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.