would a dentist want to keep using
blocks where firing is required? Yeah, that's a good question. I believe it is because it can
certainly save you some time and money. But as I said, the one thing is if you are going to want to
really highly characterize it and with some porcelain stains, you're still going to need a furnace.
So if you have a furnace, it kind of gives you flexibility. For me, it definitely does save time.
It is convenient. And those two things have been a driving force to why I've...
chosen to use that block more in my practice so what is in curiosity what is the time frame from
soup to nuts on doing let's say well veneer using this material without having to fire what are we
talking about in time well whether okay i mean it'll really vary i'm not doing as many um veneers
with the material to be honest with you right now because with those you know if they're really
highly aesthetic i i just prefer personally my lab to do that work and that's a that's a personal
preference i just uh in my hands i think my lab can do a better job of doing a porcelain veneer
however when i'm doing let's say a bicuspid and you know it's a smaller restoration i can mill it
in my mill in about maybe 12 minutes or so so overall i could do the whole procedure with a fully
crystallized block and probably, you know, you prep it,
you scan it, design it in some open software, which I use Exocad,
and then mill it. I can do it in a little over an hour.
And that's with delivery. If I wanted... That's delivery. Yeah, that's with delivery. And that's if
I... if i chose to do that in one visit and there are there's there are times where i'll do that so
and if it's a molar it'll be a little longer so take maybe about an hour and a half um and if i
were using a furnace then yeah it would definitely be two hours for me with the materials and the
and the and the equipment that i have um there are some uh equipment and technologies that are just
designed to be faster and i don't have that No, that's great information, Dr.
Shah. It's great to hear it. You know, some of it is anecdotal. That's fine. We don't have to have
evidence-based information on everything we do. Your experience is worth quite a bit.
Again, talking to the audience now, we're discussing GC initial Lisi block, which is a fully
crystallized lithium disilicate CAD-CAM block. And the idea is that you do not need to fire it.
It saves about 40% chairside time. And we're talking to Dr. Shah about his experience with it.
Apparently, he's been very happy with it almost through, like he mentioned, serendipity. He didn't
have a furnace that was operating in his office, so he needed a block that he didn't have to fire.
So I think that's how you fell upon this in the first place. Yeah, no, absolutely. And, you know,
when you say about you don't need later evidence, you know, we do, but we have it.
Like when it comes to the material that we're talking about right now. Even if it's fully
crystallized, the bottom line is it has good strength. It can approach strengths of 400 megapascals
from some of the studies. And when it's bonded to healthy tooth structure, it's pretty darn good.
Yeah, the evidence supports that. What I was referring to anecdotally was the evidence to say that
it may be more aesthetic than another block. Correct, correct. Yeah, absolutely. So we don't have
that information. No, and I think a lot of that's subjective. I think it's the amount of time that
you spend on it. And it doesn't have to be a significant amount, but how you go about polishing,
finishing it, seeding it, all of those things. Right. And I can make a restoration that I'm firing
in an oven look like crap if I don't spend time on it, right? No, absolutely. Absolutely.
We're really happy that you had the time to do this podcast, Dr. Shah. Love the insight that we got
out of it and hope to have you on future podcasts and webinars with people learning going forward.
I appreciate it very much. Thanks a lot, Phil.